Irish
Journal
MEDICAL
of
SCIENCE
Official Organ THE
ROYAL
ACADEMY
SIXTH SERIES
THE
OF
MEDICINE
NOVEMBER
DETERMINATION
IN
IRELAND
1961
OF T H E R A D I O - S E N S I T I V I T Y TUMOURS *
NO. 431
OF
B y PATRICK A. BROWNE, M.B., M.R.C.P.I.
Research Fellow in Radio-Active Isotopes, R.C.S.L A L I G N A N T tumours developing in some organs or tissues of the body can be successfully treated b y irradiation, while histologically similar tumours arising in other organs or tissues arc resistant to radiation treatment. Thus while an adenocarcinoma of the breast or cervix uteri m a y be radio-sensitive, an adenocarcinoma of the stomach is certainly radio-resistant. Again, not all tumours develop]ng in tissues in which radio-sensitive tumours are to be expected prove to be so when treated by irradiation. I t is not possible to determine whether a t u m o u r will prove to be radio-sensitive or not by the histological examination of a biopsy specimen. However, changes occur in turnout cells during and a f t e r irradiation. These changes indicate the ultimate response of the t u m o u r to t r e a t m e n t (Glucksmann and Spear, ~ Atkinl). B y the time that these histological studies have been completed the patient will have received a full course of radiation treatment. I t would be of considerable importance if a method could be devised whereby the radio-sensitivity of a t u m o u r could be determined within the first few days of treatment. W e have attempted to solve this problem b y estimating the half-life of phosphorus in tumours being treated by irradiation and ~ttempting to relate the phosphorus half-life with the radio-sensitivity of the tumour. Therapeutic radiation produces variable effects on t u m o u r cells. The effects depend on whether the tumour is radio-sensitive or not, and also on the degree of differentiation of the t u m o u r cells. T u m o u r cells can be classified into four groups, mitotic cells, degenerating cells, differentiating cells and resting or stock cells. This last group, the resting cells, constitutes the greater p a r t of most tumours. The most obvious effect of radiation on a t u m o u r is the arrest of mitosis. In these days of chemotherapy too much stress is placed on the arrest of mitosis. While the arrest of mitosis will stop the growth of a tumour, any resting cells which remain are capable of mitosis at a later date. F o r the satisfactory treatment of tumours it is the resting cells which must be
M
* C o m m u n i c a t i o n m a d e to t h e L o n d o n m e e t i n g of t h e I n t e r n a t i o n a l F e d e r a t i o n o f Surgical Colleges in October, 1960. 475
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destroyed. The resting cells are the only cells which are capable of undergoing mitosis, and when they divide the d a u g h t e r cells either degenerate, as commonly occurs, or they become other resting cells. Cade has stated that " doses of radiation which inhibit cell division also promote differentiation provided a eapacit~ ~ for differentiation exists in the tissue ,,.2 Similarly Glucksmann has stated t h a t " a t u m o u r showing little or no differentiation when a pre-radiation biopsy is examined m a y show a marked degree of differentiation a f t e r radiation " 3 I f the resting cells differentiate they are no longer capable of mitosis and f r o m the point of view of malignancy they have become " sterile " This concept of the t r e a t m e n t of m a l i g n a n c y was stated by R~gaud :~ " I t is sufficient for cure by radiation t h a t death be limited to the resting cells, the direct destruction of the offspring is not of importance since they are destined to disappear in the sirpple course of their evolution ' ' The cellular changes which occur in anaplastic t u m o u r s are different f r o m those which occur in more differentiated tumours. Anaplastic tumours are incapable of differentiation and the response to irradiation is limited to a t e m p o r a r y arrest of cell division and the a p p e a r a n c e of degenerating cells, the t u m o u r shrinks but any cells which remain are capable of mitosis (Glucksmann and Spear3). Glucksmann and Spear ~ extended the qualitative s t u d y of the effects of radiation on malignant cells into a quantitative study. I n radiosensitive t u m o u r s they found that a r a t h e r constant sequence of events occurred. I n a case which they describe, the cell population in a preradiation biopsy was as follows, mitotic cells (4 days), degenerating cells (7 days), differentiating cells (29 days), and resting cells (60 days). The tumour, a carcinoma of the cervix uteri, was treated by radiation and repeated biopsies were taken d u r i n g treatment. B y the 8th d a y of t r e a t m e n t the mitotic cells had disappeared and by the 12th day the resting cells had disappeared. As some of the resting cells had been stimulated to differentiate the percentage differentiating cells increased for some days and then decreased when they began to degenerate. The percentage degenerating cells increased slowly for the first 6 to 8 days and then more r a p i d l y when the cells which had been induced to differentiate began to die (Fig. l). The main variation which occurred in radio-sensitive t u m o u r s was in the degree of differentiation which occurred. I n radio-resistant tumours no significant change occurred in the percentage cell population (Fig. 1). This absence of change was seen in tumours which reduced in size and had a p p a r e n t l y responded satisfactorily to radiation. I n some tumours which had clinically been cleared biopsies taken from the original site of the t u m o u r showed the same cell population as was present in the pre-treatment biopsy. Olucksmann and S p e a r suggested that in these cases there would be an early recurrence. Their histological prognosis was assessed in a series of 166 eases of carcinoma of the cervix uteri treated by radiation. W i t h a follow-up period of 2 years their histological prognosis was f o u n d to be correct in over 80 per cent. of eases. Their best results were in a n u m b e r of anaplastic tumours in which recurrence developed early. As recurrences could occur in the more differentiated tumours later t h a n 2 years a f t e r
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DETERMINATION
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477
treatment, their results might have been improved if the period of study had been extended. The metabolism of phosphorus in malignant cells has been studied by Marshak ~ with tracer doses of radio-active phosphorus ('~P) in mouse ]ymphomas. The relevant findings of this work were as follows: 1. The lymphoma cells continue to take up phosphorus for 3 days after injection, and the phosphorus passes rapidly from the cytoplasm to the nucleus where it is retained. 2. Lymphoma cells take up more phosphorus than normal cells. This increased uptake was shown to be due to mitotic activity by comparing the lymphomas with regenerating liver cells in partially hepatectomised mice. 3. I f the lymphomas were irradiated with 200r. prior to the injc('tion of the :~P it was found that for some hours' injection the irradiated nuclei contained more phosphorus than controls although the total tissue content remained unchanged. This increased content was shown to be due to the inhibition of mitosis. Marshak has shown that malignant cells concentrate :~P in their nuclei and that radiation tends to enhance this concentration. Thus it would appear that if the changes in the 32p content are known it should be possible to infer what changes have taken place in the tumour cells. We have studied the changes in the ~op content of tumours being treated by irradiation and we have attempted to correlate the changes in the ~'~P content and the cellular changes described by Glueksmann and Spear. I f it is supposed that a radio-sensitive t u m o u r composed of 100 cells is undergoing radiation treatment, and that each living cell in the t u m o u r contains an amount of 32p which will give a counting rate of 1 per minute, then on the first day of treatment, since there are about 93 living cells and 7 degenerating cells (Fig. 1), the counting rate will be about 93 per minute. B y the l l t h or 12th day there are 45 living cells and 55 degenerating cells and the t u m o u r will give a counting rate of 45 per minute, corrected for physical decay of the .~2p, if it can be assumed that the ~2p of the degenerating cells is rapidly removed from the tumour. In other words the 32p content of the tumour has fallen to half in about 11 days and the half-life of the ~2p in the tumour is about 11 days. This supposition oversimplifies the problem, and there are several obvious objections to accepting it. Not all tumom' cells will take up an equal amount of ~2p. Indeed Marshak has shown that the increased uptake of "~P by tumours as compared with normal tissue was due to mitotic activity. So it must be presumed that the mitotic cells take up more 32p than the resting cells. Thus changes in the "~P content of the turnout might for the most p a r t be due to changes in the mitotic (.ells. However, the mitotic cells constitute only a small percentage of the tumour cells. Again, the mitotic cells have develop(~d from the resting cells, and the daughter cells of mitosis are either degenerating cells or are f u r t h e r resting cells. Thus it would appear that it is the changes in the resting cells that are mainly responsible for changes in
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the ~ P content of the tumour. I t has been shown that it is the behaviour of the resting cells t h a t is of p r i m e importance in the response of the t u m o u r to radiation. I t must also be proved that a n y ~ P released by the degenerating cells is r a p i d l y lost f r o m the tumour, and is not taken up again by the surviving t u m o u r cells. Obviously, if a n y 32p released by the degenerating cells were retained in the t u m o u r for a variable period 11o conclusion could be drawn f r o m the rate of fall of the ~2p content of the tumour. F o r the following reason we do not think this occurs. D u r i n g treatment the counting rate sometimes fell too low for reliable counting and it was necessary to give a second tracer dose. The uptake of this second tracer dose was sometimes nearly as great as t h a t following tlle~ initial t r a c e r dose, even though it was given as late as the second or third week of treatment. This showed that there were still cells present in the t u m o u r which were capable of taking up and retaining more s2p. i f these cells had in fact taken u p the s2P released by cellular degeneration no m a r k e d fall in the :'-~P content of the t u m o u r would have occurred. Since a definite fall does occur it m u s t be presumed t h a t the :2p released by cellular degeneration is lost to the tumour. A t a later date we hope to prove this assumption b y p r e p a r i n g auto-radiographs f r o m biopsy specimens taken before and d u r i n g treatment. F i n a l l y there is the problem of the behaviour of the differentiating cells. These cells m a y survive for a variable time. A f t e r the 12th d a y a radio-sensitive t u m o u r is composed only of differentiating and degener a t i n g cells. I f the differentiated cells survive and do not degenerate they will retain their .s2p, and the counting rate will not fall until such time as they do degenerate. Thus in these cases the counting rate would fall for some days and then remain stationary. We hope t h a t this problem can also be solved b y the p r e p a r a t i o n of auto-radiographs. I n radio-resistant t u m o u r s no significant change occurs in the percentage cell population. Thus there will be no fall in the ~2p content a p a r t f r o m that due to cellular metabolism and degeneration occurring independently of radiation. Marcus a n d Rotblat estimated the physiological half-life of '~-~P in melanomas at 26 days. U n f o r t u n a t e l y no reference is available to the physiological half-life of 32p in breast tumours. Thus on theoretical grounds it would a p p e a r t h a t a ~,2p half-life of about 11 or 12 days indicates a radio-sensitive tumour. The p a t t e r n of cellular change m a y not be identical in all tumours and some time must be allowed for the ~-~P released b y the degenerating cells to be lost f r o m the tumour. F o r these reasons the ~2p half-life of radiosensitive tumours m a y be a few days longer or shorter t h a n the 11 or 12 days estimated. Thus a 3~p half-life of 9 to 15 days p r o b a b l y indicates a radio-sensitive tumour. The 32p half-life of radio-resistant tumours would p r o b a b l y be longer tltan 20 or 25 days. Glucksmann and S p e a r do not describe a p a r t i a l l y radio-sensitive tumour, but a 32p half-life between 15 and 20 days would indicate some degree of radio-sensitivity. We have studied changes in the ~2p content of turnouts by external counting. Since the half-tissue penetration of ~'-P is only 7 into., a tumour must be within 3 or 4 mm. of the counter for satisfactory count-
THE
D E T E R M I N A T I O N OF
THE
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TUMOURS
479
ing. This limits the use of external counting methods to t u m o u r s at or v e r y near the surface of the body. The m a j o r i t y of the cases which we studied were advanced carcinomas of the breast. A tracer dose of 500 gv of :'~P was given orally and the counting rate was measured several times a week during treatment. Since Marshak has shown that t u m o u r cells continue to increase their phosphorus content for 3 days a f t e r injection, it would be more satisfactory to give the tracer dose at least 3 days before t r e a t m e n t is commenced. Several of our cases showed greater counting rates on the second or third d a y than oil the first day. I t is more satisfactory to have tht, m a x i m u m count on the first d a y of treatment. I f tl-c counting rate is initially low it will become too h)w for reliabh, counting during the second o1" t h i r d weeks. I t is then nccessm'y to give a second t r a c e r dose, and to normalise the g r a p h f r o m this point onwards. This is not a satisfactory procedure. I f the initial counting rate is low it is better to give a second tracer dose at this time and it would be advisable to give it intravenously. With the counter we used, which has a background counting rate of about 6 per minute, initial counting rates of 200 or more per minute were satisfactory. The selection of the points to be counted is of considerable importance. W e have found t h a t tumours or skin secondaries covered b y intact skin are the most suitable. The points chosen should be m a r k e d and exactly the same points counted on each occasion. I f the counter is placed on another, although v e r y similar, point the t u m o u r m a y be a small distance nearer or f a r t h e r a w a y f r o m the counter. With a half-tissue penetration of only 7 mm., distance is critical, and small changes of distance will produce m a r k e d changes in the counting rate. A f t e r about two weeks of radiation t r e a t m e n t the skin sometimes becomes oedematous, an error of distance develops, and a false reduction in the counting rate occurs. Solid t u m o u r s covered by an intact surface are also satisfactory for counting. Ulcerating surfaces and ulcer edges are not satisfactory for counting. These surfaces are usually moist and are covered by cells which arc being shed f r o m the tumour. Thus the surface m a y be covered b y '~P which is not p a r t of the ~2p of the cell population of the t u m o u r proper. I t is usually possible to obtain a sufficiently high count over the infiltrated skin j u s t outside the edge of an ulcer. Ulcer edges sometimes begin to break down a f t e r the second week of radiation. Thus a point which was previously covered b y infiltrated skin becomes a r a w surface a n d the counting rate will rise. I f these false high counts are found towards the end of t r e a t m e n t the ~2p half-life should be calculated f r o m counts taken previously. The counter which we used had an end-window d i a m e t e r of 8 ram. This makes the exact positioning of the counter too critical, and we feel that a much larger end-window would be more suitable for routine use. It is more satisfactory to take counts f r o m 3 or 4 positions on each occasion and to express the result as an average of these counts. This tends to lessen a n y error arising f r o m placing the counter in an incorrect position. I t is also more satisfactory for all the counts in a patient to be taken b y the same observer.
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The counting rate each day should be corrected for physical decay of :'~P. W h e n the counts are plotted on graph-paper an exponential type of curve is obtained. Since an exponential curve plots as a straight line on semi-log paper, we have drawn our graphs in this way because it is much easier to draw a straight line than a curve through somewhat scattered points. A fall of 0.3 on semi-log paper represents a reduction to half. We have employed this procedure in 16 cases of carcinoma of the breast and 4 cases of carcinoma of the skin. The cases are described in detail below. The details of the cases of carcinoma of the breast are summarised in Table 1. TABLE
No.
a~p h a l f - l i f e in d a y s 14-15 23 13 25
, ! I
Prognosis Clinical Result Good
Fair
Poor
X X X X
19 33 7 8 9 10 11 12 13 ]4 15 16
9 Not estimated 18 9 17 11 Not estimated Not estimated 9 10
1
X
X Y, ,',,:
:<
X
Not given
G o o d u p t o 24 rots. Poor, early recurrence. G o o d u p t o 14 m t s . Poor. No response to treatment. Fair. Re-treated at 3 rats. P o o r . :No r e s p o n s e t o treatment Died. See cas e n o t e s . Died. G o o d u p t o 12 rots. F a i r . See c a s e n o t e s . G o o d u p t o 6 rots. Good. See c a s e n o t e s . Good. See c a s e n o t e s . See e a s e n o t e s . Good at 3 mrs.
Agreement between Prognosis and Result Ye~ Yes Yes Yes Yes Yes
Yes Yes Yes
Yes
CASE No. 1 : T h i s p a t i e n t , a g e d 80 y e a r s , h a d a c a r c i n o m a i n v o l v i n g t h e l o w e r h a l f of her breast with extensive skin involvement over and outside the tumour ; there was c h a i n o f g l a n d s e x t e n d i n g u p i n t o t h e a x i l l a . She w a s t r e a t e d b y d e e p x - r a y s . T h e t u m o u r r e s p o n d e d w e l l to t r e a t m e n t , a n d 6 m o n t h s l a t e r no t u m o u r w a s p a l p a b l e i n t h e b r e a s t a n d no g l a n d s were p a l p a b l e . T w o y e a r s a f t e r t r e a t m e n t t h e r e w a s s o m e t h i c k e n i n g of t h e s k i n o ver t h e o r i g i n a l s i t e of t h e t u m o u r a n d t h e b r e a s t t i s s u e i n t h i s r e g i o n had become more indurated than previously. The patient was advised to have a mastect o m y , b u t she r e f u s e d o p e r a t i o n as she c o n s i d e r e d t h a t s he w a s t o o old. T h e a~p h a l f - l i f e w a s e s t i m a t e d a t b e t w e e n 14 a n d 15 d a y s f r o m t h e a v e r a g e of c o u n t s t a k e n o v e r t w o s k i n n o d u l e s . T h e s e n o d u l e s were c o v e r e d b y i n v o l v e d b u t i n t a c t s k i n . A l t h o u g h i t is p o s s i b l e t h a t t h e t u r n o u r is r e c u r r i n g w h e r e i n d u r a t i o n i s n o w p a l p a b l e t h e r e s p o n s e t o r a d i a t i o n h a s been s a t i s f a c t o r y . T h e g o o d p r o g n o s i s s u g g e s t e d b y t h e a~P h a l f - l i f e a g r e e s w i t h t h e c l i n i c a l r e s u l t . C.~SE No. 2 : T h i s p a t i e n t , a g e d 49 y e a r s , h a s a f u n g a t i n g c a r c i n o m a of t h e b r e a s t a n d a c h a i n o f g l a n d s e x t e n d i n g h i g h up i n t o t h e a x i l l a . She w a s t r e a t e d b y de e p x - r a y s as a pre-operative measure. Two months after treatment the ulceration was still present a l t h o u g h t h e t u r n o u t w a s s m a l l e r , a n d t h e r e w a s s t i l l a h a r d m a s s of g l a n d s on t h e l a t e r a l w a l l of t h e a x i l l a . A t t h i s t i m e she w a s g i v e n f u r t h e r deep x - r a y t r e a t m e n t . F i v e m o n t h s after the second course of deep x-rays the ulcer had healed, but a small nodule was p r e s e n t in t h e scar, t h e a x i l l a r y g l a n d s were n o t p a l p a b l e . A s i m p l e m a s t e c t o m y w a s p e r f o r m e d a n d t h e n o d u l e in t h e s c a r w a s f o u n d t o c o n t a i n a c t i v e c a r c i n o m a cells. T h e p a t i e n t . 14 m o n t h s a f t e r m a s t e c t o m y a n d 2 y e a r s a f t e r t h e i n i t i a l de e p x - r a y t r e a t m e n t , s h o w s no e v i d e n c e of a r e c u r r e n c e a n d no g l a n d s a re p a l p a b l e .
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The a2p half-life w a s e s t i m a t e d a t 23 d a y s f r o m t h e average o f c o u n t s t a k e n at t w o p o i n t s a t t h e edge of t h e ulcer. T h i s suggested t h a t t h e t u m o u r w a s r a d i o - r e s i s t a n t . The r e s p o n s e to t h e initial course o f deep x - r a y s w a s n o t s a t i s f a c t o r y , a n d a l t h o u g h the ulcer healed a f t e r f u r t h e r deep x - r a y t r e a t m e n t a recurrence w a s p r e s e n t in the scar w h e n it h a d finally healed. The axillary g l a n d s b e h a v e d r a t h e r differently. T h e y s u b s i d e d slowly after t r e a t m e n t a n d were n o t p a l p a b l e a t t h e t i m e of o p e r a t i o n ; t h e axilla w a s n o t dissected a t opera t i o n These g l a n d s h a v e n o t recurred t o date, 2 years after t r e a t m e n t . The b e h a v i o u r o f t h e g l a n d s s u g g e s t s t h a t t h e t u m o u r w a s radio-sensitive a n d it m u s t be concluded t h a t a t h e r a p e u t i c dose o f deep x - r a y s w a s n o t delivered to t h e b r e a s t t u m o u r . CASE NO. 3 : T h i s p a t i e n t , aged 56, h a d a large t u m o u r in h e r b r e a s t w h i c h i n v o l v e d the deeper skin over a wide area ; there were small g l a n d s in the axillary a n d supraclavicular regions w h i c h were of d o u b t f u l significance. T h e t u m o u r reduced steadily in size a f t e r deep x - r a y t r e a t m e n t : after 6 m o n t h s it w a s the size of a small p l u m . still slightly a t t a c h e d to s k i n ; no g l a n d s were palpable. F o u r t e e n m o n t h s after treatmerit h e r d o c t o r r e p o r t e d t h a t she w a s well a n d t h a t there w a s no evidence o f a recurrence. The a2p half-life w a s e s t i m a t e d a t 13 d a y s f r o m t h e a v e r a g e o f t w o c o u n t s t a k e n over the involved skin. The p r o g n o s i s suggested b y the 32p half-life agrees w i t h the clinica result. CAsE No. 4 : T h i s p a t i e n t , aged 67, w a s g i v e n p r e - o p e r a t i v e deep x-ray t r e a t m e n t to a large t u m o u r of t h e b r e a s t ; no g l a n d s were palpable. One m o n t h a f t e r t r e a t m e n t t h e r e w a s little c h a n g e in t h e size of t h e t u m o u r a n d a m a s t e c t o m y w a s p e r f o r m e d . The t u m o u r w a s f o u n d to be infiltrating t h e pectoral m u s c l e s . The t u m o u r w a s n o t fixed to t h e p e c t o r a l m u s c l e s w h e n she w a s first seen. The p a t i e n t died 6 m o n t h s after o p e r a t i o n w i t h diffuse s e c o n d a r y d e p o s i t s in t h e l u n g s a n d liver. The 32p half-life w a s e s t i m a t e d at 25 d a y s w h i c h indicated a r a d i o - r e s i s t a n t t u m o u r . T h i s long half-life w a s a p p a r e n t in t h e first week of t r e a t m e n t . I f it h a d been a p p r e c i a t e d at t h i s t i m e t h a t the t u m o u r w a s r a d i o - r e s i s t a n t a n d t h a t f u r t h e r deep x - r a y t r e a t m e n t o n l y served to delay o p e r a t i o n , m a s t e c t o m y could h a v e been p e r f o r m e d before the t u m o u r h a d infiltrated the p e c t o r a l m u s c l e s . CAsE No. 5 : T h i s p a t i e n t , aged 68, h a d a f u n g a t i n g c a r c i n o m a o f t h e b r e a s t and a m a s s of g l a n d s in the axilla. B o t h the t u m o u r a n d t h e g l a n d s were fixed to muscle. There w a s only a m o d e r a t e r e s p o n s e t o deep x - r a y t r e a t m e n t a n d 3 m o n t h s l a t e r t h e u l c e r a t i o n w a s still p r e s e n t . T h e b r e a s t t u m o u r w a s t h e n i m p l a n t e d w i t h r a d i u m needles. Six m o n t h s after t h e r a d i u m i m p l a n t the ulcer h a d healed. T h e p a t i e n t h a d c o m m e n c e d t a k i n g stilboestrol a s h o r t t i m e before t h e i m p l a n t . I t is n o w 1 year a n d 5 m o n t h s since she w a s first treated, t h e scar is still i n t a c t b u t is n o d u l a r a n d h a s c h a n g e d little in a p p e a r a n c e over t h e p a s t 6 m o n t h s . The p a t i e n t h a s r e c e n t l y developed s y m p t o m s of p i t u i t a r y deficiency a n d r a d i o g r a m s of her s k u l l s h o w erosion of t h e p i t u i t a r y fossa. The z2p half-life w a s e s t i m a t e d at 19 d a y s f r o m t h e average of 4 c o u n t s t a k e n at t h e edge of the ulcer. T h i s indicated s o m e degree of r a d i o - r e s i s t a n c e a n d agreed w i t h the p o o r r e s p o n s e to deep x - r a y t r e a t m e n t . The r e s p o n s e to t h e r a d i u m i m p l a n t w a s m o r e s a t i s f a c t o r y b u t b y t h i s t i m e t h e p a t i e n t w a s t a k i n g stilboestrol a n d a p r o p e r a~sessmcnt o f the r e s p o n s e to the i m p l a n t itself w a s n o t possible. CASE NO. 6 : T h i s p a t i e n t , aged 51, h a d an e x t e n s i v e c a r c i n o m a of t h e b r e a s t . T h e whole b r e a s t w a s involved, there were ulcerating n o d u l e s on t h e b r e a s t a n d in the axilla, a n d p a l p a b l e g l a n d s in t h e a x i l l a r y and s u p r a - c l a v i c u l a r regions. There w a s no r e s p o n s e to deep x-ray t r e a t m e n t : the p r o g r e s s of the disease a p p e a r e d to h a v e been slowed d o w n , b u t w i t h i n 3 m o n t h s n e w skin n o d u l e s were p r e s e n t a n d the glands were enlarging. The r e s p o n s e to h o r m o n e t h e r a p y and a d r e n a l e c t o m y was equally p o o r and she died 8 m o n t h s a f t e r initial t r e a t m e n t . T h e a2p half-life w a s e s t i m a t e d at a b o u t 33 d a y s f r o m t h e a v e r a g e o f c o u n t s t a k e n o v e r t h e skin n o d u l e s in the axilla. T h i s indicated radio-resistance a n d agreed with the clinical result. CASE :No. 7 : T h i s p a t i e n t , aged 46, h a d an extensive c a r c i n o m a of t h e b r e a s t w i t h ulcerating skin n o d u l e s on the chest wall a n d in the axilla ; there were enlarged s u p r a clavicular g l a n d s a n d fixed glands in the axilla. She h a d s e c o n d a r y infiltration o f b o t h lungs. She w a s t r e a t e d b y deep x - r a y s a n d s t a r t e d on injections of D u r a b o l i n d u r i n g the t h i r d week o f t r e a t m e n t . The p a t i e n t died s h o r t l y a f t e r discharge a n d a l t h o u g h no a s s e s s m e n t is p o s s i b l e t h e case is of s o m e interest. The ~eP half-life w a s e s t i m a t e d at 9 d a y s d u r i n g t h e first 2 weeks of t r e a t m e n t . Followinq the a d m i n i s t r a t i o n of D u r a b o l i n the c o u n t i n g rate rose i n d i c a t i n g a con-
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e e n t r a t i o n of~2P b y t h e s u r v i v i n g t u m o u r ceils a n d p o s s i b l y i n d i c a t i n g t h a t t h e t u m o u r would have been hormone-sensitive. CAS~, No . 8 : T h i s p a t i e n t , a g e d 81, h a d a l a r g e u l c e r d e s t r o y i n g a l l he r b r e a s t a n d e x t e n d i n g i n t o t h e a x i l l a ; t h e r e w e r e w i d e s p r e a d g l a n d s a n d s k i n n o d u l e s . On a d m i s s i o n she w a s t a k i n g s t i l b o e s t r o l w h i c h she c o n t i n u e d t a k i n g d u r i n g t r e a t m e n t . She w a s g i v e n d e e p x - r a y t r e a t m e n t to t h e u l c e r a t i o n . I n v i e w o f t h e f a c t t h a t t h e p a t i e n t w a s on h o r m o n e t h e r a p y t h e :2p hMf-life i s of no s i g n i f i c a n c e . I n a n y c a s e d u e t o a n e r r o r of t e c h n i q u e t h e c o u n t s were us e l e s s . A n a r r o w t o n g u e of i n v o l v e d s k i n e x t e n d i n g i n t o t h e u l c e r w a s c h o s e n a s t h e s i t e t o be c o u n t e d . A s a r e s u l t t h e ed ge of t h e c o u n t e r w a s in c l o s e p r o x i m i t y t o t w o u l c e r a t i n g e d g e s a n d t h e p o s s i b l e e r r o r of c o u n t i n g a t t h e edge of a n u l c e r w a s d o u b l e d . I n a d d i t i o n , irt response to the r a d i a t i o n the edges of the ulcer broke down and the two raw surfaces were brought, n e a r e r to t h e c o u n t e r . F o r a t i m e t h e c o u n t i n g r a t e s t e a d i l y i n c r e a s e d . CASE No . 9 : T h i s p a t i e n t , aged 72, h a d a v e r y e x t e n s i v e c a r c i n o m a of t h e b r e a s t w i t h w i d e s p r e a d u l c e r a t i o n on h e r c h e s t w a l l e x t e n d i n g i n t o t h e a x i l l a ; t h e r e w e r e s e c o n d a r y d e p o s i t s i n t h e l u n g s a n d l i v e r . She w a s g i v e n d e e p x - r a y t r e a t m e n t t o t h e u l c e r a t i o n b u t d i e d s h o r t l y a f t e r treatment.. T h e nap h alf-life w a s e s t i m a t e d at. 18 d a y s f r o m c o u n t s t a k e n a t t h e e d g e o f t h e u l c e r a t i o n . No elinieM a s s e s s m e n t w a s p o s s i b l e . CASE No. 10 : T h i s p a t i e n t , a g e d 44, h a d a s m a l l u l c e r a t i n g c a r c i n o m a of t h e t a i l o f her b r e a s t ; a s m a l l g l a n d w a s p a l p a b l e in t h e a x i l l a . She w a s g i v e n d e e p x - r a y t r e a t m e n t as a p r e - o p e r a t i v e m e a s u r e . One y e a r a f t e r t r e a t m e n t t h e u l c e r a t i o n is c o m p l e t e l y h e a l e d , a n d n o t u m o u r or g l a n d is p a l p a b l e . I n v i e w of t h e excellent, result, t h e p a t i e n t refi~scs m a s t e e t o m y . T h e "~P hMf-litb w a s e s t i m a t e d at 9 d a y s f r o m t h e a v e r a g e of c o u n t s t a k e n a t t w o p o i n t s at. t h e edge o f t h e u l c e r a t i o n . T h i s s u g g e s t e d a r a d i o - s e n s i t i v e t u m o u r , w h i c h agrees with the clinical result. CASE NO. 11 : T h i s patient., a g e d 66, h a d a fixed u l c e r i n v o l v i n g t h e u n d e r s u r f a c e o f t h e b r e a s t a n d t h e a d j o i n i n g c h e s t wall. F o l l o w i n g d e e p x - r a y t r e a t m e n t t h e b r e a s t h a s b e c o m e a d h e r e n t t o t h e c h e s t w a l l a n d t h e s i t e of t h e u l c e r a t i o n is n o w a t t h e a p e x of a d eep g r o o v e e x t e n d i n g u p b e t w e e n t h e b r e a s t a n d t h e c h e s t w a l l . I t is n o w 8 m o n t h s s i n c e t h e patient, w a s t r e a t e d a n d a l t h o u g h t h e u l c e r a t i o n is s t i l l n o t h e a l e d no t u m o u r is p a l p a b l e t h r o u g h t h e b r e a s t . T h e 32p h a l f - l i f e w a s e s t i m a t e d a t 17 d a y s f r o m c o u n t s t a k e n a t t h e e dge of t h e b r e a s t ulcer. C o u n t s w e r e a i s o t a k e n a t t h e e d g e of t h e u l c e r on t h e c h e s t w a l l , but. w h i l e t h e y were not. s a t i s f a c t o r y t h e y i n d i c a t e d a h a l L l i f e of a b o u t 22 d a y s . A s t h e u l c e r a t i o n i s not h e a l e d 8 m o n t h s aft.er t r e a t m e n t t h e f a i r p r o g n o s i s i n d i c a t e d b y t h e h a l f - l i f e o f [7 d a y s a g r e e s w i t h t h e c l i n i c a l r e s u l t . CASE No. 12 : T h i s p a t i e n t , a g e d 71, h a d a l a r g e f u n g ~ t i n g c a r c i n o m a i n v o l v i n g t h e u p p e r a n d o u t e r h a l f of h e r b r e a s t ; t h e r e were l a r g e g l a n d s i n t h e a x i l l a . She w a s treated by deep x-rays and the breast turnout was then i m p l a n t e d with r a d i u m needles. The t u m o u r r e d u c e d i n size s l o w l y a f t e r t r e a t m e n t a n d 6 m o n t h s l a t e r i t h a d p r a c t i c a l l y healed . T h e a x i l l a r y g l a n d s were t h e n s m a l l e r , b u t w e r e fixed. T w o m o n t h s l a t e r t h e patient died from metastases. The :2p h a l f - l i f e w a s e s t i m a t e d at. 11 d a y s f r o m c o u n t s t a k e n a t t h e e d g e o f t h e ulceration. This indicated a radio-sensitive tumour. The slow rate of healing was p r o b a b l y d u e to t h e l a r g e size of t h e u l c e r a n d t h e c l i n i c a l r e s u l t a g r e e d w i t h t h e p r o g n o s i s s u g g e s t e d b y t h e 3~p half-life. CASE NO. 13. T h i s p a t i e n t , a g e d 79, h a d a f u n g a t i n g t u m o u r of t h e b r e a s t ; no g l a n d s w ere p a l p a b l e . F i v e m o n t h s a f t e r t r e a t m e n t t h e u l c e r a t i o n h a d h e a l e d a n d no t u m o u r was palpable. C o u n t s were t a k e n a t 2 p o i n t s i n t h i s p a t i e n t , on e w h e r e t h e s u p e r f i c i a l s k i n w a s infiltrated and the other where deeper skin was involved. The counts showed a satisfact.ory fall for t h e first w e e k . T h e p a t i e n t w a s n o t c o u n t e d a g a i n u n t i l 6 d a y s l a t e r w h e n it w a s f o u n d t h a t t h e c o u n t i n g r a t e h a d n o t f a l l e n f u r t h e r . T h e half-life e s t i m a t e d d u r i n g t h e first w e e k w a s 10 d a y s , b u t if t h e l a t e r c o u n t s a re s i g n i f i c a n t t h e h a l f - l i f e w a s p r o b a b l y c o n s i d e r a b l y longer. U p t o 6 m o n t h s a f t e r t r e a t m e n t t h e c l i n i c a l r e s u l t i~ excellent. CASE No. 14 : T h i s p a t i e n t , a g e d 70, h a d a f u n g a t i n g t u m o u r i n t h e m e d i a l p a r t o f h e r b r e a s t w h i c h w a s somewhat, fixed t o m u s c l e ; she h a d a x i l l a r y a n d s u p r a c l a v i e u l a r g l a n d s . S i x m o n t h s a f t e r d e e p x - r a y t r e a t m e n t t h e u l c e r h a d heMed, t h e r e w a s no t u r n o u t p a l p a b l e in t h e b r e a s t a n d t h e r e were no e n l a r g e d g l a n d s . The c o u n t s t a k e n in t h i s p a t i e n t were v e r y i r r e g u l a r , a n d it w a s not p o s s i b l e t o e s t i m a t e
484
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485
a hMf-life w i t h a n y degree of accuracy. T h e hMf-life w a s p r o b a b l y less t h a n 20 days. The clinical r e s u l t u p t o 6 m o n t h s h a s b e e n v e r y satisfactory. CASE No. 15 : T h i s patient., aged 43, h a d an e x t e n s i v e u l c e r a t i n g c a r c i n o m a of t h e b r e a s t ; there were s~condary d e p o s i t s in l u n g s a n d bone. She w a s t r e a t e d b y deep x - r a y s a n d w a s given large d o s e s of D u r a b o l i n . As a r e s u l t of the h o r m o n e t h e r a p y the p a t i e n t c a n n o t be considered suitable for inclusion in t h i s series. T h e m e t a b o l i s m of 3zp b y t h e t u m o u r cells w a s altered n e t o n l y b y t h e r a d i a t i o n b u t also b y t h e h o r m o n e therapy. The a2p hMf-life w a s e s t i m a t e d at 9 d a y s f r o m c o u n t s t a k e n over t w o skin nodules. T h i s w o u l d n o r m a l l y indicate a r a d i o - s e n s i t i v e t u m o n r , b u t for the r e a s o n s s t a t e d it is o f no significance. Two m o n t h s after t r e a t m e n t t h e centre o f the ulcer h a s sloughed out, b u t o t h e r w i s e there is little change. CASE No. 16 : T h i s p a t i e n t , aged 54, h a d a large u l c e r a t i n g t u m o u r of t h e b r e a n t fixed to the p e c t o r a l m u s c l e s ; there were glands in the axillary a n d s u p r a c l a v i e u l a r regions. Three m o n t h s after deep x - r a y t r e a t m e n t t h e u l c e r a t i o n had. a l m o s t healed a n d no t u m o u r or g l a n d s were palpable. T h e u~P hMf-life w a s e s t i m a t e d at 10 d a y s f r o m the average of c o u n t s t a k e n at 4 p o i n t s a r o u n d the ulcer. The good p r o g n o s i s suggested b y the 32p hMf-life agrees w i t h t h e clinical r e s u l t to date.
The following 4 eases illustrate the use of the procedure in cases of epithelioma of the skin. CASE No. 1 : T h i s p a t i e n t h a d an e p i t h e l i o m a on his cheek w h i c h w a s t r e a t e d b y c o n t a c t x-rays. T h e asp half-life w a s e s t i m a t e d a t 20 days. The e p i t h e l i o m a healed slowly over the following t h r e e m o n t h s end w a s well one y e a r after t r e a t m e n t . CASE No. 2 : T h i s p a t i e n t h a d a v e r y e x t e n s i v e e p i t h e l i o m a on her shin mid she refused a m p u t a t i o n . She w a s t r e a t e d b y deep x-rays. T h e c o u n t s t a k e n at the edge o f the ulcer were n o t s a t i s f a c t o r y , being v e r y irregular f r o m d a y to day. T w o m o n t h s after t r e a t m e n t the ulcer a p p e a r e d necrotic a n d s h o w e d n o t e n d e n c y t o heal. A b i o p s y t a k e n at t h i s t i m e s h o w e d necrosis, but, no m a l i g n a n c y . A t t h i s t i m e t h e p a t i e n t developed g l a n d s in her groin and c o n s e n t e d to a m p u t a t i o n . She died w i t h active disease in her groin two m o n t h s later. I t is possiEle t h a t t h e failure of t h e c o u n t i n g rat.e to'fMl and the v a r y i n g c o u n t i n g rate indicated the d e v e l o p m e n t of necrosis d u r i n g t r e a t m e n t . CASE NO. 3 : This p a t i e n t h a d a small c a r c i n o m a of the lip which w a s t r e a t e d b y c o n t a c t x-rays. The :2p hMf-life w a s e s t i m a t e d at 13 days. The c a r c i n o m a w a s well healed w h e n seen one y e a r after t r e a t m e n t . CASE No. 4 : T h i s p a t i e n t h a d a large e p i t h e l i o m a on his neck w h i c h w a s t r e a t e d b y a r a d i u m i m p l a n t . T h e t u m o u r w a s c o u n t e d before the i m p l a n t a n d after t h e r a d i u m needles were r e m o v e d ; it. is n o t p o s s i b l e to c o u n t a t u r n o u t with r a d i u m needles in position. T h e a=p hMf-life w a s e s t i m a t e d at 15 days. The t u m e u r r e s p o n d e d well to t h e i m p l a n t a n d w a s fully healed w h e n seen six m o n t h s after t r e a t m e n t .
Of the 16 cases of carcinoma of the breast two (Nos. 7 and 9) died shortly a f t e r treatment, and two f u r t h e r eases (Nos. 8 and 15) were being treated with hormones. No assessment is possible in these cases. The remaining 12 cases are suitable for discussion. I n two eases (Nos. 13 and 1 4 ) t h e counts were i r r e g u l a r and a half-life could not be estimated. This m a y have been due to a technical error, but the cause is not obvious. P e r h a p s a greater n u m b e r of counts in these cases would have made it possible to estimate a definite half-life. The prognosis suggested by the 32p half-life in the remaining 10 cases agrees with the clinical result to date. The period of follow-up is too short for the results to be of any g r e a t significance, but the procedure a p p e a r s promising and w o r t h y of f u r t h e r study. A good prognosis was given in 5 cases, a f a i r prognosis in 2 cases. and a poor prognosis in 3 cases. W e feel that it is in the early detection
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of radio-resistant cases that this procedure will be of greatest use. I t is possible to detect the radio-resistant cases in the first week of treatmont. A t this time, if the t u m o u r is operable, operation can be performed because the radiation reaction will not be severe and will develop when healing is almost complete. I f the t u m o u r is inoperable radiation l r e a t m e n t can be abandoned and the patient will have been spared a needless severe radiation reaction. Although we have used this method of determining radio-sensitivity in tumours on the surface of the body the procedure could be extended to tumours in other sites by the construction of suitable counters. A longer and perhaps bigger counter would allow carcinomas of the cervix uteri to be counted. Specially constructed counters combined with instrumcntation could extend the procedure to carcinomas of the bronchus, oesophagus, l a r y n g o - p h a r y n x and bladder. The principles underlying this procedure a p p l y only to carcinomas t r e a t e d by radiation. The '~-~P half-lives indicating differcnt degrees of radio-sensitivity have been theoretically calculated on the basis of the cellular changes, described by Glucksmann a n d S p e a r : if the cellular changes which m a y occur in tumours in response to treatm e n t with hormones or chemotherapy were known it might be possible to calculate a half-life which would indicate a satisfactory rcsponse to either type of treatment. Acknowledgements T h i s w o r k was c a r r i e d o u t on a R e s e a r c h F e l l o w s h i p f r o m t h e R o y a l College o f S u r g e o n s in I r e l a n d u n d e r t h e d i r e c t i o n o f P r o f e s s o r M. H . O ' C o n n o r , M.D., Mr. T. C. J. O ' C o n n e l l , M.D., M.Ch., a n d Mr. D. J. R i o r d a n , F.R.C.S.I. T h e p a s s a g e f r o m Malignant Disease and Its Treatment by Radium is r e p r o d u c e d b y k i n d p e r m i s s i o n of Sir S t a n f o r d Cade. T h e c h a r t of t h e c h a n g e s in cell p o p u l a t i o n w h i c h occur in response to ra~liation is r e p r o d u c e d b y k i n d p e r m i s s i o n o f Dr. A. G l u e k s m a n n a n d Dr. F. G. Spear.
References l. A t k i n , N. B. (1960). Lancet, ii, 778. 2. Cade, Sir S t a n f o r d (1948). Malignunt Disease ancl Its Treatment by Radium, 2nd E~I. Wright, Bristol, 3. G l u c k s m a n n , A. (1941). B. J. Radiol., 14, 162, 181. 4. G l u c k s m a n n , A. a n d Spear, F. G. (1945). B, J. Ra~liol., 18, 214, 313. 5. Marcus, R. a n d R o t b l a t , J. (1950). B. J. Radiol.~ 23, 273, 541. 6. M a r s h a k . A. (1949). J. Cli~. Invest., 28, 6, 1324. 7. M a r s h a k . A. (1941). J. Gen. Physiol., 25, 2, 275. 8. M a r s h a k , A. (1940). Science, 92, 2394, 46(I. 9. R 6 g a u d , C. (1928). Report of Internation¢d Canoer Conyress (B.E.C.C.), L o n d o n , G4.
