CARCINOMA OF THE UTERINE BODY TREATED WITH RADIOACTIVE COBALT

BY

PAUL STRICKLAND, M.B., M.R.C.P., D.M.R., F.F.R. Assistant Radiotherapist, Mount Vernon Hospital,

Northwood, Middlesex

DURING 1950 supplies of radioactive cobalt (C06’) became available from the Ministry of Supply Atomic Pile at Harwell. and we thought we might take advantage of this in evolving a simple irradiation technique in treating car- cinoma of the uterine body. Radiocobalt has a half life of 5.3 years and emits gamma rays comparable to those of radium. It needs reactivating annually, having lost about 10 per cent of its activity.

Previous techniques have not proved entirely satisfactory. Many centres have used one or more radium tubes placed in the long axis of the uterus and left in position for 24 hours or longer. Because of screenage by the inactive ends of the tubes, the fundal portion of the uterus was probably under-irradiated. This is particularly important since a carcinoma may often take origin at the fundus, as is beautifully illustrated in Cullen’s book (1900).

In recent years, Heyman, Reuterwall and Benner (1941) have described a “packing ” method which apparently gives good results in their hands. However, elaborate apparatus is required, and the uterus has to be packed as tightly as possible with multiple radium tubes. There is an acknowledged risk of perforating the diseased uterus, and the method would not seem suitable for routine use.

We decided to design a flexible intra-uterine applicator containing multiple small sources of C060. Our criteria were that the apparatus should be simple to construct, easy to load and handle, and be capable of taking on accurately the pyriform shape of the cavity of the uterus after insertion. We aimed at a dose of irradia- tion of at least 6,000 rontgens at 1.0 cm. distant from the mucosal surface of the uterus in all

directions. We decided to deliver this dose in two sessions of about 24 hours each, separated by an interval of one week-and this paper is a preliminary report of a trial of the method in a small group of cases.

Description of Apparatus The apparatus consists of a tight spiral of

stainless steel wire, resembling base clef piano wire. The length of loop to be used is deter- mined by the passage of a uterine sound. When constituted, it is a springy appliance (labelled A in Fig. 1) and its open ends are pushed into two holes drilled in a brass cylinder (B) 2.0 cm. long and 1.95 cm. in diameter. The loop of wire thus formed is the container of the radioactive cobalt sources. It is closed by a brass plug and

With a little compression the loop can easily be passed through the “ cervix tube ” (D) which is a thin-walled brass tube of outside diameter 1.0 cm. The brass key fits snugly into a slot on the inferior surface of the cervix tube, at right angles to the plane of the loop.

Method of Loading The flexible loop and cylinder are mounted

on a small clamp and the cobalt sources are dropped into its open ends using long-handled forceps and working behind a thick lead screen. Each source is 2.0 mm. in diameter and is plated with nickel to absorb the soft beta radiation. The strength of each source is 2.8 millicuries and, in an average case, a total loading of 74 millicuries is used.

As each piece of cobalt is dropped in, an inert steel pellet follows so that the active sources are spaced equally round the loop, except at the

key (0

898

CARCINOMA TREATED WITH RADIOACTIVE COBALT

STEEL SPRING SECTIONED TO @ SHOW COBALT RODS INSIDE SPACED BY STAINLESS STEEL PEUErS

CERVfX TUBE

FLEX/BLE STEEL SPRfNG A CLOSE PUSH FIT I N DRILLED Ck’LfND.FR

FIG. 1 Exploded diagram of applicator

(Reproduced by courfesy of ‘‘ Acfa Radiologica ”)

899

fundal region where 6 contiguous cobalt sources are used. The applicator is now closed by means of the plug and secured with a silk thread which passes through suitable holes in the cylinder and plug as shown in Fig. 1. The whole apparatus is now sterilized in the usual way.

A fuller description of the apparatus, with details of dose distribution around it has pre- viously been published by Jones (1952).

Method of Use Under general anaesthesia the patient is

placed in the lithotomy position. Dilatation of the cervix is carried out, and a sound passed to determine the length of the uterus if this information is not already available. This is very important, for on it will depend the length of loop to be used. Gentle curettage is also performed to obtain material for histological study.

The anterior lip of the cervix is grasped gently with vulsellum forceps and drawn downwards. The cervix tube, on a solid metal introducer, is inserted, the introducer withdrawn and the tube remains in position. The distal end of the loop, with its attached cylinder, is now held in the right hand using modified tube-holding forceps. The cervix is steadied and the loop is gently fed through the cervix tube until it has disappeared from sight. The cylinder fits firmly into the cervix tube, and the key on the plug engages with the slot. The silk threads on the loop are twisted round a roll of flavine gauze

and the vagina packed tightly. The whole operation lasts about 10 minutes.

The apparatus is left in position for 224 hours, and is removed in the ward by simple traction on the silk threads. Removal is not unpleasant for the patient and anaesthesia is not required. The radiological appearance of the applicator in the uterus is shown in Fig. 2.

Results Eight cases have been treated; all had been

considered unsuitable for surgical treatment. The histology of the tumours was adeno- carcinoma in all cases, of varying degrees of differentiation.

Of these cases, 5 are alive today and free of disease, the 2 longest survivors (our first 2 cases) having been treated 23 years ago. Our last case in this series was treated over 18 months ago and is well. The remaining cases have a variable follow-up between these two limits.

Three cases were unsuccessful: 1, treated in June, 1951, died in October 1952 with carcino- matosis. When first seen, she had a plaque of carcinoma half way down the anterior vaginal wall which was treated with a separate radium needle implant. Two other cases have died with widespread dissemination of disease. All 3 unfortunately died outside hospital and there was no opportunity for postmortem study.

DISCUSSION The mainstay of treatment of cancer of the

uterine body is total hysterectomy, but there

900 JOURNAL OF OBSTETRICS AND GYNAECOLOGY

exists a group of cases not suitable for it. In our series, the presence of severe cardiovascular disease or gross obesity have precluded opera- tion in the opinion of the gynaecologists referring the cases.

It is now widely recognized that carcinoma of glandular origin may be just as radiosensitive as carcinoma of squamous origin as long as a sufficiently high dose of irradiation is given. This fact provides the rationale for an attempted radical radiotherapeutic technique.

Methods previously described are either too complex for routine use, or, because they employ central radium sources only, run a serious risk of underdosing the fundus uteri. If local recurrence of carcinoma occurs, it is most likely to occur there. By using an applicator moulded to the shape of the uterine cavity, and loading it differentially at its fundal end, we hope that this risk will be reduced. However, Paterson, Tod and Russell (1950), using a multiple radium tube technique, have reported that 72 out of 143 technically operable cases were clinically free of disease 5 years later, a crude survival rate of 50 per cent.

In several cases, curettage has been carried out after the completion of cobalt treatment. So far, no positive curettings have been obtained and this makes us confident that the disease can be eradicated locally. However, the method does not deal adequately with spread of disease into the parametria and, if such cases are accepted for treatment, supplementary deep X-ray therapy will be needed. Neither is a sufficient dose of gamma rays given to the upper third of the vagina, though the cervix itself is probably irradiated sufficiently.

The recurrence of cancer in the vaginal vault after hysterectomy is common, and is probably due to lymphatic permeation having occurred by the time of operation. In an attempt to deal with this, we intend in the future placing one or more radio-active sources in the vagina at the time of the insertion of the uterine applicator.

The morbidity of the method has been very slight. One or two patients have developed transient diarrhoea which has resolved unevent- fully. It is likely to occur where the uterus is mobile and retroverted and the distance between applicator and bowel consequently diminished. The bladder has not been affected, and there have been no radiation necroses.

SUMMARY A method of treatment of carcinoma of the

body of the uterus, using a flexible applicator and multiple radio-active cobalt sources is described.

The work was carried out in close collabora- tion with Mr. D. E. A. Jones, Senior Physicist, Mount Vernon Hospital. I am grateful to the Gynaecologists for referring the cases, and to Professor B. W. Windeyer, and Dr. Roy Ward for encouragement and advice.

REFERENCES Cullen, T. S. (1900): Cancer of the uterus. Kimpton,

Heyman, J., Reuterwall, O., and Benner, S. (1941):

Jones, D. E. A. (1952): Acta. radiol., Stockh., 38, 41. Paterson, R., Tod, M., and Russell, M. (1950): The

results of radiotherapy, 1940-44, Manchester. Livingstone, Edinburgh.

London.

Acta radiol., Stockh., 22, 14.

FIG. 2 (a) Radiological appearancc of applicator in treatment position

Antero-posterior vicw

P.S.

FIG. 2 (b)

Radiological appearance of applicator in treatment position

Lateral view