Radioisotopes in the Investigation of Tumours [Abridged]

Abstract

A method is described of controlling the activity of undifferentiated cerebral gliomata, within restricted limits, by means of chemotherapy, and then attempting to use this control to potentiate the effectiveness of deep X-ray therapy.In the first instance, a miniature geiger counter of type B. .N. is implanted into the tumour by a neurosurgeon. This is usually done at the time of the biopsy. The instrument is 3 mm in diameter and is under 6 cm long. No trouble has been experienced with sepsis or the presence of the counter in the brain over periods of a few weeks.The cases chosen are those for whom there is no effective alternative treatment, and whose brain damage is not already too severe.After insertion of the counter a dose of tracer radioactive phosphorus is given and a continuous record is made of the count-ra-te during the whole procedure. This count-rate is presumed to run parallel to the metabolic activity of the growth. As previously reported in other types of case (Bullen et al. 1963) a period of quiescence folloWed by 'peaking' of activity is induced, by the giving of methotrexate, or a similar agent for a few days. Deep X-ray therapy is then administered to the growth at the time of the peaks.So far, work has been limited to the gaining of experience in the application of the method. We have not tried sufficient brain tumour cases even to have definite impressions of the clinical results. Out of the first 8 cases, 4 were inconclusive from the beginning. Three were very advanced and the patients died in a few days, before deep X-ray therapy began; in another the geiger failed. Of the 4 cases in which treatment was concluded, 2 died within three months and 2 are well at the end of that time.The tracings of radiophosphorus uptake from each of the four completely treated cases were shown and clinical details were given. It is possible that similar immediate results would have been seen from orthodox deep X-ray routines alone, but it appears essential to carry this research to a conclusion, because a useful potentiation of sensitivity of the growth would enable us to evade the dangerous effects of high doses of radiation on the normal brain tissue; in addition, improvements in the local treatment of advanced and inoperable gliomata will be doubly valuable because distant metastases do not occur.