The Activity of Malignant Tumours and Response to Therapeutic Agents, Studied by Continuous Records of Radioactive Phosphorus Uptake.

FOR some time past, there has been a need for a method of selecting hormone-dependent breast cancers because of the increasing use of hypophysectomy, as well as prolonged therapy by hormones. Without selection at least 50% of the cases would derive no benefit from such surgery, but up till now one has had to be content with a partial selection based on response to trials of hormone therapy or oophorectomy. The work to be described sprang from our attempt to meet that need. Our first introduction, in this Department, to the use of radioactive-phosphorus uptake into the growth as a guide to activity, arose in two cases of secondary breast carcinoma in the eyeball. The uptake was assessed by placing a Geiger counter on the eyeball after administering a tracer dose of 32P. It was found that activity diminished after the administration of hormones and deep X-ray therapy. This simple method of surface counting is, however, useless for deep tumours, and unsatisfactory for many superficial ones, because of the short range of the beta rays, the serious errors due to small changes in position of the counters and the effects of changes of surface temperature and blood flow. The method has only been used when it is essential, e.g. in some early melanomata or very superficial skin nodules. Whenever possible, the use of a counter buried in the depth of a tumour has been preferred. The possibility of following tumour activity, after trial administration of hormones by means of serial biopsy and repeated mitotic counts, was quickly rejected as unsuitable for general clinical use. As well as using the counter buried in the growth, it was felt that continuous recording ofthe 32P uptake was essential to detect rapid or transient changes.