TUMOUR CELLS IN THE CIRCULATING BLOOD OF PATIENTS WITH CARCINOMA OF THE BREAST AND OF THE GASTROINTESTINAL TRACT.

In view of the differences in the frequency of tumour cells in various reported series and the difficulty in reconciling the presence of these cells with survival, three groups of patients were studied in the following manner. In one group of 20 patients with breast cancer, multiple 20-ml. blood samples were studied. In another group of 18 patients, a single 100-ml. sample was used. Using this technique, tumour cells were found in 82.5% of patients in Group 1 and in 89% in Group 2. Similarly, in 44 patients with cancer of the gastrointestinal tract, tumour cells were identified in 70% of the patients, using the multiple-sampling technique. It seems therefore that if a sufficient volume of blood is studied, tumour cells are present in every patient with cancer of the breast and gastrointestinal tract. The presence of tumour cells in the peripheral blood does not mean that hematogenous metastases will invariably develop, and the presence of these cells is only one of many factors responsible for the development of such metastases.