The prognostic significance of circulating tumour cells: a five-year follow-up study of patients with cancer of the breast.

One hundred and sixteen patients with proved cancer of the breast were followed up for five years to detect circulating tumour cells. Such cells were found in 61 patients, but, irrespective of the stage of the disease, the five-year survival rate in these was not significantly different from those in whom no tumour cells were found. The higher incidence of patients without circulating tumour cells in Stage I was not sufficient to influence the survival rate of the whole group. While the validity of the identification of these cells is questionable, the results of this study indicate that the presence or absence of tumour cells in the blood is of no prognostic significance.