Circulating Cancer Cells

Abstract

The techniques available for the extraction of cancer cells from the circulating blood are discussed and a preference is expressed for the iron-separation technique described by Kuper - et al. (1961). The problems of screening a relatively large volume of fluid for a small number of cells and the particular difficulties involved in the recognition of cancer cells in blood are considered. In particular, stress is laid on the value of millipore membranes to obtain accurate Quantitative results. Considerable difficulty is experienced in cytological identification when small numbers of single atypical cells are present. Similar morphological features occur in cells from normal bone-marrow, and a definite diagnosis of malignancy is unreliable unless a group of cells is examined. In particular, megakaryocytes have been incriminated as a source of false-positive results. Cancer cells were recognized in peripheral blood samples from only 11% of cancer patients. Only 6.5% of the total number of samples examined were positive. This figure is very much lower than those of several other workers, but is similar to those published by Spriggs (1960) and Kuper et al. (1961). Differences are almost certainly due to differences of cytological interpretation. Examination of the blood for cancer cells is of no diagnostic value, as most of the patients from whom such cells are isolated already suffer from obvious advanced malignant disease. Blood samples taken from local veins draining tumours yield a somewhat higher incidence of cells (15% of patients), and might be of some value in studying the dissemination of cancer cells during surgical operations. © 1964, British Medical Journal Publishing Group. All rights reserved.