Cell Kinetics of Breast Cancer: The Turnover of Nonproliferating Cells

Abstract

The kinetic properties of growing tumors and of the involved normal tissues will probably continue for some time to be of major concern to biologists and therapists dealing with the cancer problem. To the extent that abnormal growth is the explicit manifestation of the malignant process, it is obviously relevant to learn as much as possible about the differences in growth dynamics of the tumor and the normal cell. In addition, all aspects of cancer therapy have a kinetic involvement. In radiotherapy the growth kinetics affect the rate of tumor shrinkage, the design of optimal fractionation, the estimation of numbers of tumor or normal cells at risk, and the use of combination or other treatment modifications to increase the therapeutic ratio of tumor to normal response. In chemotherapy the same problems repeat themselves and in addition the use of cycle-linked agents demands a keen insight into cell-cycle behavior and the noncycling cell. Finally in surgery as well as radiotherapy and chemotherapy, knowledge of the growth rate provides the framework within which one predicts and interprets the likely times of recurrence, the response to therapy, and the probability of cure.

This work was supported in part by USPHS Grant 5 K06 CA18540, 5 K04 CA-42,352, 5 ROI CA03896 and FR 15; and by the Atomic Energy Commission (COO-3087-1). Sincere appreciation in the performance of these experiments is expressed to William Jenkins, Reba Riley, Joseph Hogg, and Steven L. Mendelsohn