Therapeutic implications from a mathematical model characterizing the course of breast cancer

A mathematical model was developed to characterize the course of human breast cancer. A brief description of the model in nonmathematical language is given, results of a test of the model are presented, and some therapeutic implications are discussed. The model utilized observations from collaborative clinical trials to obtain estimates of several parameters that describe events in the course of the disease which are not directly observable. Results indicated that two types of breast cancer can be distinguished: 1. a slow growing form (Type B), and 2. a rapid growing form (Type A). About one‐fifth of the population were of Type A. These patients had a shorter delay time, a twofold faster tumor doubling time, and risks of nodal involvement and of occult metastases which were several times greater than in Type B. A primary implication is that in many patients, subclinical metastasis has already occurred before surgery. Indications for new approaches to therapy for clinical trials are discussed.