Prognostic significance of the growth rate of breast cancer: preliminary evaluation on the follow-up of 196 breast cancers.

The doubling time (DT) of 196 consecutive breast cancers was studied by means of a double mammographic examination (average time between the 2 mammographies, 30 days) and calculated with the formula of exponential growth. On the basis of DT values the case series was divided into 3 groups of growth: fast (DT from 1 to 30 days), 31 cases (15.8%), intermediate (DT from 31 to 90 days), 84 cases (42.9%), slow (DT more than 90 days), 81 cases (41.3%). No relationship was found between growth rate and size of tumor, or menopausal status of the patient. After mastectomy fast and slow cases were equally distributed in the N- and N+ groups, whereas for the intermediate cases the N- : N+ ratio was 1 : 2. One hundred and thirty-four cases were followed for a period of 12 to 52 months. Evaluation was done on the basis of the subdivision into N- 2nd N+, and the latter group into N+ (1-3) and N+ (greater than 3). For N- tumors the course of the disease was apparently not affected by the growth rate. However, the case of fast growing tumors showed a higher proportion of recurrences with respect to N+ slow growing tumors. This difference was even more noticeable the higher the number of involved lymph nodes, but not statistically significant. The course of slow growing tumors was identical in the N- and N+ groups, but all the N+ tumors were subjected to adjuvant chemotherapy.