Cell proliferation and its relationship to clinical features and relapse in breast cancers.

The relationship between primary tumor proliferative activity and clinical and pathologic characteristics was analyzed in relation to menopausal status for 541 breast cancer patients. The thymidine-3H labeling index (LI) showed significantly higher median values in cancers from premenopausal (4.2%) and paramenopausal (4.2%) patients in comparison to that of cancers from postmenopausal (1.8%) patients. The LI was not generally correlated to tumor size. The only significant correlation was limited to tumors with negative axillary lymph nodes from premenopausal patients. The proliferative activity of primary tumors was neither correlated to the presence nor the extension of axillary metastasis. The prognostic significance of the primary tumor LI was assessed in 145 untreated patients with cancers without axillary metastases. A higher median value of LI was observed in tumors from patients who relapsed (5.7%) within 52 months than in tumors from those who did not relapse (2%). However, the difference was statistically significant (P less than 0.01) in premenopausal patients, but not in postmenopausal patients. Similarly, a significantly (P less than 0.0005) higher rate of relapse (67.4%) was observed in patients with tumors that had a LI above the median value of 4.6% in comparison to that (0%) of tumors with a LI below the median value in premenopausal patients. No statistically significant relationship was observed between proliferative activity of the primary tumor and risk of relapse in postmenopausal patients.