INFLUENCE OF PRIOR AND SUBSEQUENT PREGNANCY ON BREAST-CANCER PROGNOSIS

Purpose and Methods: The prognostic influence of pregnancies 5 years b efore (n = 173) and after (n = 50) breast cancer diagnosis was investi gated in 2,119 women less than 50 years of age with a primary operable breast cancer. The main end point was distant metastasis. Univariate and multivariate analyses were performed using the Cox proportional ha zards model. In the analyses of the effect of pregnancy after diagnosi s of breast cancer, a Cox model with a time-dependent covariate was ap plied. Results: Women with a pregnancy before diagnosis had slightly l arger tumors than the control group. However, they did not differ with respect to nodal status and estrogen receptor (ER) status. There was no evidence that women with a pregnancy during the 5-year period prece ding breast cancer diagnosis hod a worse prognosis compared with women without pregnancy during the same period. Similarly, there was no evi dence that women with a pregnancy after breast cancer diagnosis had a worse prognosis, Conclusion: The hormonal changes associated with preg nancy thus seem to have little, if any, influence on the prognosis of breast cancer. In the present study, at least, there was no indication of a worse prognosis. In fact, the relative hazard for women who beco me pregnant after diagnosis of breast cancer in comparison with women without a subsequent pregnancy was 0.48 (P = .14), which suggested a p ossible decreased risk of distant dissemination.