Pregnancy after breast carcinoma: outcomes and influence on mortality.

BACKGROUND: To the authors' knowledge, no previous studies have identified an adverse effect of pregnancy on patient survival after breast carcinoma. However, results are difficult to interpret because of failure to control for stage of disease at the time the pregnancy occurred. METHODS: Study participants were women diagnosed with invasive breast carcinoma between 1983-1992 who previously had participated in a population-based case-control study or, if deceased, proxy respondents. Information regarding subsequent pregnancies was obtained by self-administered questionnaire or telephone interview. Information regarding breast carcinoma recurrences was obtained by questionnaire and from cancer registry abstracts. Women who became pregnant after a diagnosis of breast carcinoma (n = 53) were matched with women without subsequent pregnancies based on stage of disease at diagnosis and a recurrence free survival time in the comparison women greater than or equal to the interval between breast carcinoma diagnosis and onset of pregnancy in the women with a subsequent pregnancy. RESULTS: Sixty-eight percent of women who became pregnant after being diagnosed with breast carcinoma delivered one or more live-born infants. Miscarriages occurred in 24% of the patients who became pregnant compared with 18% of the controls (women without breast carcinoma) of similar ages from the case-control study. Five of the 53 women who had been pregnant after breast carcinoma died of the disease. The age-adjusted relative risk (RR) of death associated with any subsequent pregnancy was 0.8 (95% confidence interval [95% CI], 0.3-2.3). All five deaths occurred among the 36 women who had a live birth (age-adjusted RR = 1.1; 95% CI, 0.4-3.7). CONCLUSIONS: The findings of the current study are based on a small number of deaths but do not suggest that pregnancy after a diagnosis of breast carcinoma has an adverse effect on survival.