Abstract
BACKGROUND: Counseling patients regarding the risk of future pregnancy on hormone receptor-positive breast cancer outcomes is difficult because of the minimal data and understanding of pregnancy on the breast environment. PATIENTS AND METHODS: The present retrospective analysis included 32 premenopausal women with a diagnosis of estrogen receptor-positive breast cancer from 2000 to 2010 and subsequent pregnancy within 5 years. The control cohort included 29 women matched for age and stage of breast cancer who had not become pregnant. RESULTS: No statistically significant difference was found in age, diagnosis, stage, grade, or HER2 status between the 2 groups. Of the 32 women in the pregnancy cohort and 29 women in the control cohort, 19 (63%) and 23 (82%) had received endocrine therapy (P = .25). The mean length of endocrine therapy was 42.3 months (range, 0-120 months) in the control cohort and 20.9 months (range, 0-72 months) in the pregnancy cohort (P = .008). Four women (14%) in the control cohort experienced breast cancer recurrence compared with 8 women (26%) in the pregnancy cohort (P = .34). The 5-year disease-free survival rate was 92% (95% confidence interval, 81%-100%) in the control cohort compared with 84% (95% CI, 72%-97%) in the pregnancy cohort. The difference was not statistically significant (P = .69). CONCLUSION: The results of the present study did not demonstrate poorer disease-free survival for premenopausal women with estrogen receptor-positive breast cancer who became pregnant within 5 years of diagnosis. Our study is unique because all included patients had estrogen receptor-positive disease and were offered adjuvant hormonal therapy. Further prospective investigation will be beneficial to patients and physicians as they discuss pregnancy as a key survivorship issue.