Safety of Pregnancy Following Breast Cancer Diagnosis: a Meta-analysis of 14 Studies

Background: Due to the rising trend of delaying pregnancy to later in life, more women are diagnosed with breast cancer before completing their families. Therefore, enquiry into the feasibility and safety of pregnancy following breast cancer diagnosis is on the rise. Available evidence suggests that women with a history of breast cancer are frequently advised against future conception for fear that pregnancy could adversely affect their breast cancer outcome. Hence, we conducted a meta-analysis to understand the effect of pregnancy on overall survival of women with a history of breast cancer.

Methods: Two of the authors independently performed a literature search up to September 2009 with no language restrictions. Eligible studies were published retrospective control-matched, population-based and hospital-based studies that have addressed the impact of pregnancy on the overall survival of women with history of breast cancer. Pooling of data was done using the random effect model. Unpublished statistics from three studies were obtained to perform further subgroup and sensitivity analyses. This included examining the effect of pregnancy according to age at diagnosis, healthy mother effect, type of study, nodal status and other parameters.

Results: Fourteen studies were included in this meta-analysis (1244 cases and 18,145 controls). Women who got pregnant following breast cancer diagnosis had a 41% reduced risk of death compared to women who did not get pregnant [PRR: 0.59 (90% confidence interval (CI): 0.50-0.70)]. This difference was seen irrespective of the type of the study and particularly in women with history of node-negative disease. In a subgroup analysis, we compared the outcome of women with history of breast cancer who became pregnant to breast cancer patients who did not get pregnant and were known to be free of relapse. In this analysis, we did not find significant differences in survival between either group [PRR: 0.85; 95% CI: 0.53-1.35].

Conclusions: This study confirms that pregnancy in women with history of breast cancer is safe and does not compromise their overall survival. Hence, breast cancer survivors should not be denied the opportunity of future conception.