Survival Outcomes in Pregnancy Associated Breast Cancer: A Retrospective Case Control Study

Pregnancy-associated breast cancer (PABC) has been defined as breast cancer diagnosed during pregnancy or within one year of delivery. It is believed that after adjusting for age and stage, the 5-year survival rates are the same in both pregnant and nonpregnant women. We conducted a retrospective case-control study among patients treated at our institution between 1990 and 2005 to compare the 5-year survival outcomes for PABC with women treated for breast cancer who were not pregnant. Overall survival (OS) and disease-free survival (DFS) were estimated by the Kaplan-Meier method, and log rank tests were used to assess the associations between OS, DFS and pregnancy status, HER-2 status, ER/PR status, and family history. The median age was 33 years (range 24-42) for both groups. Twenty-two (55%) patients with PABC were ER/PR receptor positive compared with 20 (50%) for the controls. Ninety percent of patients with PABC received chemotherapy compared with 87.5% in the nonpregnant group. 91.5% of patients with PABC had breast-conserving surgery and 8.5% had mastectomies compared with 86% and 14%, respectively, for the control group. The median OS was 4.9 years in the PABC group compared with 6 years for the controls (p = 0.02). The median DFS was 2.7 years for the PABC group compared with 5.1 years for the controls (p = 0.01). The most common site of relapse was bone for the PABC group (27%) and local recurrence (33%) for the controls. Univariate analysis revealed that OS and DFS were associated with pregnancy status, family history, ER/PR status, and stage. After adjusting for age and stage, PABC patients had higher risk of both death (p = 0.01) and recurrence (p = 0.02) compared with nonpregnant controls. Women with PABC had significantly shorter OS and DFS compared with nonpregnant age and stage-matched controls.