Pregnancy-associated breast cancer: a case-control study in a young population with a high-fertility rate

Pregnancy-associated breast cancer (PABC) is not a rare event. The association frequently imposes a management challenge. We intended to review the clinical features, therapy, and outcome of patients with PABC seen at a single institution over a five-year period and to compare those with that seen in a matched control group. Data of all patients with PABC diagnosed during pregnancy were retrospectively reviewed (Group I). For each patient in Group I, three matched controls with breast cancer without pregnancy were identified (matched for age, stage, and year of diagnosis, Group II). 72 patients in Group I and 216 in Group II were identified. Their median age was similar (34 vs 35 y, respectively). The median number of prior pregnancies for patients in Groups I and II was 5. Patients had shorter duration of symptoms prior to diagnosis as compared with their controls (5.6 vs 9.4 months, P < 0.0001). 3%, 31%, 40%, and 26% of patients had Stage I to IV, respectively. A pattern that was similar to that seen in our breast cancer population. Pregnancy was terminated in 34 patients (47%), while 38 (53%) had normal spontaneous vaginal delivery. 47 patients in Group I had surgery; 37 (52%) had modified radical mastectomy and 10 (14%) had conservative surgery. In 37 patients surgery was performed after termination of pregnancy and 10 had surgery performed during pregnancy. The median number of positive lymph nodes in Group I was 4 as compared with 2 for patients in Group II. No patients in Group I had systemic chemotherapy during first trimester, while only 4 (6%) and 3 (4%) received adjuvant or neoadjuvant during second and third trimester, respectively. No congenital malformation in the newborns was diagnosed. None of the patients in Group I received radiotherapy during pregnancy. Over a median of 47.5 months, 48 (67%) patients in Group I were alive as compared to 126 (58%) in Group II, with no difference in the median survival (P= 0.79). Comparing overall survival (OS) between the two groups stage for stage also showed no significant difference. Also there was no difference in progression-free survival between the two groups. Cox proportional hazard model identified advanced stage as the only independent adverse prognostic variable that influenced OS in Group I. Despite that this series included a relatively young population with a high fertility rate, the study confirmed the lack of a survival difference between patients with PABC and their matched controls.