Current or recent pregnancy is associated with adverse pathologic features but not impaired survival in early breast cancer

Background: Pregnancy-associated breast cancer (PABC) may be defined as breast cancer diagnosed during pregnancy or within 1 year of giving birth. Conflicting data exist regarding the impact of pregnancy on clinical features and prognosis of breast cancer.

Methods: A single-institution retrospective chart review was performed of 99 patients identified with PABC between 1992 and 2007. Non-PABC controls were matched 2:1 to PABC cases by year of diagnosis and age. The differences in clinical features were compared between cases and controls using chi-square tests. Univariate and multivariate analyses were performed to assess the effect of PABC on survival.

Results: Of the 99 PABC cases, breast cancer was diagnosed during pregnancy in 36 patients, and after delivery in 63. PABC cases were more likely than controls to be negative for estrogen receptor (59% vs 31%, P < .0001) and negative for progesterone receptor (72% vs 40%, P < .0001). Cases were also more likely to have advanced T class (P = .0271) and N class (P = .0104) and higher grade tumors (P = .0115). With a median follow-up of 6.3 years for cases and 4.7 years for controls, overall survival did not differ between cases and controls (P = .0787). On multivariate analysis, the independent prognostic factors for overall survival were estrogen receptor status (P = .0031) and N class (P = .0003). The diagnosis of PABC was not an independent prognostic factor (P = .1317).

Conclusions: PABC is associated with more adverse tumor features than non-PABC matched for age and year of diagnosis. After correcting for pathologic features, the diagnosis of PABC is not in itself an adverse prognostic factor for survival.