Pregnancy-associated breast cancers: do they differ from other breast cancers in young women?

The impact of pregnancy in the physiopathology of pregnancy-associated breast cancer (PABC) is still unclear. We compared the characteristics of PABCs and breast cancers not associated with pregnancy (non-PABCs) in terms of their loco-regional invasion and histological phenotype. We conducted a retrospective chart review on women less than 43 years of age treated for breast cancer from January 1, 2004 to December 31, 2010. We compared age at diagnosis, loco-regional invasion and histological data. We recorded 282 breast cancers in 276 patients. Forty-one tumors (14.5%) were PABCs. PABC patients were significantly younger than non-PABC patients. Compared with the non-PABCs, PABCs were twice more frequent advanced tumors (T3-4) and have twice more frequent HER2 over-expression and hormone negative status. The more aggressive histological profile observed in the PABCs, especially in post-partum tumors and women older than 35 years of age, seems to be a direct consequence of the association with pregnancy.