Breast cancer and pregnancy.

Pregnancy-associated breast cancer has an overall worse prognosis than nonpregnancy-associated breast cancers because a large proportion present with more advanced disease. Stage for stage, however, the prognosis is similar. The various modalities used for screening, diagnosis, and staging of breast cancer are not always applicable during pregnancy. Often, a delay in diagnosis may contribute to a more advanced stage at presentation. The management of pregnant women with breast cancer is also different because it involves assessing the possible risks to the fetus versus the maternal benefits.