Prognosis of pregnancy-associated breast cancer. The survival of patients with pregnancy-associated (PA) breast cancer is difficult to predict for two reasons: The combination is very rare, and the natural history of breast cancer that is not associated with pregnancy is intricate and varies among individuals. Valid data collection and analysis is problematic given that studies gather patients over many years. The charts of 56 women with Stages I, II, and III breast cancer, who were pregnant or within 1 year postpartum at the time of breast cancer diagnosis between 1960 and 1980, were analyzed. Patients with PA breast cancer were compared to nonpregnant women of comparable ages, who were treated at the same hospital, by the same physicians, and during the same period. Four patients were lost before 5-year follow-up, and one patient before 10-year follow-up. These five patients had distant metastases at the time they were lost to follow-up, and are considered to have died within that time. Across stages, patients with PA breast cancer have survival not significantly different from those patients with non-pregnancy-associated (non-PA) breast cancer. 