Objective. To study the possibility of pregnancy prolonging in breast cancer.

Materials and methods. 43 women with pregnancy-associated breast cancer (the main group) were examined. The control group consisted of 43 patients with breast cancer outside of pregnancy. The comparison group included 74 healthy pregnant women.

Results. When breast cancer was detected, regardless of the trimester, the patients underwent surgical treatment and several courses of systemic chemotherapy in the second and third trimesters stopped before 35 weeks of pregnancy and continued after delivery.

Conclusion. Timely treatment of breast cancer during pregnancy allows prolong the pregnancy not worsening the prognosis of breast cancer. The event-free survival rates in the main and control groups did not differ (p>0.05).