Background: The study aims to evaluate the current state and tendencies in multiple primary breast cancer incidence, behavior, and treatment in Ukraine.

Methods: A total of 2032 patients who received special treatment at the Department of Breast Tumors and Reconstructive Surgery of the National Cancer Institute from 2008 to 2015 were included in the study. Among them, there were 195 patients with multiple primary malignant neoplasms: 54.9% patients with synchronous cancer and 45.1% patients with metachronous cancer. The average age of patients was 46.6 years, and the percentage of postmenopausal women was 63.1%. Among patients with synchronous cancer, there were 56.1% patients with only breast localizations and 43.9% with combination of breast and other localizations, and among patients with metachronous cancer, there were 46.6% patients with only breast localizations and 53.4% with combination of breast and other localizations. All the patients were evaluated in terms of aggressiveness of the disease, survival rates, as well as risk factors and treatment options.

Results: A more aggressive course of breast cancer is observed in patients exposed to radiation from the Chernobyl accident under the age of 30 years (P < .01). The clinical course of disease in patients with synchronous cancer is worse and prognostically unfavorable compared with metachronous cancer (P < .01). The course of the disease in patients who underwent mastectomy is worse compared with patients who underwent breast-conserving surgery (P < .01). Plastic and reconstructive surgery in patients with synchronous cancer was proven to be reasonable in terms of increase in survival (P < .01).

Conclusions: The patients with multiple primary breast cancer should have attentive management and treatment. Multidisciplinary team should concern all the risk factors and provide the most sufficient option of management. This is crucial to continue research in this oncological area.