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.