Synchronous malignancies in patients with breast cancer

Introduction. The continuously improving cancer detection at an early stage and improving survival rates have been observed and, therefore, patients are predisposed to detection of multiple primaries. It has been reported that the incidence of multiple primaries in breast cancer patients ranges from of 4% to 17%. Materials and methods. A group of 112 breast cancer patients with synchronous malignancies was presented. They constituted 0.09% of patients (118,952 cases) who were treated for breast cancer at the same time period, and made up 3.5% of all patients (3,176 cases) with multiple primary cancers, and 21.7% of all patients (517 cases) with breast cancer who developed multiple primaries. Results. The most frequent type of synchronous primary malignancy was breast cancer (63.4%) and 90.1% of them were diagnosed at the same time or within one month following the first breast cancer diagnosis. Among cases of non-breast synchronous primaries, female genital organ malignancies were predominant (36.6%). Synchronous breast cancer was diagnosed significantly earlier than non-breast cancers (mean time was 0.4 and 1 month, respectively, p = 0.0123). Better results in the group with synchronous contralateral breast cancer in comparison to synchronous breast and non-breast cancer were observed (5-year overall survival rates were 90.9% and 66.3%, respectively, and 5-year disease-free survival rate — 62.5% and 51.3%, respectively).