Second Primary Cancers in Spanish Male Breast Cancer Patients

Introduction: Male breast cancer (BC) comprises less than 1% of all BCs. The development of second primary cancers in men with BC is an under-studied topic, with inconsistent data in the literature. The objective of this study is to analyze the cases of male BC in our series and to investigate its relationship with other primary cancers.

Material and Methods: Case series of male BC patients from our health area of Vigo diagnosed between October 1997 and March 2019.

Results: 71 men with primary BC were included, three of them presented bilateral BC. The mean age was 69.0 years (SD 9.6), with ages between 41 and 90 years. One third (33.8%) of men (24 of 71) had two or more primary cancers. Likewise, 14% of men (10 of 71) had at least three primary cancers. Of the 24 men with multiple primary cancers, we knew the familial cancer aggregation in 15 of them. More than 90% of them (14 of 15) had at least one first-degree relative with cancer and 20% (3 of 15) had a mutation in the BRCA2 gene.

Conclusion: Men with BC have a higher risk of developing a second primary cancer. This may be partly explained by the advanced age of men at the time of BC diagnosis and by the genetic predisposition associated with hereditary syndromes. These results encourage intensive and long-term follow-up and also the possibility of offering preventive measures, both for patients and their families.

Keywords: Male breast cancer; Second primary cancer; Multiple primary cancers.