The risk of invasive breast cancer in men may be linked to infertility, a new study suggests. The study looked at 1,998 men in England and Wales diagnosed with breast cancer, of whom 112 (5.6%) were infertile and 383 (19.2%) were childless. Breast cancer in men is less common than in women, and its relationship to infertility has only been investigated in small studies so far. Authors from the Institute of Cancer Research in London have investigated the potential link between infertility and the risk of breast cancer in men. The study involved 1,998 men under the age of 80 who were diagnosed with breast cancer between 2005 and 2017. They were compared with 1,597 unrelated men as a control group. Of these participants, 80 were found to be infertile in the control group. The risk of invasive breast tumors was significantly associated with male infertility, based on a study of 47 men with breast cancer (2.6%), compared with 22 controls without cancer but diagnosed with infertility (1.4%) . In further research, the authors found a greater number of men with breast cancer (383 men) who reported not having children compared to controls (174 men). However, the authors caution that childlessness does not fully reflect male infertility, as men may choose not to have children for a number of cultural and social reasons. The risk of breast cancer associated with infertility was not significant based on studies of 160 men with in situ breast tumors – such tumors consisting of cancer cells that have not spread beyond the site where they first formed, compared with 1597 controls. Evidence suggests that there may be a link between male infertility and invasive breast cancer in men. The causes of male breast cancer are largely unknown, partly because it is less common and partly because previous studies have not been comprehensive enough. The influence of a number of concomitant factors such as smoking, alcohol consumption, obesity, testicular diseases and Klinefelter syndrome was also investigated. Infertility in a couple can be due to both male and female reproductive disorders, and both factors must always be considered. The evidence presented in the current study suggests that the association between infertility and breast cancer needs to be confirmed with additional data. Research is needed into potential factors, such as hormonal imbalances and genetic abnormalities, that could be relevant to both breast cancer and infertility. References: https://dx.doi.org/10.1186/s13058-022-01517-z https://www.biomedcentral.com/articles/10.1186/s13058-022-01517-z