Potential underlying factors
“The causes of breast cancer in men are largely unknown, partly because it is rare and partly because previous studies have been small,” Dr. Jones said. “The evidence presented in our study suggests that the association of infertility and breast cancer should be confirmed with further research, and future investigations are needed into the potential underlying factors, such as hormone imbalances.”
Commenting on the study, Fiona Osgun, senior health information manager at Cancer Research UK, told this news organization: “Overall, there isn’t strong evidence that infertility is a risk factor for male breast cancer. This study helps to shed light onto a cancer type that is sadly still not very well understood, but much more research is needed to say that infertility is a risk factor for male breast cancer.”
She added that although male breast cancer is a rare condition, it’s still important for men to be aware of what looks and feels normal for them, and to be encouraged to seek medical advice if something is not quite right.
A spokesperson for Breast Cancer UK told this news organization: “[We] believe it’s important to understand what leads to breast cancer in men as well as women and that high quality, long-term studies such as this will help with this understanding.
The findings are consistent with an earlier study that found that U.S. men who have never fathered children are at higher risk of breast cancer. This new long-term U.K. study provides strong evidence, which supports this finding.
“As the authors note, the biological reasons are unclear, but may be associated with altered hormone levels. The ratio of circulating levels of estrogen and androgens (e.g. testosterone) is crucial in healthy functioning of breast tissue. Disruption to this, for example as a result of damage to testes, may affect both fertility and breast cancer risk.
“It is also possible that external factors, such as exposure to certain endocrine (hormone) disrupting chemicals (EDCs), which affect sex hormones, may also affect both fertility and breast cancer risk.
“More studies into breast cancer in men are needed to help us understand better all the risk factors associated with this disease including both hormonal factors and chemical exposures.”
Simon Vincent, PhD, director of research, support, and influencing at Breast Cancer Now, said: “Research has discovered different treatments directed at some features of breast cancer in women; however, breast cancer is not as well understood for men. This is why Breast Cancer Now funds the Male Breast Cancer Study, which looks at what might cause the disease in men. Discovering a link between infertility and male breast cancer is a step towards us understanding male breast cancer and how we could find more ways to diagnose and treat men – and possibly women – with this devastating disease.”
A version of this article first appeared on Medscape UK.
