Men with infertility could have double the risk of breast cancer

Male breast cancer accounts for around one percent of breast cancer cases in the UK and a new study suggests that men with infertility are twice as likely to develop it.

There is little awareness of the condition due to its rarity. Men who have it are often older at first presentation than women with breast cancer, and they have less favourable outcomes than women. Researchers from the Institute of Cancer Research, London have recently published the results of their breast cancer in men case–control study.

'Our study suggests that infertile men may be twice as likely as those without fertility issues to develop breast cancer. The reasons behind this association are unclear, and there is a need to investigate the fundamental role of male fertility hormones on the risk of breast cancer in men. We hope this could lead to insights into the underlying causes of male, and possibly even female, breast cancer', said Dr Michael Jones, study senior author and staff scientist in genetics and epidemiology at the Institute of Cancer Research.

Nearly two thousand men from England and Wales who had been diagnosed with breast cancer between 2005-2017, and 1597 controls, were included in the study recently published in the journal Breast Cancer Research. They took part in interviews with a nurse where they provided information on whether or not they had children or had ever sought fertility treatment. They also provided a blood or saliva sample.

Analysis showed men who reported they had been diagnosed as having infertility had double the odds of developing breast cancer when compared with those without fertility issues. Furthermore, men without offspring had 50 percent increased odds of developing breast cancer, and this difference remained significant even if restricting the analysis to married men alone.

Researchers did not look at reasons for the link but suggested that hormones could play a role, and there is already some understanding that testicular problems that could lead to infertility could also affect hormonal production.

Dave, a former police officer from Bristol, was diagnosed with breast cancer in 2015 and said: 'My mother died from ovarian cancer when she was 68-years-old, and I knew there was a link between ovarian and breast cancer, but generally little is known about male breast cancer. People will say 'I didn't realise men could get that' and to be honest, I didn't think I would ever get it!'

'It's really interesting that if you're affected by fertility issues, you could be more likely to be affected by breast cancer. I'm lucky that I haven't been impacted by fertility problems, but it's important scientists build on Breast Cancer Now's research as it could help to find out what causes some male breast cancers and one day even lead to developing new treatments.'