LONDON — Infertility could lead to breast cancer — for men, according to new research. Researchers in London say male infertility doubles the risk of the disease compared to men with higher sperm counts.
The findings come from a review of around 2,000 newly diagnosed British men over a 12-year period. Study authors believe underlying factors like hormone imbalances could be fueling the tumors.
Breast cancer is the most common cancer in women. Around one in eight U.S. women will develop breast cancer during their life. For men, however, breast cancer only affects about one in 100.
“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.”
“Breast cancer is often thought of as something that only affects women, but men can also be diagnosed with the disease. Compared with previous studies our study of male breast cancer is large. It was carried out nationwide across England and Wales and was set in motion more than 15 years ago. Because of how rare male breast cancer is, it took us over 12 years to identify and interview the nearly 2,000 men with breast cancer who were part of this study,” Dr. Jones continues.
Male breast cancer cases are very rare
The researchers interviewed 1,998 men living in England and Wales who were diagnosed with breast cancer between 2005 and 2017. They compared their results with 1,597 men who were not blood relatives. Men who reported infertility faced a significantly higher chance of having invasive breast cancer, where cancerous cells have already spread.
Whether a partner suffered from infertility, on the other hand, did not have any influence on whether they developed cancer. A greater number of males with breast cancer also reported not having any children, 383 compared to 174, the researchers found.
However, this could be because some men choose not to have children for a range of cultural or social reasons, the team cautions. Also, not having children or being infertile was not found to increase the chances of breast cancer which had not yet spread to the surrounding tissue.
“Many people don’t realize that men can get breast cancer, because incidence is much lower in men than women,” says Dr. Simon Vincent, Director of Research, Support and Influencing at Breast Cancer Now. “However, every year in the UK around 370 men are diagnosed with breast cancer, and around 80 men die from it and it’s vital that we support anyone affected by breast cancer.”
“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,” Dr. Vincent continues.
“Importantly, we hope the knowledge we have gained from this study reaches more men who might benefit from being aware of male breast cancer.”
Do pre-existing conditions play a role?
The researchers also examined other factors including people’s alcohol consumption, smoking, and family history of cancer breast and liver disease. None of these were found to have influenced their findings, although they did not account for obesity. The team did however exclude men who were severely obese from the study, as well as some who had been previously diagnosed with cancer or had testicular diseases like Klinefelter syndrome.
Relying on people to report on fertility can also prove challenging, as it is a complex process which can involve men and women. Men may prefer not to report children outside of a marriage or might not be aware that they have them. Validating infertility with medical records could help overcome some of these challenges in future research.
“I was on holiday in Florida, celebrating my birthday, when I found a lump on my chest in the shower. It wasn’t painful and I didn’t tell anyone about it because life just seemed normal,” notes study participant and former police officer “Dave,” who received a breast cancer diagnosis in 2015.
“I wasn’t aware that men should check for breast cancer, but I know that if your body changes, you shouldn’t leave it so I went to see my GP as soon as I got home and they referred me to see a specialist consultant. Despite being told it was probably just a fatty deposit, I had an ultrasound and biopsy. One week later I was diagnosed with breast cancer. The tumor was the size of a golf ball,” Dave continues.
“Of course, when I was first diagnosed I was scared and it was tough to tell my children. I had a mastectomy, treatment and almost seven years later I am in good health and still receiving a course of drugs that can reduce the rate of cancer returning.”
“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 realize 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.”
The findings, published in Breast Cancer Research, are part of the wider Male Breast Cancer Study.
“The causes of breast cancer in men are largely unknown, partly because it is rare and partly because previous studies have been small,” says Dr. Jones, according to a statement from SWNS.
“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.”
South West News Service writers Mark Waghorn and Tom Campbell contributed to this report.