Further sensitivity analyses to control for family alcohol consumption, family history, liver disease, and smoking, finds no convincing evidence that these factors affected the results.
The risk of invasive breast cancer in men may be associated with infertility, according to the results of a study published in Breast Cancer Research.
The investigators, from the Institute of Cancer Research in London, United Kingdom, interviewed 1998 males in England and Wales who were diagnosed with breast cancer, with 383, or approximately 19.2%, saying that they did not have children, 112, or approximately 5.6%, self-reporting infertility. All men who were included were under the aged 80 years old and were diagnosed with breast cancer between 2005 and 2017.
Additionally, the individuals were compared with 1597 males in a control group who were not blood relatives. Approximately 5% of men in the control group reported infertility.
Investigators aimed to investigate the potential relationship between not having children or self-reported infertility and the risk of breast cancer in men.
The risk of invasive breast cancer tumors was significantly associated with male infertility, investigators concluded.
This was based on 47 individuals with breast cancer compared with 22 males in the control group without cancer but with self-reported infertility.
Furthermore, investigators did not find any associations between the risk of breast cancer and a partner’s infertility or when the source of infertility was unknown.
After further investigation, the investigators observed a greater number of males with breast cancer reported not having any children compared with those in the control group at 383 to 174, respectively.
However, not having children does not fully reflect male infertility because of a range of cultural and social reasons for choosing to not have children, investigators said.
The associated risk of breast cancer and no children or infertility was not significant based on 160 individuals with in situ breast cancer tumors, which are cancerous cells that do not spread beyond where they are first formed compared with 1597 controls.
Investigators conducted further sensitivity analyses to control for alcohol consumption, a family history of breast cancer, liver disease, and smoking, but found no strong evidence that these factors affected results. However, investigators did not control for obesity, but did exclude data in some of the analyses from 11 males with Klinefelter syndrome, 9 with prior cancer, 29 males who were severely obese, and 169 who had testicular disease.
Additionally, 3 individuals who were born female were not included in any analyses.
Self-reported fertility has the potential for misclassification, investigators said, adding that validating infertility with medical records could reduce bias in further investigations.
“The causes of breast cancer in men are largely unknown, partly because it is rare and partly because previous studies have been small. 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,” Michael Jones, PhD, senior staff scientist in the Division of Genetics and Epidemiology at the Institute of Cancer Research, said in a statement.
Risk of breast cancer in males may be associated with male infertility. EurekAlert. News release. May 16, 2022. Accessed May 18, 2022. https://www.eurekalert.org/news-releases/952532