Infertility and risk of breast cancer in men: a national case-control study in England and Wales.

PURPOSE: Breast cancer is uncommon in men and its aetiology is largely unknown, reflecting the limited size of studies thus far conducted. In general, number of children fathered has been found a risk factor inconsistently, and infertility not. We therefore investigated in a case-control study, the relation of risk of breast cancer in men to infertility and number of children.

PATIENTS AND

METHODS

We conducted a national case-control study in England and Wales, interviewing 1998 cases incident 2005-17 and 1597 male controls, which included questions on infertility and offspring.

RESULTS

Risk of breast cancer was statistically significantly associated with male-origin infertility (OR = 2.03 (95% confidence interval (CI) 1.18-3.49)) but not if a couple's infertility had been diagnosed as of origin from the female partner (OR = 0.86 (0.51-1.45)). Risk was statistically significantly raised for men who had not fathered any children (OR = 1.50 (95% CI 1.21-1.86)) compared with men who were fathers. These associations were statistically significantly present for invasive tumours but not statistically significant for in situ tumours.

CONCLUSION

Our data give strong evidence that risk of breast cancer is increased for men who are infertile. The reason is not clear and needs investigation.