A new study published in Breast Cancer Research suggests a potential link between self-reported infertility in men and an increased risk of developing invasive breast cancer. The study, which involved 1,998 men diagnosed with breast cancer in England and Wales, found that 5.6% of these men reported infertility, while 19.2% had no children.
Male breast cancer is much rarer than female breast cancer, and its connection to infertility has not been extensively studied. Previous research has only hinted at a possible relationship between having children and breast cancer risk in men. This study, led by researchers at The Institute of Cancer Research (London), aimed to explore the connection between infertility or childlessness and male breast cancer.
Between 2005 and 2017, the researchers interviewed 1,998 men diagnosed with breast cancer and compared them to a control group of 1,597 men who did not have breast cancer and were not blood relatives of the patients. The control group had 80 men (5.0%) who reported infertility.
The results showed that men with self-reported infertility were more likely to develop invasive breast cancer. Among those with breast cancer, 2.6% reported infertility, while only 1.4% of the control group did. However, no significant association was found between breast cancer risk and a partner’s infertility or unexplained infertility.
Additionally, the researchers found that more men with breast cancer (383) reported not having children compared to those in the control group (174). However, the researchers emphasized that choosing not to have children may not necessarily be due to infertility, as some men may decide to remain childless for personal, cultural, or social reasons.
The study also showed no significant link between infertility or childlessness and the risk of developing in situ breast cancer, where cancer cells remain localized.
The researchers took steps to control for factors like alcohol use, smoking, family history of breast cancer, and liver disease. They found no strong evidence that these factors influenced the results. While they did not account for obesity, they excluded data from men with certain conditions, such as Klinefelter syndrome, prior cancer, and severe obesity, to reduce potential biases.
However, the authors noted that self-reported infertility could lead to misclassification, as men might not report children from previous relationships or could remain childless by choice. They suggest that validating infertility with medical records in future studies could help minimize errors in reporting.
Michael Jones, one of the study’s authors, stressed the need for further research into the causes of male breast cancer, which remain largely unknown due to its rarity and the small scale of previous studies. “Our findings suggest a possible link between infertility and male breast cancer, but more research is needed to understand the underlying factors, such as hormone imbalances,” he said.
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