Study Links Severe Male Infertility to Higher Thyroid and Colorectal Cancer Risks

Research indicates a potential link between male infertility and increased cancer risks. A recent study published in the European Journal of Epidemiology found that severe male infertility may be associated with a higher risk of thyroid and colorectal cancers.

The study suggests that genetic factors could play a role in this association. Lifestyle factors such as obesity and diabetes may also contribute to the elevated cancer risk. According to the World Health Organization (WHO), approximately 1 in 6 people will experience infertility at some point in their lives.

Previous research has connected male infertility to other adverse health outcomes, including cardiovascular diseases, diabetes, testicular cancer, and prostate cancer. The new study focuses on non-reproductive cancers, specifically thyroid and colorectal cancers.

Key Findings from the Study

Researchers analyzed registry data from over 1.1 million Swedish males who fathered children between 1994 and 2014. Of these, 14,450 men became fathers through intracytoplasmic sperm injection (ICSI), a technique used for severe male infertility.

The study cross-referenced the data with the national cancer registry, revealing a significantly higher risk of thyroid and colorectal cancers among men who required ICSI to conceive.

“The study found that men with severe cases of infertility run a higher risk of developing colon cancer and thyroid cancer,” said S. Adam Ramin, MD, a board-certified urologist, urologic oncologist, and medical director of Urology Cancer Specialists in Los Angeles, CA. Ramin was not involved in the study.

“The proposed relationship may be genetic mutations that predispose to cancer but also cause infertility,” he told Healthline.

Possible Causes of the Association

The study suggests that genetic mutations could impair male reproductive function while simultaneously increasing cancer risk. Over 2,300 genes are involved in reproductive function, making it plausible that mutations in these genes contribute to both infertility and cancer.

Lifestyle factors such as smoking, excessive alcohol consumption, and obesity may also increase cancer risk and are linked to low semen quality. However, the study did not include data on lifestyle factors, though it accounted for the age at which men became fathers and their educational level.

Clarifying the Role of ICSI

The researchers emphasized that the use of ICSI itself does not cause cancer. Instead, the study indicates that men with severe infertility—those who require ICSI rather than in vitro fertilization (IVF)—are at higher risk of developing these cancers.

“This research does not show that use of ICSI causes infertility,” Ramin said. “It merely indicates that men who have very severe infertility, meaning those who need ICSI rather than in vitro fertilization (IVF), are at higher risk of these cancers.”