Although previous research has established that infertile men have an increased risk of developing prostate cancer and testicular cancer, the risk of infertile men developing a nonreproductive cancer is unknown. A new study from Lund University in Sweden found an increased risk for colorectal and thyroid cancer in infertile men.

 

“[Infertile men] were found to have almost twice the risk of developing colorectal cancer and three times the risk of thyroid cancer compared with men who become fathers naturally,” said Michael Kitlinski, a medical student and one of the study’s authors.

 

Approximately 10% to 15% of men in the United States who are trying to conceive are infertile, according to the Cleveland Clinic. Worldwide, 186 million people face infertility issues, and the male partner is the cause in about half the cases.

 

Researchers used national registry data from over 1.1 million Swedish men who had their first child between 1994 and 2014. In the sample, 14,540 men had used intracytoplasmic sperm injection, a form of in vitro fertilization used to treat male infertility, to conceive.

 

When the researchers compared the men’s data against the national cancer registry, they found a significant increased risk for colorectal and thyroid cancer among men who had become fathers using intracytoplasmic sperm injection.

 

“Most men who undergo fertility testing are between 30 and 35 years old. The aim is to help them become fathers, and there is no subsequent follow-up on their health. These findings are important from a public health perspective given that cancers of the colon and rectum, as well as thyroid cancer, are on the rise among younger people. These cancers could be prevented through early screening,” said study author Angel Elenkov, a scientist and physician at Lund University.

 

Clinics in Scandinavia aim to partner with the Lund University researchers to identify biomarkers, genetic mutations, epigenetic and environmental factors that may help explain the observed increased cancer risk among infertile men.