Men who are infertile appear to have an increased risk of developing testicular cancer, according to a report in the February 23 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

Testicular germ cell cancer, the most common cancer among young men in industrialized countries, has become even more prevalent during the last 30 to 50 years, according to background information in the article. There is evidence that semen quality and male fertility have also declined during this time in industrialized nations; however, it is unclear whether these two trends are related.

Thomas J. Walsh, M.D., M.S., then of the University of California, San Francisco, and now of the University of Washington School of Medicine, Seattle, and colleagues analyzed data from 22,562 male partners of couples seeking fertility treatment between 1967 and 1998 (4,549 of whom had male factor infertility, based on a clinical presentation with abnormal semen analysis criteria). Their records were linked to the state cancer registry, which includes information about cancer cases confirmed between 1988 and 2004.

A total of 34 of the 22,562 men were diagnosed with testicular cancer at least one year after seeking treatment for infertility. Compared with men of the same age in the general population-whose records were identified using the National Cancer Institute's Surveillance Epidemiology and End Results program-men in couples seeking treatment for infertility were 1.3 times more likely to develop testicular cancer. Men with male factor infertility were 2.8 more likely to develop testicular cancer than those without this condition.

"In interpreting these data, we considered the postulate that male factor infertility or its treatment could cause testicular cancer," the authors write. "However, this theory is highly improbable given that in many cases infertility treatment involves the use of assisted reproductive technologies rather than specific medical or surgical treatment of the male partner." It is also unlikely that the results representing a screening phenomenon, in which men who seek treatment for infertility are diagnosed with a previously unrecognized cancer because of diagnostic testing. Most cases of testicular cancer in adults are diagnosed rapidly when a physical exam reveals a nodule or swelling in the scrotum.

"A more plausible explanation is that a common exposure underlies infertility and testicular cancer," the authors conclude. Faulty DNA repair, or errors in the way the body responds to small areas of damage in its genetic material, may contribute to both conditions, as may environmental factors.

This study was funded by grants from the National Institute of Child Health and Human Development and the California Urology Foundation.