Inability to Produce Sperm Linked to 8-Fold Cancer Risk in Young Men
Men who can't produce sperm are significantly more likely to develop cancer, according to a new study.
Researchers at Stanford University found that men diagnosed as azoospermic, or who are infertile because of an absence of sperm in their ejaculate, before age 30 are eight times more likely to develop cancer than the general population.
"An azoospermic man's risk for developing cancer is similar to that for a typical man 10 years older," lead researcher Dr. Michael Eisenberg, assistant professor of urology at the medical school and director of male reproductive medicine and surgery at Stanford Hospital & Clinics, said in a new release.
Around 4 million American men are infertile. Researchers said 600,000 men are azoospermic, and about 1 percent of these infertile men are of reproductive age.
Researchers said that previous studies have found that infertility may be a "barometer" for men's overall health. For example, some studies have found an association of male infertility with testicular cancer.
Researchers in the current study looked at 2,238 infertile men who were seen at a Texas andrology clinic from 1989 to 2009. The median age was 35.7 when the men were first evaluated for the cause of their infertility. Of those men, 451 had azoospermia, and 1,787 did not. Researchers noted that there were no apparent initial differences between the two groups.
The men provided semen samples and were followed for an average of 6.7 years.
The study revealed that a total of 29 of the 2,238 infertile men developed cancer over a 5.8-year average period from their semen analysis to their cancer diagnosis. Researchers said this contrasted with an expected 16.7 cases, on an age-adjusted basis for the male Texas population in general, which researchers said closely reflects cancer incidence rates for the entire U.S. population.
Researchers said this meant that infertile men were 1.7 times more likely to develop cancer compared to men in the general population.
After comparing the cancer risk of azoospermic and non-azoospermic infertile men, researchers found that azoospermic men were at a substantially elevated risk. Azoospermic men were nearly three times more likely to receive a diagnosis of cancer compared to men in the overall population. However, infertile men who weren't azoospermic were only 1.4 times more likely to develop cancer compared to the general population. Researchers said that this elevated cancer risk for and non-azoospermic infertile men was not statistically significant compared to the general population.
Researchers said the most surprising finding was that the cancer risk among azoospermic men who first had their semen analyzed before age 30 was more than eight times greater than the risk of the general population of the same age. Researchers noted that there was no relationship between age of semen analysis and risk of cancer for nonazoospermic men.
In light of the recent findings, researchers recommend that young men diagnosed as azoospermic be aware of their heightened cancer risk and go for regular check-ups.
The findings were published June 20 in the journal Fertility and Sterility.