FRIDAY, June 21 (HealthDay News) -- Men who are infertile
because they produce no sperm may have a higher-than-average risk
of developing cancer, a new study finds.
Researchers found that of more than 2,000 men with fertility
problems, those with no sperm production had an increased risk of
developing cancer over the next six years.
The men were young going into the study (about age 36, on
average), so few did develop cancer. Among men with no sperm --
what doctors call azoospermia -- just over 2 percent were diagnosed
Still, their risk was three times higher than that of the
average man their age.
"They have the cancer risk of a man about 10 years older," said lead researcher Dr. Michael Eisenberg, an assistant professor of urology at Stanford University School of Medicine.
About 15 percent of infertile men are azoospermic, according to
the study, which was published June 20 in the journal
Fertility and Sterility.
This isn't the first work to connect male infertility to cancer
risk, but it suggests the link may be concentrated among men with
the most severe type of infertility.
"This suggests that it's not male infertility in general, but azoospermia in particular," Eisenberg said.
That's an important piece of information, said a
male-infertility expert not involved in the study. If the link
between male infertility and cancer is real, you would expect that
more severe infertility would be tied to a greater cancer risk,
said Dr. Thomas Walsh, of the University of Washington in
"This reinforces the idea that this is a real relationship," Walsh said.
He said he doubts anyone would say that infertility is causing
cancer. But he and Eisenberg said it's possible that some common
genetic factors contribute to both azoospermia and a greater
vulnerability to cancer.
"When we see a man with azoospermia, we usually assume there's a genetic cause," Eisenberg said. There are certain gene mutations already tied to the condition, but a minority of azoospermic men turn out to have one of them when they are tested. That means there are likely other, as yet unknown, gene defects involved in azoospermia, Eisenberg said.
And some of those genetic flaws might be involved in cancer
susceptibility, he said.
Another infertility expert was cautious about interpreting the
findings because of the small numbers: only 10 cases of cancer
among the 451 men with azoospermia, and 19 cases among nearly 1,800
men with other types of infertility.
The idea that genetic abnormalities might underlie both
azoospermia and cancer risk has merit, said Dr. Frederick Licciardi
of NYU Langone Medical Center in New York City. But, he said,
"while this is important reasoning and is based in basic science
studies, I do not feel they have enough evidence in this paper to
bolster this theory."
Another question is whether azoospermia is linked only to
certain cancers. Past studies, including one Walsh worked on, have
found that infertile men show a higher than average risk of
testicular cancer -- a highly curable disease usually diagnosed in
Of the 10 cancers in azoospermic men in this study, two were
testicular tumors. The others included brain cancer, prostate
cancer, lymphoma and melanoma.
Eisenberg said there were too few cases of each cancer to see
whether men with azoospermia were at particular risk for any one
For now, he recommended that men with the condition "be aware of
the possible risk, and pay attention to your health." That includes
not only maintaining a healthy lifestyle, he said, but also doing
what most younger men do not -- seeing your doctor for a regular
"It's too early to make any recommendations about cancer screening," he said. But a routine visit to your doctor for a physical exam -- which can detect testicular cancer, for example -- is wise, Eisenberg said.
Licciardi agreed. "Any man -- very low sperm count or not --
should have regular physical examinations."
Walsh said much more research is needed to dig into the
connection between male infertility and cancer, including studies
that follow men over a long period since cancer rates climb with
age, as well as basic lab research to try to uncover the reasons
for the link.
Learn more about
infertilityfrom the American Society for Reproductive
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