By PAUL RECER, AP Science Writer
WASHINGTON (AP) Husbands who have many sex partners outside their marriage may bring cancer home to their wives, according to a study published today.
The study in the journal of the National Cancer Institute found that women are five to 11 times more likely to develop cervical cancer if their men frequent prostitutes or many other sex partners during a marriage.
Human papillomavirus, or HPV, which is commonly spread by sexual intercourse, is what causes the cervical cancer, said Dr. Keerti V. Shah, a professor at the Johns Hopkins University School of Medicine and a co-author of the study.
``Male behavior is the important thing in this cancer,'' said Shah. ``In effect, the husband takes cancer home to his wife.''
He said men who have many extramarital sex partners are very likely to spread the HPV virus to their wives and that up to 97 percent of cervical cancers are infected with that virus.
Although the study showed that men gave the virus to their wives, a woman can put herself at increased risk by having many different sexual partners as well, Shah said. The cancer risk for women, he said, increases with the number of either direct or indirect sexual exposures. The virus presents almost no cancer risk for men, he said.
The study was conducted in Spain because earlier studies had shown a high degree of monogamy there among married women and a low rate of cervical cancer, Shah said. This allowed the researchers to isolate behavioral patterns that differed between women who had the cancer and those who did not.
The study compared the sexual patterns of husbands whose wives have cervical cancer with a control group of husbands whose wives were healthy. It took into account other factors, such as smoking.
In the study group were 183 women with cervical cancer and their husbands. The control group had 171 couples.
Risk of cervical cancer was increased 11 times for wives of men who had 21 or more other sex partners during the marriage. The cervical cancer risk was eight times greater among wives of men who employed 10 or more prostitutes during the marriage, the study found.
Dr. Willard Barnes of Georgetown University School of Medicine said the study reinforces evidence that ``cervical cancer in many ways is similar to classic venereal disease.''
``HPV is a very common type of virus,'' he said. ``It has been known for some time that it places women at a higher risk of cervical cancer. The message from studies like this is that men should stay home.''
There are more than 75 different strains of HPV virus. Shah said the researchers found all different types of HPV strains in genital specimens taken from the husbands.
There is no treatment for HPV infections, but the body's own immune system usually eradicates the virus in six months to 18 months. The infection, however, can be restarted, over and over, if there is new exposure. And the more exposures, Shah said, the greater the chances that an infection will lead to cancer.
Correct use of condoms can lower the risk of spreading HPV, Shah noted. And women can protect themselves from cancer through regular gynecological examinations and Pap smears.
Pap smears can detect abnormal, precancerous cells which then can be removed by freezing, burning or surgery. This generally prevents the cancer, Shah said.
Routine medical screening is credited with reducing the U.S. cervical cancer rates since the 1970s. According to National Cancer Institute statistics, the cervical cancer rate in 1973 was 14.2 per 100,000 American women. In 1991, the last year for which figures are available, the rate had dropped to 8.6 per 100,000.
Detected early, cervical cancer has a five-year survival rate of about 90 percent.
At a later stage, when the cancer has spread to distant sites, the five-year
survival rate is 11.6 percent.