Women are often told they don't have to get a Pap test for cervical cancer if they're over 65, but the data behind that recommendation might underestimate their cancer risk, researchers say.
That's because many studies don't take into account that many women have had hysterectomies. The surgery removes a woman's risk of cervical cancer; no cervix, no cancer. And 20 percent of the women over age 20 in this study said they had had that surgery.
When they looked at cancer rates only in women who hadn't had a hysterectomy, the researchers found that the odds of having cervical cancer were higher; 18.6 per 100,000 women, compared to 11.7 cases without that adjustment.
And while earlier studies had found that women's risk of cervical cancer peaks in their early 40s, this analysis found that the risk was highest for women in their late 60s. They had a cervical cancer rate of 27.4 cases per 100,000. The rate was higher for African-American women, at 53 per 100,000, compared to 24.7 for white women.
"We started to come to notice that maybe hysterectomy wasn't being taken into account in all studies," says Anne Rositch, an assistant professor in the department of epidemiology and public health at the University of Maryland Medical School and first author of the study. It was published online Monday in the journal Cancer.
The U.S. Preventive Services Task Force, an independent body that sets practice guidelines, says that women over 65 who aren't at high risk don't need to be screened for cervical cancer. "There is moderate or high certainty that the service has no net benefit or that the harms outweigh the benefits," the task force guidelines say.
That might be because it can be harder to screen older women for cervical cancer, Rositch told Shots, because of changes in the cervix after menopause. Or it could be because the USPSTF reviewers saw those studies saying that older women have a lower risk. But a study on screening in older women published last year found that women who had ages 55 to 79 who did have a Pap test lowered their cancer risk over the next 5 to 7 years.
This current study doesn't delve into the question if, when and how women are getting screened for cervical cancer.
"We don't know the role that screening had for these women," Rositch told Shots. "That's the next key piece of research that we need, to figure out how best to move forward."
Because of that, it's too early to say how women and their doctors should respond to this information, Rositch says.