Women only need to get a Pap test once every three years to check for cervical cancer, and don't need to be screened until age 21 - even if they're sexually active earlier, according to new guidelines from a government-backed panel.
The statement from the United States Preventive Services Task Force, released on Wednesday, aligns closely with guidelines from three U.S. cancer groups that were also announced on Wednesday.
Once they hit 30, women also have the option of getting screened once every five years if they choose to do Pap tests together with human papillomavirus (HPV) testing every time, the committees agreed.
"The bottom line is, we strongly recommend screening," said Dr. Virginia Moyer, chair of the USPSTF and a pediatrician at Baylor College of Medicine and Texas Children's Hospital in Dallas.
The recommendation to test every three or five years is based on evidence that cervical cancer is relatively slow-growing, she said, so it's very unlikely a woman would develop advanced cancer in the few years after a negative screening.
"The women who get and die of cervical cancer are the women who aren't getting screened," Moyer told Reuters Health. "It's not the woman who hasn't had a screen in a couple years that's the problem."
Moyer's group attracted controversy late last year when it recommended against annual prostate cancer screening in men, after concluding that the possibility the tests could invite unnecessary and potentially harmful follow-up procedures outweighed their benefits.
The USPSTF's latest recommendations are based on a review of evidence on screening's success at detecting pre-cancerous lesions, as well as both physical and psychological side effects of Pap and HPV tests. Its guidelines were published in the Annals of Internal Medicine.
The task force found a benefit for Pap tests every three years in women age 21 to 65, or every five years when Pap tests and HPV tests are done together, starting at 30.
Screen more frequently, and the possibility of women getting complications from any related procedures - such as an exam and biopsy, called a colposcopy, following an abnormal Pap - outweighs any benefit to the extra tests.
Women under 30 shouldn't be tested for HPV because the sexually transmitted infection is common in young people and often goes away on its own, without increasing the cancer risk.
Women who are older than 65 and were screened regularly in the past are also probably in the clear, unless they're at particularly high risk due to a history of precancerous lesions.
Until there's more long-term data on women who've been vaccinated against HPV, they should continue getting normal screening, according to the report.
CANCER GROUPS AGREE
The guidelines broadly agree with others released by the American Cancer Society, the American Society for Colposcopy and Cervical Pathology and the American Society for Clinical Pathology. Those groups favor screening with both Pap and HPV tests every five years once women hit 30, but say every three years with Pap tests alone is also acceptable. Again, they recommend screening from age 21 to 65 in most cases.
In their report, released in CA: A Cancer Journal for Clinicians and other partner journals, the group's report estimates that without screening, 31 to 33 out of every 1,000 U.S. women would be expected to get cervical cancer in their lives. With Pap tests done every three years, that falls to five to eight per 1,000.
The relative benefit is slimmer when the tests are done more frequently, but the chance of having side effects from testing is just as high each time.
"Screening too much and too sensitively finds primarily benign infections that really would be better left unfound," said Philip Castle, head of the American Society for Clinical Pathology Institute, who worked on those guidelines.
"Doing more than what's evidence-based actually has potential harms for patients, and that shouldn't be minimized."
That includes the psychological harms of being told you have an abnormal test, he said. After that, some cervical procedures done as follow-up have been shown to increase women's chances of having a premature baby later in life.
According to the Centers for Disease Control and Prevention, about 12,000 U.S. women get cervical cancer every year - most caused by cancerous strains of HPV.
Castle said the focus needs to be on making sure that everyone gets the basic level of screening, especially poor women who live in isolated areas.
Moyer agreed that targeting those groups is going to make the biggest difference in cutting rates of new cervical cancer cases and deaths.
"We need to get the women who have not had a Pap smear in the past five years in," she said. "The women who aren't getting screened at all, that's the tragedy."