Better HPV test preventing cervical cancer than Pap smear

Better HPV test preventing cervical cancer than Pap smear

As NPR reports, it's been hard to justify replacing the Pap smear with the HPV test because, until now, there hasn't been a head-to-head comparison.

Tests that look for the human papillomavirus, or HPV, are more accurate than traditional Pap tests at detecting the precancerous lesions that lead to cervical cancer, according to a Canadian study of more than 19,000 women. Women who originally had the Pap smear were more than twice as likely to have abnormal cells. Of the women who tested negative on the HPV test only 22 women showed abnormal cells (grade 3 or worse), while from the Pap smear group, 52 women ended up with abnormal cells. Cervical cells for both the Pap and HPV tests can be collected at the same time, during a pelvic exam.

"Most cases of cervical cancer happen in women who have not been regularly screened, or who have been screened, but don't have access to appropriate treatment", she says.

Pap smears rely on the human eye to get results, says Dr. Diane Harper, a professor of medicine who researches HPV at the University of MI, "and it's far preferable to detect problems on a molecular level". A study published in JAMA Tuesday suggests that method might be preferable for women aged 30 and over.

Pap smears involve scraping cells from the cervix and examining them for cancerous changes, also known as "cytology" testing. The researchers also noted concerns over lower CIN2+ specificity with HPV testing, leading to higher screen positive rates and therefore more colonoscopies and biopsies, which could cause unintended harms for women and increased costs if the tests prove unnecessary.

"But we will gradually move to more HPV testing for primary screening", he said.

Schmeler often works in Latin America where, in countries like El Salvador, cervical cancer is one of the most common cancers in women primarily due to poor screening programs. Previous research has indicated that HPV testing alone or combined with a Pap smear is linked to increased detection of precancerous lesions in the first screening round, followed by a subsequent reduction in precancerous lesions.

The Pap test, used for over 50 years to spot the early signs of cervical cancer, may soon become a thing of the past, new research suggests. "This has been building for decades", he said, adding that the Pap smear is "crude and inaccurate" while the HPV test is much more precise, operates on the molecular level and can provide information on the specific type of HPV causing the problem.


The study documented the results of a randomized clinical trial comparing Pap smears with the use of HPV tests.

Dr. Carol Mangione, a USPSTF task force member and UCLA professor of medicine says the method of testing comes second to being sure that all women, especially high-prevalence groups like black and Hispanic women, are able to get the testing they need.

"This is one study", he said.

However, 48 months after the start of the study, there were fewer cases of CIN3+ among women who had HPV tests than among smear tests, presumably because they had been found and treated in the first round of screening.

After checking on nearly 19,000 women, they realized that detecting HPV was a more accurate way to detect early-stage cervical cancer compared to the routine Pap tests. They focused mainly on moderate or severe changes to cervical cells (pre-cancerous changes) that could lead to cervical cancer.

The new study will probably "help push that along", said Wright of NewYork-Presbyterian/Columbia University Medical Center.

Moving away from co-testing may not be a good idea, according to Mark Spitzer, an OB-GYN and past president of American Society for Colposcopy and Cervical Pathology.

Human papillomavirus (HPV) is a DNA virus from the papillomavirus family. Because the HPV test was more likely to pick up on pre-cancerous cervical lesions earlier in the study, these women were less likely to develop cervical cancer.

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