Rest assured: a Pap smear continues to be the most effective way to screen for cervical cancer.
Use of both a Pap smear and an HPV test did not identify more cervical cancers than HPV testing alone, according to results from a study of more than 1.2 million women screened since 2003.
The Pap test detected only a small percentage of precancers (3.5%) and cancers (5.9%) missed on the HPV test. Investigators observed that these cancers were more likely to be regional or distant stage.
Given the relative rarity of cervical cancer—the CDC says roughly 12,000 women are diagnosed annually—investigators concluded that adding the Pap test to HPV screening translated to earlier detection of at most 5 cases per million women per year. Cotesting is “unlikely to detect cancer cases that wouldn’t be found using HPV testing alone.”
“The choice between the two strategies and the screening interval chosen, whether three years or five years or more, depends on societal judgments (eg, cancer prevention benefits vs resource allocation) and not scientific facts,” first author Mark Schiffman, MD, division of cancer epidemiology and genetics, National Cancer Institute, et al wrote. “Nevertheless, even using cotesting at three-year intervals (the most aggressive strategy in common use), cervical cancer continues to occur rarely (albeit typically at a curable stage). Excessive screening in an attempt to prevent every case could have minimal cancer prevention benefits while increasing the harms of screening.”
HPV testing is more sensitive than the Pap test for detecting precancer. The HPV test captures the known cancer-causing viruses, but some gynecologists conduct cotesting due to reports of rare HPV-negative, Pap-test–positive cancers, even though using both tests is more expensive.
Investigators quantified the detection of cervical precancer and cancer by cotesting compared with HPV testing alone at Kaiser Permanente, where 1,208,710 women have undergone cervical cotesting every 3 years since 2003. Investigators reviewed screening histories preceding cervical cancers in 623 women and precancers in 5369 women to assess the relative contributions of the Pap test and HPV test components in identifying patients.
Read full article: Cotesting Unlikely to Detect More Cervical Cancers Than HPV Testing Alone
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