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Whether routine human papillomavirus (HPV) testing should be integrated into screening for cervical neoplasia remains uncertain. In a partially industry-funded Canadian trial, investigators enrolled more than 10,000 nonpregnant women (age range, 30–69) from 2002 to 2005. Participants underwent sequential screening with both conventional cytology (Pap) and HPV DNA testing. Women with atypical squamous cells of undetermined significance (ASCUS) or higher-grade cytologic results and those with positive HPV tests were referred for colposcopy, which also was performed in a random sample of participants with negative screening tests. Most grade ≥2 lesions found on colposcopic biopsy were treated with excisional procedures (loop electrosurgical excision procedure or conization).
The sensitivity of HPV testing in detecting high-grade neoplasia cases was significantly higher than that of Pap testing (94.6% vs. 55.4%). The Pap test had a slightly but significantly higher specificity than HPV testing (96.8% vs. 94.1%). Negative predictive values for both tests were higher than 99%. Combining the results of Pap and HPV testing increased sensitivity to 100% and resulted in more referrals for colposcopy (7.9%) than did Pap (2.9%) or HPV testing (6.1%) alone.
Mayrand M-H et al. Human papillomavirus DNA versus Papanicolaou screening tests for cervical cancer. N Engl J Med 2007 Oct 18; 357:1579.
Comment
Many U.S. clinicians have integrated HPV testing into the screening of women with ASCUS Pap results. Under this “reflex testing” scheme, women with ASCUS cytology who are also positive for oncogenic HPV are triaged to colposcopy. Although routine cotesting increases sensitivity, this approach substantially increases screening costs, complicates triage decisions, and incrementally increases referrals for colposcopy.
Consistent with other reports, this study showed that HPV testing alone is substantially more sensitive than Pap testing in screening for high-grade cervical lesions, with only a minimal decrease in specificity. The high sensitivity of HPV testing makes this approach particularly appealing for infrequently screened populations. Overall, these important results seem likely to push cervical cancer screening programs away from reliance on cytology-based evaluation and toward routine HPV testing. Recent guidelines (to be covered in detail in an upcoming feature) encourage HPV testing in many clinical case scenarios, although not as the sole test for routine screening.