HPV screening more protective against cervical cancer than cytology

Issue: December 25, 2013

Screening for HPV is 60% to 70% more protective against invasive cervical cancer than cytology-based cervical screening, researchers from the International HPV working group reported in The Lancet.

“Until now, there have been no direct estimates of the relative efficacy of HPV-based vs. cytology-based screening for prevention of invasive cancer in women who undergo screening, of how variables like age affect this efficacy and the duration of protection,” Guglielmo Ronco, MD, of the Center for Cancer Epidemiology and Prevention in Turin, Italy, said in a press release. “Our analysis shows that HPV-based screening appears to prevent more invasive cervical cancers than does cytology, and on this basis, we recommend implementation of HPV-based cervical screening with triage from age 30 years, at intervals of at least 5 years.”

Ronco and colleagues conducted a follow-up study of four randomized trials that included 176,464 women aged 20 to 64 years. They were randomly assigned to HPV-based screening or cytology-based screening. The women were followed for a median of 6.5 years.

There were 107 invasive cervical carcinomas, with a rate ratio of 0.6 (95% CI, 0.4-0.89). During the first 2.5 years of follow-up, detection was similar between the two methods, but after, detection was lower in the HPV-based screening arm, with a rate ratio of 0.45 (95% CI, 0.25-0.81). Among women with a negative test at study entry, the rate ratio was 0.3 (0.15-0.6).

Among women with a negative test at study entry, the incidence of invasive cervical carcinoma was 4.6 per 100,000 (95% CI, 1.1-12.1) at 3.5 years and 8.7 per 100,000 (95% CI, 3.3-18.6) at 5.5 years in the HPV-based screening arm. In the cytology-based screening arm, the rates were 15.4 per 100,000 (95% CI, 7.9-27) at 3.5 years and 36 per 100,000 (95% CI, 23.2-53.5) at 5.5 years.

The increased protection was especially prevalent for women aged 30 to 35 years. The researchers also found that HPV screening every 5 years, compared with cytology every 3 years, was most protective against cervical cancer.

In an accompanying comment, Sandra Isidean and Eduardo Franco, DrPH, of McGill University in Montreal, wrote that HPV testing will probably be incorporated into cervical cancer screening in high-resource settings, a “strategy that particularly befits the post-HPV vaccination era.”

Broad implementation of primary HPV testing, as well as lengthening the testing intervals, may cost less money and provide greater safety than cervical cytology, they wrote.

“To reap the benefits of this implementation, however, nations will need to consider important logistical challenges, including: setting on the type of HPV screening test to be used; ascertaining appropriate screening ages and intervals; defining triage and management policies for HPV-positive women; and ensuring quality of and adherence to revised policies,” Isidean and Franco wrote.

For more information:

Isidean S. Lancet. 2013;doi:10.1016/S0140-6736(13)62028-0.

Ronco G. Lancet. 2013;doi:10.1016/S0140-6736(13)62218-7.

Disclosure: Ronco and Isidean report no relevant disclosures. Franco has served as a consultant or advisory board member for Cytyc, Gen-Probe, GlaxoSmithKline, Ikonisys, Merck, Qiagen and Roche.