Testing for high-risk types of HPV DNA can be effective in preventing invasive cervical cancer

Jan 19 2010

Results from a study of more than 90,000 Italian women published by the Lancet Oncology found that testing for high-risk types of the human papillomavirus (HPV) DNA is significantly more effective in preventing invasive cervical cancer than cytology (Pap testing) alone. The trial used QIAGEN's digene® HPV Test (also known as the digene® HC2 HPV DNA Test), which detects the high-risk types of HPV that can cause cervical cancer.

The New Technologies for Cervical Cancer (NTCC) study assessed the benefits and risks of shifting to HPV testing from standard cytology (Pap testing) in cervical cancer screening programs to increase effectiveness in preventing invasive cervical cancer.

"Our study is the first, to our knowledge, to show a greater efficacy for HPV testing versus cytology for preventing invasive cancers in a developed country, where cytological screening has been in place for years and advanced cervical cancers are extremely rare among screened women," wrote study author Guglielmo Ronco and colleagues in the Unit for Cancer Epidemiology, Centro per la Prevenzione Oncologica in Turin, Italy. The NTCC study was conducted within organized screening programs with more than 70% of eligible women enrolled, which, according to study authors, suggests that "results are applicable to routine practice." The study was released online in advance of publication on the Lancet Oncology Website.

The two-phase, randomized trial showed "a significantly lower number of cases in the HPV group versus the cytology group over the two screening rounds, indicating that the HPV-based screening is more effective than cytology in preventing cervical cancer," wrote the study authors, who attributed the higher efficacy of HPV DNA testing to its earlier detection of clinically relevant lesions, which allowed for earlier treatment of precancers and prevention of invasive cancer. "For women aged 35 years or more, our results support the use of HPV DNA testing for primary screening at prolonged intervals, with cytology reserved for triage of HPV-positive women."

"This study clearly demonstrates that a decrease in advanced cervical cancer is achievable - and hence lives saved - when HPV screening using the digene HPV Test is implemented, regardless of the region and level of cervical cancer prevention program in place," said Peer Schatz, CEO of QIAGEN. "With cervical cancer prevention programs under evaluation by health ministries and government agencies across Europe and around the world to assess the most cost-effective strategies to protect women, this study could have significant implications. With our digene HPV test approved in the U.S. and Europe, and our careHPV test in development for use specifically in the developing world, we believe that regionally tailored cervical cancer prevention strategies that include HPV DNA testing can efficiently save millions of women's lives."

The NTCC study, which shows the ability of HPV testing to reduce invasive cervical cancer in an industrialized setting, complements an April 2009 study published in the New England Journal of Medicine demonstrating that in low-resource settings in rural India a single round of HPV testing significantly reduced the numbers of advanced cervical cancers and deaths, compared with other screening methods. Numerous studies of HPV testing have focused on clinical efficacy data and the high sensitivity of HPV testing to detection cervical lesions and cancers, while the NEJM and Lancet Oncology studies importantly show an actual reduction in the incidence of invasive cervical cancer.

NTCC Study Design and Results

In the NTCC study, two rounds of screening were performed in more than 90,000 women age 25-60. In phase one, women were randomly assigned to a control group with conventional cytology (Pap) only or to an intervention group where women had HPV DNA testing plus liquid-based cytology. In phase two, which was conducted two years later, with three to five years of follow-up, the control group received conventional cytology and the women in the intervention group received HPV testing alone.

In the first round of screening a comparable number of cancers were detected in each group (nine in the cytology group vs. seven in the HPV group). However, following the second phase conducted two years later, a significant decrease in cases of invasive cancer was detected in the HPV group (zero cases) compared with the cytology group (nine cases). After two screening rounds there was a significantly lower number of cases in the HPV group (7) versus the cytology group (18), indicating that HPV-based screening is more effective than cytology in preventing invasive cervical cancer. Also of note, a high proportion of cancers detected in the cytology group at the second round of screening were adenocarcinomas, which echo results reported in earlier studies that cytology is less effective in preventing adenocarcinoma than squamous-cell carcinoma.  

"HPV-based screening is more effective than cytology in preventing invasive cervical cancer by detecting persistent high-grade lesions earlier and providing a longer low-risk period," conclude the authors.  An additional finding revealed that "detection of CIN2 was higher in the HPV than cytology group at round one, but only slightly lower at round two, suggesting that some regressive CIN2 lesions were identified and treated in young women." CIN2 refers to potentially premalignant lesions, which in some cases are cleared by the body's immune system before they become cancerous.

"HPV testing shows a great deal of promise to revolutionize cervical cancer screening," wrote Dr. Philip Castle and Dr. Hormuzd Katki of the National Cancer Institute, who provide patient management recommendations in an accompanying editorial. "Data from the current study could be used to develop risk estimates to make the promise of more effective and cost-effective cervical cancer prevention a reality."

Worldwide, cervical cancer affects approximately 500,000 women annually and is the second-most-common malignancy found in women. HPV testing identifies women with high-risk HPV infections that can cause cervical cancer, enabling diagnosis and treatment to be put in place before cervical cancer develops. The digene HPV Test is approved in the U.S. for use together with a Pap test ("co-testing") in women 30 years and older, and as follow-up to inconclusive Pap test results ("ASCUS triage"). It is regarded as the "gold standard" in testing for high-risk types of HPV and is recommended in guidelines from leading U.S. medical organizations. In Europe, it is approved as an initial general population screening test either alone ("primary" or "frontline" screening) or together with a Pap test, as well as for ASCUS triage. The performance of the digene HPV Test has been published in more than 300 peer-reviewed journal articles and studied in clinical trials involving more than a million women worldwide.  More than 40 million tests for carcinogenic HPV have been performed with the digene HPV Test.