by Victoria A. Fisher, M.P.H., and Wendy Schneider-Levinson
In June, Hormuzd A. Katki, Ph.D., a tenure-track investigator in the Biostatistics Branch, spoke at the American Society of Clinical Oncology (ASCO) annual meeting in Chicago, Illinois, on his research demonstrating the benefits of incorporating human papillomavirus (HPV) testing into cervical cancer screening programs. The study included nearly 332,000 women who underwent combined HPV and Pap testing at Kaiser Permanente Northern California (KPNC). Dr. Katki’s research, conducted in collaboration with KPNC researchers and Dr. Philip Castle (formerly of DCEG, now at the American Society for Clinical Pathology), was reported in a paper titled “Cervical cancer risk for women undergoing concurrent testing for human papillomavirus and cervical cytology: A population-based study in routine clinical practice” that was published in Lancet Oncology. This research also was featured in Clinical Cancer Advances 2011: Annual Report on Progress Against Cancer from the American Society of Clinical Oncology, an annual, independent review of advances in cancer research that have had the greatest impact on patient care.
Dr. Katki found that for women aged 30 and older, a single negative HPV test sufficed to provide strong reassurance against being diagnosed with cervical cancer over five years, supporting current guidelines recommending a three-year screening interval for women older than age 30 who have a negative HPV test and a normal Pap test. HPV testing also resulted in earlier identification of women at high risk of cervical cancer, especially cervical adenocarcinoma, a tumor that is rising in incidence in the United States. Finally, having a normal Pap test and a negative HPV test was associated with about the same cancer risk as a negative HPV test alone. This finding strongly suggests that reserving Pap testing only for HPV-positive women could protect women while reducing the number of Pap tests by 95 percent within this population.
This paper lays the groundwork for Dr. Katki’s ultimate goal of using cervical cancer risk estimates to inform the development of screening guidelines. He is developing a risk model for cervical pre-cancer and cancer that would incorporate HPV vaccination, results of HPV tests and Pap smears, and other clinically available biomarkers to classify women in risk-based management groups. If fully successful, this risk calculator could simplify and improve future screening guidelines.