Setback for Cancer Test Hopes
In younger women with low-grade cytological abnormalities during cervical screening, a polymerase chain reaction human papillomavirus (HPV) test would not be useful for determining which patients need urgent follow-up, a new study suggests. Other studies have found HPV testing could be a useful tool for identifying women at high risk of cervical cancer. At several centers, the National Health Service has been piloting the addition of HPV testing.
About 6 percent of women who undergo screening have a borderline or mildly abnormal result. Only a very small minority will go on to develop cervical cancer.
The study, which was funded by the Medical Research Council, enrolled 4,439 women ages 20-59 whose cytology tests showed borderline abnormalities or mild dyskaryosis. High-risk HPV status was determined for all women by HPV test, with results shielded from participants and caregivers. Stratified by HPV status, patients were then randomized to six-monthly cytological screening in primary care or referral to colposcopy. All were followed for three years. The researchers assessed sensitivity, specificity, positive and negative predictive values of HPV testing for predicting cervical intraepithelial neoplasia grade 2 or worse (CIN2+) and implications for choice of management between cytological management or immediate colposcopy.
"There were no significant interactions between management and HPV status," wrote lead author Dr. Maggie Cruickshank, University of Aberdeen, and colleagues. Sensitivity of HPV testing for detection of CIN2+ was 75.2 percent among women with mild dyskaryosis and 69.9 percent among those with borderline nuclear abnormalities. Specificity was higher for BNA (71.3 percent) than for mild dyskaryosis (46.9 percent). Sensitivity decreased with increasing age, though specificity increased.
For all women, 22 percent who had CIN2+ were HPV-negative, whereas 40 percent of those HPV-positive did not have CIN, the authors found. "HPV was a much more reliable predictor in women aged over 40 years," according to the study.
"The most important thing is to attend for cervical cancer screening, the most effective way of preventing cervical cancer," said Cruickshank. "This new additional test may not add value. Our study is showing that HPV is such a common infection in younger women that testing for it doesn't help decide which is the best action to take."
The full study, "The Role of Human Papillomavirus Testing in the Management of Women with Low-Grade Abnormalities: Multicenter Randomized Controlled Trial," was published online by the British Journal of Obstetrics and Gynecology (2010;doi:10.1111/j.1471-0528.2010.02519.x).