A new screening method for cervical cancer risk may replace the uncomfortable, dreaded Pap smear, according to a study published in JAMA. Testing for cancer-related human papillomavirus (HPV), which causes 99.7 percent of cervical cancer, outperformed the effectiveness of Pap smears in women over the age of 30.
Testing for HPV is a less intrusive method for cancer screening. Instead of a physician scraping the cells from the back of a woman’s cervix before visually inspecting them for signs of abnormality, an HPV test analyzes cells found in vaginal and cervical secretions.
Researchers compared the HPV test against Pap smear screenings over the course of four years in a randomized trial of more than 19,000 Canadian women. At the start, half of the women were tested for HPV while the other half had a Pap smear screening. Those who tested negative with the HPV test returned four years later. Those in the Pap group who tested negative returned two years later for another and, if they tested negative again, returned at the end of the four-year study. At the four-year mark, all women were tested using both methods.
“Primary HPV testing of women detects precancerous lesions earlier, and more accurately than the Pap test,” said the authors in a statement. Generally speaking, women who had the Pap smear were more than twice as likely to have abnormal cells; HPV testing resulted in 22 cases whereas the Pap smear had 52 women with abnormal cells.
It’s possible these results were skewed because women received both treatment options at the end of the study. Because the HPV test was more likely to pick up on pre-cancerous cervical lesions earlier in the study, these women were less likely to develop cervical cancer. Since all women who received a Pap smear at the end of the study, additional cases of early cancer were also detected. However, the authors note that participants were highly-educated and rural and remote communities were not well-represented.
As NPR reports, it’s been difficult to justify replacing the Pap smear with the HPV test because, until now, there hasn’t been a head-to-head comparison. The study is important in informing screening methods as the American Cancer Society estimates around 13,000 American women will be diagnosed with cervical cancer, and about 4,170 will die from it. But because the HPV test is more sensitive to these abnormal cells, it could result in more women with positive rates resulting in a need for more colposcopies and biopsies, something the authors say could have unintended harm and increases in health care costs.
Currently, the US Preventive Services Task Force recommends women aged 30-65 receive both a Pap and HPV testing every five years.