New HPV Test for Cervical CancerPosted: June 24, 2011
The FDA has approved a new way to screen for warning signs of cervical cancer — good news indeed as more than 12,000 American women develop this life-threatening disease each year, and some 4,000 die from it. On a global scale, the World Health Organization estimates that there are 470,000 new cases of cervical cancer annually — a figure that translates into 275,000 deaths. Now, finally, a significantly more sensitive version of the test — called cobas HPV — has arrived, and it is sure to bring about a major reduction in those frightening numbers.
The new cobas HPV test, developed by Roche, identifies 14 strains of the human papillomavirus (HPV), the sexually transmitted virus that causes nearly all cervical cancers. In combination with regular Pap smears, this test can help you get an earlier and more accurate diagnosis.
A MORE SENSITIVE HPV TEST
A single Pap test can detect a precancerous lesion only 50% to 80% of the time. In contrast, current HPV tests can tell us whether or not a woman has one of a dozen cancer-linked HPV strains (indicating a possible precancer) but is not able to specifically identify the strains. This new level of analysis afforded by the cobas HPV test detects more than 90% of existing precancers, notes Mark H. Stoler, MD, a professor and associate director of surgical pathology and cytopathology at the University of Virginia Health System. He told me that the test specifically identifies the HPV-16 and HPV-18 viruses — the two highest-risk varieties of HPV that are responsible for seven out of 10 cervical cancers. The test can also identify 12 other high-risk types as well (31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68).
While doctors have successfully used Pap tests to detect the possibility of cervical cancer for more than a half-century, cutting its incidence rate by up to 75% in the past 50 years, the new cobas HPV test provides even greater accuracy in detection (and thus protection) because it analyzes specific HPV genotypes that put women at highest risk. In their analysis of data from the Roche ATHENA trial (Addressing THE Need for Advanced HPV Diagnostics), the largest registration study ever conducted for cervical cancer screening and encompassing more than 47,000 women in the US, Dr. Stoler and his colleagues found that 25% to 30% of women who tested positive for HPV-16 or HPV-18 had a precancerous lesion even though their Pap test results were only minimally abnormal. In other words, these women were at a much more significant risk than was previously appreciated. These results were published online in a recent issue of the American Journal of Clinical Pathology. This is just the first in a series of reports to be published from the large-scale ATHENA study, so stay tuned.
GET AN EARLY AND MORE ACCURATE DIAGNOSIS
Now that it has been approved, Dr. Stoler expects the cobas HPV test to become widely available over the next several months to a year. He anticipates that insurers will cover the cost (which will probably run $50 to $100), since they already cover current HPV tests in that price range.
At present, the FDA has approved the cobas HPV test for adjunctive use with Pap smears in women 30 and older and to help sort quickly through those Pap tests that appear abnormal. If you test negative on both the Pap and the cobas HPV, Dr. Stoler says you can wait at least three years to be screened again. If you test positive for HPV — especially HPV-16 or HPV-18 — your doctor will order further testing, such as a cervical exam (colposcopy) or a cervical biopsy, to confirm or rule out the possibility of cervical cancer.
Many advances in cancer screening have disappointed in recent years. Against this backdrop, I’m happy to be able to tell you about this major new success. By combining the cobas HPV test with a Pap, we have what seems to be a safe, accurate and reliable tool that represents a real step forward in cervical cancer screening practice.
Source: Mark H. Stoler, MD, professor of pathology, cytology and gynecology, associate director, surgical pathology and cytopathology and director, gynecological pathology fellowship program, University of Virginia School of Medicine, Charlottesville, Virginia.