As I’ve recently blogged- gone are the days of the annual pap smear. But, is the pap smear itself going to disappear? Currently, most hospitals I know are recommending combined screening- a pap smear and HPV test, but could an HPV test alone take over?
The top seven gynecology organizations in the United States, including the Society for Gynecologic Oncology and the American Society for Colposcopy and Cervical Pathology convened for over a year to discuss the recommendations for cervical cancer screening. The groups officially recommend co-testing and cytology-only testing. However, they also allow for HPV-only testing because it has “equivalent or superior effectiveness.”
How did they come to this conclusion? They examined 12 different studies including hundreds of thousands of women. If a woman has a negative pap smear, she has a 0.8% chance of going on to have precancer in the next three years. If a woman has a negative HPV test result, she has a 0.3% chance of going on to have precancer in the next three years. If she has a negative pap smear and negative HPV, the risk of precancer over the next three years stays at 0.3%. Therefore, a negative HPV test gives more safety reassurance than a negative pap smear. Therefore, the seven organizations have ruled that high risk HPV testing every three years is a reasonable screening protocol.
What happens if the HPV test is positive? First of all- it depends on what type of HPV was detected. HPV 16 and 18 cause 70% of all cervical cancers, so these require the most intensive response- colposcopy. For instance, 25% of women with a positive HPV 16 test result will go on to have precancer or worse in the next three years. During a colposcopy, a doctor examines the cervix under a special microscope called a colposcope and takes biopsies of the tissue for further pathological examination. If the test result is positive for another of the over 100 known types of HPV, then a pap smear is recommended. If the pap smear is abnormal, then she goes on to have a colposcopy. If the pap smear is normal, then she should follow up in 1 year.
Over the last 30 years, women and their doctors have decreased cervical cancer by half, largely thanks to screening. But- this is not enough! Novel screening protocols may allow us to help the 12,000 women who will receive a new diagnosis of cervical cancer this year and the 4,200 who will die from cervical cancer. Remember to get your cervical cancer screening- whether that is a pap, HPV test, or both!