Today we are discussing cervical cancer screening guidelines with Dr. Karen Smith-McCune, of the department of obstetrics, gynecology, and reproductive sciences at the University of California in San Francisco, and Dr. Debra Papa, who specializes in gynecology at the UMass Memorial Medical Center in Wooster, Mass. The US Preventive Services Task Force and the American Cancer Society (ACS), American Society for Colposcopy and Cervical Pathology, and American Society for Clinical Pathology updated their guidelines for the prevention and early detection of cervical cancer in 2012, incorporating the newer human papillomavirus (HPV) testing along with the established Pap smear screening test that has been widely implemented and is the routine cervical cancer screening method.
—Interviewed by Anna Azvolinsky, PhD
Cancer Network: Dr. McCune, could you differentiate between the US Task Force guidelines and those that were issued by the ACS cervical cancer guideline committee?
Dr. McCune: Both groups recommend two options for screening for women between the ages of 30 and 65. Those women can have a Pap smear test every 3 years or the Pap plus HPV test, or the co-test every 5 years. One set of guidelines from the ACS group classifies the co-test as the preferred strategy, which they base on the evidence, but they did indicate that the evidence for this recommendation is weak. The guidelines from the Task Force do not give a preferred designation to either of the options. In fact, the Task Force recommendations highlight the patient’s preference by indicating that co-testing is an option for women who want to lengthen their screening interval. So, we are left with the question—is co-testing the preferred option as indicated by the ACS group or are really both options the same? And that is really the question I addressed in my recent [viewpoint] article in JAMA Internal Medicine.
Cancer Network: How have these guideline changes and, specifically, the incorporation of the newer HPV test, how has this changed screening practices and for which women? Dr. Papa, let’s start with you?
Dr. Papa: As Dr. McCune said, the addition of the HPV test to Pap smears is for women 30 and older because HPV is so common for women in their 20s, so it’s not a good screen at that time. But what it does do if both tests are negative— studies out of Kaiser in California have shown that a woman’s risk is very low if both test results are negative. The test has a very good negative predictive value so the interval can be 5 years [between screenings]. So, the addition of HPV has allowed us to lengthen the interval. It has also been shown that the HPV test is able to detect cervical dysplasia earlier. However, what has happened is that you can get a normal Pap smear and a positive HPV test and so there are guidelines for that finding as well.
Cancer Network: Dr. McCune, do you have anything to add?
Dr. McCune: I have a slightly more negative view of what has resulted with the incorporation of the HPV test. I agree that it does give a very confident result if both are negative and that should really drive a change in practice towards less frequent screening. However, it has led to a lot of confusion. There is now the potential of two results from two different tests with a grid of possible results that, frankly, becomes quite confusing for clinicians. So if the result is that the Pap is negative and the HPV test is negative, that is very good and very reassuring that the woman has nothing potentially dangerous happening and doesn’t need another test for 5 more years. And like I said, I hope that will drive practices toward less frequent screening. The worst outcome is if co-testing is adopted but people continue to screen as they are doing now, every year or every other year, which will just result in a huge burden on the healthcare system.
Dr. Papa: I agree with that. I think that physicians do need to change their mindset and so do patients. Sometimes, it is not easy for patients to understand that a Pap test can be given every 3 years or a co-test every 5 years. And I do agree that a negative Pap and a positive HPV test can be confusing and also that patients usually are upset knowing that they are HPV positive, so we as clinicians need to reassure them and try to educate about guidelines for how handle the Pap negative, HPV-positive test.
Cancer Network: In April of this year, the FDA approved the cobas HPV test for primary cervical cancer screening, so that is one of the HPV tests we are discussing. Does that FDA approval have any additional impact on clinical practice?
Dr. McCune: I would just hope that clinical practice won’t change until the evidence for the cobas test is published because we have not seen those final trial data in the literature yet. And I would wait for the evidence from that test to be reviewed by guideline committees that are hopefully free of financial and intellectual conflicts of interest. And then we’ll see what the clinical guidelines would recommend about using that test. Until that happens, I hope nothing will change.
Dr. Papa: I agree 100%. I don’t think we should not change anything clinically at this point until we do get guidelines. Pap smears are not going to go away. Because what we don’t want to do is increase costs, and we don't want to increase the number of women going for colposcopies and the cobas HPV test may have that potential, and we don't yet fully know how to use it. Right now, we are still adopting these newer guidelines from 2012 which we still need to straighten out and have everyone on board. So I agree, we won’t do anything in the near future, certainly not until we have guidelines come out from committees.
Cancer Network: How do both of you facilitate your patient’s decision for cervical cancer screening? Dr. McCune, let’s start with you.
Dr. McCune: I think it’s important to talk to a patient about her preference for a screening interval because that is the main difference between the two testing strategies. Some women who grew up in the era of the annual Pap smear may want an option that gives them a more frequent test so they would be appropriate to screen with a Pap every 3 years. Other women will prefer the convenience of less frequent testing so co-testing is perfect for them. I think women should be made aware that the co-test option could lead to a cycle of repeated testing and evaluation because HPV infection is usually just a benign and self-limited infection and doesn't reflect a risk of cancer. So as long as women are aware of that risk going into the co-test I think it may help to reduce their anxiety and stigmatization that can occur if they find out that they have HPV.
Dr. Papa: I do co-testing essentially on my women who come in for their annual exam. And if they are Pap normal but HPV positive I will genotype them for HPV16 and HPV18 [strains] and do a colposcopy if they are 16 and 18 positive. If they are not 16 and 18 positive, I will repeat the co-test in a year. The ATHENA study seemed to show that again this can detect cancer earlier but again you have to be careful so that you are not referring too many women for a colposcopy because that is the full goal of this type of screening. We are already doing a very good job in the United States, and we have decreased the rate of cervical cancer because of the advent of Pap smears. So we have to be careful because we have been doing a good job already, and we don’t want to just increase the number of women having to go for colposcopies. So I absolutely do co-testing for women.
Cancer Network: Thank you both so much for joining us today.
Dr. McCune: Sure.
Dr. Papa: My pleasure. Thank you very much for having me.