By Molly A. Brewer, DVM, MD, MS
Professor and Chair, Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, University of Connecticut Health Center, Farmington
Dr. Brewer reports no financial relationships relevant to this field of study.
US Preventive Services Task Force; Curry SJ, et al. Screening for cervical cancer: US Preventive Services Task Force Recommendation Statement. JAMA 2018;320:674-686.
The U.S. Preventive Services Task Force (USPSTF) recently updated its recommendations for cervical cancer screening. Practitioners currently following guidelines published by ASCCP (and supported by ACOG) will not find any discrepancies in the new USPSTF position. The revised USPSTF guidelines recommend against screening women younger than 21 years of age (D recommendation = USPSTF recommends against the service. There is moderate or high certainty that the service has no net benefit or that the harms outweigh the benefits). This is in line with what most practitioners already have adopted. The Surveillance, Epidemiology, and End Results (SEER) database1 estimates that 0.01% of all cervical cancers occur in this young age group, and the prevalence of CIN 3 is 0.2%. The false-positive rate of cytology is 3.2%, leading to a very small benefit in screening women younger than 21 years of age. Moreover, there is the risk of overtreatment affecting fertility or obstetrical outcomes when aggressive treatment, such as a cone biopsy or loop electrical excision procedure, is performed in these young women. The USPSTF also recommends against (D recommendation) screening women older than 65 years of age with a history of adequate screening (e.g., three consecutive negative cytology results or two consecutive negative co-testing results within 10 years). However, for women older than 65 years of age without a history of adequate screening, or those with new risk factors, screening should continue. The task force also recommends against (D) screening women with a history of total hysterectomy (with prior adequate screening).
The new USPSTF guidelines recommend screening women between 21 and 29 years of age every three years with cytology alone (A recommendation = USPSTF recommends the service. There is high certainty that the net benefit is substantial). Since the majority of human papillomavirus (HPV) infections are transient in this age group, and overtreatment can lead to undue morbidity (as in the younger than 21 years of age group), HPV testing generally is not helpful or recommended.
In contrast, the guidelines recommend screening women 30-65 years of age every three years with cytology alone, or every five years with either high-risk HPV testing alone or co-testing (A recommendation). The task force concluded that all three of these strategies offer a reasonable balance between benefits and harms for women aged 30 to 65 years, and encouraged women to discuss the pros and cons of each approach with their healthcare provider. It noted that evidence from randomized clinical trials and decision-modeling studies suggest that while screening with cytology alone results in lower detection rates for CIN 2 and CIN 3 than screening with high-risk HPV testing (alone or with co-testing), use of HPV testing results in more colposcopy exams (potential for harm) without an increase in cancer detection.
COMMENTARY
So how should we interpret these recommendations? The commentary section of the USPSTF paper notes that the majority of cervical cancer cases and deaths occur in women who have not been screened. It also states there is a lack of evidence that vaccination prevents cervical cancer. For this reason, the USPSTF recommends screening all women with a cervix, regardless of sexual history or HPV vaccination status. The task force also points out that these recommendations only apply to low-risk women with no prior diagnosis of a high-grade squamous lesion or cervical cancer. By focusing our attention to screening of high-risk women, we have the opportunity to improve health outcomes without enormous unnecessary cost. Based on these recommendations, clinicians should consider carefully who needs screening and avoid unnecessary screening of younger and older women. Investing limited healthcare dollars in outreach programs and in the follow-up of abnormal results makes sense. Hispanic, African-American, and Native American women have an increased mortality from cervical cancer compared to white women; we must address this health disparity.
Clinicians also should advocate for HPV vaccination of all girls and boys. Although we lack data showing a reduction in mortality from cervical cancer among vaccinated women, studies have shown a decrease in high-grade dysplasia among women who received the HPV vaccine over 10 years of follow-up.2 There is ample evidence that the precursor lesion for cervical cancer is high-grade dysplasia.
We now understand the biology of cervical cancer well and know what to do to prevent death and morbidity from this disease: 1) the majority of cervical cancers are caused by high-risk HPV infections; 2) these infections can be prevented with early vaccination; and 3) the majority of cervical cancers occur in women who are not regularly screened with either HPV testing or with cytology. Therefore, our healthcare investment should be focused on educating and vaccinating all young people and on providing outreach to encourage screening in underserved populations. We don’t need more randomized trials of screening approaches for cervical cancer. Instead, we should invest our precious healthcare dollars in vaccination and screening.
REFERENCES
- National Cancer Institute. Surveillance, Epidemiology, and End Results Program. Cancer Stat Facts: Cervical Cancer. Available at: https://seer.cancer.gov/statfacts/html/cervix.html. Accessed Sept. 11, 2018.
- Lehtinen M, et al. Ten-year follow-up of human papillomavirus vaccine efficacy against the most stringent cervical neoplasia end-point — registry-based follow-up of three cohorts from randomized trials. BMJ Open 2017;7:e015867.
