EXECUTIVE SUMMARY

Results from a large retrospective study of women undergoing cervical cancer screening indicate that overweight and obese women had an increased risk of cervical cancer compared to normal weight women.
  • The study analyzed screening data from about 1 million women ages 30 to 64 undergoing routine cytology and human papillomavirus DNA testing in the Kaiser Permanente Northern California healthcare system.
  • In 2017, the U.S. Preventive Services Task Force issued draft guidance that states that for average-risk women ages 30-65, cervical cancer testing may be conducted with either cervical cytology alone every three years or with high-risk human papillomavirus (HPV) testing. Co-testing no longer is required.

Results from a large retrospective study of women undergoing cervical cancer screening indicate that overweight and obese women had an increased risk of cervical cancer compared to normal weight women.1 The study analyzed screening data from about 1 million women ages 30 to 64 undergoing routine cytology and human papillomavirus (HPV) DNA testing in the Kaiser Permanente Northern California healthcare system.

Although obesity is a strong risk factor for other female reproductive cancers, its relationship with cervical cancer has been less clear, says Megan Clarke, PhD, a postdoctoral fellow in the National Cancer Institute’s Division of Cancer Epidemiology & Genetics, Clinical Genetics Branch. Some studies have reported an association of obesity with increased risk of cervical cancer incidence and death, she notes. Through a clinical observation during chart reviews of women with cervical cancer, a Kaiser Permanente Northern California technologist noted that many of the cancers were diagnosed in obese women, says Clarke.

“We undertook a study to test whether this clinical observation was a true association in our population of women participating in cervical cancer screening,” explains Clarke, lead author of the current paper. “Our study was large enough so that we were able to analyze the effects of body weight on all stages of the disease process, including infection with human papillomavirus (the cause of cervical cancer), cervical precancer, and cancer.”

Body mass index, defined as weight in kilograms divided by height in meters squared, was categorized as normal/underweight (below 25 kg/m2), overweight (25 to less than 30 kg/m2), or obese (30 kg/m2 or greater). Researchers were able to confirm the clinical observation in the epidemiologic analysis, says Clarke. Data show that obese women had the lowest five-year risk of precancer (0.51%; 95% confidence interval [CI], 0.48-0.54% vs. 0.73%; 95% CI, 0.70-0.76% in normal/underweight women; P < .001). However, obese women had the highest five-year risk of cancer (0.083%; 95% CI, 0.072-0.096% vs. 0.056%; 95% CI, 0.048-0.066% in normal/underweight women; P < .001).1

The evidence suggests that obesity may increase risk for cervical cancer due to reduced effectiveness of cervical cancer screening in women with a high body mass index, Clarke states.

Andrew Kaunitz, MD, University of Florida term professor and associate chairman of the Department of Obstetrics and Gynecology at the University of Florida College of Medicine-Jacksonville, observes that compliance with screening does not explain the findings in the current study. If obesity serves as a risk factor for invasive cancer, it also should increase precancer as well, he says. Adequate visualization and sampling of the cervix can be challenging in women with higher BMI; this may explain the study’s findings.

“My clinical impression is that a vaginal speculum exam is often more uncomfortable for obese women than for other patients,” says Kaunitz. “Maintaining good communication with patients during the pelvic examination and employing appropriately sized vaginal speculums may pay off with improved cervical cancer screening efficacy in an increasing obese patient population.”

Check Your Practice

In 2017, the U.S. Preventive Services Task Force issued draft guidance that states that for average-risk women ages 30-65, cervical cancer testing may be conducted with either cervical cytology alone every three years or with high-risk human papillomavirus (HPV) testing. Co-testing no longer is required.2 The Task Force recommends screening for cervical cancer in women ages 21-29 every three years with cervical cytology alone. For women ages 30-65, the advisory group recommends either screening with cervical cytology alone every three years or screening with high-risk human papillomavirus testing alone every five years. (Contraceptive Technology Update reported on the guidance; see the December 2017 article, “Task Force Issues Cervical Cancer Screening Guidance: What Changes Can Clinicians Expect?” available at: http://bit.ly/2ErPxud.)

The American College of Obstetricians and Gynecologists (ACOG) continues to affirm its clinical guidance, which recommends that for women ages 30-65, co-testing with cytology and high-risk HPV testing every five years is preferred, and screening with cytology alone every three years is acceptable. The Task Force recommends against screening for cervical cancer in women younger than 21 years of age.3

The Task Force’s draft recom-mendations for routine cervical cancer screening in women younger than 21 years of age, for women ages 21-29, and for women older than age 65 who have been screened adequately previously have not changed and remain the same as ACOG’s current guidance.

Regular screening for women ages 21 to 65 greatly reduces the rate of cervical cancer and the number of deaths resulting from cervical cancer.4 The most effective screening method depends on the woman’s age, according to the USPSTF evidence search. For women 21-29 years of age, many infections with HPV will resolve on their own, so the Pap test is most effective for this age group.5 For women from 30-65 years of age, HPV infections are more likely to lead to cancer, so either Pap tests or high-risk HPV tests are effective for screening in this group, the evidence review noted.1

REFERENCES

  1. Clarke MA, Fetterman B, Cheung LC, et al. Epidemiologic evidence that excess body weight increases risk of cervical cancer by decreased detection of precancer. J Clin Oncol 2018; doi: 10.1200/JCO.2017.75.3442.
  2. U.S. Preventive Services Task Force. Draft Recommendation Statement: Cervical Cancer: Screening. September 2017. Available at: http://bit.ly/2h73xLJ. Accessed Feb. 16, 2018.
  3. American College of Obstetricians and Gynecologists, Committee on Practice Bulletins Gynecology. Practice Bulleting No. 168: Cervical cancer screening and prevention. Obstet Gynecol 2016;128:e111-130.
  4. Safaeian M, Solomon D, Castle PE. Cervical cancer prevention cervical screening: Science in evolution. Obstet Gynecol Clin North Am 2007;34:739-ix.
  5. Kotaniemi-Talonen L, Anttila A, Malila N, et al. Screening with a primary human papillomavirus test does not increase detection of cervical cancer and intraepithelial neoplasia 3. Eur J Cancer 2008;44:565-571.