Clarke MA, et al. - This study was designed to test the hypothesis that increased body mass might decrease detection of cervical precancer and increase risk of cervical cancer even in women undergoing state-of-the-art screening. Findings showed an increased risk of cervical cancer in screened overweight and obese women; underdiagnosis of cervical precancer appeared to be the likely cause. To attenuate cervical cancer incidence, improvements in equipment and/or technique to assure adequate sampling and visualization of women with elevated body mass might be effective.

• This retrospective cohort study included a total of 944,227 women age 30 to 64 years who underwent cytology and human papillomavirus DNA testing (ie, cotesting) at Kaiser Permanente Northern California (January 2003 to December 2015).
• Researchers classified body mass index as normal/underweight (< 25 kg/m²), overweight (25 to < 30 kg/m²), or obese (≥ 30 kg/m²).
• They used logistic Weibull survival models to estimate 5-year cumulative risks of cervical precancer and cancer by category of body mass index.

• With increasing body mass index, lower risk of cervical precancer (n = 4,489) and higher risk of cervical cancer (n = 490) was observed.
• Researchers found that the 5-year risk of precancer was lowest specifically among obese women (0.51%; 95% CI, 0.48% to 0.54% v 0.73%; 95% CI, 0.70% to 0.76% in normal/underweight women; P trend < .001).
• In contrast, the highest 5-year risk of cancer was reported in obese women (0.083%; 95% CI, 0.072% to 0.096% v 0.056%; 95% CI, 0.048% to 0.066% in normal/underweight women; P trend < .001).
• In subgroups defined by age (30 to 49 v 50 to 64 years), human papillomavirus status (positive v negative), and histologic subtype (glandular v squamous), consistent outcomes were reported.
• In addition, in the women in this study who underwent routine cervical screening, nearly 20% of cervical cancers could be attributed to overweight or obesity.