Associations of Obesity with Post-Treatment Risks of Cervical Precancer and Cancer

Background: Individuals with obesity have an increased risk of cervical cancer, in part related to challenges associated with cervical sampling and visualization that result in missed detection of cervical precancers. The influence of obesity on the effectiveness of excisional treatment of detected cervical precancers and post-treatment disease risk is unknown.

Objectives: The aim of this study was to evaluate post-treatment risks of cervical precancer and cancer by body mass index (BMI).

Study design: This retrospective cohort study included individuals aged 25 years and older undergoing excisional treatment for cervical precancer, either cervical intraepithelial neoplasia (CIN) grade 2 or 3 or adenocarcinoma in situ (AIS) as of January 2017 with follow-up through February 2023. Patients were excluded if they were missing BMI, had cancer upon excision or had hysterectomy in lieu of excision, or were missing a valid referral screening visit. We categorized BMI as: Underweight/Normal (<25 kg/m²), overweight (25 to <30 kg/m²), and obesity (≥30kg/m²), as well as by class (I-III) of obesity. We calculated two-year risks of CIN3 and cancer (combined as CIN3+) using Kaplan Meier methods and evaluated multivariable adjusted associations of BMI with CIN3+ using Cox Proportional Hazards regression analyses, accounting for age at treatment, race and ethnicity, and treatment type.

Results: Among 10,614 patients, a total of 680 (6.4%) developed post-treatment CIN3+; most (91%) within two years of treatment. Two-year CIN3+ and cancer risks were highest in those with obesity (8.65%, 95% CI, 7.6-9.9% and 0.79%, 95% CI, 0.5-1.2%, respectively) and lowest in those with normal weight (5.57%, 95% CI, 4.9-6.3% and 0.29%, 95% CI, 0.2-0.5%, respectively). Hazard ratios measuring associations of BMI with risk of post-treatment CIN3+ ranged from 1.19 (95% CI, 1.0-1.4) among those with overweight to 1.89 (95% CI, 1.4-2.6) among those with class III obesity (p-trend <0.0001). A similar trend was observed for cancer, from 1.62 (95% CI, 0.8-3.3) for overweight and 3.50 (95% CI, 1.3-9.3) for class III obesity (p-trend =0.016).

Conclusions: Patients with obesity undergoing excisional treatment for cervical precancer have a higher risk of residual or recurrent disease, likely due to incomplete excision.