Association between BMI and oncologic outcomes in epithelial ovarian cancer: a predictors-matched case-control study

We aimed to study the association between obesity and survival in ovarian cancer (OC) patients, accounting for confounders as disease stage, histology, and comorbidities.

Retrospective matched case-control study of consecutive patients, with epithelial OC. Obese (body mass index [BMI] ≥ 35 kg m^-2) patients were matched in a 1:4 ratio with patients having lower BMIs (BMI < 35 kg m^-2) based on disease stage, cytoreduction state, tumor histology and ASA score. We compared the 3-year and total recurrence-free survival and overall survival through Kaplan-Meier survival curves and Cox proportional hazards.

Overall, 153 consecutive patients were included, of whom 32 (20.9%) had a BMI ≥ 35. and 121 a BMI < 35. The median follow-up time was 39 months (interquartile range 18-67). Both study groups were similar in multiple prognostic factors, including American Society of Anesthesiologists physical status, completion of cytoreduction, histology and stage of disease (p = 0.981, p = 0.992, p = 0.740 and p = 0.984, respectively). Ninety-five (62.1%) patients underwent robotic surgery and conversion rate from robotic to laparotomy was similar in both groups 2 (6.3%) in obese group vs. 6 (5.0%) in lower BMI patients, p = 0.673. During the follow-up time, the rate of recurrence was similar in both groups; 21 (65.6%) in obese group vs. 68 (57.1%), p = 0.387 and the rate of death events was similar; 16 (50.0%) in obese group vs. 49 (40.5%), p = 0.333). The 3-year OS was higher in the obese group (log rank p = 0.042) but the 3-year RFS was similar in both groups (log rank p = 0.556). Median total OS was similar in both groups 62 months (95% confidence interval 25-98 months) in obese vs. 67 months (95% confidence interval 15-118) in the lower BMI group, log rank p = 0.822. Median RFS was similar in both groups; 61 months (95% confidence interval 47-74) in obese, vs. 54 (95% confidence interval 43-64), log rank p = 0.842. In Cox regression analysis for OS, including obesity, age, laparotomy and neoadjuvant treatment - only neoadjuvant treatment was independently associated with longer OS: odds ratio 1.82 (95% confidence interval 1.09-3.05) and longer RFS: odds ratio 2.16 (95% confidence interval 1.37-3.41).

In the present study on consecutive cases of ovarian cancer, obesity did not seem to be associated with outcome, except for an apparent improved 3-year survival that faded away thereafter.