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

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