Objective: Smoking and overweight are associated with poorer prognosis in several cancer types. The prognostic effect of smoking and body mass index (BMI) on ovarian cancer is unknown.
Methods: Ovarian cancer cases were from the Danish MALOVA (MALignant OVArian cancer) study. Information on smoking status and BMI was obtained from a personal interview conducted closely after primary surgery. Cox regression models were used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (95% CI) for ovarian cancer-specific death in relation to smoking variables and BMI.
Results: A total of 295 women with stage III epithelial ovarian cancer were identified and followed to death or for a median of 7.3 years (range, 5.4-9.5 years). Median survival time for normal-weight never smokers was 2.8 years (95% CI, 2.3-3.2) compared with 1.2 years (95% CI, 0.8-2.3) for overweight current smokers. Current smokers had a significantly increased risk of ovarian cancer death compared with never smokers in multivariate Cox analysis (HR, 1.65; 95% CI, 1.22-2.24). The negative effect of smoking diminished with increasing time since a former smoker had stopped smoking (HR, 0.89; 95% CI, 0.80-0.98 per 5 years since stop of smoking). Overweight women also had an increased risk of ovarian cancer death (HR, 1.83; 95% CI, 1.38-2.42) compared with normal-weight women.
Conclusion: Smoking at the time of diagnosis and premorbid overweight were negative prognostic factors for ovarian cancer-specific survival. The negative effect of smoking decreased with increasing time since stop of smoking.