Obesity negatively impacts outcome in elderly female patients with aggressive B-cell lymphomas treated with R-CHOP: results from prospective trials of the German high grade non-Hodgkin's lymphoma trial group.

To study if obesity is a risk factor in elderly patients (>60 years) with aggressive B-cell lymphoma, the outcomes of 576 elderly patients treated with rituximab in the RICOVER-60 trial were analysed in a retrospective study with regard to body mass index (BMI) and gender. Of the 576 patients, 1% had low body weight (BMI < 18.5), 38% were normal weight (18.5 = BMI < 25), 42% were overweight (25 = BMI < 30) and 19% were obese (BMI >/= 30). Event-free (EFS), progression-free (PFS) and overall survival (OS) according to BMI showed no significant differences for all and for male patients. EFS (P = 0.041), PFS (P = 0.038) and OS (P = 0.031) were significantly better for female non-obese patients. A multivariate analysis adjusted for International Prognostic Index risk factors confirmed these results, with the following hazard ratios (HR) for obesity (BMI >/= 30) for EFS/PFS/OS: all patients - 1.4/1.4/1.4 (not significant); male patients - 1.2/1.2/1.0 (not significant) and female patients - 1.7 (P = 0.032)/1.9 (P = 0.022)/2.0 (P = 0.017). In conclusion, obesity is a risk factor that influences treatment outcome in elderly female patients with aggressive B-cell lymphoma treated with R-CHOP (rituximab + cyclophosphamide, doxorubicin, vincristine, prednisolone). The inferior outcomes in obese female patients may be due to faster rituximab clearance in obese females.