Effect of body mass index on the outcomes of patients with upper and lower urinary tract cancers treated by radical surgery: Results from a Canadian multicenter collaboration

ObjectiveTo evaluate the effect of body mass index (BMI) on the outcomes of patients with urinary tract carcinoma treated with radical surgery.Materials and methodsData were collected from 10 Canadian centers on patients who underwent radical cystectomy (RC) (1998-2008) or radical nephroureterectomy (RNU) (1990-2010). Various parameters among subsets of patients (BMI<25, 25≤BMI<30, and BMI≥30 kg/m2) were analyzed. Kaplan-Meier and multivariate analyses were performed to assess the effect of BMI on overall survival, disease-specific survival, and recurrence-free survival (RFS).ResultsAmong the 847 RC and 664 RNU patients, there was no difference in histology, stage, grade, and margin status among the 3 patient subsets undergoing either surgery. However, RC patients with lower BMIs (<25 kg/m2) were significantly older (P = 0.004), had more nodal metastasis (P = 0.03), and trended toward higher stage (P = 0.052). RNU patients with lower BMIs (<25 kg/m2) were significantly older (P = 0.0004) and fewer received adjuvant chemotherapy (P = 0.04) compared with those with BMI≥30 kg/m2; however, there was no difference in tumor location (P = 0.20), stage (P = 0.48), and management of distal ureter among the groups (P = 0.30). On multivariate analysis, BMI was not prognostic for overall survival, disease-specific survival, and RFS in the RC group. However, BMI≥30 kg/m2 was associated with more bladder cancer recurrences and worse RFS in the RNU group (HR = 1.588; 95% CI: 1.148-2.196; P = 0.0052).ConclusionsIncreased BMI did not influence survival among RC patients. BMI≥30 kg/m2 is associated with worse bladder cancer recurrences among RNU patients; whether this is related to difficulty in obtaining adequate bladder cuff in patients with obesity requires further evaluation.