Obesity and prognosis in muscle-invasive bladder cancer: the continuing controversy

To investigate the association between body mass index and clinicopathological features of bladder cancer, and to assess the prognostic value of body mass index in patients undergoing radical cystectomy for bladder cancer.

The medical records of 714 patients who underwent radical cystectomy for bladder cancer were reviewed. The association of body mass index at surgery with clinicopathological features was examined, and the prognostic value of body mass index for recurrence-free survival and cancer-specific survival was analyzed using the Kaplan-Meier method and Cox regression models. Additional survival analyses were carried out in a subgroup of 534 patients with N0M0 disease.

Of 714 patients, 304 (42.6%), 184 (25.8%) and 226 (31.7%) had a body mass index of <23 (normal), 23-25 (overweight), and ≥25 (obese) kg/m(2) , respectively. Patients with high body mass index had a lower pathological T stage, fewer lymph node metastases and a lower frequency of lymphovascular invasion than those with low body mass index (P < 0.05). Multivariable analysis showed that obese status was an independent predictor of recurrence-free survival (obese vs normal: P < 0.001; overweight vs normal: P = 0.008) and cancer-specific survival (obese vs normal: P < 0.001; overweight vs normal: P = 0.019), along with pathological T stage, lymph node metastasis, and lymphovascular invasion. In addition, obesity was significantly associated with recurrence-free survival (P = 0.018) and cancer-specific survival (P = 0.019) in patients with N0M0 status.

The present findings suggest that overweight and obesity are associated with favorable pathological features and prognosis in patients with bladder cancer undergoing radical cystectomy.