Predictors of residual T1 high grade on re-transurethral resection in a large multi-institutional cohort of patients with primary T1 high-grade/grade 3 bladder cancer

The aim of this multi-institutional study was to identify predictors of residual high-grade (HG) disease at re-transurethral resection (reTUR) in a large cohort of primary T1 HG/Grade 3 (G3) bladder cancer patients. A total of 1155 patients with primary T1 HG/G3 bladder cancer from 13 academic institutions that underwent a reTUR within 6 weeks after first TUR were evaluated. Logistic regression analysis was performed to assess the association of predictive factors with residual HG at reTUR. Residual HG cancer was found in 288 (24.9%) of patients at reTUR. Patients presenting residual HG cancer were more likely to have carcinoma in situ (CIS) at first resection (p<0.001), multiple tumors (p=0.02), and tumor size larger than 3 cm (p=0.02). Residual HG disease at reTUR was associated with increased preoperative neutrophil-to-lymphocytes ratio (NLR) (p=0.006) and body mass index (BMI)>=25 kg/m 2 . On multivariable analysis, independent predictors for HG residual disease at reTUR were tumor size >3cm (OR = 1.37; 95% CI: 1.02-1.84, p=0.03), concomitant CIS (OR 1.92; 95% CI: 1.32-2.78, p=0.001), being overweight (OR= 2.08; 95% CI: 1.44-3.01, p<0.001) and obesity (OR 2.48; 95% CI: 1.64-3.77, p<0.001). A reTUR in high grade T1 bladder cancer is mandatory as about 25% of patients, presents residual high grade disease. Independent predictors to identify patients at risk of residual high grade disease after a complete TUR include tumor size, presence of carcinoma in situ, and BMI >=25 kg/m 2 .