Predictive clinico-pathological factors to identify BCG, unresponsive patients, after re-resection for T1 high grade non-muscle invasive bladder cancer

Abstract

Introduction: Seventy-five percent of bladder cancers are non-muscle invasive. The treatment strategy includes the transurethral resection of bladder tumor (TURB) followed by intravesical immunotherapy with the bacillus of Calmette-Guerin (BCG) or chemotherapy, depending on the grade of bladder tumor. Despite a proper BCG intravesical instillations schedule, up to 40% of patients present a failure within 2 years. The aim of this retrospective study was to investigate the predictive factors in the response to BCG in patients with a high-grade non-muscle invasive bladder cancer diagnosis.

Materials and methods: Patients with non-muscle invasive bladder cancer from 13 hospitals and academic institutions were identified and treated, from January 1, 2002, until December 31, 2012, with TURB and a subsequent re-TURB for restaging before receiving BCG. Follow-up was performed with urine cytology and cystoscopy every 3 months for 1 year and, successively every 6 months. Univariate and multivariate Cox regression models addressed the response to BCG therapy. Kaplan-Meier overall survival (OS) and cancer-specific survival (CSS) estimates were determined for BCG responsive vs. BCG unresponsive patients.

Results: A total of 1,228 patients with non-muscle invasive bladder cancer were enrolled. Of 257 (20.9%) patients were BCG unresponsive. Independent predictive factors for response to BCG were: multifocality (HR: 1.4; 95% CI 1.05-1.86; P = 0.019), lymphovascular invasion (HR: 1.75; 95% CI 1.22-2.49; P = 0.002) and high-grade on re-TURB (HR: 1.39; 95% CI 1.02-1.91; P = 0.037). Overall survival was significantly reduced in BCG-unresponsive patients compared to BCG-responsive patients at 5 years (82.9% vs. 92.4%, P < 0.0001) and at 10 years (44.2% vs. 74.4%, P < 0.0001). Similarly, cancer-specific survival was reduced in BCG-unresponsive patients at 5 years (90.6% vs. 97.3%, P < 0.0001) and at 10 years (72.3% vs. 87.2%, P < 0.0001).

Conclusion: Multifocality, lymphovascular invasion, and high-grade on re-TURB were independent predictors for response to BCG treatment. BCG-unresponsive patients reported worse oncological outcomes.

Keywords: BCG; Non-muscle invasive bladder cancer; re-TURB.