Risk of Progression of High-grade Primary T1 Non-muscle-invasive Bladder cancer in a Contemporary Cohort.

Patients with high-risk non-muscle-invasive bladder cancer (NMIBC) receive bacillus Calmette-Guérin (BCG) instillations to reduce the risk of progression. For patients with very high-risk NMIBC, immediate radical cystectomy may be considered, as patients who experience disease progression despite BCG treatment have a worse prognosis. However, guideline-recommended stratification for the risk of progression is based on data from patients who were not exposed to BCG. We evaluated the risk of progression in a contemporary cohort of patients with primary high-grade/grade 3 (HG/G3) T1 NMIBC (n = 1268) who received at least one BCG instillation and underwent at least one cystoscopic evaluation. The primary endpoint was the 1-yr risk of progression for all patients and for the subgroup that received adequate BCG, defined as at least five induction instillations and at least two instillations provided as a second BCG course within 6 mo. Progression was defined as detrusor muscle invasion or lymph node or distant metastasis. The 1-yr risk of progression was 6.5% (95% confidence interval [CI] 5.2-8.0) for patients with primary HG/G3 T1 NMIBC who started BCG treatment, and 4.6% (95% CI 3.3-6.4) 1 yr after the first instillation of the second BCG course for patients who received adequate BCG (n = 746). In conclusion, the contemporary risk of progression for patients with HG/G3 T1 NMIBC who receive BCG appears to be low, especially for patients who receive adequate BCG treatment. PATIENT SUMMARY: Our study shows that for patients with a high-grade bladder tumor who received in-bladder BCG (bacillus Calmette-Guérin), the risk of disease progression was 6.5% at 1 yr after their first BCG instillation. For patients who continued with BCG maintenance treatments, the risk of progression was 4.6% after the first BCG maintenance instillation.