Impact of lymphovascular invasion and histological variants on BCG-treated high-grade NMIBC prognosis

Purpose: This study aimed to evaluate the impact of lymphovascular invasion (LVI) and histologic subtypes on prognosis following Bacillus Calmette-Guérin (BCG) therapy in high-grade non-muscle invasive bladder cancer (NMIBC). Methods: We retrospectively analyzed 245 patients who underwent transurethral resection of bladder tumor (TURBT) for high-grade Ta, T1, or carcinoma in situ (CIS) and received BCG therapy between January 2010 and December 2020. Effects of LVI and histologic subtypes on recurrence-free survival (RFS) and progression-free survival (PFS) were assessed using Kaplan-Meier and Cox regression analyses. Results: At median follow-up of 48.5 months, LVI was detected in 25.7% of patients and histologic subtypes in 36.3%. During follow-up, disease recurrence occurred in 98 patients (40.0%) and progression in 45 patients (18.4%). In multivariate analysis, LVI (HR: 2.28, 95% CI: 1.68–3.10, p < 0.001) and histologic subtypes ≥1% (HR: 1.95, 95% CI: 1.45–2.62, p < 0.001) were independent risk factors for recurrence. Similarly, LVI (HR: 2.85, 95% CI: 1.98–4.11, p < 0.001) and histologic subtypes ≥1% (HR: 2.34, 95% CI: 1.67–3.28, p < 0.001) were independent risk factors for progression. Patients with concurrent LVI and histologic subtypes demonstrated highest risk of progression (HR: 4.15, 95% CI: 2.85–6.05, p < 0.001) with 5-year PFS rate of 45.2%. Conclusion: In high-grade NMIBC patients receiving BCG therapy, LVI and histologic subtypes are strong independent risk factors for disease recurrence and progression. Patients with both factors have highest risk and may require more aggressive treatment strategies including consideration of early radical cystectomy. These findings support the importance of detailed pathological assessment in treatment selection for BCG-treated NMIBC patients.