Oncological Outcomes of Trimodal Therapy in Primary Versus Secondary Muscle-invasive Bladder Cancer: A Multicenter Retrospective Study.

BACKGROUND AND

OBJECTIVE

Muscle-invasive bladder cancer (MIBC) may present de novo (primary MIBC [pMIBC]) or progress from non-muscle-invasive disease (secondary MIBC [sMIBC]). While sMIBC has been associated with adverse outcomes after radical cystectomy, its prognostic impact in patients undergoing trimodal therapy (TMT) is unclear. We aimed to compare the outcomes between pMIBC and sMIBC in a multicenter cohort treated with bladder-preserving TMT.

METHODS

We conducted a retrospective study including patients with MIBC treated with curative-intent TMT. Eligible patients had stage ≥T2 disease and completed TMT without discontinuation. Patients were classified as those having pMIBC (≥T2 at diagnosis) or sMIBC (progression after prior non-muscle-invasive bladder cancer [NMIBC]). The primary endpoint was recurrence-free survival; the secondary endpoints were metastasis-free survival, cancer-specific survival (CSS), overall survival, and treatment-related toxicity. Survival was assessed using Kaplan-Meier methods and multivariable Cox regression.

KEY FINDINGS AND LIMITATIONS: Among 294 patients (234 with pMIBC and 60 with sMIBC), the median age was 77 yr. The median follow-up was 34 mo for pMIBC and 24 mo for sMIBC. The 3-yr CSS rate was 78% for pMIBC and 79% for sMIBC. After adjustment for clinical covariates, sMIBC was not associated with an increased risk of recurrence (hazard ratio [HR] 1.35, 95% confidence interval [CI] 0.85-2.13) and cancer-specific death (HR 0.88, 95% CI 0.44-1.76). Toxicities were mostly of grade 1-2; grade ≥3 events were rare. Limitations include the retrospective design, a smaller sMIBC subgroup, and a relatively short follow-up.

CONCLUSIONS AND CLINICAL IMPLICATIONS: Outcomes after TMT were broadly similar between pMIBC and sMIBC, although overall survival was lower in patients with secondary disease. A prior NMIBC history should therefore not preclude consideration of bladder-preserving therapy in appropriately selected patients.