Front-line (1L) treatment and recurrence patterns among patients with high-risk non–muscle-invasive bladder cancer (HR-NMIBC) with papillary carcinoma (PAP) or carcinoma in situ (CIS) following bacillus Calmette-Guérin (BCG) or other intravesical therapies (IVT).

Abstract

708 Background: HR-NMIBC carries substantial burden and high recurrence risk. Guidelines recommend BCG as 1L therapy, with other IVTs for BCG-unresponsive patients. This study aimed to describe real-world patterns of 1L treatment and recurrence rates among patients with HR-NMIBC, with PAP or CIS, initiating BCG or other IVT in the United States. Methods: This retrospective cohort study using SEER-Medicare data (1/1/2007-12/31/2022) included treatment-naïve patients ≥65 years old with HR-NMIBC with PAP (T1 disease or high-grade Ta) or CIS (Tis staging or diagnosis code), who received ≥1 instillation of BCG (BCG cohort) or other IVT (IVT cohort; mitomycin, gemcitabine, valrubicin, docetaxel, epirubicin) as 1L treatment. Index date was the first instillation. Among BCG-treated patients with sufficient follow-up, induction and maintenance patterns were assessed. Recurrence was defined as reinitiation of the same therapy after a gap (BCG: ≥180-day gap; other IVT: ≥90-day gap), transurethral resection of bladder tumor (TURBT), biopsy, or initiation of a new treatment (i.e., alternative IVT, systemic chemotherapy, radiotherapy, cystectomy, immunotherapy [including pembrolizumab], hormonal therapy, or other antineoplastic therapy). Kaplan-Meier (KM) analyses assessed time to recurrence stratified by cohort, with censoring at the earliest of end of continuous enrollment, plan switch, death, or end of data. Results: Among 17,495 patients initiating 1L treatment, 12,792 (73%) received BCG (mean age: 76 years; 79% male; 91% White) and 861 (5%) other IVTs (mean age: 77 years; 76% male; 93% White). Of BCG-treated patients, 56% initiated within 3 months of diagnosis, 84% received adequate induction (≥5 instillations within 70 days), and 54% received adequate induction plus maintenance (≥7 installations within 274 days). Median time to recurrence was 7.8 months (95% confidence interval [CI]: 7.6, 8.1), with KM recurrence rates of 21% at 3 months, 43% at 6 months, 61% at 12 months, and 74% at 24 months. Among IVT-treated patients, most received mitomycin (64%) or gemcitabine (25%). Median time to recurrence was 5.8 months (95% CI: 5.1, 6.7), and KM recurrence rates were 30% at 3 months, 51% at 6 months, 65% at 12 months, and 72% at 24 months. Conclusions: In this real-world study of Medicare-insured patients with HR-NMIBC with PAP or CIS, over 60% experienced recurrence within 12 months of initiating 1L BCG or IVT. While most BCG-treated patients received adequate induction, just over half had adequate maintenance. Current intravesical options show limited durability, underscoring the need for more effective, bladder-sparing treatments. Without clinical measures available, recurrence estimates may be affected by claims-based definitions.