Contemporary Data on Incidence, Treatments and Outcomes of Tis, High-Grade Ta, and High-Grade T1 Non-Muscle Invasive Bladder Cancer Patients in the US
Jinlin Song, PhD1, Mihaela V. Georgieva, PhD2, Iryna Bocharova, BA2, Eric Wu, PhD2, Amy Guo, PhD3, Sam Spigelman, MD3, Ashish M. Kamat, MD4
1Analysis Group, Inc., Los Angeles, CA, 2Analysis Group, Inc., Boston, MA, 3Ferring Pharmaceuticals, Parsippany, NJ, 4Department of Urology, Division of Surgery, University of Texas MD Anderson Cancer Center, Houston, TX
BACKGROUND: Intravesical immunotherapy with Bacillus Calmette-Guérin (BCG) therapy is the best treatment for patients with Tis, high-grade Ta, or high-grade T1 non-muscle invasive bladder cancer (NMIBC); for those who fail, options are limited other than radical cystectomy. This study examined SEER-Medicare data to provide a snapshot of the patterns of BCG use and outcomes in this patient population in the US.
METHODS: We performed a retrospective analysis of the SEER-Medicare database to identify patients diagnosed with NMIBC between 2008 and 2015. Continuous enrollment in Medicare Parts A and B was required for ≥12 months prior to diagnosis and until death or end of Medicare claims availability (December 2016), whichever occurred first. Percentage of patients receiving BCG therapy was summarized. Proportions of patients who received cystectomy (partial or total) at 1, 3, and 5 years after BCG initiation were estimated among patients who received BCG using Kaplan-Meier analysis.
RESULTS: Among the 54,444 patients diagnosed with bladder cancer, 39,789 (73.1%) had non-muscle invasive disease (Tis: 7.0%, Ta: 63.1%, T1: 29.9%) and 16,837 (42.3%) of the patients with NMIBC were Tis, high-grade Ta, or high-grade T1. Surprisingly, only slightly over half (56.5%) of these patients received at least one instillation of BCG therapy (median follow-up since first BCG was 37.2 months). The mean age at BCG initiation was 77.5 years (SD=6.9), with 7,611 (80.0%) being male. The mean Charlson Comorbidity Index (CCI) score was 1.4 (SD=1.7), with 5,797 (60.9%) of patients having CCI score ≥1. The most common comorbidities were diabetes (35.7%) and chronic pulmonary disease (33.7%). Approximately 4.4% of patients receiving BCG underwent cystectomy within 1 year of BCG initiation, 8.8% within 3 years, and 10.8% within 5 years.
CONCLUSIONS: In the contemporary era, approximately 40% of patients with NMIBC have Tis, high-grade Ta, or high-grade T1 disease at diagnosis. Only about half the patients receive BCG instillation therapy. Whether the low cystectomy rates seen at 1, 3, and 5 years after BCG initiation are due to comorbidity burden or other factors needs to be further studied.
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