ASCO GU 2023: Study of Real-World Treatment Patterns and Adherence to Bacillus Calmette-Guerin (BCG) in the Context of Guideline Recommendations for Patients with High-Risk Non-Muscle Invasive Bladder Cancer (NMIBC)

(UroToday.com) On the second day of the American Society for Clinical Oncology (ASCO) Genitourinary Cancer Symposium 2023 focussing on urothelial cancer, the Poster Session B: Prostate Cancer and Urothelial Carcinoma included a presentation from Dr. Andrea Ireland outlining real world treatment patterns and adherence to bacillus Calmette-Guerin (BCG) for patients with high-risk non-muscle invasive bladder cancer (NMIBC).

For patients with high-risk NMIBC, intravesical BCG is considered the standard first-line (1L) treatment. Since the presence of carcinoma in situ (CIS) is associated with increased disease progression rates and poor clinical outcomes, BCG is prioritized in clinical guidelines for NMIBC patients with CIS. Unfortunately, in the US, there have been substantial shortages of BCG in recent years which may negatively affect clinical outcomes in patients. Thus, these authors sought to evaluate the adequacy of BCG treatment patterns among NMIBC patients, including a subgroup with CIS.

Using the de-identified IBM MarketScan Commercial, Medicare, and Medicaid Databases from 1/1/2010 to 2/28/2021, the authors identified adult patients with NMIBC treated with BCG. Treatment patterns were assessed from the first BCG claim (triggering the start of 1L treatment) until the end of the patient’s observation. Consistent with real-world literature, adequate BCG induction was defined as ≥5 BCG claims within 70 days of the first BCG claim whereas adequate BCG induction and maintenance was defined as ≥7 BCG claims within 274 days of the first BCG claim.

The proportion of patients with adequate BCG induction and maintenance were compared between CIS subgroup and overall NMIBC cohorts using chi square tests.

Among the 5,803 NMIBC patients treated with 1L BCG, 1,182 (20.4%) had documentation of CIS. The overall study cohort and the subset with CIS had similar mean age (67 years; range 18-101 years). After 1L BCG, patients with CIS were significantly more likely (71.8%) than the overall cohort (56.6%) to have had another treatment (P<.001).

While 86.9% and 90.0% of the overall and CIS cohorts had adequate BCG induction (P=0.003), only 41.5% and 50.8% had adequate BCG maintenance (P<.001). More patients in the CIS cohort had a cystectomy (13.9% vs 9.7%; P<.001) compared to the overall cohort.

Thus, these authors concluded that most NMIBC patients treated with BCG received adequate induction. Unfortunately, for most patients, BCG maintenance was inadequate and most patients had another treatment following 1L BCG. Patients with CIS were more likely to have cystectomy after BCG, suggesting higher risk of progression in this subgroup.