3360 - Toxicity Outcomes in Bladder Cancer Treated with Tri-Modality Therapy Using Hypofractionated Bladder Only Radiation with or without Immunotherapy
Presenter(s)
A. S. Wanna1, S. Koduri2, J. R. Teruel3, C. Oh4, M. P. Economides5, S. Niglio1, D. R. Wise5, J. Wysock1, K. Murray1, W. Huang6, S. Taneja6, T. B. Daniels1, A. J. Evans7, M. J. Zelefsky1, and P. B. Schiff7; 1NYU Langone Health, New York, NY, 2Department of Radiation Oncology, NYU Langone Health, New York City, NY, 3Department of Radiation Oncology, NYU Langone Health, New York, NY, 4Biostatistics, Department of Population Health, NYU Langone Health, New York, NY, 5Department of Medicine, Perlmutter Cancer Center at NYU Langone Medical Center, New York, NY, 6Department of Urology, Perlmutter Cancer Center at New York University Grossman School of Medicine, New York, NY, 7Department of Radiation Oncology, NYU Langone Health and Perlmutter Cancer Center, New York, NY
Purpose/Objective(s): Tri-modality therapy (TMT), consisting of resection and concurrent chemoradiation therapy, is an effective treatment for muscle-invasive bladder cancer (MIBC). Hypofractionated radiation therapy (RT) as part of TMT has been commonly used at our institution since 2016. In that time, we have participated in multiple clinical trials investigating the addition immunotherapy (IO) to TMT. This study reports acute and late toxicities for patients treated with TMT using hypofractionated bladder only RT with or without concurrent and consolidative IO. Our hypothesis is that patients receiving IO with TMT will have greater gastrointestinal (GI) and genitourinary (GU) toxicity than those who do not.
Materials/Methods: We retrospectively reviewed all patients with cT2-T4N0M0 MIBC who received TMT with hypofractionated bladder only RT at our institution between 2016 and 2024. RT regimens were 52Gy or 55Gy in 20 fractions. Patients could receive concurrent chemotherapy, concurrent and consolidative IO, both or neither. All GI, GU and IO related toxicities were scored using the CTCAE 5.0 system. Acute toxicities were defined within 90 days of treatment completion, and late toxicities were defined as any time after that. IO related toxicities were not designated as acute or late. Differences in treatment groups were analyzed using the Pearson’s Chi-squared test.
Results: A total of 49 patients were identified, with a median age of 77 years (range 56-97). Median follow up for all patients was 28.9 months (range 0-96 months). Most patients (90%) were stage II (cT2N0). Twenty-six (53%) patients received 52Gy and 23 (47%) patients received 55Gy. Most patients (92%) received concurrent chemotherapy, and 30 (61%) patients received IO. All IO was given as concurrent and consolidative. The median number of IO cycles was 4 (range 1-22). All patients who received IO also received concurrent chemotherapy. For the entire cohort, rates of acute toxicities were as follows: 28.6% grade 1-2 GI, 4.1% grade 3 GI, 59.2% grade 1-2 GU, 0% grade 3 GU. Late toxicity rates for the entire cohort were as follows: 22.4% grade 1-2 GI, 4.1% grade 3 GI, 69.4% grade 1-2 GU, 22.4% grade 3 GU. Two patients required cystectomy due to toxicity, and both received IO (6.7% of IO cohort). Any grade 1-2 IO related toxicity occurred in 3 (10%) patients. One (3.3%) patient had a grade 3 IO related toxicity. There was significantly less acute grade 1-2 GU toxicity in patients who received IO vs those who did not (40.0% vs 89.5% p=0.002). There were no other statistically significant differences in acute or late toxicities between patients who did and did not receive IO or between patients who received 52Gy vs 55Gy.
Conclusion: The addition of concurrent and consolidative IO to TMT with hypofractionated bladder only RT did not significantly increase rates of acute or late grade 1-3 GI or GU toxicity, but more patients who received IO required cystectomy due to toxicity compared to patients who did not. IO use was also associated with less acute grade 1-2 GU toxicity.