University of Pennsylvania Health System Philadelphia, PA
A. Pepin1, P. Maitre2, R. Mamtani3, V. Murthy2, and J. P. Christodouleas4; 1Department of Radiation Oncology, Abramson Cancer Center, Hospital of University of Pennsylvania, Philadelphia, PA, 2Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, India, 3University of Pennsylvania, Department of Medical Oncology, Philadelphia, PA, 4Elekta, Stockholm, Sweden
Purpose/Objective(s): Radical cystectomy series of muscle invasive bladder cancer (MIBC) suggest that micrometastatic disease in pelvic lymph nodes range from 25-44%. The role of elective nodal irradiation in the setting of hypofractionated radiotherapy (RT) is still debated. Herein, we describe the patterns of failure for MIBC patients treated with hypofractionated RT to the bladder only with weekly gemcitabine (gemX). Materials/
Methods: We extracted all patients treated with curative intent gemX for node-negative MIBC between 2020-2022. We analyzed patterns of first failure into local (non-MIBC, MIBC) recurrence, pelvic nodal recurrence, distant recurrence, or a combination thereof. Results: A total of 29 gemX pts received bladder only radiotherapy. This cohort had a median follow up 1.6 years, median age was 83, 17.2% received neoadjuvant chemotherapy, 89.7% had T2 disease, and 89.7% completed the course of radiation therapy. All patients received concurrent gemcitabine. In total, there were 13 relapses. The most common first failure site was distant (n=5, 17.2%) and local (n=7, 24.1%; of which, 2 were MIBC recurrences) in the bladder only cohort. There were no pelvic nodal failures. One patient failed both locally and distantly. On Kaplan Meier analysis, the 2-year invasive local recurrence free survival 84.6%, invasive disease-free survival 60.0%, and metastasis-free survival 65.0%. Conclusion: Bladder-only gemX demonstrated low rates of pelvic nodal failures. Abstract presentation will include a pattern of failure comparison with a cohort treated to the bladder and elective nodes.
