3346 - Salvage Stereotactic Radiotherapy Post-Nephrectomy for Recurrent Renal Cell Carcinoma
Presenter(s)
T. Song1, J. Kwon2, A. Yen2, M. Miljanic2, A. Garant2, D. X. Yang2, K. Gaston3, X. Meng3, S. Woldu3, R. D. Timmerman2, J. Cadeddu3, V. Margulis3, and R. Hannan2; 1Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, 2Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, 3Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX
Purpose/Objective(s): Treatment options for local recurrence of renal cell carcinoma (RCC) following nephrectomy remain poorly defined. Prior surgery increases the complexity and risks associated with salvage resection, making stereotactic ablative radiotherapy (SAbR) a potential alternative. In this study, we analyze and report the safety and efficacy of salvage SAbR for recurrent RCC after nephrectomy.
Materials/Methods: This IRB-approved, single-institution retrospective study included RCC patients with locoregional recurrence after nephrectomy who underwent salvage treatment with SAbR. Data on patient demographics, tumor characteristics, local and systemic treatments, and treatment-related toxicities were collected and analyzed. Local control, progression-free survival and overall survival were analyzed using Kaplan–Meier method. Progression was defined using RECIST 1.1 and toxicity was graded using CTCAE v5.
Results: We retrospectively reviewed 21 patients with locoregional RCC recurrence between 2008 to 2021, with a median follow-up of 35.6 months. At initial diagnosis, 13 (61.9%) patients had pT3 disease. Radical nephrectomy was performed in 11 patients (52.4%), while 10 (47.6%) underwent partial nephrectomy. Positive surgical margins were observed in only 2 patients (9.5%), and 4 patients (19.0%) received adjuvant systemic therapy at time of initial neprectomy. The median time to local recurrence was 26.5 months (95% CI: 8.4–44.6 months). While all patients had local recurrence, 13 patients (61.9%) also had distant metastatic recurrence either prior to or at the time of local recurrence.
The median dose and fractionation for SAbR were 39Gy delivered in 3 treatments. The median time to progression from the completion of salvage SAbR was 20.9 months (95% CI: 9.4–32.4 months). The 2-year overall survival rate following salvage SAbR was 92.8% and the 2-year local control rate was also 92.8%. The overall response rate to locally recurrent RCC treated with SAbR was 95.2% with 2 patients (9.5%) achieving complete response, 12 (57.1%) with partial response, and 6 (28.6%) maintaining stable disease for more than 6 months. Grade 3 toxicity was observed in only 1 patient (4.8%).Conclusion: SAbR is a safe and effective salvage option for locally recurrent RCC following nephrectomy.