Stereotactic ablative radiation therapy (SBRT) is an emerging treatment option for primary renal cell carcinoma (RCC), particularly in patients who are unsuitable for surgery. The aim of this review is to assess the effect of increasing the biologically equivalent dose (BED) via various radiation fractionation regimens on clinical outcomes.
A literature search was conducted in PubMed (Medline), EMBASE, and the Cochrane Library for studies published up to October 2023. Studies reporting on patients with localized RCC receiving SBRT were included to determine its effectiveness on local control, progression-free survival, and overall survival. A random effects model was used to meta-regress clinical outcomes relative to the BED for each study and heterogeneity was assessed by I2.
A total of 724 patients with RCC from 22 studies were included, with a mean age of 72.7 years (range44.0-81.0). Local control was excellent with an estimate of 99 % (95 %CI: 97-100 %, I2 = 19 %), 98 % (95 %CI: 96-99 %, I2 = 8 %), and 94 % (95 %CI: 90-97 %, I2 = 11 %) at one year, two years, and five years respectively. No definitive association between increasing BED and local control, progression-free survival and overall survival was observed. No publication bias was observed.
A significant dose response relationship between oncological outcomes and biologically effective dose was not identified, and excellent local control outcomes were observed at the full range of doses. Until new evidence points otherwise, we support current recommendations against routine dose escalation beyond 25-26 Gy in one fraction or 42-48 Gy in three fractions, and to consider de-escalation or compromising target coverage if required to achieve safe organ at risk doses.
Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. 2024 Mar 08 [Epub ahead of print]
Ryan S Huang, Ronald Chow, Pradnya Chopade, Andrew Mihalache, Asad Hasan, Gabriel Boldt, Rachel Glicksman, Charles B Simone, Michael Lock, Srinivas Raman
Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada., Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Princess Margaret Cancer Centre, Temerty Faculty of Medicine, University of Toronto, Toronto, Canada; London Regional Cancer Program, London Health Sciences Centre, Schulich School of Medicine, University of Western Ontario, London, ON, Canada; New York Proton Center, New York, NY, USA., Princess Margaret Cancer Centre, Temerty Faculty of Medicine, University of Toronto, Toronto, Canada., University of British Columbia, Vancouver, British Columbia, Canada., London Regional Cancer Program, London Health Sciences Centre, Schulich School of Medicine, University of Western Ontario, London, ON, Canada., New York Proton Center, New York, NY, USA., Princess Margaret Cancer Centre, Temerty Faculty of Medicine, University of Toronto, Toronto, Canada. Electronic address: .