Hypofractionated radiation therapy (RT) may be a more viable treatment option for oligometastatic renal cell carcinoma (RCC) than is generally recognized, a recent literature review has suggested.
Advances in stereotactic RT offer “new opportunities in RCC management” with limited toxicity, reported Francesca De Felice, PhD, of Sapienza University in Rome and her coauthor. The authors suggested that future studies investigate RT in combination with immunotherapy.
“Due to the assumption that RCC is a radioresistant tumor,” the authors wrote in, “RT has long been considered a futile approach to manage primary disease” and is predominantly used for treatment of distant metastases with palliative intent. “This review provides highlights in current RCC strategies to potentially suggest a more tailored treatment approach in clinical daily practice.”
The investigators concluded that hypofractionated RT (greater than 3 Gy/fraction) deserves more serious consideration. “It has enormous advantages,” the authors wrote, “assuring ablative doses to the target meanwhile preserving surrounding normal tissues. Using stereotactic technique, surprising high local control rates have been achieved in several tumors (such as lung, liver, and bone), in both primary and oligometastatic setting[s].”
In five studies, single-dose RT (ranging from 8 to 24 Gy) was used to treat patients with RCC and extracranial metastases. Of the patients in these studies, 89% of them achieved local control, median overall survival (OS) ranged from 11.7 months to 21 months, and severe RT-related toxicity occurred 0%-4% of the time.
“Although [there is a] high level of data heterogeneity,” the authors wrote, “this systematic review suggested that stereotactic RT is associated with excellent local control rates and low toxicity incidence. Thus, if feasible, stereotactic RT represents an effective and safe approach to treat RCC metastasis.”
The authors cautioned that “the optimal high dose required for local tumor control has not yet been defined.”
The authors suggested that, in the future, immunotherapy in combination with RT may “produce synergistic effects, resulting in better response rate and duration, given the known immune-modulated abscopal effect of RT.” First, questions about treatment sequencing, dosing, and patient selection would need to be answered. “Further research should be aimed at these clinical needs in order to achieve the maximum benefit to RCC patient[s].”
This study did not receive specific funding.
SOURCE: Felice F et al. Crit Rev Oncol Hematol. 2018 Aug 1.