As reported in The Lancet Oncology by Siva et al, long-term outcomes of an Australian-Dutch phase II study (TROG 15.03 FASTRACK II) support the safety and local disease control seen with stereotactic ablative body radiotherapy (SABR) in patients with primary kidney cancer who did not undergo surgery.
Study Details
Between July 2016 and February 2020, the multicenter trial enrolled 70 patients who were medically inoperable, high risk, or declined surgery and had tumors measuring 10 cm or less and N0–N1 disease. Patients received either a single fraction of SABR at 26 Gy for tumors 4 cm or less in maximum diameter, or 42 Gy in three fractions delivered 48 hours apart for tumors more than 4 cm in maximum diameter. The primary outcome measure was freedom from local progression.
Key Findings
Median follow-up was 62 months (interquartile range = 60–72 months). Median tumor size was 46 mm (range = 37–55 mm), with 24 patients (34%) having T1a disease, 39 (56%) having T1b disease, 6 (9%) having T2a disease, and 1 (1%) having T3a disease. One patient (1%) had nodal involvement (N1).
100% local control with SABR was observed at 36, 60, and 84 months.
Seven patients (10%) had at least one grade 3 adverse event within 9 months of SABR that was considered at least possibly related to treatment: nausea and vomiting (4%); abdominal, flank, or tumor pain (6%); colonic obstruction (3%); and diarrhea (1%). No new safety signals, grade 4 events, or treatment-related deaths were observed.
The investigators concluded: “Long-term follow-up supports the safety and local control of SABR for nonsurgical patients with renal cell carcinoma, with no observed local recurrences or cancer-related deaths in this cohort, which had predominantly T1b disease or higher.”
Shankar Siva, MBBS, PhD, of Peter MacCallum Cancer Centre, Melbourne, Australia, is the corresponding author for The Lancet Oncology article.
DISCLOSURE: The study was funded by The Cancer Australia Priority-driven Collaborative Cancer Research Scheme and Varian. For full disclosures of the study authors, visit thelancet.com.
