The following is a summary of “Long-Term Outcomes of TROG 13.01 SAFRON II Randomized Trial of Single- Versus Multifraction Stereotactic Ablative Body Radiotherapy for Pulmonary Oligometastases,” published in the July 2023 issue of Oncology by Siva, et al.
In a randomized phase II clinical trial conducted by the Trans Tasman Radiation Oncology Group, the effectiveness of single-fraction versus multifraction stereotactic ablative body radiotherapy (SABR) was compared in 90 patients with 133 lung oligometastases. Initial findings showed no significant differences in safety, efficacy, systemic immunogenicity, or survival between the treatment arms. However, based on cost-effectiveness, single-fraction SABR was favored. For a study, researchers presented the final analysis of survival outcomes with updated data.
Patients in the study received either single-fraction or multifraction SABR, and no concurrent or post-therapy systemic therapy was given until disease progression. Modified disease-free survival (mDFS) was defined as any progression not manageable by local therapy or death. After a median follow-up of 5.4 years, the estimated 3-year and 5-year overall survival (OS) rates were 70% (95% CI, 59 to 78) and 51% (95% CI, 39 to 61), respectively. There were no significant differences in OS between the single-fraction and multifraction arms (HR, 1.1 [95% CI, 0.6 to 2.0]; P = .81). The estimated 3-year and 5-year disease-free survival rates were 24% (95% CI, 16 to 33) and 20% (95% CI, 13 to 29), respectively, with no significant differences between the treatment arms (HR, 1.0 [95% CI, 0.6 to 1.6]; P = .92). Similarly, the estimated 3-year and 5-year mDFS rates were 39% (95% CI, 29 to 49) and 34% (95% CI, 24 to 44), respectively, with no significant differences observed between the single-fraction and multifraction arms (HR, 1.0 [95% CI, 0.6 to 1.8]; P = .90).
The results indicated that one-third of the patients in the study achieved long-term survival without disease progression. Additionally, there were no significant differences in survival outcomes based on the fractionation schedule (single-fraction or multifraction) of SABR. Therefore, both treatment approaches appeared to be equally effective in the context.