As reported in the Journal of Clinical Oncology by Shankar Siva, PhD, and colleagues, long-term outcomes of the Trans Tasman Radiation Oncology Group (TROG) 13.01 SAFRON II phase II trial showed no difference in overall survival with single-fraction vs multifraction stereotactic ablative body radiotherapy (SABR) in patients with pulmonary oligometastases.
Study Details
In the multicenter trial, 90 patients with 133 oligometastases to the lung were randomly assigned to undergo single-fraction treatment with 28 Gy (n = 45) or multifraction treatment with 48 Gy in four daily 12-Gy fractions on nonconsecutive days over 2 weeks (n = 45).
Key Findings
Median follow-up was 5.4 years. Estimated 3- and 5-year overall survival in the entire population was 70% (95% confidence interval [CI] = 59%–78%) and 51% (95% CI = 39%–61%), with no significant difference between the multifraction vs single-fraction groups (hazard ratio [HR] = 1.1, 95% CI = 0.6–2.0, P = .81).
Shankar Siva, PhD
Estimated 3- and 5-year disease-free survival in the entire population was 24% (95% CI = 16%–33%) and 20% (95% CI = 13%–29%), with no difference between the multifraction vs single-fraction groups (HR = 1.0, 95% CI = 0.6–1.6, P = .92).
Estimated 3- and 5-year modified disease-free survival in the entire population—in which disease progression salvaged with local treatment (SABR, thermal ablation, or surgery) was not counted as an event—was 39% (95% CI = 29%–49%) and 34% (95% CI = 24%–44%), with no difference between the multifraction and single-fraction groups (HR = 1.0, 95% CI = 0.6–1.8, P = .90).
The investigators concluded, “In this patient population, where patients receive SABR in lieu of systemic therapy, one in three patients are alive without disease in the long term. There were no differences in outcomes by fractionation schedule.”
Dr. Siva, of Peter MacCallum Cancer Centre, Melbourne, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by Cancer Australia, Auckland Medical Research Foundation, National Health and Medical Research Council, and others. For full disclosures of the study authors, visit ascopubs.org.
