Long-term results of the Stereotactic Ablative Radiotherapy for Comprehensive Treatment of Oligometastatic Cancers (SABR-COMET) study published June 2, 2020 in the Journal of Clinical Oncology showed positive increases in overall survival for patients with multiple sites of metastasis when treated with stereotactic ablative radiotherapy (SABR) versus standard-of-care.1 Through the extended follow-up, the impact of SABR on overall survival was larger in magnitude than in the study's initial analysis published last year in The Lancet.2
"The durability of the randomized data indicates a paradigm shift in our approach to the treatment of patients with low burden metastatic disease," commented senior study author Suresh Senan, MRCP, FRCR, PhD, Professor of Radiation Oncology at the Amsterdam University Medical Centres in Amsterdam, the Netherlands. "These data add to a growing body of evidence that supports the use of SABR as an ablative therapy for oligometastatic cancers."
As outlined in the latest study results, patients in the international randomized phase II trial who received SABR demonstrated a 22-month improvement in 5-year median overall survival compared with patients who received a standard-of-care approach alone, corresponding to an absolute survival benefit of 24.6%.3 This is a marked improvement from the results of the initial analysis2 in which the patients receiving SABR demonstrated a 13-month improvement in median overall survival over the control group.
"The size of the effect on long-term survival in this seminal study marks a step-change in the way clinicians should treat metastases from the highest incidence cancers," said Ricky Sharma, MD, PhD, vice president of Clinical Affairs at Varian (NYSE: VAR). "With over one million stereotactic body radiotherapy cases treated on TrueBeam® alone, Varian continues to invest heavily to incorporate artificial intelligence, extraordinary precision, and unrivalled patient workflow into our industry leading delivery platforms for radiosurgery. We believe our continued pursuit of innovation and investment will ultimately help change the trajectory of cancer outcomes for all patients."
While systemic therapy, including chemotherapy, has been offered to patients with multiple metastases, the SABR-COMET data add to the growing body of evidence that suggests the addition of non-invasive treatments such as SABR can improve long-term outcomes for patients. Phase III randomized trials are ongoing to confirm the magnitude of the survival benefit for patients with a variety of metastatic cancers, including the international, multi-center SABR-COMET-3 clinical trial funded by Varian.
Mirroring the most common cancers treated across the world, primary tumor types in the study were breast, lung, colorectal and prostate. All patients enrolled had one to five new metastatic lesions. Although patients treated with radiotherapy were 20% more likely to suffer adverse events, there was no long-term impairment of quality of life. The study further showed that even with SABR, patients may progress with new metastases, likely due to the presence of micrometastatic disease, but that some can receive salvage therapy with repeat SABR.
1 J Clin Oncol 2020 Jun 2;JCO2000818 doi: 10.1200/JCO.20.00818
3 J Clin Oncol 2020 Jun 2;JCO2000818 doi: 10.1200/JCO.20.00818
SABR-COMET Updates Underscore SABR Effectiveness for Metastatic Cancer Treatment. Appl Rad Oncol.