A SAbR full-length feature.
The Study: The phase 2 SABR-COMET trial is now out in full form. As a reminder, it included 99 patients with 1-3 (n= 92) or even up to 4-5 (n= 7) mets from any cancer without progression at the primary site at least 3 months—but usually a lot longer—after definitive treatment. They were randomized 1:2 to standard care (n=33) versus consolidative stereotactic body radiation (SBRT) to all active metastatic sites (n=66). Two-thirds of enrollees had one of the big four: breast, colorectal, lung or prostate cancers. Of note, median time from cancer diagnosis was well over 2 years, and 21/33 patients in the control arm received “palliative, non-ablative” radiation to symptomatic sites as would standardly be recommended. To rehash, the primary endpoint of overall survival was dramatically improved from a median of 28 months in the control arm to 41 months in the SBRT arm. This is probably due to patterns of progression: 15/33 (45%) in the control arm progressed at sites present at time of enrollment versus only 8/66 (12%) in the SBRT arm, translating to a doubling of median progression-free survival from 6 → 12 months. Worth a final mention are the 3/66 patients in the SBRT arm with grade 5 toxicities: one due to radiation pneumonitis (ok, we get it), one to subdural hemorrhage after SBRT-related gastric perforation repair (kinda see where they’re coming from), and one to pulmonary abscess (...).
Bottom Line: This represents a complete paradigm shift in the management of oligometastatic disease, where patients with low-volume disease standardly receive consolidative SBRT early in their metastatic disease course. | Palma, Lancet 2019