Stereotactic ablative radiotherapy before resection to avoid delay for early‐stage lung cancer or oligometastases during the COVID‐19 pandemic: Pathologic outcomes from the SABR‐BRIDGE protocol

Abstract

AbstractBackgroundDuring coronavirus disease 2019 (COVID‐19)–related operating room closures, some multidisciplinary thoracic oncology teams adopted a paradigm of stereotactic ablative radiotherapy (SABR) as a bridge to surgery, an approach called SABR‐BRIDGE. This study presents the preliminary surgical and pathological results.MethodsEligible participants from four institutions (three in Canada and one in the United States) had early‐stage presumed or biopsy‐proven lung malignancy that would normally be surgically resected. SABR was delivered using standard institutional guidelines, with surgery >3 months following SABR with standardized pathologic assessment. Pathological complete response (pCR) was defined as absence of viable cancer. Major pathologic response (MPR) was defined as ≤10% viable tissue.ResultsSeventy‐two patients underwent SABR. Most common SABR regimens were 34 Gy/1 (29%, n = 21), 48 Gy/3–4 (26%, n = 19), and 50/55 Gy/5 (22%, n = 16). SABR was well‐tolerated, with one grade 5 toxicity (death 10 days after SABR with COVID‐19) and five grade 2–3 toxicities. Following SABR, 26 patients underwent resection thus far (13 pending surgery). Median time‐to‐surgery was 4.5 months post‐SABR (range, 2–17.5 months). Surgery was reported as being more difficult because of SABR in 38% (n = 10) of cases. Thirteen patients (50%) had pCR and 19 (73%) had MPR. Rates of pCR trended higher in patients operated on at earlier time points (75% if within 3 months, 50% if 3–6 months, and 33% if ≥6 months; p = .069). In the exploratory best‐case scenario analysis, pCR rate does not exceed 82%.ConclusionsThe SABR‐BRIDGE approach allowed for delivery of treatment during a period of operating room closure and was well‐tolerated. Even in the best‐case scenario, pCR rate does not exceed 82%.