SUNSET: Stereotactic Radiation for Ultracentral Non–Small-Cell Lung Cancer—A Safety and Efficacy Trial

Risk‐adapted stereotactic body radiation therapy for central and ultra‐central early‐stage inoperable non‐small cell lung cancer

“…Organs at risk contouring was adopted from RTOG 0813, EORTC LungTech, SUNSET, and RTOG 1106 contouring atlas, and normal tissue constraints were adopted from RTOG 0813 and previous HILUS studies . Meanwhile, maximum point dose and volumetric maximum dose analyses were evaluated for OAR including esophagus, heart, pulmonary artery, pulmonary vein, spinal cord, ipsilateral lung, contralateral lung, lung total, trachea, mainstem bronchi, lobe bronchi, and proximal bronchial tree.…”

“…Organs at risk contouring was adopted from RTOG 0813, 35 EORTC LungTech, 36 SUNSET, 18 and RTOG 1106 contouring atlas, 37 and normal tissue constraints were adopted from RTOG 0813 and previous HILUS studies. 6,[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] Meanwhile, maximum point dose and volumetric maximum dose analyses were evaluated for OAR including esophagus, heart, pulmonary artery, pulmonary vein, spinal cord, ipsilateral lung, contralateral lung, lung total, trachea, mainstem bronchi, lobe bronchi, and proximal bronchial tree. Treated doses were converted to biologically effective doses (BED) based on the formula: nd [1 + d/(α/β)], where n is number of fractions, and d is dose/fraction (Gy); assuming α/β value of 10 for NSCLC (ie BED 10 ) and α/β value of 3 for normal tissues (ie BED 3 ).…”

“…Our hypothesis is that those with ultra‐central tumors have poorer OS, PFS, LC, or higher toxicity rates than those with central tumors. The results of this study may provide clinical guidance in the use of SBRT for early‐stage NSCLC patients, and they may be used to interpret the results from the RTOG 0813, EORTC LungTech, and SUNSET prospective clinical trials. It would be very interesting if these studies subdivided their results into central and ultra‐central tumors.…”

“…In the 2010s, a new subgroup within the cohort of patients with central tumors was designated as “high‐risk” or “ultra‐central” tumors, or those that abut the PBT . Ultra‐central tumors have increased grade 4+ toxicity, even with conservative radiotherapy fractionation .…”

“…11,12 In the 2010s, a new subgroup within the cohort of patients with central tumors was designated as "high-risk" or "ultra-central" tumors, or those that abut the PBT. 7,[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] Ultra-central tumors have increased grade 4+ toxicity, even with conservative radiotherapy fractionation. 25 Of concern, Haseltine et al reported that in patients with PBT-abutting tumors who received conservative dose-fractionation SBRT plus bevacizumab, two patients experienced grade 5 pulmonary hemorrhages.…”