The HILUS trial found an unacceptably high rate of grade 5 bronchopulmonary hemorrhage after 56 Gy in 8 fractions for ultracentral lung tumors within 1cm of the mainstem bronchi or trachea. However, the trial was small with 65 patients overall and just 39 with tumors within 1cm of the bronchi and trachea. This study pooled data from 230 patients treated with 56 Gy in 8 fractions for tumors within 2cm of the bronchi or trachea. The rate of grade 5 toxicity was 13% with ⅔ of those deaths from bronchopulmonary hemorrhage. Tumor compression of tracheobronchial tree and maximum dose to the mainstem or intermediate bronchi were the factors significantly associated with grade 5 toxicity in multivariable analysis. The rate of grade 5 toxicity was 43% when there was tracheobronchial compression. Another important finding was that the bronchus intermedius carried the same risk as the mainstem bronchi. Overall, the median D0.001cc 98 Gy EQD2 whereas it was 119 Gy EQD2 in patients who developed grade 5 events. No grade 5 events occurred when the D0.001cc was below 92Gy EQD2. | Lindberg, Int J Radiat Oncol Biol Phys 2023
