Adaptive intensity-modulated radiotherapy with simultaneous integrated boost for stage III non-small cell lung cancer: Is a routine adaptation beneficial?

PurposeTumor and anatomical changes during radiotherapy have been observed in stage III non-small cell lung cancer (NSCLC) from many previous studies. We hypothesized that a routinely scheduled adaptive would clinical important dose benefits to lower the risk of toxicities, without increasing tumor recurrences.MethodsWe retrospectively reviewed 92 consecutive patients with inoperable NSCLC between November 2017 March 2019. All eligible should received simultaneously integrated boost (SIB) using intensity-modulated radiation therapy (IMRT). A mid-treatment CT simulation new adapted plan were given after first 20 fractions. The organs at (OARs) delineated per RTOG 1106 atlas. Dose-volume histograms quantitatively compared initial composite plans. Logistic regression was applied analyze dose–response relationship. Clinical endpoints included acute symptomatic pneumonitis (RP2) esophagitis (RE2), local regional control, progression-free survival (PFS).ResultsSixty-four SIB-IMRT consecutively included. GTVs reduced by median ?38.2% 42 44 Gy fractions radiotherapy. By adapting changes, dosimetric parameters OARs decreased significantly. mean an average ?74.8 cGy, esophagus 183.1 cGy. found grade 2 or higher RP 11 (17.2%), RE2 28 (43.8%). Commonly used metrics significantly associated RP2 RE2. adaptation could reduce probability 3%, 5%. Subgroups larger shrinkage may get more toxicities benefits. estimated PFS 12.5 months start radiotherapy.ConclusionsWe demonstrated strategy surrounding normal tissues, potentially RE, recurrences.