Abstract IA31: Radiation therapy in lung cancer: Recent trends and future directions

Radiation techniques for lung cancer have evolved substantially over the past decade. While previously many patients were treated with 3D conformal therapy, with large uniform margins placed to estimate respiratory motion in the “average” tumor, patients are now simulated with sophisticated, real-time monitoring of internal motion such that treatment volumes can be individualized to maximize normal tissue sparing through image-guided radiation therapy (IGRT). In addition, many patients are now treated with intensity-modulated radiation therapy (IMRT), which has served to drastically improve conformality in select cases and increase the proportion of patients in which high doses are achievable. Concurrent with these advances, proton beam therapy (PBT) has been implemented in a limited number of centers, with the hope of utilizing the dosimetric distribution advantage of the Bragg Peak to further reduce toxicity. The role of PBT in both early-stage and locally advanced non-small cell lung cancer continues to be defined, as results from a phase II multicenter randomized trial predominantly in patients with stage II-III disease did not demonstrate superiority with PBT and concurrent chemotherapy when compared to similar regimens with IMRT. Finally, there have been much data produced with regard to dosing regimens. In early-stage disease, there has been increased implementation of stereotactic ablative body radiation (SABR), with prospective data emerging for both peripheral and central lesions. In the locally advanced setting, results from RTOG 0617 demonstrated no difference when comparing 60 Gy vs. 74 Gy in the setting of chemoradiation. There has also been a trend towards hypofractionation for patients who are unable to tolerate concurrent chemoradiation or those with oligometastatic disease, yet the benefit of hypofractionated radiation sequentially vs. combined modality treatment will need to be further assessed in prospective randomized trials, particularly in the era of immunotherapy. Citation Format: Daniel R. Gomez. Radiation therapy in lung cancer: Recent trends and future directions [abstract]. In: Proceedings of the Fifth AACR-IASLC International Joint Conference: Lung Cancer Translational Science from the Bench to the Clinic; Jan 8-11, 2018; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(17_Suppl):Abstract nr IA31.