Effect of Segmental Abutting Esophagus-Sparing Technique to Reduce Severe Esophagitis in Limited-Stage Small-Cell Lung Cancer Patients Treated with Concurrent Hypofractionated Thoracic Radiation and Chemotherapy

SIMPLE SUMMARY: The “gold standard” for limited-stage small cell lung cancer (LS-SCLC) is 45 Gy in 1.5 Gy twice-daily fractions (HYPER) thoracic radiotherapy (TRT) scheduled concurrently with platinum-etoposide chemotherapy. However, the HYPER TRT regimen has failed to be universally implemented, mainly due to its inconvenience and notably increased acute esophageal toxicity (Grade ≥3, 19–27%). We successfully innovated the segmental abutting esophagus-sparing (SAES) technique in order to reduce the radiation dose of the esophagus. Based on a cohort derived from a prospective phase III clinical trial, the SAES technique significantly reduced severe acute esophagitis (≥Grade 3: 3.3%) in patients receiving hypofractionated (HYPO) radiotherapy (45 Gy in 3 Gy once-daily fractions) concurrently with chemotherapy. Thus, the SAES technique could help to achieve better tolerance of the HYPO schedule and provide good feasibility for dose escalation, which may translate to better local control and prognosis in the future. ABSTRACT: The aim of the current study is to evaluate the effect of segmental abutting esophagus-sparing (SAES) radiotherapy on reducing severe acute esophagitis in patients with limited-stage small-cell lung cancer treated with concurrent chemoradiotherapy. Thirty patients were enrolled from the experimental arm (45 Gy in 3 Gy daily fractions in 3 weeks) of an ongoing phase III trial (NCT 02688036). The whole esophagus was divided into the involved esophagus and the abutting esophagus (AE) according to the distance from the edge of the clinical target volume. All dosimetric parameters were significantly reduced for the whole esophagus and AE. The maximal and mean doses of the esophagus (47.4 ± 1.9 Gy and 13.5 ± 5.8 Gy, respectively) and AE (42.9 ± 2.3 Gy and 8.6 ± 3.6 Gy, respectively) in the SAES plan were significantly lower than those (esophagus 48.0 ± 1.9 Gy and 14.7± 6.1 Gy, AE 45.1 ± 2.4 Gy and 9.8 ± 4.2 Gy, respectively) in the non-SAES plan. With a median follow-up of 12.5 months, only one patient (3.3%) developed grade 3 acute esophagitis, and no grade 4–5 events happened. SAES radiotherapy has significant dosimetric advantages, which are successfully translated into clinical benefits and provide good feasibility for dose escalation to improve local control and prognosis in the future.