204 - Contralateral Esophageal-Sparing Technique Reduces High-Grade Esophagitis in Locally Advanced Small Cell Lung Cancer: Updated Results from a Randomized Trial

Purpose/Objective(s):

Acute esophagitis, especially grade 3 or higher, is a major limiting toxicity in the concurrent chemoradiotherapy for locally advanced small cell lung cancer (LS-SCLC) , which can severely impact patient quality of life and treatment outcomes. The primary objective of this study was to evaluate whether the contralateral esophageal-sparing technique (CEST) could reduce the incidence and severity of high-grade esophagitis in LS-SCLC patients. The secondary objectives included assessing esophageal dose-volume parameters and overall treatment efficacy.

Materials/Methods:

This single-center, prospective, randomized controlled trial enrolled 70 eligible LS-SCLC patients with tumors a within 1 cm of the esophagus. They were randomly assigned to the standard therapy group (CON) and the CEST group in a 1:1 ratio. All eligible patients received concurrent chemoradiotherapy (45 Gy radiotherapy in 30 fractions, twice-daily for 3 weeks with chemotherapy). In the CEST group, the CE was contoured as an avoidance structure with specific dose-volume constraints (CE maximum dose < 42 Gy, V36 < 0.5 cc, V30 < 3.5 cc). Acute esophagitis (AE) events were graded in line with the RTOG acute toxicity grading system. Ethical approval was obtained, and all patients provided informed consent.

Results:

In this study, 70 patients were recruited (34 in CEST group, 36 in CON group). Eventually, 62 patients (31 in each group) were included in the analysis due to patient withdrawals and incomplete radiotherapy. In the CEST group (n=31), the incidence of acute esophagitis was 19.4%, and no cases of grade 3 or higher adverse events (AE) were observed. In the CON group (n=31), the incidence rate was 83.9%, including 4 cases (12.9%) of grade 3 AE. Dosimetric analysis revealed that the median maximum esophageal dose in the CEST group was 38.0 Gy, which was significantly lower than that in the CON group (47.8 Gy). The CEST group had better volume parameters, such as V45 of 0 cc, V36 of 0.01 cc, and V30 of 0.30 cc, compared to the CON group's 3.15 cc, 7.88 cc, and 9.31 cc, respectively (all P < 0.01). For treatment efficacy, analyses of progression-free survival (PFS) and overall survival (OS) showed no significant differences between the two groups (all P>0.05).

Conclusion:

This study shows that the application of CEST in LS-SCLC patients can significantly reduce the incidence and severity of acute esophagitis, making it worthy of further clinical promotion. CEST helps improve the quality of life for patients undergoing concurrent chemoradiotherapy and may optimize treatment standards.