Definitive chemoradiotherapy +/- induction chemotherapy in esophageal cancer: A real-world experience.

Abstract

e16072 Background: The SEER 5-year overall survival rate for all stages of esophageal cancer (EC) was 25% in 2019. Definitive chemoradiation (CRT) remains the primary treatment approach for locally advanced EC in the US, however, there are data to support use of induction chemotherapy (CT) in addition to CRT, particularly in adenocarcinoma (AC) histology. The purpose of our study was to assess outcomes in EC patients treated with definitive CRT (+/- induction) to determine which prognostic factors predicted for better survival in a recent, real-world cohort of patients, including those with limited stage IV disease. Methods: This retrospective study included Stages II-IVB (AJCC 8th ed.) EC patients treated with definitive CRT (radiation dose of ≥40 Gy and at least two cycles of concurrent CT [+/- induction CT, +/- esophagectomy]) at our institution between 2008 and 2020. To analyze prognostic factors and estimate OS, univariate models (UVA) and a multivariate (MVA) Cox proportional hazards regression model including age, Stage (II, III, IVA, IVB), AC vs. SCC, esophagectomy, ECOG performance status (PS), and induction CT were performed. Results: Of the 183 patients treated with definitive CRT, 18 were stage II, 119 stage III, 21 stage IVA, and 25 stage IVB. There were 45 SCC and 138 AC patients (Table). Prognostic factors associated with prolonged OS on MVA included lower PS (p<0.01) and esophagectomy (p = 0.05). Stage IVA was associated with shorter survival (p<0.01). Induction CT (delivered in 53% of AC, 31% SCC) was associated with improved survival on UVA (p=0.04), but not MVA (p = 0.08). By histology, 5-year survival rate was 42.7% and 18.2% for AC and SCC, respectively. Conclusions: At our institution, those who received an esophagectomy and those with lower ECOG scores had better survival. The 5-year survival rate was higher for AC patients compared to SCC, with more AC patients receiving esophagectomy and induction CT (significant on UVA, but not MVA). The 5-year survival rate for AC in our study was nearly identical to that seen in the CROSS trial (Shapiro et al. 2015) AC cohort but included >25% stage IV patients. This modern cohort also included poor PS (ECOG≥2) patients (9.2% AC and 13.6% SCC), suggesting induction CT, in addition to pre-operative CRT + surgery, may have added benefit in a real-world practice. Thus, further prospective study is needed.[Table: see text]