249. OVERALL SURVIVAL OF PATIENTS WITH ESOPHAGEAL CANCER TREATED WITH DEFINITIVE CHEMORADIOTHERAPY: INSIGHTS FROM A RETROSPECTIVE STUDY

Abstract Background Neoadjuvant chemoradiotherapy followed by esophagectomy is the standard of care for patients with locally advanced esophageal cancer. However, definitive chemoradiotherapy (dCRT) may be considered as an alternative for those with unresectable disease, cervical location of the tumor or if a non-surgical approach is preferred based on the patient's condition. Heterogeneity in indications for dCRT makes it challenging to draw generalized conclusions regarding outcomes and survival. The aim of this study was to evaluate overall survival (OS) and recurrence patterns in patients with specified homogeneous indications for dCRT. Methods Patients with esophageal cancer treated with dCRT (50.4 Gy radiotherapy concomitant with 6 cycles of carboplatin/paclitaxel) between 2012-2022 in a tertiary referral center were identified from our institutional database. Primary endpoint was OS calculated from date of diagnosis until date of death or last day of follow-up, using the Kaplan Meier method. Secondary endpoints included the proportion of patients that completed the dCRT regimen, 30- and 90-day mortality following dCRT and disease recurrence. Results 162 patients were included, median follow-up was 74.6 months (IQR 46.2-99.3). The full dCRT regimen was completed by 116 (73.9%) patients. The 30- and 90-day mortality were 2.5% and 8.3%, respectively. The median OS was 23.7 months (95% CI 6.65-40.66) for cervical location of the tumor, 13.7 months (95% CI 7.92-29.8) for irresectable disease, 28.2 months (95% CI 12.10-44.22) for patients unfit for surgery and 20.6 months (95% CI 14.14-27.13) for those with preference for dCRT (p=0.15). Disease recurrence was observed in 74 patients (46%), located locoregional (46%), distant (19%) or both locoregional and distant (35%). Conclusion(s) Treatment with dCRT resulted in a 5-year OS of 35% and is associated with a high 90-day mortality. Disease recurrence was mostly locoregional located and was observed in 46% of patients. This emphasizes the critical necessity for enhanced treatment strategies centered on improving locoregional disease control.