Patterns of disease, treatment, and outcomes of esophageal cancer arising within a previous radiation treatment field.

Abstract

328 Background: Esophageal cancer arising within a previous radiation treatment field (ECRF) is rare. The patterns of disease, treatment and outcomes in these patients (pts) have not been well characterized. Methods: A retrospective analysis was performed for pts treated for esophageal cancer at the Princess Margaret Cancer Centre from 2002-2016. Electronic medical records of all pts with a histologic diagnosis of esophageal cancer occurring within the field of previous radiotherapy were reviewed. The Kaplan-Meier method was used to calculate progression free survival (PFS) and overall survival (OS). Results: Of 31 ECRF pts identified, the most common prior cancer was head and neck (45%), median radiation (RT) dose 50Gy, median time to diagnosis of esophageal cancer 12 years. Features at diagnosis of ECRF included: median age 71 years, 58% male, 87% with performance status (PS) 0-1, 77% squamous cell carcinoma, 19% stage IV. Treatment intent was curative in 16 pts, palliative in 15 (Table). Reasons for palliative treatment were: 40% metastatic, 53% comorbidities/PS, 7% anatomic factors. Of resected pts, 36% had a pT1-2 tumour, 55% pN0, 69% R0. For curative pts, median PFS was 26.2 months (95%CI 10.9-34.4) with a 3 year PFS rate of 35% (95% CI 15-81). Median OS for curative pts was 26.4 months (95%CI 17.8-105.5) with a 3 year OS rate of 43% (95% CI 22-83). Most palliative pts were unable to have chemotherapy due to comorbidities and PS. Median OS for palliative pts was 9.5 months (95% CI 3.6-15.4). Conclusions: Most ECRF pts presented with earlier stage disease; however, more than a third of these could not have aggressive curative treatment due to comorbidities and/or PS. Most curative pts had surgery alone. Few palliative pts had chemotherapy, largely due to poor clinical status. Our data suggest that outcomes in both curative and palliative ECRF pts may be limited by the ability to tolerate standard of care treatments. [Table: see text]