Patterns of recurrence and outcomes after curative resection of locally advanced HER2-positive gastroesophageal cancer (HPGEC).

Abstract

147 Background: Literature on recurrence and outcomes of HPGEC is scarce. The aim of this study was to determine pattern of recurrence and outcomes after curative intent surgery for locally advanced HPGEC. Methods: A retrospective database was used to identify consecutive patients with gastroesophageal adenocarcinomas undergoing curative intent resection between 2011 and 2016 at the Princess Margaret Cancer Centre. Clinico-demographic data were extracted from the electronic health record. Patterns of relapse are classified as nonvisceral (defined as recurrences in the bone, peritoneal or both), visceral (not nonvisceral, including the brain), or both. Time to relapse (TTR) and overall survival (OS) were calculated from date of histologic diagnosis. Results: Of 45 patients with HPGEC, 78% were male, and 91% were non-Asian. Median age was 64.4 years (interquartile range [IQR] 53, 70); 60% were gastroesophageal junction, 24% were gastric, and 16% were esophageal adenocarcinomas; 31% were poorly differentiated tumors while 68% had clinical or pathological node positive disease. Complete R0 resection occurred in 93%, and 84% had received perioperative therapy (31% with perioperative chemotherapy; 40% with pre-operative chemoradiation; 9% with post-operative chemoradiation). With a median follow-up time of 26.0 months. relapse rate of HPGEC at last follow-up was 78%. Among first relapses, 94% were distant, while 6% were local recurrences. Among distant relapses, visceral recurrences occurred in 85%, nonvisceral in 3%, and 12% patients had both visceral and nonvisceral recurrences. None had peritoneal only recurrence. Median TTR was 12.2 months (IQR 8.8, 23.5), while median post-recurrence survival was 9.7 months (IQR 4.7, 16.3). Of the entire cohort, 2-year OS was 53% and 3-year OS was 26%. Conclusions: More than three-quarters of patients with HPGEC experienced recurrence after curative intent multimodality therapy. Our results suggest that HPGEC rarely relapse with peritoneal only disease or local recurrence, thereby calling into question the utility for aggressive surveillance, pending verification from larger cohorts.