What are NCI-designated cancer centers using for gastric and esophageal cancer HER2 testing?

Abstract

e15010 Background: HER2 testing in gastric and esophageal cancers (GEC) is a new area with evolving research on which testing methods are best. Based on the ToGA trial, guidelines recommend IHC/reflex to FISH, but studies show effectiveness of other protocols as well (e.g. Yan et al, J Clin Pathol 2011). Our study provides a benchmark on practices for GEC HER2 testing at NCI Cancer Centers. Methods: We conducted an IRB approved web survey of 58 NCI cancer centers (pathologists and oncologists) providing adult GEC care. The survey included 14 questions on HER2 testing methods, reflex and retest practices and awareness of institutional lab accreditation. Results: The study achieved a response rate of 93% (54/58 sites). In this cohort, 41% (22/54) of sites conduct HER2 GEC tests using concurrent FISH and IHC methods. An IHC testing method with reflex to FISH is used at 39% (21/54) of sites, of which all 21 sites reflex IHC 2+ results, and 9 of 21 automatically reflex IHC beyond 2+ (see table, results are not mutually exclusive). FISH only testing is done at 15% (8/54); concurrent FISH and CISH testing at 2% (1/54); concurrent SISH and IHC testing at 2% (1/54), and SISH only testing at 2% (1/54) of sites. The survey separately asked about HER2 testing methods for breast cancer (BC), which were compared by site to GEC HER2 practices: 65% (35/54) of sites conduct HER2 testing in a similar manner - analogous methods in similar order (p= 0.0471); 19% (10/54) of sites use primary IHC in GEC but primary FISH in BC, and 17% (9/54) of sites conduct primary or concurrent FISH testing in GEC but primary IHC in BC. Lab CAP certification for their sites was known by 89% (56/63) of GEC pathologists vs 34% (19/56) of GEC oncologists (p < .0001). 67% (42/63) of GEC pathologists were aware of whether their lab underwent a HER2 IHC and/or FISH proficiency test, vs 4% (2/56) of GEC oncologists (p<.0001). Conclusions: For gastric and esophageal HER2 testing, concurrent FISH and IHC and expanded reflex testing, beyond IHC 2+ results, are the common practice at the NCI cancer centers. [Table: see text]