648P - Concordance of HER2 expression in primary and metastatic upper gastrointestinal adenocarcinoma

Date 29 September 2014
Event ESMO 2014
Session Poster Display session
Topics Gastrointestinal Cancers
Pathology/Molecular Biology
Translational Research
Presenter Charlotta Hedner
Citation Annals of Oncology (2014) 25 (suppl_4): iv210-iv253. 10.1093/annonc/mdu334
Authors C. Hedner1, B. Nodin2, K. Jirström2, J. Eberhard2
  • 1Clinical Sciences, Lund, Lund University, 22185 - Lund/SE
  • 2Department Of Clinical Sciences, Division Of Oncology And Pathology, Lund University, Skåne University Hospital, Lund/SE

Abstract

Aim

Upper gastrointestinal, i.e. gastric and esophageal, cancers have a dismal prognosis and, hence,there is an evident need for better prognostic and treatment biomarkers for improved clinical management of patients with these cancer forms.Treatment with trastuzumab has in a large, randomized study been shown to improve survival rates for patients with HER2-overexpressing advanced gastric cancer, but the prognostic value of HER2 overexpression remains uncertain. Here, we examined the expression and prognostic value of HER2 expression in primary upper gastrointestinal adenocarcinoma, and concordance in expression between primary tumours and a subset of paired lymph node metastases.

Methods

Immunohistochemical HER2 expression was examined in tissue microarrays with all primary tumours and 81 paired lymph node metastases from 175 patients with esophageal and gastric adenocarcinoma. Scoring criteria developed for gastric cancer were used and cases denoted as 2-3+ or 3+ were considered overexpressed. Kaplan Meier curves and log rank test were used to assess OS and recurrence free survival according to HER2 expression.

Results

HER2 was overexpressed in 33/174 (19.0%) or 17/174 (9.8%) primary cancers, with the highest proportion in esophageal carcinoma, and 18/79 (22.8%) or 13/79 (16.5%) matched lymph node metastases. A positive conversion from primary tumour to lymph node metastasis was seen in 5/62 (8.1%) cases and a negative conversion in 3/17 (18.8%) cases. HER2 overexpression was significantly associated with a prolonged OS in patients with esophageal cancer (p = 0.026), but not in the entire cohort or in patients with gastric cancer.

Conclusions

Our results demonstrate a discordant expression of HER2 in primary compared to metastastic adenocarcinomas of the upper gastrointestinal tract. These findings indicate that assessment of HER2 status in the primary tumour alone is not sufficient for treatment predictive purposes. Moreover, given the higher proportion of HER2 overexpression in esophageal adenocarcinoma, the potential benefit of treatment with trastuzumab should also be explored in patients with proximal esophageal adenocarcinoma.

Disclosure

All authors have declared no conflicts of interest.