P-0054 - The change of serum HER2 extra cellular domain concentration before and after resection in operable gastric cancer patients in Japan; consider relat...

Date 28 June 2014
Event World GI 2014
Session Poster Session
Topics Gastric Cancer
Pathology/Molecular Biology
Surgery and/or Radiotherapy of Cancer
Presenter Keisei Taku
Citation Annals of Oncology (2014) 25 (suppl_2): ii14-ii104. 10.1093/annonc/mdu165
Authors K. Taku1, M. Watanabe1, M. Suzuki1, H. Miyato2, K. Ootani2, T. Yamaguchi2, M. Maeda3, Y. Ikematsu4, M. Hirai4, S. Mizuno5, M. Takagi1, D. Tsuji6
  • 1Shizuoka General Hospital, Shizuoka/JP
  • 2Yaizu City Hospital, Yaizu/JP
  • 3Shizuoka City Shizuoka Hospital, Shizuoka/JP
  • 4Hamamatsu Medical Center, Hamamatu/JP
  • 5Shizuoka-Kosei General Hospital, Shizuoka/JP
  • 6University of Shizuoka, Shizuoka/JP

Abstract

Introduction

HER2 extra cellular domain (ECD) can be detected in the serum of healthy person, these concentrations are raised in the patients with cancer; this is dependent on tumor HER2 status and tumor burden. In previous reports, serum HER2-ECD status is useful for judgement of efficacy of anti-HER2 therapy in patients with HER2-positive breast cancer. Although, similarly to breast cancer, approximately 20% gastric cancer show HER2 amplification or overexpression and the efficacy of trastuzumab has been reported, we don't have enough date for serum HER2-ECD of gastric cancer patients. The purpose of this prospective study was to evaluate the status of serum HER2-ECD, the change in pre and post complete resection and correlation to pathological HER2 status by IHC and FISH in operable gastric cancer patients in Japan.

Methods

Patients with clinical stage IB-IIIC (T2-4N0-3M0) operable gastric adenocarcinoma were enrolled. The serum HER2-ECD samples for each patients were taken before and one month or more after R0 gastrectomy with D2 lymphadenectomy. We used Chemilumi-Centaur-HER2/neu system (Simens healthcare Japan) to measure the serum HER2-ECD levels. After surgery, we use surgical specimens to examine the pathological HER2 status. We used VENTANA HER2 IHC companion diagnostic assay (Roche Tissue Diagnostics) for IHC and PathVysion HER2 DNA Probe Kit (Abbott Molecular) for FISH. In this study, pathological HER2 positive prescribed IHC3+ and IHC2+ with FISH(+), negative prescribed IHC0, 1+ and IHC2+ with FISH(-).

Results

From September 2011 to December 2012, data from 60 patients were recruited from 4 centers in Shizuoka Japan, and we analyzed data on 60 patients of them. The background of 60 patients were as the following; median age, 68 (range: 39-80); male/female, 50/10; ECOG PS 0/1, 57/3 and clinical stage IB/IIA/IIB/IIIA/IIIB/IIIC, 16/23/9/4/7/1. Pathological HER2 status positive/negative was 8/52, positive rate 13.3%. Median of serum HER2-ECD concentrations pre and post surgery was 10.3 (range: 5.9-14.5) ng/ml and 9.2 (range: 5.9-15.7) ng/ml, median difference between pre and post surgery was 1.3 (range: 0.0-4.9) ng/ml (paired t-test: p = 0.00058). In pathological HER2 positive 8 patients; pre 9.2 (range: 5.9-11.3) ng/ml and post 10.3 (range: 7.5-13.1) ng/ml, median difference 1.2 (range: 0.3-2.8) ng/ml (paired t-test: p = 0.03018), negative 51 patients; pre 10.3 (range: 7.7-14.5) ng/ml, 9.1 (range: 5.9-15.7) ng/ml, median difference 1.3 (range: 0.0-5.0) ng/ml (paired t-test: p = 0.00019).

Conclusion

We could not recognize a clear difference of serum HER2-ECD concentration in pre and post gastrectomy, regardless of pathological HER2 positive and negative status. The possibility that serum HER2-ECD did not reflect pathological HER2 status was suggested in operable gastric cancer patients in Japan.