650P - A prospective study of re-evaluation of the HER2 status in metastatic or recurrent lesions in gastric cancers with HER2-negative primary tumors: GA...

Date 29 September 2014
Event ESMO 2014
Session Poster Display session
Topics Gastric Cancer
Pathology/Molecular Biology
Translational Research
Presenter Sook Ryun Park
Citation Annals of Oncology (2014) 25 (suppl_4): iv210-iv253. 10.1093/annonc/mdu334
Authors S.R. Park1, M.H. Ryu1, Y.S. Park2, H. Jung3, B. Ryoo1, Y. Kang1
  • 1Department Of Oncology, Asan Medical Center, University of Ulsan College of Medicine, 138-736 - Seoul/KR
  • 2Department Of Pathology, Asan Medical Center, University of Ulsan College of Medicine, 138-736 - Seoul/KR
  • 3Department Of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, 138-736 - Seoul/KR

Abstract

Aim

To investigate the HER2 positivity rate in corresponding metastatic or relapse lesions in gastric cancers (GCs) with HER2-negative primary tumors.

Methods

Patients (pts) with unresectable, metastatic or recurrent gastric/gastroesophageal junction (GEJ) adenocarcinoma and who will receive 1st-line chemotherapy, were eligible if HER2 was negative in primary gastric tumor. HER2 positivity was defined as IHC 3+ or IHC 2 + /FISH+ by the GC scoring system. HER2 status was evaluated in metastatic or recurrent lesions.

Results

From May 2011 to Feb 2014, 175 eligible pts were enrolled. Baseline characteristics were as follows: initially metastatic/locally advanced/recurrent disease = 60(34.3%)/1(0.6%)/114(65.1%); primary tumor location, GEJ ∼ fundus/body/antrum/diffuse stomach = 15(8.6%)/92(52.6%)/56(32.0%)/12(6.9%); Lauren classification, intestinal/diffuse/mixed = 57(32.6%)/101(57.7%)/17(9.7%); primary tumor specimens for HER2 assessment, biopsy/gastrectomy = 52(29.7%)/123(70.3%); and HER2 IHC score in primary tumor, 0/1/2 = 144(82.3%)/18(10.3%)/13(7.4%). The median time interval of HER2 assessment between primary and relapse sites was 28.8 months (range 3.7-158.2). HER2 in metastasis or recurrence was evaluated in peritoneum (21.1%), liver (16.6%), ovary (16.6%), lymph node (12.6%), locoregional site (13.7%), and others (19.4%). Adjuvant chemotherapy had been given in 91 pts (52.0%) between HER2 assessment at primary and relapse sites. Since HER2 re-evaluation in metastasis or relapse identified 10 pts with HER2-positive tumor, the conversion rate for HER2 positivity was 5.7% (95% CI 2.3-9.1%). HER2 assessment in liver metastasis was significantly associated with the converted HER2 positivity (liver vs others = 5/29 [17.2%] vs 5/146 [3.4%]; p = 0.012) while other baseline characteristics, disease status, a type of specimen, time interval between primary and metastatic/recurrent lesions, and prior exposure to chemotherapy did not show significant associations.

Conclusions

Re-evaluation for the HER2 status should be considered in metastatic or recurrent lesions even if the primary tumor is HER2-negative in GC.

Disclosure

All authors have declared no conflicts of interest.