In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 35, No. 4_suppl ( 2017-02-01), p. 15-15
Abstract:
15 Background: HER2 testing is routine for metastatic gastric or gastroesophageal junction cancer (mGC/GEJC). Differing HER2-positivity rates are considered to be potential indicators of inter- and intra-laboratory deviations in testing quality. The influence of patient-, sample-, or method-related factors on HER2-positivity has not been assessed systematically. Methods: This observational, prospective study collected routine HER2 test result, patient- and tumor-related factors, sample source, and testing method data to identify factors influencing HER2-positivity rates in mGC/GEJC. Influencing factors were identified using stepwise multiple logistic regression and a statistical model was developed to predict probability of HER2-positivity. Institutes with deviations in HER2-positivity rates were identified by comparing 95% confidence intervals (CI) of documented and predicted rates. Results: From Jan 2013 to Dec 2015, data were collected from 2761 mGC/mGEJC routine diagnostic specimens at 50 pathology institutes in Germany. Final analyses included 2033 specimens with HER2 test results (1554 mGC and 479 mGEJC cases). Overall HER2-positivity rates across centers was 19.8% for mGC and 30.5% for mGEJC. Lauren classification showed the highest correlation with HER2-positivity, followed by HER2 testing rate, tumor location, type of sample (resection vs biopsy), and testing method (immunohistochemistry vs fluorescence in situ hybridization) (all P 〈 .05). Four institutes were identified with predicted HER2-positivity rates outside the 95% CI of the documented rate. Conclusions: This is the first study to report on multifactorial parameters that impact HER2-positivity rates in routine mGC/GEJC diagnostics. Results suggest that effective assessment of HER2 testing quality based on positivity rates should consider tumor characteristics, testing rate, type of specimen, and testing method, as they affect HER2-positivity. As therapy options for HER2-positive mGC/GEJC continue to evolve, reliably identifying the right patients is key.
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/JCO.2017.35.4_suppl.15
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2017
detail.hit.zdb_id:
2005181-5
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