Gastric Cancer Stage IV clinical trials

Trastuzumab to Patients With Advanced Gastric Cancer With HER2 Positive Expression in CTC

BACKGROUND: Gastric cancer is one of the most common cancers and is one of the most deadly cancers. Most patients have advanced disease and should receive first-line trastuzumab-associated chemotherapy when the biopsy is positive for immunocytochemical expression and / or HER2 gene amplification. A study conducted by our group noted that there may be disagreement in HER2 expression between circulating tumor cells (CTCs) and tumor tissue. However, the effectiveness of using anti-HER2 treatment when only CTC express HER2 is unknown. The present study aims to evaluate the expression of HER2 in patients with relapsed or metastatic gastric cancer and what would be the efficacy of adding trastuzumab to chemotherapy when tumor tissue is negative for HER2, but there is expression of this gene in CTCs. OBJECTIVES: The primary objectives are to evaluate HER2 expression in circulating tumor cells of relapsed or metastatic gastric cancer patients with negative HER2 expression on tissue biopsy and response to standard treatment with combined anti-HER2 chemotherapy in this population. Secondary objectives are to assess the prognostic impact of HER2 positivity on circulating tumor cells in advanced gastric tumors and to evaluate HER2 expression in CTCs at the time of treatment progression. METHODS: The investigators will prospectively evaluate HER2 expression in CTC and its response to treatment with standard chemotherapy and addition of trastuzumab in patients with relapsed or metastatic gastric cancer with positive expression of HER2 only in CTC. HER2 expression in tissue and in CTC will be evaluated by immunocytochemistry. Descriptive statistics will be used to report the results of categorical and continuous variables, and respective dispersion measures. Time-to-event variables will be reported in Kaplan Meyer medians and curves. EXPECTED RESULTS: Upon completion of the study the investigators expect to show the frequency of HER2 expression in this specific population, higher radiological response rate with trastuzumab combination compared to chemotherapy alone, determine the prognostic impact associated with HER2 expression in CTCs and show the frequency of HER2 expression in CTCs at the time of study treatment progression. This study may open a new opportunity for anti-HER2 treatment for gastric cancer patients.