Trastuzumab to Patients With Advanced Gastric Cancer With HER2 Positive Expression in CTC
Status:
Recruiting
Trial end date:
2025-01-01
Target enrollment:
Participant gender:
Summary
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.