Results of the use of trastuzumab combined with different chemotherapy regimens in first-line treatment of HER2-positive disseminated gastric cancer

Abstract

Gastric cancer (GC) is one of the most common types of malignant tumour worldwide and is ranked fifth in the cancer incidence pattern and third in the cancer mortality pattern. In the Russian Federation, 39.9% of patients are diagnosed with stage IV gastric cancer, 46.6% of patients die within the first year after diagnosis. The combinations of trastuzumab with platinum derivatives and fluoropyrimidines (trastuzumab + doublet) are regarded as the standard therapy against HER2 positive disseminated gastric cancer. We studied the efficacy and toxicity of the combination of trastuzumab with three-component (triple) chemotherapy regimens (docetaxel or irinotecan + platinum derivatives and fluoropyrimidines). In combination of trastuzumab with triplet chemotherapy, an objective response was achieved in 76.7% of cases, with doublet chemotherapy it was achieved in 60% (p = 0.228), of which complete tumour regression was observed in 10%, control of the disease was reported in 96.7% and 95.0 % (p = 1.0) patients, respectively. The median progression-free survival in patients, who received trastuzumab in combination with triplet chemotherapy, was 9.66 months, in combination with doublet chemotherapy was 11.07 months, the difference was not statistically significant (p = 0.800; OR = 0.908; 95% CI: 0.430–1.918). Median survival of patients is not achieved. The obtained results showed that adding a third cytostatic agent to the standard duplet chemotherapy in combination with trastuzumab does not lead to improvement in the treatment outcomes of first-line therapy in patients with HER2-positive disseminated gastric cancer.