The Role Of ERCC1 Protein Expression And S-1maintenance Chemotherapy In The Treatment Of Advanced Gastric Cancer

ObjectiveTo study the expression of ERCC1 in advanced gastric cancer(AGC)and its correlation with efficacy of first-line oxaliplatinbased chemotherapy and prognosis;and observe the survival and safety of low-dose S-1 maintenance chemotherapy after the first-line oxaliplatinbased chemotherapy.MethodsExpression of ERCC1 protein in the tissues of 85 cases of initial treatment advanced gastric cancer was measured by immunohistochemistry(SP method).Patients were treated with the first-line combined chemotherapy of S-1 combined with oxaliplatin(SOX)(oxaliplatin 130mg/m2 iv,d1;dose of S-1 according to body surface area(<1.25 m2 80 mg/d,?1.25~<1.5 m2 100 mg/d,?1.5 m2 120 mg/d)twice daily for14 days;every 21 days was a cycle)6 cycles at most.The patients who responded to the therapy were assigned to either the group with low-dose S-1 maintenance chemotherapy(S-1 80mg/d)or the observation group with follow-up.The maintenance therapy was continued until disease progression or intolerable toxicity.ResultsThe positive rate of ERCC1 protein was 31.76%.The response rate to chemotherapy in ERCC1 protein expression positive was 25.93%,the response rate to chemotherapy in ERCC1 negative group was 63.79%,the difference between the two groups was statistically significant(P<0.05).Median time to progression(mTTP)in thepositive and negative group was 4.5 and 6.0 months respectively(P<0.05);The median overall survival(mOS)in the positive and negative group was 10.7 and 14.6 months respectively(P< 0.05).Among the 60 patients who responded to the combined therapy,28 patients entered the maintenance group and 32 patients entered the observation group.Median time to progression(m TTP)in the treatment group(n=28)and observation group(n=32)was 8.3 and 6.0 months respectively(P<0.05).The median overall survival(mOS)in the treatment group and observation group was 15.8 and 14.4 months respectively(P=0.063).The incidence rate of leuk-openia,neutropenia,thrombocytopenia in treatment group was higher than that in observation group(P<0.05).Mostly I~II degrees,rare III~IV degree,were improved after symptomatic treatment.ConclusionERCC1 protein expression level in advanced gastric cancer tissue has an relationship to be the efficacy of first-line oxaliplatinbased chemotherapy and prognosis of patients.Low-dose S-1 maintenance chemotherapy may delay the tumor progression of patients with advanced gastric cancer after the first-line chemotherapy.