Predictive value of chemotherapy-induced neutropenia for the efficacy of oral fluoropyrimidine S-1 in advanced gastric carcinoma

Myelosuppression that occurs during chemotherapy has been reported to be a predictor of better survival in patients with breast or lung carcinomas. We evaluated the prognostic implications of chemotherapy-induced neutropenia in advanced gastric carcinoma. Data from a prospective survey of oral fluoropyrimidine S-1 for advanced gastric cancer patients in Japan were reviewed. We identified 1055 untreated patients with adequate baseline bone marrow function. During treatment with S-1, a total of 293 (28%) patients experienced grade 1 or higher neutropenia. The adjusted hazard ratio of death for the presence of neutropenia, as compared with the absence of such toxicity, from a multivariate Cox model was 0.72 (95% confidence interval, 0.54-0.95; P=0.0189) for grade 1 neutropenia, 0.63 (0.50-0.78; P<0.0001) for grade 2 neutropenia and 0.71 (0.51-0.98; P=0.0388) for grade 3-4 neutropenia. These findings suggest that the occurrence of neutropenia during chemotherapy is an independent predictor of increased survival in patients with advanced gastric cancer, whereas the absence of such toxicity indicates that the dosages of drugs are not pharmacologically adequate. Monitoring of neutropenia in patients who receive chemotherapy may contribute to improved drug efficacy and favourable survival. © 2007 Cancer Research UK.