[Risk associated with severe hematological toxicity in patients with advanced or recurrent colonic cancer receiving combination chemotherapy of S-1 and irinotecan hydrochloride].

The aim of this study was to analyze the risk factors for grade 3 to 4 hematological toxicity after primary chemotherapy (Tegafur, gimeracil, oteracil potassium (S-1)/irinotecan hydrochloride (CPT-11)) in 87 (56 male, 31 female; median age 66.1 years) patients with unresectable or recurrent colonic cancer between April 2005 and May 2009, and to prepare a risk classes (low-risk, intermediate-risk or high-risk groups). The rate of grade 3 to 4 hematological toxicity was 16.1%. At multivariate analysis, risk factors for grade 3 to 4 hematological toxicity were baseline WBC, Cr, female (p<0.05). The toxicity index (TI) consisted of risk factors and regression coefficient. We were stratified patients into three groups according to TI that was calculated for each patient. The group with high value was found to include patients with grade 3 to 4 hematological toxicity with a significantly higher frequency than the group with low value (4.2% vs 57.1%, p=0.004). This risk classes could be useful to identify patients at high risk for chemotherapy-induced grade 3 to 4 hematological toxicity.