Utility-based evaluation of the quality of life of patient's with gastric cancer who receive chemotherapy: Comparison of patients' quality of life between oral TS-1 and conventional injectable combination therapy

We tried to clarify the applicability of "utility" for the evaluation of patient's QOL with gastric cancer after chemotherapy and attempted to compare differences in QOL after treatment with the oral antitumor agent TS-1 or with a conventional injectable combination. Three items, moving activity, pain, and gastrointestinal symptoms, were employed as indicators of patient QOL, and then the assessment of utility was compared based on the expected outcomes that 9 pharmacists working on a ward, 9 nurses working on a neurosurgery ward, and 9 nurses working on a gastrointestinal surgery ward estimated directly using the three methods of standard gamble, time trade-off, and rating scale according to predictive scenarios based on each scenario. The QOL of patients who received the two different types of chemotherapy were also compared as the average utilities from the direct estimation depending on patient conditions as used for chart review. Furthermore, the average utilities were compared with the utility of the mapping method, which can be estimated by applying a utility-converting table defined in the EQ-5D survey. The average utility from each practitioner using the direct estimation revealed that the assessed utility from nurses working on a neurosurgery ward was higher than those of the pharmacists. The average utility obtained using the standard gamble method was higher than those using the rating scale and time trade-off methods. The average utility in the TS-1 therapy group was 0.84-0.94, and that in the conventional injectable therapy group was 0.52-0.79 (p<f0.05). The result suggests that utility is applicable for estimation of gastric cancer patient QOL after chemotherapy, and that TS-1 therapy is superior to the traditional injectable combination therapy.