Hisashige Akinori, Sasako Mitsuru, Nakajima Toshifusa
The Institute of Healthcare Technology Assessment, 2-24-10, Shomachi, 770-0044, Tokushima, Japan.
BMC Cancer. 2013 Oct 1;13:443. doi: 10.1186/1471-2407-13-443.
The effectiveness of specific regimens of adjuvant therapy for gastric cancer has not been verified by large clinical trials. Recently, several large trials attempted to verify the effectiveness of adjuvant therapy. The Adjuvant Chemotherapy Trial of TS-1 for Gastric Cancer in Japan, a randomized controlled trial of adjuvant S-1 therapy for resected gastric cancer, demonstrated significant improvement in overall and relapse-free survival, compared to surgery alone. To evaluate value for money of S-1 therapy, cost-effective analysis was carried out.
The analysis was carried out from a payer's perspective. As an economic measure, cost per quality-adjusted life-year (QALY) gained was estimated. Overall survival was estimated by the Kaplan-Meier method, up to 5-year observation. Beyond this period, it was simulated by the modified Boag model. Utility score is derived from interviews with sampled patients using a time trade-off method. Costs were estimated from trial data during observation, while in the period beyond observation they were estimated using simulation results. To explore uncertainty of the results, qualitative and stochastic sensitivity analyses were done.
Adjuvant S-1 therapy gained 1.24 QALYs per patient and increased costs by $3,722 per patient for over lifetime (3% discount rate for both effect and costs). The incremental cost-effectiveness ratio (95% confidence intervals) for over lifetime was estimated to be $3,016 ($1,441, $8,840) per QALY. The sensitivity analyses showed the robustness of these results.
Adjuvant S-1 therapy for curatively resected gastric cancer is likely cost-effective. This therapy can be accepted for wide use in Japan.
胃癌辅助治疗特定方案的有效性尚未经大型临床试验验证。最近，多项大型试验试图验证辅助治疗的有效性。日本的胃癌TS-1辅助化疗试验，一项针对切除术后胃癌的辅助S-1治疗的随机对照试验，表明与单纯手术相比，总生存期和无复发生存期有显著改善。为评估S-1治疗的性价比，进行了成本效益分析。
分析从支付方角度进行。作为一项经济指标，估算了每获得一个质量调整生命年（QALY）的成本。采用Kaplan-Meier法估计总生存期，观察期长达5年。超过此期限，采用改良的Boag模型进行模拟。效用评分通过使用时间权衡法对抽样患者进行访谈得出。观察期间的成本根据试验数据估算，而观察期之后的成本则根据模拟结果估算。为探究结果的不确定性，进行了定性和随机敏感性分析。
辅助S-1治疗每位患者获得1.24个QALY，每位患者终生成本增加3722美元（效果和成本的贴现率均为3%）。终生的增量成本效益比（95%置信区间）估计为每QALY 3016美元（1441美元，8840美元）。敏感性分析表明这些结果具有稳健性。
根治性切除胃癌的辅助S-1治疗可能具有成本效益。该治疗在日本可被广泛接受使用。
