Irinotecan as the Key Chemotherapeutic Agent inSecond-Line Treatment of Metastatic Gastric Cancerafter Failure of First-Line S-1 or S-1/CDDP Therapy 後藤啓 and ほか, 癌と化学療法, 38, 1461-1466 (2011), DOI:http://dx.doi.org/