Toshifumi Yamaguchi1,2, Atsuo Takashima3, Kengo Nagashima4, Rie Makuuchi5, Masaki Aizawa6, Manabu Ohashi7, Keitaro Tashiro8, Tatsuya Yamada9, Takahiro Kinoshita10, Hiroaki Hata11, Yasuyuki Kawachi12, Ryohei Kawabata13, Toshikatsu Tsuji14, Jun Hihara15, Takeshi Sakamoto16, Takeo Fukagawa17, Hitoshi Katai18, Kazuhide Higuchi1, Narikazu Boku2. 1. Cancer Chemotherapy Center and Second Department of Internal Medicine, Osaka Medical College, Osaka, Japan. 2. Gastrointestinal Oncology Division, National Cancer Center Hospital, Tokyo, Japan. 3. Gastrointestinal Oncology Division, National Cancer Center Hospital, Tokyo, Japan. atakashi@ncc.go.jp. 4. Research Center for Medical and Health Data Science, The Institute of Statistical Mathematics, Tokyo, Japan. 5. Division of Gastric Surgery, Shizuoka Cancer Center, Shizuoka, Japan. 6. Department of Gastroenterological Surgery, Niigata Cancer Center Hospital, Niigata, Japan. 7. Department of Gastroenterological Surgery, Cancer Institute Hospital, Tokyo, Japan. 8. Departments of General and Gastroenterological Surgery, Osaka Medical College Hospital, Osaka, Japan. 9. Department of Gastroenterological Surgery, Saitama Cancer Center, Saitama, Japan. 10. Gastric Surgery Division, National Cancer Center Hospital East, Kashiwa, Japan. 11. Department of Surgery, National Hospital Organization Kyoto Medical Center, Kyoto, Japan. 12. Department of Surgery, Nagaoka Chuo General Hospital, Niigata, Japan. 13. Department of Surgery, Osaka Rosai Hospital, Osaka, Japan. 14. Department of Gastroenterological Surgery, Ishikawa Prefectural Central Hospital, Kanazawa, Japan. 15. Department of Surgery, Hiroshima City Asa Citizens Hospital, Hiroshima, Japan. 16. Department of Gastroenterology, Hyogo Cancer Center, Hyogo, Japan. 17. Department of Surgery, Teikyo University Hospital, Tokyo, Japan. 18. Department of Gastric Surgery, National Cancer Center Hospital, Tokyo, Japan.
Abstract
BACKGROUND: Gastric cancer (GC) patients with positive peritoneal lavage cytology (CY1) and/or localized peritoneum metastasis (P1a) are defined as stage IV in the 15th edition of the Japanese Classification of Gastric Cancer. In Japan, the most common treatment for patients with CY1 and/or P1a is gastrectomy followed by postoperative chemotherapy. PATIENTS AND METHODS: Subjects in this multi-institutional retrospective study were GC patients with CY1 and/or P1a who received surgical resection that leaves no macroscopically visible disease. Patients were selected from 34 institutions in Japan between 2007 and 2012. Selection criteria included adenocarcinoma, no distant metastasis except CY1 and P1a, and no prior treatment for GC before surgery. RESULTS: Among 824 patients registered, 506 were identified as eligible, with a background of P0CY1, P1aCY0, or P1aCY1 (72.5%, 16.0%, and 11.5% of subjects, respectively). Sixty-two patients had not received postoperative chemotherapy (no-Cx), whereas 444 patients had received postoperative chemotherapy: S-1 monotherapy (S-1; n = 267, 52.7%), cisplatin plus S-1 (CS; n = 114, 22.5%), and others (n = 63, 12.6%). Overall survival (OS) was 29.5, 24.7, 25.4 and 9.9 months in the S-1, CS, 'others', and no-Cx groups, respectively [CS vs. S-1: hazard ratio (HR) 1.15, 95% confidence interval (CI) 0.89-1.50; p = 0.275]. In multivariate analysis, OS was similar between the S-1 and CS groups (CS vs. S-1: HR 1.19, 95% CI 0.92-1.55; p = 0.18). CONCLUSIONS: Postoperative chemotherapy after gastrectomy that leaves no macroscopically visible disease may have some survival benefits for GC patients with CY1 and/or P1a. In contrast, S-1 plus cisplatin seems to have no additional benefit over S-1 treatment alone.
BACKGROUND:Gastric cancer (GC) patients with positive peritoneal lavage cytology (CY1) and/or localized peritoneum metastasis (P1a) are defined as stage IV in the 15th edition of the Japanese Classification of Gastric Cancer. In Japan, the most common treatment for patients with CY1 and/or P1a is gastrectomy followed by postoperative chemotherapy. PATIENTS AND METHODS: Subjects in this multi-institutional retrospective study were GC patients with CY1 and/or P1a who received surgical resection that leaves no macroscopically visible disease. Patients were selected from 34 institutions in Japan between 2007 and 2012. Selection criteria included adenocarcinoma, no distant metastasis except CY1 and P1a, and no prior treatment for GC before surgery. RESULTS: Among 824 patients registered, 506 were identified as eligible, with a background of P0CY1, P1aCY0, or P1aCY1 (72.5%, 16.0%, and 11.5% of subjects, respectively). Sixty-two patients had not received postoperative chemotherapy (no-Cx), whereas 444 patients had received postoperative chemotherapy: S-1 monotherapy (S-1; n = 267, 52.7%), cisplatin plus S-1 (CS; n = 114, 22.5%), and others (n = 63, 12.6%). Overall survival (OS) was 29.5, 24.7, 25.4 and 9.9 months in the S-1, CS, 'others', and no-Cx groups, respectively [CS vs. S-1: hazard ratio (HR) 1.15, 95% confidence interval (CI) 0.89-1.50; p = 0.275]. In multivariate analysis, OS was similar between the S-1 and CS groups (CS vs. S-1: HR 1.19, 95% CI 0.92-1.55; p = 0.18). CONCLUSIONS: Postoperative chemotherapy after gastrectomy that leaves no macroscopically visible disease may have some survival benefits for GC patients with CY1 and/or P1a. In contrast, S-1 plus cisplatin seems to have no additional benefit over S-1 treatment alone.