Prognostic factors of conversion surgery for stage IV gastric cancer: A multi‐institutional retrospective analysis oleh Atsushi Takeno, Masaaki Motoori, Kentaro Kishi, Takeshi Omori, Motohiro Hirao, Toru Masuzawa, Kazumasa Fujitani, Kazuyoshi Yamamato, Yukinori Kurokawa, Yuichiro Doki