Efficacy of chemotherapy in elderly patients with unresectable pancreatic cancer: a multicenter review of 895 patients oleh Taira Kuroda, Teru Kumagi, Tomoyuki Yokota, Nobuaki Azemoto, Aki Hasebe, Hirotaka Seike, Mari Nishiyama, Nobu Inada, Naozumi Shibata, Hideki Miyata, Tomoe Kawamura, Yusuke Imai, Akiko Ueno-Toshimori, Yoshinori Tanaka, Takashi Terao, Yoshiki Imamura, Mitsuhito Koizumi, Hirofumi Yamanishi, Yoshinori Ohno, Yoichi Hiasa, on behalf of the Ehime Pancreato-Cholangiology (EPOCH) Study Group