Institutional enrollment volume and clinical outcomes after surgery or chemoradiotherapy for clinical stage I esophageal squamous cell carcinoma: a supplementary analysis of JCOG0502 - Kazuhiro Shiraishi; Ken Kato; Yuya Ishikawa; Keita Sasaki; Hiroyuki Daiko; Yoshinori Ito; Takeshi Kajiwara; Takashi Kojima; Hiroshi Miyata; Masaki Ueno; Satoru Nakagawa; Shinsuke Sato; et al. (Esophagus, 2026)