Efficacy of thoracotomy and thoracoscopic-assisted esophageal surgery in conversion and salvage surgeries: a retrospective study.

This was a single-center cohort study wherein clinical data were retrospectively registered. This study was approved by the Chiba Cancer Center review board (H29-262). All procedures adhered to the ethical standards of the responsible committee on human experimentation and the Helsinki Declaration of 1964 and its later amendments.