<p>Background: </p><p>Although the number of cancer survivors has increased, the return to work (RTW) status among employed cancer patients and effectiveness of promoting health and employment support remains unclear.</p><p>Cases: </p><p>The patient was a 50-year-old male with a diagnosis of cholangiocarcinoma. He worked as a liquefied petroleum gas station filler. He underwent pancreaticoduodenectomy for the cholangiocarcinoma. A postoperative pancreatic fistula was treated by drainage for 41 days. The skeletal muscle index (8.7→7.7), 6-minute walk distance (518→460 m), and work ability index (WAI: 37→20 points) were lower postoperatively than preoperatively. Because the patient was anxious about RTW, an intervention by the Department of Occupational Medicine (DOM) was initiated. In the RTW project by the DOM, a team approach was used, and the primary physician, occupational physician, and company cooperated to support the patient. His physical therapist reported declining physical performance and WAI at the RTW meeting. The team recommended resuming work in steps. The patient resumed work partly for two months and completely three months after surgery while undergoing oral adjuvant chemotherapy. The WAI improved to 35 points.</p><p>Conclusion: </p><p>Perioperative rehabilitation in collaboration with the DOM may contribute to a smooth RTW for cancer patients with decreased work ability after surgery.</p><p>Ethical consideration: </p><p>In accordance with the Declaration of Helsinki and the Ethical Guidelines for Medical and Health Research Involving Human Subjects, the case reports were explained to the subjects, and their consent was obtained, taking into consideration the protection of personal information.</p>