A pathological complete response after neoadjuvant triplet chemotherapy for locally advanced transverse colon cancer

INTRODUCTION: Perioperative chemotherapy could improve oncological outcomes for patients with advanced colon cancer. However, the effectiveness of triplet chemotherapy in the neoadjuvant setting is still unknown. PRESENTATION OF CASE: A 61-year-old man was referred to our hospital due to abdominal distention. Abdominal computed tomography showed a huge, 18-cm mass in the right upper abdomen. Biopsy showed well-differentiated adenocarcinoma. Locally advanced transverse colon cancer T4b N2a M0 Stage IIIC was diagnosed. Considering the extensive invasion to surrounding organs and difficulties in achieving margin-negative surgery, an emergency ileostomy was performed first. Then, neoadjuvant chemotherapy (NAC) consisting of a combination of 5-fluorouracil (5-FU), oxaliplatin, irinotecan, and leucovorin (FOLFOXIRI) was planned, followed by primary tumor resection. After 6 courses of treatment, the primary tumor shrank remarkably. Finally, laparoscopic radical extended right hemi-colectomy was performed. There were no residual tumor cells in resected specimens, including the primary tumor and surrounding lymph nodes. The pathological diagnosis was complete response. CONCLUSION: A case of pathological complete response after neoadjuvant treatment followed by radical resection was reported. Further research is needed to confirm the appropriate indications for neoadjuvant FOLFOXIRI therapy for patients with LACC.