To investigate the efficacy and toxicities of neoadjuvant chemoradiotherapy (neoCRT) in the management of unresectable locally advanced adherent colon cancer (LAACC).

A retrospective analysis was performed on the clinical records of 40 patients with initially diagnosed unresectable LAACC who received preoperative neoCRT in our center from October 2010 to December 2015.

Thirty-nine patients completed the preoperative neoCRT.Thirty-four patients underwent radical resection after neoCRT, and the R₀ resection rate, pathological complete response rate (pCR), tumor downstaging rate, nodal downstaging rate, and clinical downstaging rate were 91%, 24%(8/34 patients), 76%(26/34 patients), 100%(32/32 patients), and 94%(32/34 patients), respectively. Among the 21 patients with bladder invasion, the full bladder was preserved in 7 patients (33%) and partial cystectomy was performed in 11 patients (52%). During the course of neoCRT, the grade 3-4 hematologic toxicity rate, grade 3 hand-foot syndrome rate, grade 3 radiodermatitis, and incomplete intestinal obstruction rate were 23%, 3%, 3%, and 5%, respectively. The 3-year sample size was 25 patients. For all the patients, the 3-year overall survival (OS) and progression-free survival (PFS) rates were 75% and 80%, respectively. Of the 34 patients who received surgical radical resection, the 3-year OS and disease-free survival (DFS) rates were 87% and 81%, respectively. In addition, local tumor recurrence was identified in 3 patients, and distant metastasis was identified in 6 patients.

NeoCRT is an effective treatment for unresectable LAACC that results in significant tumor downstaging and enhanced R₀ resection rate without an increase in surgical complications. The patients treated with radical surgical resection after neoCRT show a satisfactory short-term outcome. Further studies will be required to determine the clinical value of neoCRT in treating LAACC.

Intestinal neoplasms/radiotherapy; Intestinal neoplasms/chemotherapy; Short-term effect