Thoracic recurrence in patients with curatively-resected colorectal cancer: incidence, risk factors, and value of chest CT as a postoperative surveillance tool

To investigate the incidence of thoracic recurrence and the diagnostic value of chest CT for postoperative surveillance in curatively-resected colorectal cancer (CRC) patients. This retrospective study consisted of 648 CRC patients (M:F, 393:255; mean age, 66.2 years) treated with curative surgery between January 2010 and December 2012. The presence of CRC recurrence over follow-ups was analysed and recurrence-free survival and risk factors of recurrence were assessed using Kaplan–Meier analysis with log-rank test and Cox-regression analysis, respectively. Over a median follow-up of 57 months, thoracic recurrence occurred in 8.0% (52/648) of patients with a median recurrence-free survival rate of 19.5 months. Among the 52 patients with thoracic recurrence, 18 (2.7%) had isolated thoracic recurrence, and only five (0.8%) were diagnosed through chest CT. Risk factors of overall thoracic recurrence included age, positive resection margin, presence of venous invasion, positive pathologic N-class, and presence of abdominal recurrence (odds ratio [OR] = 1.78, 19.691, 2.993, 2.502, and 31.137; p = 0.045, 0.004, 0.001, 0.005, and p < 0.001, respectively). As for isolated thoracic recurrence, serum carcinoembryonic antigen level ≥ 5 ng/mL during postoperative follow-up (OR = 9.112; p < 0.001) was demonstrated to be the only predictive factor. There were no thoracic recurrences in patients with CRC stages 0 and I. In patients with curatively-resected CRCs, routine surveillance using chest CT may be of limited value, particularly in those with CRC stages 0 or I, as recurrence only detectable through chest CT was shown to be rare. • Postoperative thoracic recurrence only detectable through chest CT was shown to be rare. • There were no thoracic recurrences in colorectal cancers stage 0 and I. • Postoperative surveillance chest CT is of limited value in patients with curatively resected colorectal cancers.