Surveillance after curative resection for colorectal cancer with computed tomography (CT) of abdomen, pelvis and chest is a standard practice, but the optimal interval of surveillance CT is unclear. Usually recommended interval is 6 to 12 months, but in South Korea, earlier follow-up CT during adjuvant chemotherapy for stage II or III disease is a common practice. This study aimed to show clinical utility of early follow-up CT (EFCT) within 6 months after surgery.
The medical records of patients with stage II or III colorectal cancer who received oxaliplatin-based adjuvant chemotherapy between January 2011 and December 2014 in Asan Medical Center were retrospectively reviewed. Those who started adjuvant chemotherapy beyond 3 months after surgery and who were dead or lost to follow-up before 6 months after surgery were excluded. Information on the results of EFCT and subsequent treatment was obtained.
In a total of 678 patients, 597 (88%) underwent EFCT. EFCT was associated with advanced stage: 78% (74/95) of stage II, 88% (317/359) of low-risk stage III (pT1-3 and N1), and 92% (206/224) of high-risk stage III (pT4 or N2) checked EFCT (p = 0.002). EFCT revealed recurrence in 6 (1%); 0 of stage II, 1 (0.3%) of low-risk stage III, and 5 (2.4%) of high-risk stage III (p = 0.132). Only 1 of 6 patients with recurrence underwent surgical resection of curative intent. There were no differences in overall survival (OS), disease-free survival (DFS), and cumulative occurrence of local treatment for DFS events according to undergoing EFCT with adjustment to age, gender, and stage.
Early recurrence within 6 months after surgery occurred in 1% of patients who were treated with oxaliplatin-based adjuvant chemotherapy, mostly in high-risk stage III disease. The practice of EFCT was associated with advanced stage but did not affect OS, DFS, or cumulative occurrence of local treatment. Clinical utility of EFCT seems to be low and should be discouraged especially in stage II or low-risk stage III disease.
Clinical trial identification
Legal entity responsible for the study
Asan Medical Center.
Has not received any funding.
All authors have declared no conflicts of interest.