Retrospective Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Surg. Sep 27, 2021; 13(9): 1012-1024
Published online Sep 27, 2021. doi: 10.4240/wjgs.v13.i9.1012
Optimal postoperative surveillance strategies for stage III colorectal cancer
Min Young Park, In Ja Park, Hyo Seon Ryu, Jay Jung, Minsung Kim, Seok-Byung Lim, Chang Sik Yu, Jin Cheon Kim
Min Young Park, Colon and Rectal Surgery, Asan Medical Center, Seoul 05505, South Korea
In Ja Park, Hyo Seon Ryu, Jay Jung, Minsung Kim, Seok-Byung Lim, Chang Sik Yu, Jin Cheon Kim, Colon and Rectal Surgery, Asan Medical Center and University of Ulsan College of Medicine, Seoul 05505, South Korea
Author contributions: Kim JC, Yu CS, and Lim SB guaranted the integrity of the study; Park IJ conceptualized the study; Park IJ and Park MY collected the data, edited the manuscript; Park MY did statistical analysis and prepared manuscript; Park IJ, Park MY, Ryu HS, Jung J, and Kim MS reviewed manuscript; all authors have read and approve the final manuscript.
Institutional review board statement: This study was approved by the Institutional Review Board of Asan Medical Center, No: 2017-0955.
Informed consent statement: Patients were not required to give informed consent to the study because the analysis used anonymous clinical data that were obtained after each patient agreed to treatment.
Conflict-of-interest statement: We have no financial relationships to disclose.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: In Ja Park, MD, PhD, Doctor, Professor, Surgeon, Colon and Rectal Surgery, Asan Medical Center and University of Ulsan College of Medicine, No. 88 Olympic-ro, Songpa-gu, Seoul 05505, South Korea. ipark@amc.seoul.kr
Received: February 24, 2021
Peer-review started: February 24, 2021
First decision: May 13, 2021
Revised: June 3, 2021
Accepted: August 2, 2021
Article in press: August 2, 2021
Published online: September 27, 2021
ARTICLE HIGHLIGHTS
Research background

Optimal surveillance strategies for stage III colorectal cancer (CRC) are lacking, and intensive surveillance has not conferred a significant survival benefit.

Research motivation

Evaluating appropriate surveillance intensity would be helpful to improve oncologic outcomes or decrease un-necessary imaging studies during surveillance.

Research objectives

We examined the association between surveillance intensity and recurrence and survival rates in patients with stage III CRC.

Research methods

Data from patients with pathologic stage III CRC who underwent radical surgery between January 2005 and December 2012 at Asan Medical Center, Seoul, Korea were retrospectively reviewed. Surveillance consisted of abdominopelvic computed tomography (CT) every 6 mo and chest CT annually during the 5 year follow-up period, resulting in an average of three imaging studies per year. Patients who underwent more than the average number of imaging studies annually were categorized as high intensity (HI), and those with less than the average were categorized as low intensity (LI).

Research results

Among 1888 patients, 864 (45.8%) were in HI group. The HI group had more advanced T and N stage (P = 0.002, 0.010, each). A high degree of malignant differentiation was more common in the HI group than in the LI group (P = 0.027). Perineural invasion (PNI) was significantly more identified in the HI group (21.4% vs 30.3%, P < 0.001).

The mean overall survival (OS) and Recurrence-free interval (RFI) was longer in the LI group (P < 0.001, each). Multivariate analysis indicated that surveillance intensity was negatively associated with RFI [odds ratio (OR) = 1.999; 95% confidence interval (CI): 1.680–2.377; P < 0.001] and OS [OR = 1.531, 95%CI: 1.295–1.808; P < 0.001]. The mean post-recurrence survival (PRS) was significantly longer in patients who received curative resection (P < 0.001). Curative resection rate of recurrence was not different between HI (29.3%) and LI (23.8%) groups (P = 0.160). PRS did not differ according to surveillance intensity (P = 0.802).

Research conclusions

Frequent postoperative surveillance with CT scan alone do not improve OS and RFI. Curative resection is the most important factors to improve PRS and we need to find a way to increase curative treatment of recurrent disease via optimal surveillance.

Research perspectives

Role of other imaging modalities according to risk of recurrence would be evaluated rather than increasing surveillance frequency to improve oncologic outcomes.