Retrospective Study
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Dec 26, 2022; 10(36): 13284-13292
Published online Dec 26, 2022. doi: 10.12998/wjcc.v10.i36.13284
Classification of rectal cancer according to recurrence types - comparison of Japanese guidelines and Western guidelines
Hiroshi Miyakita, Yutaro Kamei, Lin Fung Chan, Kazutake Okada, Hajime Kayano, Seiichiro Yamamoto
Hiroshi Miyakita, Yutaro Kamei, Lin Fung Chan, Kazutake Okada, Hajime Kayano, Seiichiro Yamamoto, Department of Digestive System Surgery, Tokai University School of Medicine, Isehara 259-1193, Kanagawa, Japan
Author contributions: Miyakita H designed the research; Miakita H and Chan LF performed the research; Miyakita H and Kamei Y contributed new reagents/analytic tools; Miyakita H, Okada K and Kayano H analyzed the data; Miyakita H and Yamamoto S wrote the paper.
Institutional review board statement: Approval code issued by the institutional review board: 20R-238 Tokai University.
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 by written consent.
Conflict-of-interest statement: All authors have no conflict of interest to declare in association with this study.
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: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Hiroshi Miyakita, MD, PhD, Doctor, Surgeon, Surgical Oncologist, Department of Digestive System Surgery, Tokai University School of Medicine, 143 Shimokasuya Isehara, Isehara 259-1193, Kanagawa, Japan. mykt0124@tokai-u.jp
Received: August 31, 2022
Peer-review started: August 31, 2022
First decision: October 20, 2022
Revised: November 5, 2022
Accepted: December 9, 2022
Article in press: December 9, 2022
Published online: December 26, 2022
Processing time: 117 Days and 8.1 Hours
Abstract
BACKGROUND

Rectal cancer is characterized by more local recurrence (LR) and lung metastasis than colon cancer. However, the diagnosis of rectal cancer is not standardized as there is no global consensus on its definition and classification. The classification of rectal cancer differs between Japanese and Western guidelines.

AIM

To clarify the characteristics of rectal cancer by comparing the tumor location and characteristics of rectal cancer with those of colon cancer according to each set of guidelines.

METHODS

A total of 958 patients with Stage II and III colorectal cancer were included in the analysis: 607 with colon cancer and 351 with rectal cancer. Localization of rectal cancers was assessed by enema examination and rigid endoscopy. According to Japan guidelines, rectal cancer is classified as Rb (below the peritoneal inversion), Ra (between the inferior margin of second sacral vertebrae and Rb) or RS (between Ra and sacral promontory).

RESULTS

There were no significant differences between RS rectal cancer and colon cancer in the rates of liver and lung metastasis or LR. Lung metastasis and LR were significantly more common among Rb rectal cancer (in Japan) than in colon cancer (P = 0.0043 and P = 0.0002, respectively). Lung metastases and LR occurred at significantly higher rates in rectal cancer measuring ≤ 12 cm and ≤ 10 cm than in colon cancers (P = 0.0117, P = 0.0467, P = 0.0036, P = 0.0010). Finally, the rates of liver metastasis, lung metastasis, and LR in rectal cancers measuring 11 cm to 15 cm were 6.9%, 2.8%, and 5.7%, respectively. These were equivalent to the rates in colon cancer.

CONCLUSION

High rectal cancer may be treated with the same treatment strategies as colon cancer. There was no difference in the classification of colorectal cancer between Japan and Western countries.

Keywords: Colon cancer; Metastasis; Local recurrence; Classification of rectal cancer; Western guidelines; Japanese guideline

Core Tip: Local recurrence and lung metastasis are more common in rectal cancer than in colon cancer. However, the diagnosis of rectal cancer is not standardized as there is no global consensus on its definition and classification. The classification of rectal cancer differs between Japanese and Western guidelines. High rectal cancer may be treated with the same treatment strategies as colon cancer. There was no difference in the classification of colorectal cancer between Japan and Western countries.