Retrospective Cohort Study
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Oncol. Oct 15, 2019; 11(10): 877-886
Published online Oct 15, 2019. doi: 10.4251/wjgo.v11.i10.877
Fat clearance and conventional fixation identified ypN0 rectal cancers following intermediate neoadjuvant radiotherapy have similar long-term outcomes
Nan Chen, Ting-Ting Sun, Zhong-Wu Li, Yun-Feng Yao, Lin Wang, Ai-Wen Wu
Nan Chen, Ting-Ting Sun, Yun-Feng Yao, Lin Wang, Ai-Wen Wu, Department of Gastrointestinal Surgery, Peking University Cancer Hospital, Beijing 100142, China
Zhong-Wu Li, Department of Pathology, Peking University Cancer Hospital, Beijing 100142, China
Author contributions: Chen N, Sun TT, and Li ZW contributed equally to this work; Wang L and Wu AW designed the research; Chen N, Sun TT, Li ZW, and Yao YF collected and analyzed the data; Chen N and Wang L drafted the manuscript.
Supported by National Natural Science Foundation of China, No. 81773214; Beijing Municipal Science and Technology Commission (Capital Characteristic Clinical Study), No. Z15110004015105; Beijing Health System High Level Talented Scholar of Medicine Fund (The 215 Project); Science Foundation of Peking University Cancer Hospital, No. 2017-13.
Institutional review board statement: This study was performed under the ethics approval of the Ethic Committee of Beijing Cancer Hospital.
Informed consent statement: All patients were informed and consented.
Conflict-of-interest statement: No competing interest is claimed from all authors.
STROBE statement: The manuscript was revised according to the STROBE.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (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: Lin Wang, MD, Assistant Professor, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Gastrointestinal Center, Peking University Cancer Hospital and Institute, 52 Fucheng Road, Haidian District, Beijing 100142, China. wanglinmd@foxmail.com
Telephone: +86-10- 88196086 Fax: +86-10-88196086
Received: April 6, 2019
Peer-review started: April 8, 2019
First decision: June 3, 2019
Revised: July 23, 2019
Accepted: August 20, 2019
Article in press: August 21, 2019
Published online: October 15, 2019
Processing time: 194 Days and 19.2 Hours
Abstract
BACKGROUND

As a prognostic factor for colorectal cancer, lymph node (LN) status, particularly the number of LN harvested, has been demonstrated to be essential in the evaluation of quality control in terms of surgical specimen. Neoadjuvant chemoradiation, however, decreases the LN harvest. Therefore, certain approaches (such as fat clearance or methylene blue) has drawn significant attention in order to raise LN yield.

AIM

To compare the long-term oncologic outcome of ypN0 rectal cancer identified using fat clearance (FC) or conventional fixation (CF) following 30 Gy in 10 fractions (30 Gy/10f) of neoadjuvant radiotherapy (nRT).

METHODS

Three hundred and eighty-two patients with resectable and locally advanced rectal cancer were treated by 30 Gy/10f intermediate nRT (biologically equivalent dose of 36 Gy) plus total mesorectal excision. Two specimen fixation methods (FC or CF) were non-randomly used. The ypN0 status was identified in 124 and 101 patients in the FL and CF groups, respectively. Primary endpoints were local recurrence-free survival (LRFS) and cancer-specific survival (CSS).

RESULTS

The median follow-up of patients was 5.1 years. The median numbers of retrieved LNs in the FC and CF groups were 19.5 (range, 4-47) and 12 (range, 0-44), respectively, with a significant difference (P = 0.000). The percentages of patients with 12 or more retrieved nodes were 82.3% and 50.5% (101/159) in the FC and CF groups, respectively, with a significant difference (P = 0.000). The LRFS at 5 years were 95.7% and 94.6% in the FC and CF groups, respectively, without statistical difference (P = 0.819). The CSS at 5 years were 92.0% and 87.2% in the FC and CF groups, respectively, without statistical difference (P = 0.482).

CONCLUSION

For patients with ypN0 rectal cancer who underwent 30 Gy/10f preoperative radiotherapy, the increased retrieval of LNs using fat clearance is not associated with survival benefit. This time-consuming fixation method has a low efficacy as a routine practice.

Keywords: Neoadjuvant radiotherapy; Rectal cancer; Fat clearance; Survival; Lymph node; Conventional fixation

Core tip: Enhanced lymph node (LN) yield has been noticed to be associated with increasing accuracy in tumor staging and putative prognosis. By the means of fat-clearance technique, the LN retrieval was significantly higher in the fat-clearance group, compared with convention fixation. In terms of survival, however, for patients with negative LN, increased LN harvest was not associated with prolonged survival.