Retrospective Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Oncol. Apr 15, 2021; 13(4): 252-264
Published online Apr 15, 2021. doi: 10.4251/wjgo.v13.i4.252
Predictive factors for early distant metastasis after neoadjuvant chemoradiotherapy in locally advanced rectal cancer
Hyojung Park
Hyojung Park, Departments of Radiation Oncology, Dankook University Hospital, Dankook University College of Medicine, Cheonan 46115, South Korea
Author contributions: Park H analyzed the data and wrote the manuscript.
Institutional review board statement: This study was reviewed and approved by the Ethics Committee of the Dankook University Hospital.
Informed consent statement: All study participants or their legal guardian provided informed written consent about personal and medical data collection prior to study enrolment.
Conflict-of-interest statement: The authors have no conflicts 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: Hyojung Park, MD, Doctor, Departments of Radiation Oncology, Dankook University Hospital, Dankook University College of Medicine, 201 Manghyang-ro, Dongnam-gu, Cheonan 46115, South Korea. hj0714.park@dkuh.co.kr
Received: September 10, 2020
Peer-review started: September 10, 2020
First decision: November 3, 2020
Revised: January 11, 2021
Accepted: March 16, 2021
Article in press: March 16, 2021
Published online: April 15, 2021
Processing time: 211 Days and 0.8 Hours
Abstract
BACKGROUND

Distant relapse is the leading cause of cancer-related death in locally advanced rectal cancer. Neoadjuvant chemoradiation (NACRT) followed by surgery inevitably delays delivery of systemic treatment. Some patients show early distant metastasis before systemic treatment.

AIM

To identify the most effective treatments. We investigated prognostic factors for distant metastasis, especially early distant metastasis, using the standard treatment paradigm to identify the most effective treatments according to recurrence risk.

METHODS

From January 2015 through December 2019, rectal cancer patients who underwent NACRT for having clinical T 3-4 or clinical N 1-2 disease according to the 8th American Joint Committee on Cancer staging system were included. Radiotherapy was delivered to the whole pelvis with concomitant chemotherapy. Patients received surgery 6-8 wk after completion of NACRT. Adjuvant chemotherapy was administered at the physician’s discretion.

RESULTS

A total of 127 patients received NACRT. Ninety-three patients (73.2%) underwent surgery. The R0 resection rate was 89.2% in all patients. Pathologic tumor and node downstaging rates were 41.9% and 76.3%. Half the patients (n = 69) received adjuvant chemotherapy after surgery. The 3-year distant metastasis-free survival (DMFS) and overall survival (OS) rates were 81.7% and 83.5%. On univariate analyses, poorly differentiated tumors, > 5 cm, involvement of mesorectal fascia (MRF), or presence of extramural involvement (EMVI) were associated with worse DMFS and OS. Five patients showed distant metastasis at their first evaluation after NACRT. Patients with early distant metastasis were more likely to have poorly differentiated tumor (P = 0.025), tumors with involved MRF (P = 0.002), and EMVI (P = 0.012) than those who did not.

CONCLUSION

EMVI, the involvement of MRF, and poor histologic grade were associated with early distant metastasis. In order to control distant metastasis and improve treatment outcome, selective use of neoadjuvant treatment according to individualized risk factors is necessary. Future studies are required to determine effective treatment strategies for patients at high risk for distant metastasis.

Keywords: Rectal cancer; Neoadjuvant chemoradiotherapy; Distant metastasis; Extramural venous invasion

Core Tip: This is a retrospective study to investigate prognostic factors for distant metastasis, especially early distant metastasis, using the standard treatment paradigm to identify the most effective treatments according to recurrence risk. Poorly differentiated tumors, involvement of mesorectal fascia, or presence of extramural involvement were associated with distant metastasis and early distant metastasis. For patients with these risk factors, early systemic chemotherapy could be beneficial. Selective use of neoadjuvant treatment other than the current standard treatment according to individualized risk factors is necessary.