Retrospective Study
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Aug 6, 2020; 8(15): 3230-3239
Published online Aug 6, 2020. doi: 10.12998/wjcc.v8.i15.3230
Colorectal adenocarcinoma patients with M1a diseases gain more clinical benefits from palliative primary tumor resection than those with M1b diseases: A propensity score matching analysis
Cheng-Lin Li, De-Rong Tang, Jian Ji, Bao Zang, Chen Chen, Jian-Qiang Zhao
Cheng-Lin Li, De-Rong Tang, Jian Ji, Bao Zang, Chen Chen, Jian-Qiang Zhao, Department of Thoracic Surgery, The Affiliated Huaian No. 1 People’s Hospital of Nanjing Medical University, Huaian 223300, Jiangsu Province, China
Author contributions: Li CL and Zhao JQ designed the research and critically revised the manuscript for important intellectual content; all authors performed the research, analyzed the data, and wrote the paper.
Institutional review board statement: The study was approved by the Bioethics Committee of the Affiliated Huaian No. 1 People’s Hospital of Nanjing Medical University, China.
Informed consent statement: All patients from the SEER database have agreed to participate in scientific research.
Conflict-of-interest statement: All authors declare no competing financial interests.
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: Jian-Qiang Zhao, MD, Doctor, Department of Thoracic Surgery, The Affiliated Huaian No. 1 People’s Hospital of Nanjing Medical University, No. 1 West Huanghe Road, Huaian 223300, Jiangsu Province, China. shenglee6871@sina.com
Received: January 14, 2020
Peer-review started: January 14, 2020
First decision: April 12, 2020
Revised: April 25, 2020
Accepted: June 29, 2020
Article in press: June 29, 2020
Published online: August 6, 2020
Processing time: 205 Days and 8.3 Hours
Abstract
BACKGROUND

Surgical resection is regarded as the only potentially curative treatment option for patients with metastatic colorectal cancer (CRC). The National Comprehensive Cancer Network clinical practice guidelines do not recommend palliative surgery unless there is a risk of severe symptoms. However, accumulating evidence has shown that palliative surgery is associated with more favorable outcomes for patients with metastatic CRC.

AIM

To investigate the separate role of palliative primary tumor resection for patients with stage IVA (M1a diseases) and stage IVB (M1b diseases) colorectal adenocarcinoma (CRA).

METHODS

CRA patients diagnosed from 2010 to 2015 with definite M1a and M1b categories according to the 8th edition of American Joint Committee on Cancer staging system were selected from the Surveillance Epidemiology and End Results (SEER) database. To minimize potential selection bias, the data were adjusted by propensity score matching (PSM). Baseline characteristics, including gender, year of diagnosis, age, marital status, primary site, surgical information, race, grade, chemotherapy, and radiotherapy, were recorded and analyzed. Univariate and multivariate analyses were performed to explore the separate role of palliative surgery for patients with M1a and M1b diseases.

RESULTS

A total of 19680 patients with metastatic CRA were collected from the SEER database, including 10399 cases of M1a diseases and 9281 cases of M1b diseases. Common independent prognostic factors for both M1a and M1b patients included year of diagnosis, age, race, marital status, primary site, grade, surgery, and chemotherapy. After PSM adjustment, 3732 and 3568 matched patients in the M1a and M1b groups were included, respectively. Patients receiving palliative primary tumor resection had longer survival time than those without surgery (P < 0.001). For patients with M1a diseases, palliative resection could increase the median survival time by 9 mo; for patients with M1b diseases, palliative resection could prolong the median survival time by 7 mo. For M1a diseases, patients with lung metastasis had more clinical benefit from palliative resection than those with liver metastasis (15 mo for lung metastasis vs 8 mo for liver metastasis, P < 0.001).

CONCLUSION

CRA patients with M1a diseases gain more clinical benefits from palliative primary tumor resection than those with M1b diseases. Those patients with M1a (lung metastasis) have superior long-term outcomes after palliative primary tumor resection.

Keywords: Colorectal adenocarcinoma; Palliative primary tumor resection; Distant metastasis; Propensity score matching; Surveillance Epidemiology and End Results; Overall survival

Core tip: The National Comprehensive Cancer Network clinical practice guidelines do not recommend palliative surgery for metastatic colorectal adenocarcinoma (CRA). Using the Surveillance Epidemiology and End Results database, we found that patients with M1a diseases had a significant survival benefit compared to those with M1b diseases and patients with M1a (lung metastasis) got best long-term outcomes with median overall survival prolonged by 15 mo compared with those without surgical treatment. These findings provide further evidence to support the use of palliative surgical procedure to treat metastatic CRA and develop effective individualized treatment strategy.