Retrospective Cohort Study
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Surg. May 27, 2019; 11(5): 247-260
Published online May 27, 2019. doi: 10.4240/wjgs.v11.i5.247
Prediction of overall survival following colorectal cancer surgery in elderly patients
Isaac Seow-En, Winson Jianhong Tan, Sreemanee Raaj Dorajoo, Sharon Hui Ling Soh, Yi Chye Law, Soo Yeun Park, Gyu-Seok Choi, Wah Siew Tan, Choong Leong Tang, Min Hoe Chew
Isaac Seow-En, Wah Siew Tan, Choong Leong Tang, Department of Colorectal Surgery, Singapore General Hospital, Singapore 169608, Singapore
Winson Jianhong Tan, Min Hoe Chew, Department of General Surgery, Sengkang General Hospital, Singapore 544886, Singapore
Sreemanee Raaj Dorajoo, Department of Pharmacy, National University of Singapore, Singapore 117559, Singapore
Sharon Hui Ling Soh, Yi Chye Law, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
Soo Yeun Park, Gyu-Seok Choi, Colorectal Cancer Center, Kyungpook National University Chilgok Hospital, Kyungpook National University School of Medicine, Daegu 702-210, South Korea
Author contributions: Chew MH conceived the research and study design; Seow-En I, Dorajoo SR, Soh SHL, Law YC and Park SY contributed to data acquisition and analysis; Seow-En I, Tan WJ, Dorajoo SR and Park SY were involved in interpretation of data and writing of the manuscript; Tan WJ, Choi GS, Tan WS, Tang CL and Chew MH contributed to editing and revision of the article; all authors read and approved the final manuscript.
Institutional review board statement: The study was reviewed and approved by the SingHealth Institutional Review Board.
Informed consent statement: Informed consent was not required for this retrospective study and all details that might disclose the identity of the subjects under study was omitted or anonymized.
Conflict-of-interest statement: All authors declare no conflict-of-interest.
STROBE statement: The authors have read the STROBE Statement-checklist of items, and the manuscript was prepared and revised according to the STROBE Statement-checklist of items.
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: Isaac Seow-En, FRCS (Ed), MBBS, Doctor, Surgeon, Associate Consultant, Department of Colorectal Surgery, Singapore General Hospital, Outram Road, Singapore 169608, Singapore. isaac.seow.en@singhealth.com.sg
Telephone: +65-96423931
Received: April 1, 2019
Peer-review started: April 2, 2019
First decision: April 20, 2019
Revised: May 9, 2019
Accepted: May 23, 2019
Article in press: May 23, 2019
Published online: May 27, 2019
Processing time: 56 Days and 22.5 Hours
Abstract
BACKGROUND

With advanced age and chronic illness, the life expectancy of a patient with colorectal cancer (CRC) becomes less dependent on the malignant disease and more on their pre-morbid condition. Justifying major surgery for these elderly patients can be challenging. An accurate tool demonstrating post-operative survival probability would be useful for surgeons and their patients.

AIM

To integrate clinically significant prognostic factors relevant to elective colorectal surgery in the elderly into a validated pre-operative scoring system.

METHODS

In this retrospective cohort study, patients aged 70 and above who underwent surgery for CRC at Singapore General Hospital between 1 January 2005 and 31 December 2012 were identified from a prospectively maintained database. Patients with evidence of metastatic disease, and those who underwent emergency surgery or had surgery for benign colorectal conditions were excluded from the analysis. The primary outcome was overall 3-year overall survival (OS) following surgery. A multivariate model predicting survival was derived and validated against an equivalent external surgical cohort from Kyungpook National University Chilgok Hospital, South Korea. Statistical analyses were performed using Stata/MP Version 15.1.

RESULTS

A total of 1267 patients were identified for analysis. The median post-operative length of stay was 8 [interquartile range (IQR) 6-12] d and median follow-up duration was 47 (IQR 19-75) mo. Median OS was 78 (IQR 65-85) mo. Following multivariate analysis, the factors significant for predicting overall mortality were serum albumin < 35 g/dL, serum carcinoembryonic antigen ≥ 20 µg/L, T stage 3 or 4, moderate tumor cell differentiation or worse, mucinous histology, rectal tumors, and pre-existing chronic obstructive lung disease. Advanced age alone was not found to be significant. The Korean cohort consisted of 910 patients. The Singapore cohort exhibited a poorer OS, likely due to a higher proportion of advanced cancers. Despite the clinicopathologic differences, there was successful validation of the model following recalibration. An interactive online calculator was designed to facilitate post-operative survival prediction, available at http://bit.ly/sgh_crc. The main limitation of the study was selection bias, as patients who had undergone surgery would have tended to be physiologically fitter.

CONCLUSION

This novel scoring system generates an individualized survival probability following colorectal resection and can assist in the decision-making process. Validation with an external population strengthens the generalizability of this model.

Keywords: Colorectal cancer surgery; Elderly; Overall survival; Pre-operative prognostic score

Core tip: Ageing results in a decreased functional reserve along with various comorbid diseases. Many elderly patients express age-related concerns when advised for operative intervention. This is the first predictive survival model specific for older patients planned for elective colorectal surgery and provides a visual guide to facilitate the counselling process.

Seow-En I, Tan WJ, Dorajoo SR, Soh SHL, Law YC, Park SY, Choi GS, Tan WS, Tang CL, Chew MH. Prediction of overall survival following colorectal cancer surgery in elderly patients. World J Gastrointest Surg 2019; 11(5): 0000-0000 URL: https://http://www.wjgnet.com/1948-9366/full/v11/i5/0000.htm DOI: https://dx.doi.org/10.4240/wjgs.v11.i5.0000