Retrospective Cohort Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Oncol. Nov 10, 2018; 9(7): 140-147
Published online Nov 10, 2018. doi: 10.5306/wjco.v9.i7.140
Interconversion of two commonly used performance tools: An analysis of 5844 paired assessments in 1501 lung cancer patients
Kuruswamy Thurai Prasad, Harpreet Kaur, Valliappan Muthu, Ashutosh Nath Aggarwal, Digambar Behera, Navneet Singh
Kuruswamy Thurai Prasad, Harpreet Kaur, Valliappan Muthu, Ashutosh Nath Aggarwal, Digambar Behera, Navneet Singh, Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh 160012, India
Author contributions: Prasad KT was involved in data collection and analysis, and initial drafting and final approval of the manuscript; Kaur H, Muthu V, Aggarwal AN, and Behera D were involved in data collection and gave final approval of the manuscript; Singh N was involved in conception of the study, data collection and analysis, initial drafting and final approval of the manuscript, and is the guarantor of the overall content.
Institutional review board statement: The manuscript was approved by Postgraduate Institute of Medical Education and Research, Chandigarh.
Informed consent statement: Informed consent was obtained from all the subjects.
Conflict-of-interest statement: All authors declare no conflicts of interest related to this article.
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/
Correspondence to: Navneet Singh, MD, Additional Professor, Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research (PGIMER), Room No 4, Level IV, F block, Nehru Hospital, Chandigarh 160012, India. navneetchd@hotmail.com
Telephone: +91-172-2756826
Received: April 30, 2018
Peer-review started: April 30, 2018
First decision: June 6, 2018
Revised: August 6, 2018
Accepted: October 8, 2018
Article in press: October 8, 2018
Published online: November 10, 2018
Abstract
AIM

To establish the Karnofsky performance status (KPS) categories which would facilitate the interconversion of the KPS scale to the Eastern Cooperative Oncology Group (ECOG) performance status (PS) scale.

METHODS

This was a retrospective analysis of all patients attending the lung cancer clinic at a tertiary care center over a 5-year period (September 2009 to August 2014). All patients were assessed with both KPS and ECOG PS scales at each visit. Correlation between KPS and ECOG PS was assessed using Spearman’s correlation coefficient. KPS categories equivalent to ECOG PS scores were compared using hit rate and weighted kappa (κw).

RESULTS

A total of 1501 patients were assessed over the study period, providing 5844 paired KPS and ECOG PS assessments. The study cohort had a mean (standard deviation; SD) age of 58.4 (10.8) years, with the majority being current or ex-smokers (76.9%) and males (82.3%). Non-small cell lung cancer was the most common histological type (n = 1196, 79.7%) with the majority having advanced (stage IIIB/IV) disease (83.4%). Mean baseline KPS and ECOG PS scores were 77.6 (SD = 14.4) and 1.5 (SD = 1) respectively. The most frequent KPS score was 80 (29%), and the most frequent ECOG PS score was 1 (43%). The overall correlation between KPS and ECOG PS was good (Spearman r = -0.84, P < 0.0001) but ranged from -0.727 to -0.972 between visits. KPS categories derived from our cohort [10-40 (ECOG 4), 50-60 (ECOG 3), 70 (ECOG 2), 80-90 (ECOG 1), 100 (ECOG 0)] performed better [hit rate 78.1%, κw = 0.749 (0.736-0.762) P < 0.0001] than those suggested in the past literature.

CONCLUSION

The current study provides the largest set of paired KPS-ECOG assessments to date. We suggest that the KPS categories 10-40, 50-60, 70, 80-90, and 100 are equivalent to ECOG PS categories of 4, 3, 2, 1, and 0 respectively.

Keywords: Karnofsky performance status, Eastern Cooperative Oncology Group, Performance status, Lung cancer, Chemotherapy

Core tip: Karnofsky performance status (KPS) scale and Eastern Cooperative Oncology Group (ECOG) scale are the most commonly used performance status (PS) tools worldwide for patients with cancer. Since the number of scoring points in each scale is different, these scales are not readily interconvertible. However, most clinical studies use only one of these two scales (either KPS or ECOG PS) to assess PS, rendering interpopulation comparisons difficult. In this study, we analyze the largest set of paired KPS-ECOG assessments to date in a cohort of lung cancer patients for a solution.