Published online Nov 10, 2018. doi: 10.5306/wjco.v9.i7.140
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
Processing time: 194 Days and 16.4 Hours
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.
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).
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.
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.
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.