Content area
Full Text
Abstract
The Karnofsky Performance Status (KPS) scale is used to assess functional impairment. KPS scores have been shown to be one of the most crucial predictive factors in the survival of cancer patients. The objective was to determine whether overall survival predicted by KPS scores in patients receiving palliative radiation has increased from 2007-2012. A retrospective chart review was conducted to collect demographic information, including primary cancer site, clinic date, KPS score, and date of death. Overall survival (OS) was calculated. Kaplan-Meier survival curves and univariate Cox proportional hazard model were conducted for all patients and within KPS subgroups. A p-value <0.05 was considered statistically significant. All patients who were seen at an outpatient radiotherapy clinic in Toronto, Canada, from 2007-2012 were included in the study. Of a total 2,690 patients, 2257 (84%) were deceased. The median OS time was 2.9 months (95% CI: 2.7-3.1). All patients seen from 2007-2008 (p<0.0001) and 2009-2010 (p=0.03) had shorter survival than those seen from 2011-2012. Survival was shorter for patients with KPS of 50-70 seen in 2007-2008 (p=0.007) and 2009-2010 (p=0.049) compared to 2011-2012. Survival of patients with KPS 80-100 nearly doubled from 6.6 to 12.1 months (p=0.005) for those seen in 2007-2008 compared to those seen in 2011-2012. Survival has increased for patients within the same KPS categories from 2007-2012. Survival prognostic models that incorporate KPS may need to be temporally validated, taking into consideration latest systemic therapies with survival benefits.
Keywords: Karnofsky Performance Status, overall survival, prognostic models, advanced cancer, palliative radiation therapy
Introduction
Health care professionals are constantly faced with the challenge of predicting prognosis in order to help patients and their families make end-of-life and treatment decisions (1, 2). In the advanced cancer population, this is increasingly difficult due the heterogeneity in functional ability and level of care required for activities of daily living (1). Currently, the Karnofsky Performance Status (KPS) is one of the most commonly used tools in clinical oncology to predict prognosis (2-4).
This scale was introduced in the 1940s with the advent of cancer chemotherapy in order to describe patients' functional ability and amount of care they require in a meaningful way (3, 5). It is assessed on an 11-point scale increasing by increments of 10, with scores...