Kynurenic acid as chronic pain biomarker for future cancer pain management

Abstract

The prevalence of chronic pain ranges from 30-50% in patients with cancer undergoing active therapy. Kynurenic acid, xanthurenic acid, and quinolinic acid are significant biomarkers for assessing pain objectively. This study aims to investigate the scientific evidence of the effect of serum kynurenic acid levels on the severity and duration of chronic cancer pain. It is a cross-sectional study with 80 subjects consisting of 19 male and 61 female patients in the palliative outpatient clinic of Dr Soetomo Hospital. The pain assessment was performed using the NRS, and the biochemical analysis of serum kynurenic acid was assessed using the ELISA method. Of the total of 80 subjects, 26 patients had pelvic organ cancer (33.7%), 24 patients had respiratory organ cancer (30.1%), 17 patients had breast cancer (21.7%), 9 patients had abdominal organ cancer (9.6%), 3 patients had malignant melanoma (3.6%), and 1 patient had sternal bone cancer (1.2%). Kynurenic acid significantly correlated with the severity of pain (p = 0.043), with (r) of -0.218. However, kynurenic acid showed no significant correlation with the duration of pain (p = 0.052). Kynurenic acid affected the severity of pain but did not affect the duration of pain in chronic cancer pain patients.