Quinolinic Acid and Chronic Cancer Pain

Pain is a complex phenomenon that is influenced by both objective and subjective factors. In patients with cancer undergoing active therapy, the prevalence of chronic pain is estimated to range from 30% to 50%. Given the complex nature of cancer patients' conditions, including impaired physical function, psychological distress, and various other problems, a comprehensive pain assessment is necessary to ensure effective pain management, reduce morbidity, and prevent opioid dependence. Objective measurement of pain is essential to improve the quality of chronic pain services for malignancy, and several biomarkers have been identified as potentially useful tools for measuring chronic pain more objectively. Quinolinic acid is one of these significant biomarkers that have been found to be useful for assessing pain. This study represents the first investigation in Indonesia of the relationship between quinolinic acid and chronic cancer pain. A cross-sectional study was conducted with 85 participants, including 29 male and 56 female patients. The pain scale was measured using the Numerating Rating Scale (NRS) with a range of 0-10, and serum quinolinic acid levels were measured using ELISA. Of the 85 study participants, 29 patients (34.12%) had pelvic organ cancer, 21 patients (24.71%) had head and neck cancer, 12 patients (14.12%) had abdominal organ cancer, 7 patients (8.24%) had breast cancer, 5 patients (5.88%) had pulmonary cancer, 4 patients (4.71%) had skin cancer, and 7 patients (8.24%) had other types of cancer. The study found that the effect of quinolinic acid on the degree of pain was significant (p = 0.024), with a correlation coefficient (r) of 0.244. However, the effect of kynurenic acid on the duration of pain was not significant (p = 0.135). In conclusion, quinolinic acid was found to be correlated with the degree of pain in chronic cancer patients, but it had no correlation with the duration of pain. Further research is needed to explore the potential of quinolinic acid as a biomarker for chronic pain assessment and management in cancer patients.