Pain biomarkers in cancer: An overview

Background: Pain is a common symptom in oncologic patients and its management is generally guided with reference to pain individually perceived by patients and expressed through self-reported scales. How-ever, the utility of these tools is limited as it strongly depends on patients’ opinions. For this reason, more objective instruments are desirable. Objective: In this overview, scientific articles indicating potential markers to be used for pain management in cancer were collected and discussed. Methods: Research was performed on principal electronic scientific databases by using the words “pain”, “can-cer”, “markers” and “biomarkers” as the main keywords, and findings describing potential biomarkers for the management of cancer pain were reported. Results: Studies on pain markers not specific for cancer typology (inflammatory, genetic markers predicting response to analgesic drugs, neuroimaging markers) and pain markers for specific types of cancer (bone cancer, breast cancer, lung cancer, head and neck cancer, prostate cancer, cancer in pediatrics) have been presented and commented on. Conclusion: This overview supports the view of the involvement of inflammatory mediators in the mechanisms underlying cancer pain. Only a small amount of data from research up till today is available on markers that can help in the management of pain, except for pro-inflammatory cytokines and other inflammatory indexes such as C-reactive protein (CRP). However, biomarkers are a promising strategy useful to predict pain intensity and to objectively quantify analgesic response in guiding decisions regarding individual-tailored treatments for cancer patients.