Clinical Implications of Opioid Pharmacogenomics in Patients With Cancer

Background: Pain can be a significant burden for patients with cancer and may have negative effects on their quality of life. Opioids are potent analgesics and serve as a foundation for pain management. The variation in response to opioid analgesics is well characterized and is partly due to genetic variability. Methods: We reviewed the results of clinical studies to evaluate the relationships between genetic variants and select genes involved in the pharmacokinetics and pharmacodynamics of opioids, with an emphasis on patients with cancer. Results: In patients with cancer-related pain, genetic variation in OPRM1, COMT, and ABCB1 is associated with response to morphine, which is the most well-studied opioid. Although it has not been studied in patients with cancer-related pain, the effect of CYP2D6 variation is well characterized with codeine and tramadol. Evidence is limited for associating the genetic variation and pain response of oxycodone, hydrocodone, and fentanyl in patients with cancer. Conclusion: The clinical availability of pharmacogenomic testing and research findings related to these polymorphic genes suggest that genotyping patients for these genetic variants may allow health care professionals to better predict patient response to pain and, thus, personalize pain treatment.