January 2024 | George M. Pikler, M.D., Ph.D., FACP

Opioid Analgesics for Nociceptive Cancer Pain

Pain is one of the most common and burdensome symptoms associated with cancer, and opioid analgesics are considered the mainstay of cancer pain management. Pain affects up to three of four people with cancer and adversely affects their quality of life. Causes of cancer pain are complex and varied but typically arise from a verifiable lesion that produces pain through direct tissue injury, metastatic disease, and/or cancer-related inflammatory processes. In some cases, it may also arise from cancer treatment(s). For example, pain at the site of injection and pain from oral mucositis, colitis, or musculoskeletal pain are documented adverse events from commonly used anticancer treatments.

Investigators in Australia have uncovered concerningly large gaps in evidence regarding the true benefits of opioids for pain relief in patients with cancer and their findings were recently published. The new findings could challenge the commonly held view that opioids are the most powerful pain relievers. Morphine is often considered the standard treatment option for moderate to severe cancer pain because of its low cost and accessibility. Few studies have compared commonly used opioids like morphine, oxycodone, and methadone with placebo in this patient population.

Data of over 150 clinical trials involving patients treated with opioids for cancer pain were analyzed. Among the placebo-controlled trials, the investigators found evidence of moderate certainty that Tapentadol (Nucynta) may be more effective than placebo at treating background pain. Opioids commonly thought of as weaker such as codeine; nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, piroxicam, ketorolac, and diclofenac; and the antidepressant imipramine may be just as effective at treating background pain, but with fewer side effects.

They found no convincing evidence that morphine was better or safer than other opioids for background cancer pain outside of end-of-life care. Additionally, morphine and other opioids were found to potentially affect the body’s ability to fight cancer. Nonetheless, more research may be needed to determine whether there are negative interactions between opioids and cancer therapy or the immune system to ensure that pain management does not negatively impact survival.

CA: A Cancer Journal for Clinicians. 18 December 2023
Erica

Erica Cross, PA

PA

Erica is a board certified Physician Assistant. She obtained her Master’s degree in Physician Assistant studies from Our Lady of the Lake College in Baton Rouge, LA. She began practicing in 2011 and has worked clinically in Orthopedics and Dermatology. The majority of her career has been spent in a Dermatology practice where she assisted in Mohs surgery, treating various types of skin cancer. She also teaches in the medical simulation department at the University of South Alabama and enjoys every aspect of medical education.