Cancer Pain

Overview

  • ~1.75 million people are diagnosed with cancer every year
  • Up to 90% of patients with advanced cancer have pain that significantly impacts function, mood, sleep
  • In 1984, WHO stepladder was introduced for management of cancer pain
Traditional WHO Step Ladder
  • Pain management typically relies on the WHO stepladder, but analgesia may be inadequate for 10-25% of cancer patients
  • Interventional options such as nerve blocks and intrathecal therapy may be appropriate
    • Celiac plexus block/neurolysis for abdominal pain
    • Superior hypogastric plexus block/neurolysis for pelvic pain
    • Intrathecal therapy for regional cancer-related nociceptive or neuropathic pain

Clinical Use

Clinical Challenges

  • Cancer-related pain is very broad
  • Can be directly caused by the tumor itself or be an effect of treatment
    • E.g. chemotherapy-induced peripheral neuropathy, arthritis from immunotherapy, radiation neuropathies
  • May be either nociceptive or neuropathic
    • Nociceptive pain: bony metastases, soft tissue involvement, pathological fractures, visceral involvement
    • Neuropathic pain: tumor invasion, nerve injury after surgery (post-thoracotomy pain, post-mastectomy pain), radiation neuritis, tumor invasion into nerves
  • Cancer pain is a moving target: disease may spread to many locations, cause different patterns of pain, or have mixed etiologies
  • Side effects of treatment may overlap with underlying disease and treatment effects
    • For example, fatigue could be due to opioids, but also due to or compounded by chemotherapy treatment, disease progression or the experience of chronic pain itself.
    • Altered mental status may be due to opioids, but could also be due to or compounded by organ failure, metabolic derangements or metastatic brain disease. 

Clinical Recomendations

  • Start with oral/parenteral medications for cancer pain 
  • Don’t forget about adjuvant medications like neuropathic medications for cancer-related pain
  • Progressive disease may require quick uptitration of opioid medications.
  • Interventional options, such as nerve blocks and intrathecal pumps, are appropriate for patients with poorly controlled pain or intolerable side effects.

Special Considerations

  • Patients’ cancer-targeted therapies may increase risk associated with interventional procedure:
    • Chemotherapeutics may cause myelosuppression leading to neutropenia, thrombocytopenia, or coagulopathies
    • Certain immunotherapeutics, such as bevacizumab, a VEGF inhibitor, can cause severe bleeding and poor wound healing
      • May want to avoid placing perioperative epidurals for these patients as well!
      • Bevacizimab must be held for 28 days before and after elective surgery.
  • May have physiological alterations to gut, liver, kidneys as a result of cancer/surgical intervention that may affect absorption, pharmacokinetics of many medications
References
  1. World Health Organization. Cancer Pain Relief. 1984
  2. Careskey H, Narang S. Interventional Anesthetic Methods for Pain in Hematology/Oncology Patients. Hematol Oncol Clin North Am. 2018 Jun;32(3):433-445. doi: 10.1016/j.hoc.2018.01.007. PMID: 29729779.
  3. Lau J, Flamer D, Murphy-Kane P. Interventional anesthesia and palliative care collaboration to manage cancer pain: a narrative review. Can J Anaesth. 2020 Feb;67(2):235-246. English. doi: 10.1007/s12630-019-01482-w. Epub 2019 Sep 30. PMID: 31571119.
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