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 try 2.png

  • 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: 

World Health Organization. Cancer Pain Relief. 1984

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.

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.

Author: 
Ann Cai Shah