Treatment Options for Chronic Cancer Pain
The management of chronic cancer pain requires a systematic approach using both pharmacological and non-pharmacological interventions, with opioids being the mainstay of treatment for moderate to severe pain, complemented by adjuvant medications and interventional techniques based on pain type and severity. 1
Pain Assessment and Classification
Comprehensive Assessment
Screen for pain at each patient encounter using standardized tools 2:
- Visual Analog Scale (VAS)
- Numerical Rating Scale (NRS)
- Verbal Rating Scale (VRS)
Evaluate pain characteristics:
- Location, radiation, and referral patterns
- Intensity (at rest and with movement)
- Quality (aching, stabbing, burning, etc.)
- Timing (onset, duration, persistent or intermittent)
- Impact on function and quality of life 2
Identify pain type:
- Nociceptive (somatic or visceral)
- Neuropathic
- Mixed 2
Pharmacological Management
WHO Analgesic Ladder Approach
Step 1: Mild Pain
Step 2: Moderate Pain
- Weak opioids plus non-opioids:
- Codeine, tramadol
- Alternative: Low-dose strong opioids 2
Step 3: Severe Pain
- Strong opioids:
Opioid Administration Principles
- Use regular scheduling with breakthrough dosing
- Titrate dose based on response and side effects
- Calculate breakthrough doses as 10-15% of total daily dose
- Consider increasing baseline dose if >4 breakthrough doses needed daily 1
- When converting to transdermal fentanyl, use appropriate conversion tables based on 24-hour morphine equivalents 3
Adjuvant Medications for Specific Pain Types
For Neuropathic Pain
Anticonvulsants:
- Gabapentin (100-1200 mg three times daily)
- Pregabalin (100-600 mg/day divided in 2-3 doses)
- Carbamazepine (100-400 mg three times daily) 2
Antidepressants:
For Inflammatory Pain
- NSAIDs or glucocorticoids 2
For Bone Pain
- NSAIDs plus opioids
- Consider bisphosphonates or denosumab 1
For Localized Pain
- Topical agents:
- Lidocaine patch 5%
- Diclofenac gel/patch 1
Non-Pharmacological Interventions
Physical Interventions
- Physical therapy and rehabilitation
- Heat/cold therapy
- TENS (Transcutaneous Electrical Nerve Stimulation)
- Individualized exercise programs 2, 1
Psychological Interventions
Interventional Procedures
- For refractory pain:
- Nerve blocks
- Neuraxial infusion (epidural/intrathecal)
- Vertebroplasty/kyphoplasty for vertebral metastases 2
Disease-Modifying Approaches
- Radiation therapy for bone metastases
- Chemotherapy or targeted therapy for tumor response
- Surgery for pathological fractures or spinal cord compression 2, 1
Managing Side Effects
- Constipation: Prophylactic laxatives with opioid initiation
- Nausea/vomiting: Antiemetics (metoclopramide, ondansetron)
- Sedation: Dose adjustment, consider psychostimulants
- Respiratory depression: Monitor closely, especially in opioid-naive patients 1
Common Pitfalls to Avoid
- Undertreatment due to fear of addiction or side effects
- Failure to address breakthrough pain
- Neglecting the neuropathic component of cancer pain
- Ignoring psychosocial aspects of pain
- Abrupt discontinuation of opioids 1
- Using combination opioid products (with acetaminophen/NSAIDs) when high doses are needed 2
Special Considerations for Cancer Survivors
- Chronic post-cancer treatment pain requires different approaches than active cancer pain
- Consider long-term side effects of opioids
- Focus on functional improvement and quality of life
- Integrate more non-pharmacological approaches 2, 4
- Address psychological distress which can amplify pain perception 2
By following this systematic approach to chronic cancer pain management, clinicians can significantly improve patients' quality of life and functional status while minimizing adverse effects.