Managing Cancer Pain

---
name: managing-cancer-pain
language: en
description: Structures cancer pain assessment with WHO ladder application and breakthrough dosing. Use when managing cancer pain, titrating opioids, or implementing cancer pain protocols.
tags:
  - management
  - oncology
metadata:
  author: casemark
  practice_areas:
    - Medical Oncology
    - Hematology-Oncology
    - Radiation Oncology
  document_types:
    - Management Report
  skill_modes:
    - Management
    - Coordination
---

# Managing Cancer Pain

Structures cancer pain assessment with WHO ladder application and breakthrough dosing.

## Why This Skill Exists

Pain affects 55–66% of cancer patients receiving active treatment and up to 70–80% of patients with advanced disease. Despite decades of WHO analgesic ladder use, cancer pain remains undertreated in 30–50% of patients. The consequences of undertreated pain include decreased functional status, treatment non-adherence, depression, reduced quality of life, and increased healthcare utilization. Conversely, inappropriate opioid prescribing without structured assessment leads to adverse effects, regulatory scrutiny, and diversion risk.

NCCN Adult Cancer Pain guidelines, WHO analgesic ladder, and ASCO guidelines provide evidence-based frameworks. State prescription drug monitoring programs (PDMPs), DEA regulations for controlled substances, and institutional opioid stewardship programs require documented pain assessment, treatment rationale, and monitoring. This skill ensures cancer pain is assessed systematically, treated per evidence-based guidelines, and documented to meet clinical, regulatory, and quality standards.

---

## Checkpoint A: Pre-Draft Intake (Mandatory)

1. What is the cancer type, stage, and current treatment status? (Default: [VERIFY])
2. What is the patient's current pain score and location(s)? (Default: use 0–10 numerical rating scale)
3. What is the pain character (nociceptive/somatic, visceral, neuropathic, or mixed)? (Default: assess)
4. What is the current pain management regimen (medications, doses, frequency)? (Default: document)
5. What is the patient's current opioid tolerance status? (Default: opioid-naive vs. opioid-tolerant per FDA definition)
6. Are there renal or hepatic function impairments affecting drug metabolism? (Default: review labs)
7. Is there a history of substance use disorder? (Default: assess with validated tool, e.g., CAGE-AID)
8. What is the patient's functional status and pain impact on daily activities? (Default: assess)

### Documents to Request

- Current medication list with all analgesics, doses, and schedules
- Pain assessment history (serial pain scores with dates)
- PDMP report (state prescription monitoring database)
- Relevant imaging (to identify pain source — bone metastases, nerve compression, visceral involvement)
- Renal function (CrCl) and hepatic function (LFTs, albumin, INR) labs
- Prior interventional pain procedures if applicable
- Palliative radiation therapy history if applicable
- Substance use disorder screening results

---

## Step 1: Conduct Comprehensive Pain Assessment

**OPQRSTUV mnemonic for cancer pain assessment:**

| Element | Assessment | Documentation |
|---------|-----------|--------------|
| **O**nset | When did the pain start? Acute vs. chronic? | Date of onset, temporal pattern |
| **P**rovocative/Palliative | What makes it worse or better? | Movement, position, medications |
| **Q**uality | What does it feel like? | Sharp, dull, burning, aching, shooting |
| **R**egion/Radiation | Where is the pain? Does it radiate? | Anatomic location, radiation pattern |
| **S**everity | Pain score 0–10 | Current, worst, least, average |
| **T**iming | Constant vs. intermittent? Breakthrough? | Pattern, frequency, duration |
| **U**nderstanding | Patient's understanding of the pain cause | Correlation with disease |
| **V**alues | Pain goal (acceptable pain level)? | Patient's target pain score |

**Pain classification:**
- **Nociceptive (somatic):** Well-localized, aching, throbbing — bone metastases, post-surgical
- **Visceral:** Poorly localized, deep, crampy — organ involvement, peritoneal disease
- **Neuropathic:** Burning, shooting, electric — nerve compression, plexopathy, chemotherapy-induced
- **Mixed:** Most cancer pain is mixed — identify each component for targeted treatment

---

## Step 2: Apply the WHO Analgesic Ladder with Modifications

**WHO Three-Step Ladder (modified for current oncology practice):**

| Step | Pain Severity | Medications | Notes |
|------|-------------|-------------|-------|
| Step 1 | Mild (1–3/10) | Non-opioid: acetaminophen, NSAIDs ± adjuvants | NSAIDs particularly effective for bone pain. Limit acetaminophen to ≤3g/day (≤2g/day with hepatic dysfunction) |
| Step 2 | Moderate (4–6/10) | Low-dose strong opioid (morphine, oxycodone at low doses) ± non-opioid ± adjuvants | WHO now supports skipping weak opioids (codeine, tramadol) and using low-dose strong opioids |
| Step 3 | Severe (7–10/10) | Strong opioid (morphine, oxycodone, hydromorphone, fentanyl) ± non-opioid ± adjuvants | Titrate to effect; no ceiling dose for pure opioid agonists |

**Adjuvant analgesics by pain type:**
- **Neuropathic pain:** Gabapentin (300–3600mg/day), pregabalin (75–300mg BID), duloxetine (60mg/day), TCAs (nortriptyline, desipramine)
- **Bone pain:** NSAIDs, corticosteroids (dexamethasone 4–8mg), bisphosphonates (zoledronic acid), denosumab, palliative radiation
- **Visceral pain:** Corticosteroids for obstruction/capsular stretch, octreotide for bowel obstruction
- **Muscle spasm:** Baclofen, cyclobenzaprine, benzodiazepines (short-term)

---

## Step 3: Opioid Initiation and Titration

**For opioid-naive patients:**
- Start with short-acting opioid: morphine 5–15mg PO q4h, or oxycodone 5–10mg PO q4h
- Avoid methadone and fentanyl patches in opioid-naive patients
- Assess response at 24–48 hours; titrate by 25–50% for inadequate relief

**Conversion to long-acting (when stable dose established):**
1. Calculate total 24-hour opioid consumption
2. Convert to morphine equivalent daily dose (MEDD) using equianalgesic table:

| Opioid | Oral Dose Equivalent to Morphine 30mg PO |
|--------|----------------------------------------|
| Oxycodone | 20 mg PO |
| Hydromorphone | 6 mg PO |
| Fentanyl transdermal | ~12.5 mcg/hr (for MEDD 30–44mg) |
| Methadone | Variable ratio — requires specialist dosing |

3. Reduce by 25–50% for incomplete cross-tolerance when switching opioids
4. Prescribe breakthrough dose: 10–20% of total 24-hour MEDD as immediate-release q1-2h PRN

**Breakthrough pain management:**
- Breakthrough dose = 10–20% of total 24-hour opioid dose
- If ≥4 breakthrough doses used per day, increase the around-the-clock dose by adding total breakthrough opioid used to the daily regimen
- Transmucosal fentanyl (TIRF products) for rapid-onset breakthrough: restricted to opioid-tolerant patients via TIRF REMS

---

## Step 4: Manage Opioid Side Effects and Monitor Safety

**Mandatory prophylaxis:** Start a bowel regimen with every opioid prescription — senna + docusate or PEG daily. Opioid-induced constipation does not develop tolerance.

**Common side effects and management:**

| Side Effect | Prevalence | Management |
|------------|-----------|-----------|
| Constipation | 40–95% | Senna/docusate, PEG, methylnaltrexone (for refractory OIC) |
| Nausea | 15–30% | Usually transient; prochlorperazine, ondansetron, or haloperidol |
| Sedation | Common initially | Usually resolves in 3–5 days; reduce dose if persistent; methylphenidate as rescue |
| Pruritus | 10–20% | Antihistamines, opioid rotation |
| Respiratory depression | Rare with proper titration | Naloxone 0.04–0.4mg IV; dilute and titrate in cancer patients to avoid pain crisis |
| Myoclonus | With high doses or renal failure | Opioid rotation, benzodiazepines, dose reduction |

**Safety monitoring:**
- PDMP check at initiation and periodically during treatment
- Urine drug testing: consider at baseline and periodically, applied with sensitivity in cancer patients
- Assess for opioid-induced hyperalgesia (increasing pain despite increasing doses without disease progression)
- Document risk-benefit assessment for opioid continuation at each visit

---

## Checkpoint B: Post-Draft Alignment (Mandatory)

1. Is pain assessed using a standardized tool with documented pain score and functional impact?
2. Is the analgesic plan matched to pain severity (WHO step) and pain type (nociceptive, neuropathic, mixed)?
3. Are equianalgesic calculations documented for opioid conversions and rotations?
4. Is a breakthrough dose prescribed at 10–20% of total daily opioid and available on the regimen?
5. Are opioid side effects proactively managed (bowel regimen prescribed, nausea plan in place)?

---

## Quality Audit

- [ ] Comprehensive pain assessment (OPQRSTUV or equivalent) documented
- [ ] Pain classified by type (nociceptive, visceral, neuropathic, mixed)
- [ ] WHO analgesic ladder step appropriate for pain severity
- [ ] Adjuvant analgesics prescribed for neuropathic or bone pain components
- [ ] Opioid selection appropriate for patient status (naive vs. tolerant)
- [ ] Equianalgesic calculations documented for opioid conversion
- [ ] Cross-tolerance reduction (25–50%) applied when rotating opioids
- [ ] Breakthrough dose calculated at 10–20% of total daily dose
- [ ] Bowel regimen prescribed with every opioid
- [ ] PDMP checked and documented
- [ ] Substance use disorder risk assessed with validated screening tool
- [ ] Pain score reassessment scheduled with specific timeline
- [ ] Non-pharmacologic interventions considered (radiation, nerve blocks, physical therapy)
- [ ] Naloxone prescribed for patients at risk of respiratory depression

---

## Guidelines

- Cancer pain requires regular, around-the-clock dosing — PRN-only regimens are inadequate for moderate to severe chronic cancer pain
- There is no maximum dose for pure opioid agonists (morphine, oxycodone, hydromorphone, fentanyl) — titrate to effect as tolerated
- Always start a bowel regimen when initiating an opioid — opioid-induced constipation does not resolve with tolerance
- Fentanyl patches are only for opioid-tolerant patients (per FDA: ≥60mg oral morphine equivalent per day for ≥1 week)
- Avoid meperidine in cancer patients — neurotoxic metabolite (normeperidine) accumulates with repeated dosing
- Methadone has unique pharmacology (variable half-life, NMDA receptor activity, QTc prolongation risk) — initiate only with specialist guidance or established institutional protocol
- Palliative radiation for painful bone metastases can provide relief in 60–80% of patients — consider for localized pain
- Interventional procedures (nerve blocks, intrathecal pumps, vertebroplasty) should be considered when systemic opioid doses are escalating with inadequate relief or intolerable side effects