Cancer Pain ManagementSuzana Makowski, MD MMM FACP FAAHPM

Prevalence of Cancer Pain

• 50 to 90 percent of oncology inpatients report breakthrough pain

• 35 percent of community based oncology practices patients report breakthrough pain

• 1 in 3 patients with active cancer report pain• 3 out of 4 of patients with advanced cancer report pain

Common Causes

• Bone metastases• Visceral metastases• Immobility• Neuropathic pain• Soft tissue• Constipation• Esophagitis• Lymphedema• Muscle cramps• Chronic postoperative scar

• Adapted from Twycross R, Harcourt J, Bergl S: A survey of pain in patients with advanced cancer. J Pain Symptom Manage 1996;12:273-282.

Effects of under treated pain

Physical Emotional Existential• Increased catabolic demands:

poor wound healing, weakness, muscle breakdown

• Decreased limb movement: increased risk of DVT/PE

• Respiratory effects: shallow breathing, tachypnea, cough suppression increasing risk of pneumonia and atelectasis

• Sodium and water retention Decreased gastrointestinal mobility

• Tachycardia and elevated blood pressure

• Decreased functional status• Increased chronic pain

DepressionAnxietyDecreased intimacySuicidality

Suffering – “why me?”

Effects of under treated pain

Barriers to Pain Control

• System barriers to treating pain• Clinical,• Patient-related• System-related

• Racial and ethnic barriers exist• Language• Perceptions

• Concern about addiction• Differences between addiction, • dependence, • tolerance & • pseudoaddiction

Pain Assessment

Intensity • Location • Quality • Timeline • Alleviating factors • Meds tried

Intensity

What about for patients who cannot self-report?

Pain Quality

Category Cause Symptom Examples

Physiologic  

Brief exposure to a noxious stimulus

Rapid yet brief pain perception

Touching a pin or hot object

Nociceptive/inflammatory 

Somatic or visceral tissue injury with mediators having an impact on intact nervous tissue

Moderate to severe pain, described as crushing or stabbing 

Surgical pain, traumatic pain, sickle cell crisis 

Neuropathic Damage or dysfunction of peripheral nerves or CNS

Severe lancinating, burning or electrical shock like pain

Neuropathy, CRPS. Postherpetic Neuralgia

MixedCombined somatic and nervous tissue injury

Combinations of symptoms; soft tissue plus radicular pain

Low back pain, back surgery pain 

Timeline

Prior medications & other tx

• What worked?• What doses?• What side

effects?

Side effects

Common

• Constipation• Nausea• Sleepiness/somnolence• Pruritus• Myoclonus

Rare

• Respiratory suppression• Neurotoxicity• Seizures

Opioid Pharmacology

Opioid Pharmacology

Short-acting Long-acting

• Hydrocodone/APAP• Oxycodone +/- APAP• Morphine• Hydromorphone• Oral transmucosal fentanyl

• Transdermal fentanyl• methadone• morphine ER• oxycodone ER

• Cmax ~ 45 min• T1/2 ~ 4 hours• Except fentanyl

Cmax and T1/2 vary based on formulation and drug

Opioid pharmacology

• Conjugated by liver• 90-95% excreted in urine• Dehydration, renal failure, severe hepatic failure• Decrease interval/dosing size• If oliguria/anuria• STOP routine dosing (basal rate) of morphine

• Use ONLY PRN

Opioid Pharmacology

What is the half life (range) for opioids?• 2-4 hours

How many half lives to get to steady state? • 4-5

What do you base your scheduled dosing on: Cmax or T1/2?

• T1/2

What do you base your breakthrough dosing on: Cmax or T1/2?

• Cmax

Equianalgesic dosing

WHO Step-Ladder

What is the challenge with Step 2 of the ladder?

Case – part 1 - outpatient

Hector G - 65 yo man with colon cancer and bone metastases

Your colleague first started Mr. G on hydrocodone 5 mg + acetaminophen 325 mg one tablet by mouth every 4 hours prn for his hip and rib pain. He also ordered senna + docusate 2 tabs po qday to prevent opioid‐induced constipation.

Today, he tells you he is taking the Vicodin 1 tablet every 4 hours around the clock (including at night). His pain is generally constant, aching and he rates it as 5/10, but worsens to 8/10 with certain positions and movements.

• How will you titrate his opioid pain medication?

Case – Part 1

• Convert from Vicodin to Morphine• How to convert to a combination of long- and short-

acting morphine (the latter for breakthrough pain)?• What co-analgesics and other treatments might you

choose?

Case – Part 2 – NPO inpatient

• Hector comes to hospital for a procedure. He is made NPO. His pain has been well managed. How do you manage his pain?

• Home regimen: MSContin 30mg BID, Roxanol 10mg q2 hours prn, requiring 2 – 4 doses per day.

• What if he were on Oxycodone/Oxycontin instead?

Case – part 3

• Mr. G presents to the ER after several days of escalating hip and rib pain, despite taking the maximum dose of morphine he was prescribed as an outpatient. “I can’t take it anymore.” You admit him for pain management while trying to treat his escalating pain.

• Home medications: MSContin PO 30mg bid, Morphine liquid 10mg PO q2 hours prn (taking every dose)

In addition to imaging him, calling radiation oncology for evaluation, how do you manage his pain?

Pain crisis

• This is as much of a crisis as a code (JAMA 2008;299(12):1457-1467. doi: 10.1001/jama.299.12.1457)

• http://jama.ama-assn.org/content/299/12/1457.full.pdf

Advanced pain techniques

Non-interventional

• Methadone (opioid + NMDA)

• Ketamine (NMDA) infusion

• Lidocaine infusion

Interventional

• Nerve blocks• Intrathecal pain pumps

Pain at End-of-Life

• Choosing to be CMO does not automatically increase opioid requirement

• Caution with renal failure

CMO ≠ Continuous Morphine Only

Summary: Top 10

• Pain is common in cancer. Undertreated pain worsens prognosis

• On a good day, patients should not need PRNs, and on a bad day, should not need it more than 4 times per day.

• When converting to IV from PO – don’t forget to include the long-acting opioid.

• Opioid conversion is not mysterious• Pain Crises is as serious as a code• Methadone is a great drug – but is complicated• Avoid morphine and hydromorphone in renal failure • Match pain pattern with opioid pharmacology• CMO ≠ continuous morphine only• We’re here to help

Free CME from NCI

• https://cissecure.nci.nih.gov/ncipubs/detail.aspx?prodid=Q014