Cancer%20pain Diagnosis

• All cancer patients should be screened for pain at each contact

Nociceptive Pain

• Caused by ongoing tissue damage to somatic and/or visceral structures that results in the activation of nociceptors found in the skin, viscera, muscle and connective tissues
• Can be subclassified as:
  • Somatic pain that often occur after surgical procedures or from bone metastasis
    • The pain is described as sharp, aching, stabbing, well localized, throbbing and pressure-like
  • Visceral pain is caused by tumor involvement of organ causing pain, may also be due to compression, infiltration or distension of abdominal or thoracic viscera
    • The pain is described as more diffuse and difficult to localize; gnawing or cramping if secondary to obstruction of hollow viscus; aching, sharp or throbbing when due to tumor involvement of organ capsule

Neuropathic Pain

• Sustained from peripheral or central nervous system damage or dysfunction
• Pain described as burning, pricking, electric-like, stabbing, sharp or shooting and sometimes may have a deep aching component
• Pain is usually located in the area innervated by the compressed/damaged peripheral nerve, plexus, nerve root or spinal cord that is often associated with loss of sensation in the painful region
• Allodynia or dysesthesia may be present
• Please see Neuropathic Pain disease management chart for further information

Breakthrough Pain

• Pain that occurs even when pain is adequately treated or even in a relatively well controlled baseline pain
  • It has rapid onset, moderate to severe in intensity and relatively short in duration (median 30 minutes)
• Rescue doses of short-acting opioids are usually given up to every 3-4 hours given on as-needed basis (10-20% of the 24-hour total of long-acting or regularly scheduled oral opioid dose)
  • Dose may be increased to once an hour on as-needed basis if pain control is inadequate; reassess regimen if hourly dosing is needed for >3 cycles

Incident Pain

• Pain that occurs after a specific activity or event (eg exercise, physical therapy, routine procedures)
• Rescue doses of short-acting opioids are given in anticipation of those events
• Rapidly-acting transmucosal Fentanyl can be considered in opioid-tolerant patients for brief episodes of incident pain not relieved by immediate-release opioids and not caused by inadequate dosing of around-the-clock opioid

End-of-Dose Failure Pain

• Pain that occurs toward the end of dosing interval for regularly scheduled opioid
• Regularly scheduled opioid dose or frequency is increased to manage this type of pain

Uncontrolled Persistent Pain

• Pain that occurs due to inadequate management of existing regularly scheduled opioid
• Dose schedule adjustment are done to manage this kind of pain

• In order to manage cancer pain effectively, comprehensive assessment of pain is a necessary first step
• It is important that the intensity of pain be quantified and qualitatively described by the patient itself whenever possible
• Aside from using pain rating scale, pain assessment includes:
  • Location, referral pattern, and radiation of pain 
  • Quality of pain: Aching, stabbing, throbbing, or pressure; gnawing, cramping, aching, or sharp pain; burning, tingling, shooting, or electric/shocking pain
  • Timing: Onset, duration, course, persistent or intermittent
  • Presence of breakthrough pain
  • Current and prior non-pharmacologic and pharmacologic treatments used and their impact on pain
  • Adequate comfort, satisfaction with pain relief
  • Provider assessment of adequacy of function
  • Presence of risk factors for undertreatment of pain (eg advanced age, communication barriers, history of substance abuse, cultural factors)
  • Any special issues for the patient relevant to pain treatment

• Behaviors and discomfort (ie facial expression, body movements, verbalization or vocalizations, changes in interpersonal interactions, changes in routine activity) can also be a way of assessing presence of pain
• Pain assessment aims to determine:
  • Nature and pathophysiology of pain
  • Pain severity
  • Impact of pain on functions and quality of life
  • Response to interventions

• Numerical levels of pain intensity or pain scores are:
  • 1-3 is mild
  • 4-6 is moderate
  • 7-10  is severe
• For nonverbal patients, a multi-faceted approach is recommended, combining direct observation, family/caregiver input, and evaluation of response to pain medicines or non-pharmacologic interventions

Pain Assessment Tools

• Used in assessing the intensity of pain and the effectiveness of management

Unidimensional Assessment Tools

• Reliable, easily implemented (with minimal training) and sustained in outpatient practice
• Numerical rating scale may be done by verbally asking the patient to describe the pain from 0-10 with 10 as the worst pain or by asking the patient to write or encircle the number that describes the intensity of pain experience
• Categorical scale can be done by asking the patient to give a word or words that describes the pain experience
• Visual Analogue/Pictorial/Faces Pain rating scale is done by assessing the facial reaction of the patient to pain

Multidimensional Assessment Tools

• Reliable, but needs more evidence in regards to validity
• Brief Pain Inventory (BPI) is the most frequently used
  • Assess the severity of pain by its intensity and how it affects the patient’s life
  • Quantifies these measures using a 0 to 10 numerical scale

• EORTC QLQ-C30 Pain Scale, SF-36 Bodily Pain Scale and the Short Form McGill Pain Questionnaire are other multidimensional scales used

Pain Assessment Tools for Nonverbal Patients

• Tools that may be used in intubated or unconscious patients
• Behavioral Pain Scale (BPS) and Critical-Care Pain Observation Tool (CPOT) have been tested in adults and intensive care

Psychosocial Assessment

• Psychosocial distress assessment should be done as pain is an important stressor in all kinds of cancers that can cause psychological distress and disability
• Inadequately controlled pain may cause substantial psychological distress
• Validated tools should be used in screening for psychological distress
  
  

• It is essential to have a good history taking for accurate assessment and diagnosis of causes of pain
• History should consists of:
  • Characteristics of pain: Location, intensity and frequency
  • Cancer history: Type and staging of carcinoma, chemotherapeutic regimen and duration
  • Medication: Prior treatments received for pain, maintenance treatments
  • Comorbidities
  • Psychosocial status

• Confirms the clinical diagnosis formed after comprehensive history taking
• Gives information on the patient’s condition and extent of problems
• Neurological exam should be done in all patients especially with suspected neuropathic pain
  
  

• Tumor markers
• Hepatic and renal clearance

• Bone scans
• Magnetic resonance imaging (MRI)