Indian Society for Study of Pain, Cancer Pain Special Interest Group Guidelines, for the Diagnosis and Assessment of Cancer Pain

What is cancer pain?

Pain attributable to cancer or its therapy in a patient with cancer is considered as cancer pain. It includes all components of the experience of pain (physical, behavioural, cognitive, emotional, spiritual, and interpersonal aspects).[19] These multidimensional aspects of pain should be followed while assessing and managing patients with cancer pain.

A comprehensive assessment should therefore include:

• Physical manifestations of pain

• Interference with activities of daily living

• Psychosocial factors (anxiety, mood, cultural influences

• Fears, effects on interpersonal relationships, etc.)

• Spiritual aspects.

Why should we assess pain?

Accurate assessment and diagnosis of the type of pain, its severity, and effect on the patient are necessary to plan treatment or interventions.[19] Etiology of pain should be identified and should not or cannot always be attributed to the cancer itself. Approximately, 5%–10% of patients with cancer may report pain due to other conditions.[20] Careful history, active listening, and a detailed physical examination will help diagnose the type of pain and understand the patient's expectations, which, in turn, helps to plan pain therapy and provide pain relief to a comfortable level in order to perform certain activities with minimal and bearable pain. Assessment of pain helps in the selection of drug and route for the treatment of pain. It also helps to evaluate the effectiveness of the treatment given for pain relief.

Who should assess patient's pain?

The patient himself/herself is the most reliable assessor of the pain and should, whenever possible, be the prime assessor of his or her pain as he/she can better relate to its impact on his/her quality of life.[21]

Due to frailty, cognitive impairment, or communication deficits, many patients are not able to express their problems and find completion or filling of pain scoring tools difficult. In such cases, family or health-care professionals may help in extracting or eliciting the patient's problems.

How should pain be assessed?

Careful history taking and engaging in listening nonjudgmentally and attentively help to diagnose the type of pain and this in turn dictates the therapy.

For assessing cancer pain, unidimensional tools such as Numeric Rating Scale (NRS), Visual Analog Scale (VAS), and Verbal Rating Scale (VRS) should always be used routinely. Patients with cancer pain should routinely be screened for distress and other psychological disorders, using the Patient Health Questionnaire-9 (PHQ-9).

The PI will determine which step of the therapeutic intervention of the WHO ladder would need to be used.

How often should the pain be assessed?

The key to successful cancer pain control is a regular review to identify the effectiveness of the treatment that is being implemented. Hence, patients should be reviewed regularly. The severity of pain and the associated distress determines the frequency of the assessment, which is conducted daily or more often when pain is not well controlled.

History

Detailed history of pain:

1. Site/location of pain: A patient may have more than one site of pain

2. Types of pain: A patient may have more than one type of pain. Each should be assessed including those not due to cancer

3. Intensity of pain: Based on patient's self-report using:

   • A 0–10 Numerical Rating Scale [Figure 1] or

   • A pictorial scale [Figure 2] (Faces Pain Rating Scale).

4. Timing of pain:

   • Onset

   • Duration

   • How has pain changed over time

   • Intermittent or persistent

   • Spontaneous or with some activity

   • Whether controlled by medication and recurs at certain times or at the end of dose interval.

5. Characteristics of the pain (pathophysiology): Allow patient to describe the pain using pain descriptors as well as in his/her own words

   • Nociceptive pain: Injury to somatic and visceral structures with activation of nociceptors

   • Somatic: Sharp, well localized, throbbing, aching, stabbing, pressure like

   • Visceral: Diffuse, aching, cramping, gnawing

   • Neuropathic pain: Injury or diseases affecting the peripheral or central somatosensory nervous system. Described as burning, pricking, pins and needles, numb, sharp, shooting, and tingling.

6. Aggravating and relieving factors; All factors which make the pain worse or relieve it (e. g., cough, exercises, and walking)

7. Interference with daily activities: General activity, sleep, mood, appetite using a validated assessment tool (e. g., The Brief Pain Inventory Short Form [BPI])

8. Etiology of pain: Is the pain caused by:

   • Cancer

   • Cancer therapy: Radiation, chemotherapy, surgery, or procedure-related pain

   • Unrelated to cancer.

9. Analgesic drug history: Current/past pain medication

   • What medications?

   • What dose, how often, and how long?

   • Who prescribed?

   • Why was it prescribed?

   • What was the response?

   • Pain relief and amount of pain relief

   • Side effects and treatment of side effects

   • Reason for discontinuation.

10. Patient's and family's knowledge, beliefs about pain, and its treatment should be assessed and discussed which include:

    • Concerns related to fear of addiction

    • Tolerance

    • Side effects

    • Fear that use of opioid means the end stage of the disease

    • Nearly 28%–38% of all cancer pain patients do not comply with their analgesic regimes[22] and hence these issues which hinder adherence should be addressed.

    Educational interventions can change patients' cancer pain-related beliefs and behaviour, as shown by two randomized controlled trials carried out in Taiwan.[2223]

11. Patients' goals and expectations regarding pain management

12. Oncologic treatment includes:

    • Chemotherapy: Ongoing and prior

    • Radiation therapy

    • Surgery.

13. Medical history

    • Presence of other illnesses/comorbidities such as diabetes mellitus and kidney disease

    • Preexisting chronic pain.

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Figure 1

A 0–10 Numerical Rating Scale

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Figure 2

Wong–Baker Faces Pain Rating Scale

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Physical examination

In addition to routine physical examination, it is essential to perform a comprehensive neurological and musculoskeletal examination as well.

1. General physical examination

   • General constitution

     • Height, weight, and body mass index

     • Vital signs: Pulse, blood pressure, respiratory rate, temperature and pain score (VAS)

     • Appearance, development, deformities, nutrition, grooming, etc., to be noted.

   • Skin and mucous membrane

     • Check for colour, temperature, rash, soft-tissue edema, and pressure sores in bedbound patients

     • Trophic changes of skin, nails, and hair are seen in complex regional pain syndromes, especially in advanced stages

     • Oral mucous membranes for candidiasis/mucositis: Special attention to be given for the evaluation of lymphedema in postsurgical/advance metastatic/haemato-oncological patients, especially lymphomas

     • Check for any possible site of infection, especially in patients with diabetes, vascular disease, and peripheral neuropathy. The infection must be treated and risk should be assessed before implanting devices such as spinal cord stimulators or infusion pumps.

   • Pain behaviour

     • Facial expression, colour, and grimacing should be noted

     • Some patients may in their attempt to convince the physician and may grunt, moan, twitch, grab the painful area, and exaggerate their posture to show that they are suffering from a great deal of pain.

   • Cardiovascular system

     • Check for murmurs and irregular rhythm.

     A systolic murmur could point to an aortic stenosis, such a patient may not tolerate hypovolemia and rapid vasodilation as they may occur with neuraxial local anaesthetics and sympathetic or celiac plexus block.

     An irregular rhythm may mean atrial fibrillation and such patients may be on anticoagulants. History of cardiac comorbidities and stroke and use of anticoagulants and antiplatelet drugs should be confirmed.

   • Check capillary refill or return

   • Respiratory system

     • Abnormal breath sounds such as crackles may be a sign of congestive cardiac failure

     • Rhonchi or wheezes are signs of chronic obstructive pulmonary disease

     • Patients should be optimized prior to any interventional procedure. Extreme caution should be exercised while conducting blocks around the chest cavity, as there is an increased risk of pneumothorax.

2. Neurological examination:

   • Mental status

     • Alertness level

     • Orientation to time, place, and person

     • General appearance

     • Behaviour and mood including suicidal ideations

     • Intellect including comprehension, attention, insight, and memory.

   • Motor system

     • Appearance of muscles: Check muscle bulk, tone, and spasm. Look for atrophy. Measure the circumference of both limbs at the calf and thigh levels. A ≥2 cm difference at the same level is indicative of atrophy

     • Tone

     • Strength: Test muscle strength in both upper and lower extremities

     • Gait: Gives information on muscle strength and impaired vestibular, cerebellar, or dorsal column function. It also informs if braces or assistive devices are needed for stability/safety (e. g. limit foot drop)

     • Look for latent weakness by asking patients to walk on their toes and heels. Heel walking is most sensitive for detecting the weakness of foot dorsiflexion. Toe walking helps detect early weakness of foot plantar flexion.

   • Sensory perception: Elicited by the application of various stimuli such as light touch, pin prick, temperature (hot and cold stimuli), and pressure/vibration to the suspect area. An ice cube or a freshly opened alcohol wipe may be used to elicit deficit in cold perception or to elicit cold allodynia.

     The following may be observed in neuropathic pain conditions:

   • Hyperesthesia: Increased sensitivity to stimulation, excluding special senses

   • Dysesthesia: An unpleasant abnormal sensation, either spontaneous or evoked

   • Allodynia: Pain caused by a stimulus that is normally not painful

   • Hyperalgesia: A heightened response to a stimulus that is normally painful

   • Hyperpathia: Clinical symptom of certain neurological disorders wherein nociceptive stimuli evoke exaggerated levels of pain. Therefore, the threshold for pain is decreased

   • Summation: A repetitive pinprick stimulus at intervals of < 3 s, resulting in a gradually increasing sensation of pain with each subsequent stimulus

   • Deep tendon reflexes: Tendon reflexes that are not under voluntary control and alterations indicate signs of neurological dysfunction. Pathological reflexes such as Babinski (foot) and Hoffmann (hand) must be tested. Positive tests indicate upper motor neuron dysfunction

   • Cranial nerve function: The 12 cranial nerves relay messages between the brain and the head and neck. They mediate motor and sensory functions including vision, hearing, smell, tongue, and vocal cord movements. The fifth cranial nerve or the trigeminal nerve is involved in trigeminal neuralgia, which requires assessment of facial sensations, jaw strength and movement, and corneal reflexes.

3. Musculoskeletal examination is also important:

   • Pain may be secondary to postural changes

   • Deconditioning may lead to muscle atrophy

   • The patient may adopt abnormal patterns of movement and have loss of range of movements in the spine and other joints

   • Bedbound patients need to be evaluated for deep-vein thrombosis.

All of which can result in loss of function and increasing pain and worsen trophic changes.

• Specific examination of major joints

  • Note active and passive ranges of movements at all major joints. Any pain on palpation

  • Shoulders: Examine for brachial plexopathy with radicular pain down the arm into the hand. Also, check for inflammatory or adhesive capsulitis

  • Elbows: Signs of ligamentous or tendon inflammation

  • Wrists: For signs of carpal tunnel syndrome

  • Hands and fingers: For signs of arthritis

  • Knees: Tenderness and abnormal patellar tracking

  • Hips: For trochanteric bursitis

  • Ankles and feet: For plantar fasciitis.

• Spine examination

  • Signs of kyphosis, scoliosis, and pelvic tilt

  • Palpate midline for tenderness over the spinous processes (collapse of vertebral bodies) and discs, paravertebrally for facet joint tenderness

  • Flexion, extension, lateral flexion, and rotation. Pain on flexion may suggest muscle spasm. Pain on extension/rotation or ipsilateral pain on lateral flexion may point to facet-related pain

  • Sacroiliac joint palpation: May be positive in case of inflammation. Straight leg raising or sitting leg extension resulting in pain radiating to the foot or in the contralateral low back may indicate lumbosacral nerve root irritation or compression from lumbar disc protrusion or spinal stenosis.

Diagnostic and investigation tools

These tools are only conducted if they help us in planning further management of pain. If patients are going to be treated empirically anyway (e.g. end of life), don't expose them to cost/pain of additional testing.

• Complete blood count: White blood cells and platelet count (to know overall general condition of patient)

• Coagulation profile: International normalized ratio (will help if planning for any interventions)

• Renal function test: Serum creatinine (to consider nonsteroidal anti-inflammatory drugs)

• Liver function test: Enzymes

• Imaging

• X-rays or radiographs provide details of bone structure and identify fractures

• Bone scans are more sensitive in detecting skeletal pathology than X-rays. They help rule out:

• Occult fractures, i.e. small fractures not visible on routine X-rays

• Inflammatory processes including infection and tumours

• A new vertebral compression fracture from an old one. The new fracture will show an uptake, whereas an old one will not.

A bone scan, however, has a low specificity and cannot differentiate between a tumour, an infection, and a fracture. Computed tomography (CT) or magnetic resonance imaging (MRI) helps characterize such lesions.

• CT: Delineates the bony structures well

• Positron emission tomography-CT will identify whether there is ongoing tumour activity

• MRI: Uses no ionizing radiation. Provides superior contrast of soft tissues, especially neural tissues in comparison with CT.

The imaging needs to be read in conjunction of background history and examination findings.

All imaging findings do not require treatment and may not correlate with symptoms as well.

Pain assessment tools

Several pain assessment tools are used worldwide with a considerable amount of inconsistency between them while assessing cancer pain. There is no universally accepted tool for the assessment of cancer pain.

To overcome this problem, the European Association of Palliative Care has recommended the use of standardized pain assessment tools in palliative care in research and clinical practice.[24] These include the VAS, the Numerical Rating Scale (NRS), and the Verbal Rating Scale (VRS)

• VAS – A 10-cm line [Figure 3] and end point descriptors. Patient marks the point on the line which best represents his/her PI

• NRS – An 11-point scale [Figure 1], with 0 at one end represents “no pain” and 10 represents “worst possible pain”

• VRS – Employs descriptors of PI [Figure 4] such as “none,” “mild,” “moderate,” and “severe.”

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Figure 3

The Visual Analog Scale

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Figure 4

The Verbal Rating Scale

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The above-mentioned are unidimensional pain scales which evaluate only one dimension of pain that is the pain severity or intensity.

Multidimensional pain scales assess not only the intensity of pain but also give an insight into the interference of pain with various aspects of daily living such as general activity, sleep, mood, and appetite, to name a few.

The McGill Pain Questionnaire and the BPI are two commonly used multidimensional pain scales that incorporate the NRS and VRS which have been validated in different languages and cultures including India.[2526]

VAS, Numerical Rating Scale (NRS), and Verbal Rating Scale (VRS) are the most commonly used unidimensional assessment tools which are valid and adequately reliable.[27282930] There is a nonlinear relationship between cancer pain severity and functional interference,[31] with mild pain = 1–4, moderate pain = 5–6, and severe pain = 7–10 marked on NRS (BPI).

Psychological assessment

• Presence of clinically significant psychological disorder, anxiety or depression, coping skills

• Previous or current substance abuse

• Risk of opioid misuse

• Spiritual and religious beliefs that may affect pain and its management.

In a single-cohort study involving 194 Taiwanese cancer patients, it was shown that patients who have a stronger belief in the role of medication to control pain and weaker beliefs in their own ability to manage pain are more likely to adhere to medications. This study suggests that to enhance adherence to medications, pain beliefs should be assessed and integrated into pain management and patient education.[32] The PHQ-9 is a screening instrument with nine items, developed to measure depression. For each item, the patients are asked to assess how much they were bothered by the symptoms over the last 2 weeks. There are four answer options: not at all (0), several days (1), more than half of the days (2), and nearly every day (3). The sum score (range: 0–27) indicates the degree of depression, with scores of ≥ 5, ≥10, and ≥ 15 representing mild, moderate, and severe levels of depression, respectively. The PHQ-9 is comprised of items that measure several aspects of depression,[33] but that it is nevertheless useful to maintain the PHQ-9 as a unidimensional scale in practical applications.

Oncological emergencies

Consider whether pain is related to an oncologic emergency such as:

• Bone fracture or impending fracture of weight-bearing bone

• Neuraxial metastasis with nerve damage or threatened neural injury

• Brain metastasis

• Epidural metastasis (is impending spinal cord compression)

• Leptomeningeal metastasis

• Infection

• Obstructed or perforated viscus.

Disclaimer

The contents of this publication are guidelines to clinical practice, based on the best available evidence at the time of development. These guidelines should neither be construed or serve as a standard of care.

These guidelines do not represent the minimum standard of practice, nor are they a substitution for good clinical judgment. These guidelines need to be used in conjunction with patient assessment and may be individualized as per patient need.

These guidelines were developed in 2018-2019 and may be reviewed again in 2024 or sooner, based on the availability of new evidences.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.