Chronic persistent pain in patients with cancer

Abhimanyu Rana, MBBS, DNB, DA FIPM (pain specialist)

Hina Garg, PT, PhD, NCS (physical therapist)

The life expectancy for people diagnosed with cancer continues to increase after advanced and emerging cancer therapies. However, cancer survivors often report long-term and debilitating symptoms of pain and fatigue affecting their function and quality of life. Between 30% to 85% of patients with cancer report pain; 66% with advanced cancer, 55% of whom with simultaneous cancer treatment, and 30% of patients who have completed the cancer treatments. Approximately 50% of patients with cancer who report pain develop chronic pain despite receiving the mainstay pain therapies. The chronic nature of pain is often less understood by the patients and may take away from their success of ‘beating’ cancer. Developing the diagnosis of cancer can be frightening and emotional. It brings up emotions of fear of death, vicious side effects of the disease, therapies and associated helplessness. Questions about survival, personal and family responsibilities, late onset of symptoms are frequently associated with the diagnosis, therefore contributing to the pain & cancer related memories.

In general, patients with cancer report to lack enough knowledge on pain during or after the cancer diagnosis and treatment. Education and information on pain relief options, support and resources are frequently required in this population, therefore, necessitating the need for implementing interventions based on the biopsychosocial framework. Patients enduring pain from cancer are typically fighting on multiple fronts, and the weakness and resentment of incapacitation further worsens the situation. The significant distress of developing, surviving and accepting cancer, and the associated pain, is indescribable, as the patients frequently report wanting to live their remaining days with grace and ‘free’ of pain. It is, therefore, crucial that patients with cancer should be equipped with pain education and self-management skills, in addition to the medical management, to control their pain. Self-management refers to the combined knowledge, ability, and confidence of patients with any chronic condition to manage their symptoms, treatments, and lifestyle changes in daily life. When patients feel confident in their ability to control their health and fight the ‘inner enemy’, they tend to have greater success in attaining their health goals.

What causes the Pain in Cancer patients?

To better understand cancer-related pain, it’s important to differentiate between the 3 major pain types (nociceptive, neuropathic and central sensitization pain).

• Nociceptive pain typically refers to a ‘nociceptive’ input activating the pain receptors which occurs when a tumor starts encroaching nearby tissues causing the receptors to be activated.
• Neuropathic pain is caused by a primary lesion or disease of the somatosensory nervous system. This is the most common type of pain reported by patients with cancer, which commonly occurs due to direct neurological insult during surgery and lymph node dissection, chemotherapy or radiotherapy which can cause numbness, tingling sensation , irritation and redness.
• Central sensitization is a common pathophysiological mechanism which explains symptoms (including pain) for which no specific organic cause can be found. Often referred to as the ‘nociplastic pain’, it includes an altered nociception despite no clear evidence of actual or threatened tissue damage causing the activation of peripheral nociceptors or evidence for disease or lesion of the somatosensory system.
• Mixed pain can occur from combined mechanisms listed above, and is commonly seen.
• A rare kind of pain is seen in patients undergoing amputation of body parts, known as Phantom pain. The incidence of Phantom Limb pain and Phantom limb Sensation is almost 40% at 12 months post amputation but it improves with time.
• Also note that it’s possible that the pain and tumor doesn’t originate from the same organ. An example of this type of ‘referred’ pain could be in right shoulder due to liver cancer.

Despite the increasing emphasis on management of cancer pain, this symptom continues to be one of the biggest factors leading to functional impairment, poor quality of life and psychological distress in patients with cancer.

Why is it so difficult to manage cancer pain?

1. Under reporting of pain
2. Fear of addiction to opioids.
3. Poor compliance to medications
4. Lack of Financial support
5. Lack of pain management knowledge and self-management skills

What needs to be done?

Successful cancer pain management includes a multi-disciplinary and multi-pronged approach, therefore, highlighting the need to adequately train the clinicians on current and evidence-based biopsychosocially-driven pain management strategies. Some are emphasized below.

1. Modification of pathology – surgery, chemotherapy, radiotherapy
2. Pharmacological management – analgesics, opioids (oral, injection, dermal patches), neuromodulating agents, anti-psychotics
3. Psychological management – coaching, education, counselling, cognitive behavioral therapy
4. Complementary and alternative medicine – cannabis, meditation, yoga, acupressure, nutrition
5. Exercise, pain neuroscience education, physiotherapy or physical therapy, use of splints and immobilization.
6. Interruption of pain pathways – nerve blocks, neurolysis, radiofrequency ablation of pain conducting pathways, transcutaneous electrical stimulation (TENS) therapy.

WHO has advised to use the ‘Analgesic Ladder’ as an established structure to manage pain in cancer or other chronic, non-malignant conditions. The analgesics can be administered with other advisories as per the patient needs. However, due to the complex nature of chronic pain, an integrative approach combining modern medicine with complementary, alternative, and holistic medicine is most applicable to patients with cancer or other medical conditions. A person with adequate management of pain can lead a fulfilling life and can enhance the quality of life for not only themselves but also their family and friends.

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References:

1. You E. Nontraditional and Home-Based Self-management Interventions in Cancer Patients With Pain: A Mixed-Method Systematic Review. Holistic Nursing Practice. 2020;(3):138.

2. Nijs J, Wijma AJ, Leysen L, et al. Explaining pain following cancer: a practical guide for clinicians. Brazilian Journal of Physical Therapy / Revista Brasileira de Fisioterapia. 2019;23(5):367-377.