Pain

What is pain? What may contribute to pain?

What is pain?

Pain is both a physical sensation and an emotional experience. It is one of the most common, burdensome, and feared symptoms experienced by people with cancer¹Sheinfeld Gorin S, Krebs P et al. Meta-analysis of psychosocial interventions to reduce pain in patients with cancer. Journal of Clinical Oncology. 2012 Feb 10;30(5):539-47. and is often underreported, underdiagnosed, and undertreated.²Levy MH, Chwistek M, Mehta RS. Management of chronic pain in cancer survivors. Cancer Journal. 2008 Nov-Dec;14(6):401-9. 

Pain begins with signals from receptors within injured tissues or from peripheral nervous system malfunction associated with neuropathy. These signals ultimately result in pain, resulting in sensory, emotional, and cognitive processing within the brain.³Chapman CR, Gavrin J. Suffering and its relationship to pain. Journal of Palliative Care. 1993;9(2):5-13.

Between 50% and 70% of people with cancer report pain during cancer treatment, as well as about 65% of people with advanced disease.⁴Pujol LA, Monti DA. Managing cancer pain with nonpharmacologic and complementary therapies. Journal of the American Osteopathic Association. 2007 Dec;107(12 Suppl 7):ES15-21; van den Beuken-van Everdingen MH, de Rijke JM et al. Prevalence of pain in patients with cancer: a systematic review of the past 40 years. Annals of Oncology. 2007 Sep;18(9):1437-49. 

Acute and persistent pain

Pain commonly experienced by people with cancer can be acute or persistent. Acute pain is short-term and usually ends after the source of the pain is addressed and the painful area heals—for example, incision pain after surgery. Persistent pain, on the other hand, is present frequently or constantly most of the day and persists beyond the time when a painful area is expected to heal. In persistent pain, the cause of the pain may not be resolvable. Many people with cancer fear that they will have persistent pain, but such pain is not common except perhaps with advanced cancer.

Different approaches are used to manage acute and persistent pain. Palliativerelieving pain or suffering without dealing with the cause of the condition; palliative care is specialized medical care that focuses on providing patients relief from pain and other symptoms of a serious illness care is one of the most useful approaches for managing persistent pain. 

Commentary

Chronic pain or persistent pain?

CancerChoices Senior Clinical Consultant Laura Pole, RN, MSN, OCNS: Chronic pain is “long-standing pain that persists beyond the usual recovery period or occurs along with a chronic health condition, such as arthritis. Chronic pain may be ‘on and off’ or continuous.”⁵Chronic Pain. Johns Hopkins Medicine. Viewed August 19, 2022. Someone could have chronic shoulder pain, for instance, that rears its ugly head several times a year. That is an “on and off” type of chronic pain. When the pain is either continuous or occurs frequently throughout the day, that type of chronic pain is called persistent pain.

Many of us who work in palliative care have come to favor using the term persistent cancer pain rather than chronic cancer pain. The word “persistent” more accurately describes pain that is frequent or continuous and calls for a specific approach to managing it.

Example: The persistent sensation of pain in someone with bone metastasis in advancing cancer requires a far different management approach than on-and-off chronic pain. To bring metastatic pain down to an acceptable level and keep it there may mean prescribing a regular schedule of long-acting pain medications that work for 8, 12, or even 72 hours.

What are the signs or symptoms of persistent cancer-related pain? 

Symptoms and associated problems vary depending on the cause, type, and location of pain. 

In general, people with cancer may experience some basic types of pain. Being careful in describing where and when you feel pain and what it feels like will help your healthcare team determine the cause and the treatment.

Nociceptive pain

The most common type of pain among people with cancer, nociceptive pain involves signals from pain detection nerves (nociceptors) in response to damage to body tissue such as bone fractures or damaged soft tissue.⁶Weatherspoon D. Nociceptive Pain. Healthline. September 18, 2018. Viewed August 19, 2022. Nociceptive pain includes somatic pain and visceral pain.

• Somatic pain is localized to one area, such as bones, muscle, or skin, and may feel aching, cramping, gnawing, throbbing, or sharp.
• Visceral pain is in internal organs and tissues and feels vague and diffuse, sometimes radiating to other areas such as your back, chest, jaw, or arms. This pain is often described as squeezing, dull aching, moving, twisting, colicky, deep, or pressure.

Neuropathic cancer pain 

Pain linked to nerve damage due to cancer and/or treatments such as chemotherapy, radiotherapy and surgery is called neuropathic pain. In this situation, a tumor can be directly invading or compressing nerves, or nerves can be injured by toxicity from chemotherapy or radiotherapy. Both high sensitivity symptoms (burning, tingling, electrical feeling) and low sensitivity symptoms (numbness and muscle weakness) are common.⁷Yoon SY, Oh J. Neuropathic cancer pain: prevalence, pathophysiology, and management. Korean Journal of Internal Medicine. 2018 Nov;33(6):1058-1069. 

What may cause or contribute to pain?

Pain is usually caused by tissue damage or nerve damage. It can also have psychological contributions, as with pain caused by nerve damage that becomes interconnected with fear, depression, stress, or anxiety.⁸Saling J. Pain types and classifications. Web MD. August 23, 2021. Viewed May 6, 2022. 

Injury and inflammation

Injury is a common cause of pain. Pain can also be caused by inflammation, whether brought on by direct injury or not, such as in a chronic state of inflammation. 

Stress response

“A prolonged or exaggerated stress response may perpetuate cortisol dysfunction, widespread inflammation, and pain.”⁹Hannibal KE, Bishop MD. Chronic stress, cortisol dysfunction, and pain: a psychoneuroendocrine rationale for stress management in pain rehabilitation. Physical Therapy. 2014 Dec;94(12):1816-25. 

Hormone imbalances

Hormone imbalances or deficiency can contribute to pain and can serve as biomarkers for the presence of severe pain.¹⁰Tennant F. Hormone testing and replacement in pain patients made simple. Practical Pain Management. 2012;12(6); Tennant F. The physiologic effects of pain on the endocrine system. Pain and Therapy. 2013 Dec;2(2):75-86. For instance, lower estrogen levels among premenopausal women is linked to increased pain and an increased risk of developing chronic pain due to impairment of pain pathways.¹¹Henry NL, Conlon A et al. Effect of estrogen depletion on pain sensitivity in aromatase inhibitor-treated women with early-stage breast cancer. Journal of Pain. 2014 May;15(5):468-75.

The central nervous system produces a group of hormones called neurohormones whose natural function is neuroprotection and neurogenesis. Their clinical use in centralized pain states is new, and early reports indicate that they may have considerable benefit for treatment.¹²Tennant F. Hormone testing and treatment enters pain care. Hospital Practice. (1995). 2014 Dec;42(5):7-13.

Depression

The relationship between pain and depression is bidirectional—each can trigger and impact the other.¹³Theobald DE. Cancer pain, fatigue, distress, and insomnia in cancer patients. Clinical Cornerstone. 2004;6 Suppl 1D:S15-21. 

Medications and therapies

Many medications can cause pain. Some examples:¹⁴Orrange S. 9 common medications that cause joint pain, cholesterol drugs to asthma inhalers. GoodRx Health. May 6, 2022. Viewed May 6, 2022.

• Some chemotherapy drugs can cause nerve damage (peripheral neuropathy).
• Hormonal cancer treatments anastrozole, exemestane, and letrozole are linked to joint pain.
• Hormone medications used to treat hot flashes and other symptoms related to menopause or low estrogen are linked to joint pain.
• Fluoroquinolone antibiotics and statins are linked to joint or muscle pain.
• Non-steroidal anti-inflammatory medications › such as aspirin ›, Advil, or Aleve are linked to abdominal pain.
• Bisphosphonates prescribed for osteoporosis are linked to joint pain.
• Oral steroids, injected steroids, or inhaled steroids for asthma are linked to a severe and painful bone complication.
• The beta blocker carvedilol (Coreg), used to treat high blood pressure and heart failure, is linked to joint aches and back pain.

Conventional cancer treatments—chemotherapy, hormone therapy, radiation therapy, or surgery—can cause pain syndromes.¹⁵ Paice JA, Portenoy R. Management of chronic pain in survivors of adult cancers: American Society of Clinical Oncology clinical practice guideline. Journal of Clinical Oncology. 2016 Sep 20;34(27):3325-45.

Some complementary therapies may cause or trigger pain not related to cancer, usually a temporary side effect of use:

• Acupuncture ›
• Astragalus ›
• Moxibustion ›

Low-dose naltrexone › blocks the analgesia effect of opioids; people using opioids should not use LDN, as it can trigger withdrawal symptoms and a return of pain.

Risk factors for pain

The type and invasiveness of the tumor, the treatment regimen used, the time since cancer treatment, and the effectiveness of your initial pain therapy can all influence your risk of chronic or persistent pain.¹⁶Paice JA, Portenoy R et al. Management of chronic pain in survivors of adult cancers: American Society of Clinical Oncology clinical practice guideline. Journal of Clinical Oncology. 2016 Sep 20;34(27):3325-45.

Advanced cancer is a risk factor for persistent pain, and obesity is a risk factor for chronic pain.¹⁷Totsch SK, Waite ME, Sorge RE. Dietary influence on pain via the immune system. Progress in Molecular Biology and Translational Science. 2015;131:435-69. 

Decreased levels of social activities and social support are linked to higher levels of pain among people with cancer.¹⁸Zaza C, Baine N. Cancer pain and psychosocial factors: a critical review of the literature. Journal of Pain and Symptom Management. 2002 Nov;24(5):526-42.

Risk factors for developing chronic or persistent pain after breast cancer surgery:¹⁹Gärtner R, Jensen MB et al. Prevalence of and factors associated with persistent pain following breast cancer surgery. JAMA. 2009 Nov 11;302(18):1985-92. 

• More invasive surgery
• Radiation therapy after surgery
• Significant acute postoperative pain
• Young age (18-39 years)
• Axillary lymph node dissection
• Pain in other parts of the body linked to increased risk of pain in surgical area

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