Definition of Cancer Pain – according to aetiology and pathogenesis
Cancer-related pain results from the treatment for cancer or from the cancer itself. Cancer-related pain depends upon type of cancer, the stage of the disease and the pain threshold (tolerance for pain) of the person with cancer mostly due to compression or infiltration of hollow organs, soft tissues, bones or nerves. But it could also be caused by the treatment or the tests done to diagnose cancer.
The aetiology of the pain varies to some degree. It may be:
- cancer-related (60-90%)
- cancer-associated (10-25%)
- treatment-related (5-20%)
- non-cancer-dependent (3-10%)
Most pain is directly related to the cancer, and results from the infiltration or compression of hollow organs, soft-tissues, bones or nerves.
Definition according to pathogenesis
Categorizing pain in cancer patients according to its pathogenesis is important in order to identify and choose the most appropriate treatment.1
The pain can be characterized as nociceptive, neuropathic, or mixed nociceptive/neuropathic.
Somatic nociceptive pain is often described as a sharp or throbbing pain, with a precise location to the pain – usually within bone, joint, muscle, skin, or connective tissue, while visceral nociceptive pain is often described as an ache or "crampy" pain, with no precise location – although within visceral organs such as the gastrointestinal tract or pancreas.
Neuropathic pain is caused by a primary lesion or dysfunction of the peripheral or central nervous system, and may result from the tumour.
The pain is typically described as tingling, burning, electric-like, stabbing, or shooting.1
In some conditions, the pain falls into neither pure nociceptive or neuropathic pain; it might be caused by a complex mixture of nociceptive and neuropathic factors.
Examples of the causes of disease-related cancer pain, and the underlying pathogenic pain type, include somatic nociceptive pain, visceral nociceptive pain and neuropathic pain.2
1 Paice JA et al. The management of cancer pain. Ca CA Cancer J Clin. 2011; 61:157-82.
2 Gutgsell T et al. A prospective study of the pathophysiology and clinical characteristics of pain in a palliative medicine population. Am J Hosp Palliat Care. 2003; 20:140-8.