Cancer pain: Classification and pain syndromes)

Abstract

Inspite the new informations about the physiology and biochemistry of pain, it remains true that pain is only partially understood. Cancer pain is often experienced as several different types of pain, with combined somatic and neuropathic types the most frequently. If the acute cancer pain does not subside with initial therapy, patients experience pain of more constant nature, the characteristics of wich vary with the cause and the involved sites. Chronic pain related to cancer can be considered as tumor-induced pain, chemotherapy-induced pain, and radiation therapy-induced pain. Certain pain mechanisms are present in cancer patients. These include inflammation due to infection, such as local sepsis or the pain of herpes zoster, and pain due to the obstruction or occlusion of a hollow organ, such as that caused by large bowel in cancer of colon. Pain also is commonly due to destruction of tissue, such as is often seen with bony metastases. Bony metastases also produce pain because of periostal irritation, medullary pressure, and fractures. Pain may be produced by the growth of tumor in a closed area richly supplied with pain receptors (nociceptors). Examples are tumors growing within the capsule of an organ such as the pancreas. Chest pain occurring after tumor of the lung or the mediastinum due to invasion of the pleura. Certain tumors produce characteristic types of pain. For example, back pain is seen with multiple myeloma, and severe shoulder pain and arm pain is seen with Pancoast tumors.

Classification of pain in cancer patients – a systematic literature review

“…59 Two of the educational papers each focused on one primary cancer diagnosis, genitourinary cancer 39 and breast cancer, 30 , whereas one focused on pancoast tumours. 55 A total of 13 of the educational papers reviewed cancer pain in patients with advanced cancer or metastatic disease, 21,31,32,35,37,39,45,48,51,[53][54][55]59 one of these focused on patients with terminal disease. 31 Five educational papers reviewed breakthrough pain.…”

Tumor-induced neurogenesis and immune evasion as targets of innovative anti-cancer therapies

“…Cancer patients suffer neuropathic pain. 37 The underlying neuro-oncogenic processes include pressure on fibers as tumor volume increases, 38 secretion of stimulatory factors on peripheral fibers with depolarizing effects, 39,40 axon demyelination, 41 and pathological neural plasticity induced by tumorderived factors. [42][43][44] Moreover, cancer treatments, including chemotherapy (as platinum analogs, taxanes, and vinca alkaloids) and radiation, affect the nervous system causing pain.…”

“…Therefore, cancer treatments commonly include painkillers, some of them extremely potent and addictive. 38,45 Besides being a victim of cancer growth and dissemination, the nervous system is engaged by cancer cells and tumor infiltrated leukocytes to promote tumor growth and dissemination (as described in Section "Reciprocal communication between cancer cells and the nervous system promotes tumor progression"). For instance, a rat model of breast and bone cancer in which persistent pain coincided with tumor growth, served to reveal a mechanistic link between pain and tumor growth.…”

A Contemporary Perspective on Therapeutic Measures and Approaches to Pain Management in Lung Cancer

“…In addition, the short and long term consequences of radiotherapy and chemotherapy treatments can be painful 7,18 .…”

“…Specifically, lung cancer can cause pain locally by invading the parietal pleura, ribs, thoracic spinal cord or brachial plexus or elsewhere in the body by metastasis. In addition, the short and long term consequences of radiotherapy and chemotherapy treatments can be painful 7,18 .…”