Similarities and Differences in Tumor Growth, Skeletal Remodeling and Pain in an Osteolytic and Osteoblastic Model of Bone Cancer

Transcutaneous electrical nerve stimulation (TENS) for cancer bone pain

In the cancer population, painful bony metastases are common, difficult to treat and significantly reduce quality of life. Common treatments include opioid analgesics, bisphosphonates, and radiotherapy; yet these have significant side effects and are not universally effective. Transcutaneous electrical nerve stimulation (TENS) is inexpensive, relatively free from side effects, and widely available. We present a case study of successful TENS therapy in a patient with cancer bone pain and discuss the rationale for using TENS in this setting.

Skeletal metastases: decreasing tumor burden by targeting the bone microenvironment

Several common cancers often metastasize to the skeleton in advanced disease. Bone metastases are incurable and cause protracted, severe symptoms. Growth of tumor in bone is driven by a vicious cycle: tumor-secreted factors stimulate bone cells, which in turn release growth factors and cytokines. The bone-derived factors fuel the vicious cycle by acting back on the tumor cells. The vicious cycle offers novel targets for the treatment of advanced cancers. Treatments can inhibit bone cells (osteoclasts and osteoblasts) that are stimulated by tumor-secreted factors. Drugs can also inhibit tumor responses to factors enriched in the bone microenvironment, such as transforming growth factor-beta. Animal models show that these approaches, especially combination treatments, can reduce tumor burden. The results suggest a novel paradigm in which tumor growth can be effectively inhibited by drugs that target cells in the bone microenvironment and not the tumor cells themselves.

Management of painful bone metastases

PURPOSE OF REVIEW

This review examines recent data on the pathophysiology and mechanisms of bone pain; it highlights the use of multiple and interdisciplinary treatments rather than sole use of traditional analgesics.

RECENT FINDINGS

Bone pain has been shown to have a unique pathophysiology. Recent experimental (animal) models have revealed that, parallel to increased bone destruction, ipsilateral spinal cord segments that receive primary input from the cancerous femur exhibit several notable neurochemical changes. These mandate the use of opioid doses sufficient to inhibit the observed nociceptive behaviours; these doses are greater than those required to alleviate pain behaviours of comparable magnitude generated by inflammatory pain. Several substances have been tested in this animal model.

SUMMARY

According to new preclinical data, treatment of bone cancer pain requires multidisciplinary therapies such as radiotherapy applied to the painful area along with systemic treatment (hormone therapy or chemotherapy) and supportive care (analgesic therapy and bisphosphonates). In some selected cases use of radioisotopes and other noninvasive or minimally invasive techniques may be useful in the management of metastatic bone pain. The treatment should be individualized according to the patient's clinical condition, life expectancy, and quality of life.