Most commonly, but not exclusively, cancer pain is a result of late-stage metastatic cancers and primary and metastatic cancers that grow in the bone. Cancer pain, like the disease itself, is widely diverse in its quality and extent, and can result from many different causative factors. Many factors have been implicated in the causation and maintenance of cancer pain. Neuropathic pain results from damaged peripheral or central neuronal tissue and from chronically altered neuronal signalling resulting from central and peripheral sensitization. Neuronal tissue can be damaged by direct invasion by tumour cells, as is the case of tumours of the central nervous system (CNS) or by invasion of peripheral neurons in peripheral host tissues. Cancer cells and associated cells also secrete a large number of chemical factors, some of which can directly damage or simulate neurons. Direct physical interaction between the tumour mass and the altered host tissues with neuronal tissue can also cause neuropathic damage through nerve disruption and destruction. Cancer cells and associated cells including stromal and immune cells also secrete a host of chemical signalling molecules that can directly and indirectly stimulate nociceptors. Thermal stimuli of sensory neurons can become pathological following peripheral and central sensitization, which decreases the threshold temperature at which thermally sensitive neurons will respond. Pain is also often a side effect of many treatments of cancer, although the mechanisms of these treatment-induced conditions are beyond the scope of this review. Treatment of cancer pain itself largely relies on analgesics and therapies directed against the cancers themselves, although specific treatments for cancer pain are more recently becoming available. It is often the case, however, that cancer pain conditions become intractable, or are poorly controlled. Breakthrough pain which is prevalent in cancer pain is defined by its relationship to treatment where it is an episodic painful event that occurs during a routine of normally effective pain control. Cancer pain is a serious and prevalent oncodynamic effect that arises from a highly variable array of stimuli. The study of cancer pain as a distinct phenomenon is still in its infancy.