Traditionally, cancer pain syndrome is classified according to the structures involved, such as somatic, visceral, and neuropathic. Somatic pain can be experienced throughout the body, while visceral pain tends to be localized to the internal organs in the abdominal cavity. Neuropathic pain is more frequently felt in the extremities such as the hands and feet. Associated pain can range from acute to chronic, with the final stage known as intractable. Pain may result from tumor impingement on other organs or nerve endings. To complicate matters, side effects of modern, more aggressive cancer treatment can also be responsible for inflicting significant pain. This is evident due to the greater potential for damage to the peripheral nervous system leading to neuropathic pain. Cancer drugs that are toxic to nerve cells can leave a patient with chronic pain in the hands and feet.
At the end stage of disease, patients may feel abandoned by the medical community. They are told there is nothing more that can be done and instructed to get their affairs in order. All that remains is to provide some type of pain relief. Currently, the most common form of pain management involves the use of opioid s (narcotics) such as morphine. Unfortunately, this is often not entirely effective in eliminating pain and often merely results in drowsiness. For this reason, methadone, is sometimes substituted for morphine. However, since it can remain in the body for up to two days, repeated doses of methadone can accumulate in the blood to toxic levels.