Pain expert Dr. Scott Fishman answers questions about cancer pain:

Q: How common is bone pain in people with cancer, and what is the best way to treat it?

A: Many cancer patients experience bone pain regardless of where the disease first strikes. Bone pain is usually the result of a tumor invading bone or due to weakened bones. It can be either close to the original cancer or in a distant part of the body.

Cancer that has spread (metastasized) can find its way to any bone but frequently lodges in the spine, the pelvis, and/or long bones. Patients say bony pain often has a constant dull or deep ache that gets worse at night or when the patient moves or carries heavy objects.

A bone scan may confirm suspicions of bone invasion but not always. In past decades, doctors struggled mightily with trying to control this almost omnipresent cancer pain and usually failed. Medical historians believe this may have contributed to the coining of the expression, "intractable pain."

Cancer's complex chemistry and mechanisms make bone pain obstinate. The pain may be the result of many possibilities, including tiny fractures from weakened, disintegrating bones or bones that are forced to accommodate an intruding tumor.

One of my first interventions for bone pain may be to refer a patient for radiation therapy to stem the tumor invasion and slow the painful bone disintegration. Even in patients whose tumors cannot be contained, radiation can shrink cancer growth enough to relieve pain. Strontium 89, a radioactive drug, is an alternative to radiation.

It helps retard bone breakdown related to certain (not all) tumors and may help prevent more deterioration. The drug has shown best results in easing pain from the bone metastasis of prostate cancer. Strontium 89 generally has a more widespread effect than radiation, but like radiation therapy, it also has a delayed action, needing three or four weeks to take effect.

Drugs can be powerful adversaries of bone pain, particularly anti-inflammatories like corticosteroids and nonsteroidal anti-inflammatory drugs (NSAIDs). Surprisingly, for certain bony pains, NSAIDS, even over-the-counter NSAIDs such as ibuprofen, can have extremely potent effects-sometimes even greater than morphine.

Steroids have the added advantage for some patients of stimulating appetite and elevating mood. However, side effects from corticosteroids and NSAIDs pose serious limitations. There is hope, though, that the new family of NSAIDs, the COX-2 inhibitor drugs, also may work for bone pain with substantially fewer side effects.

Clinicians have recently discovered that a group of drugs called bisphosphonates (pamidronate is the most commonly used) halt bone corrosion and even reverse bone loss in some cases. These drugs also have shown potency in controlling pain.

In rare cases when nothing else works, miraculous results have sometimes come from a surgical procedure whose effectiveness cannot be explained. Doctors have discovered that removing part of a patient's pituitary gland has a remarkable deadening effect on the pain of bony metastasis.

They theorize that it may have something to do with altering hormone activity, but they have no solid explanations. Nevertheless, the surgery has produced immediate pain relief for some cancer patients. However, doctors are less convinced about long-term results, and the surgery remains controversial because it has not been thoroughly studied.

Yet another unusual method of attack on bone pain is percutaneous electrical nerve stimulation (PENS), which delivers a mild electrical current to the painful region. It is quite new and not well studied, but is beginning to show good results, especially for bony metastasis. Using needles similar to those used in acupuncture, doctors deliver about thirty minutes of stimulation and may repeat the treatments depending on how the patient feels.