BONE PAIN

Bone metastases commonly occur in carcinomas of the prostate, breast and bronchus. Bone pains (and related nerve compression pains) account for 40% of cancer pains.

Assessment – The pain is typically worse on movement, often well-localized, and tender to pressure or percussion. There may be a dull ache, even at rest. However, bone pain is occasionally vague and poorly localized with no obvious bony tenderness. There can be radiating pains due to nerve compression in the arm, leg or around the chest (often bilaterally).

Metastases on x-ray can be both lytic and sclerotic. Sclerotic metastases are particularly common in carcinoma of the prostate. Pure lytic lesions occur in myeloma, leukemia and lymphoma. Where x-rays are negative or equivocal, an isotope bone scan is the investigation of choice.

Management options:

1. NSAIDs

2. Opioid analgesics

3. Palliative radiotherapy (localized or hemi-body)

4. Radio-isotopes

5. Chemotherapy

6. Hormone manipulation

7. Calcitonin

«  Palliative radiotherapy is the treatment of choice whenever possible.

1. NSAIDs should be first choice as analgesics for bone pain. Anti-inflammatory drugs (prostaglandin inhibitors) can reduce pain from bone metastases. There is some evidence that osteolytic activity in bone metastases is mediated at least in part by prostaglandins. There are no comparative controlled trials demonstrating their efficiency. Clinical experience suggests that about 80% of patients show a response to NSAIDs (about 20% complete, and 60% partial). The drug of first choice is naproxen 500mg 2 times a day. About 10% of patients complain of dyspepsia, which can sometimes be controlled by adding ranitidine. (see NSAIDs)

2. Opioid analgesics – Mild bone pain may respond to acetaminophen 1g every 4 hours. More severe bone pain can be reduced by morphine, in titrated doses as always. Morphine will reduce any constant aching pain, but is ineffective for the sharp pains on movement typical of bone pain, which respond better to an NSAID. (see Morphine)

3. Radiotherapy – Local external radiotherapy is the treatment of choice for local painful bone metastases. 80% of patients get a response (50% complete, 30% partial) within 1 to 2 weeks (occasionally it takes 3 to 4 weeks).

A single radiotherapy treatment of 800cGy can be just as effective as multiple fractions. In one prospective study of 288 patients with bone pain randomized to either 800cGy in a single treatment, or 3,000cGy in ten daily fractions, there was no difference in speed of onset or duration of pain relief, and pain relief was independent of the histology of the primary tumor.

For patients with a short prognosis, the difference between a single visit and 10 visits for radiotherapy is considerable. Some radiotherapists have used a single treatment of 800cGy for painful bone metastases for years. It is safe and effective and all patients should be offered this simpler treatment.

Many patients have multiple bone metastases and several areas of pain, particularly in carcinoma of the prostate and myeloma. Wide field irradiation can be used. 800cGy in a single treatment is given to either the upper or lower hemibody followed, if necessary, with treatment to the other half six weeks later. (Only half of the body can be treated at one time.) This provides useful pain relief in 75% of patients, usually within 24 to 48 hours, with a duration of several months.

Wide field irradiation produces side effects:

•  Nausea and vomiting (especially upper half)
•  Radiation pneumonitis (especially upper half)
•  Neutropenia (especially lower half)
•  Malaise

Patients must be carefully selected for wide field irradiation, and in-patient admission is necessary. Pre-medication is given (anti-emetics and steroids), and the blood count must be monitored for 2 weeks, with hematological support if necessary. Isolated painful areas that persist or arise can still be treated with local radiotherapy.

4. Radio-isotopes – Treatment with radioactive phosphorus has been replaced by treatment with radioactive strontium (87Sr) which is given intravenously. It is preferentially concentrated in areas of increased osteoblastic activity, but delivers a lower dose to the bone marrow than radioactive phosphorus. About 70% of patients get a response, and pain relief can occur rapidly within 1 to 2 days. Treatment can be repeated after several weeks. Local sites can still be treated with local radiotherapy. Further research is needed into this treatment.

5. Chemotherapy – No effective chemotherapy is available for carcinomas of the lung, prostate or kidney (except for small (oat) cell lung cancer). In myeloma or breast cancer with bone pain, chemotherapy may be considered, particularly if there is active disease elsewhere.

«  The relief of bone pain by chemotherapy can take weeks or months, so the correct use of analgesics and NSAlDs to control bone pain is necessary as well.

6. Hormone manipulation – Bone pain in metastatic breast cancer will respond to:

• Aminoglutethimicle in 35% of patients
• Tamoxifen in 20% of patients
• Progestogens in 20% of patients

Bone pain in metastatic prostate cancer responds to the first hormone manipulation in 85% of patients. For this reason, use of hormone preparations should be delayed until symptoms occur.

«  The response to hormone manipulations can take up to 6 weeks to occur, so the correct use of analgesics and NSAIDs to control bone pain is necessary as well.

7. Calcitonin can produce useful pain relief in about 40% of patients, but it has to be given as an injection 2 times a day, and causes very severe nausea and vomiting in a significant number of patients. It is expensive. It has no place in routine management. (New oral biphosphonates may prove useful for bone pain, but are presently experimental.)

Mr. L.I., age 59, had carcinoma of the stomach with chest pain. Increasing doses of MS-Contin had failed to relieve the pain, and a specialist in symptom control was asked by the family doctor to visit the patient at home. Clinical examination revealed that the inappropriately high doses of morphine were causing drowsiness, confusion, falls and severe constipation, and the main finding in the chest was severe bilateral rib tenderness due to bone involvement. An anti-inflammatory drug was prescribed (naproxen 500mg 2 times a day). The dose of MS-Contin was reduced from 120mg 2 times a day to 30mg 2 times a day, because his wife remembered that previously this dose had reduced the pain without causing drowsiness. Within 24 hours Mr. L.I. was much less confused, which meant that his wife now felt able to continue looking after him at home, which was his particular wish. He was pain-free at rest, with minimal pain on movement. A visiting nurse gave enemas to clear the lower bowel, and the dose of oral laxatives was increased. He died peacefully at home two weeks later.

The author and publisher have taken precautions to ensure that the information in this book is error-free. However, readers must be guided by their own personal and professional standards of good practice in evaluating and applying recommendations made herein. The contents of this book represent the views and experience of the author, and not necessarily those of the publisher.