Clinical practice guidelines for the care and treatment of breast cancer: the management of chronic pain in patients with breast cancer (summary of the 2001 update)

This article provides a summary of changes made by Health Canada's Steering Committee on Clinical Practice Guidelines for the Care and Treatment of Breast Cancer to the article “Clinical practice guidelines for the care and treatment of breast cancer: 10. The management of chronic pain in patients with breast cancer,” originally published in 19981 (the 2001 update can be found online at www.cma.ca/cmaj/vol-165/issue-9/breastcpg/guideline10rev.htm). Although the updated guideline does not contain many changes, it highlights the importance of optimal pain management in these patients (Table 1).

Pain is a common problem in women with metastatic breast cancer. The principles of pain management, such as thorough assessment, judicious investigation, comprehensive management and frequent reassessment, remain the same. There is an emphasis on determining the type of pain — somatic, visceral or neuropathic — as a means of determining the best treatment. The principle of the patient as the primary source of information about her pain, its severity and response to medication is emphasized.

Once again, a stepwise approach to the use of analgesics is recommended. Mild to moderate pain can be managed with the use of acetaminophen or an NSAID. Since the publication of the 1998 guideline, selective cyclo-oxygenase-2 (COX-2) inhibitor NSAIDs have become available. They have been evaluated in patients with osteoarthritis and rheumatoid arthritis.2^,3 Compared with older NSAIDs, COX-2 inhibitors reduced the risk of gastrointestinal bleeding; however, no difference was detected in efficacy against arthritis. Currently, there are no data from randomized controlled trials of the use of selective COX-2 inhibitors in cancer patients. Based on available data from the arthritis trials, the guideline recommends that these medications be considered if dyspepsia develops. When pain is not adequately controlled with acetaminophen or an NSAID, a weak opioid such as codeine or oxycodone should be added. When pain is severe or unresponsive to the previous approach, one should immediately switch to potent opioids with or without NSAIDs. The 1998 guideline recommended that, when switching from long-term oral use of an opioid to parenteral use, a ratio of 3:1 should be used. The determination of equivalent analgesic doses of oral versus subcutaneous administration of the same narcotic or of 2 different agents is derived from single-dose studies, which may not be generalizable to long-term use.4 The updated recommendation for switching doses using a ratio of 2:1 instead of 3:1 is based on consensus and clinical experience. Finally, there are additional data supporting the use of bisphosphonates in patients with metastatic cancer to bone.5