NEW YORK--American and European epidemiologic surveys indicate that as many as 90% of patients with end-stage cancer have pain severe enough to warrant treatment with opioid drugs. Other surveys indicate that this pain is widely undertreated. A survey of roughly 1,100 oncologists in the Eastern Cooperative Oncology Group (ECOG) showed that poor assessment of pain is perhaps the most common cause of inadequate treatment.
Speaking during a teleconference broadcast across the US and Canada, Russell K. Portenoy, MD, urged clinicians to consider cancer pain in the broader clinical context of palliative care.
"The comprehensive assessment of pain includes identifying the degree to which pain contributes to the overall suffering of the patient," said Dr. Portenoy, chairman of the Department of Pain Medicine and Palliative Care at Beth Israel Medical Center, New York. "Cancer pain occurs in the context of many physical, psychological, social, and spiritual factors that can undermine the quality of life," he said. The goal of pain-relieving therapy must address these concerns and help patients live better with their disease, he added.
Dr. Portenoy believes that this broad-based approach--palliative care--must be developed into its own medical specialty and brought into the mainstream of clinical practice. Such an approach, coupled with specific pharmacotherapy, would offer a well-rounded pain management program for all cancer patients.
The World Health Organizations analgesic ladder approach for the management of cancer pain aids in the selection of analgesic drugs for patients with increasing amounts of pain, he said. In this schema, mild-to-moderate pain can be treated with a nonsteroidal anti-inflammatory drug (NSAID) along with adjuvant agents, if necessary.
Moderate-to-severe pain warrants opioid therapy with or without an NSAID and/or an additional adjuvant drug. Adjuvant drugs include those agents not indicated for pain relief but that have pain-relieving effects, such as antidepressants, anticonvulsants, oral local anesthetics, corticosteroids, and drugs used to treat the side effects of opioids.
While this framework offers some structure to pain management, Dr. Portenoy pointed out that there is no drug of choice for pain treatment. "Physicians may need to rotate different drugs in order to find the best balance between analgesia and side effects," he said.
The routes of administration of the chosen drugs are equally important. Oral agents are usually considered first because of their ease of use, but in patients who cannot swallow well or who prefer other routes, there are transdermal, subcutaneous, intravenous, rectal, and intrathecal routes to consider.
"Because opioid therapy for relieving cancer pain is effective, physicians treating cancer patients have many treatment options," Dr. Portenoy said. Yet, once a drug is chosen, certain guidelines must be followed to maximize the analgesic effects without excess side effects, he said.
For example, because 50% to 60% of cancer patients have "breakthrough" pain, or severe episodes of pain that punctuate the continuous pain, short-acting "rescue doses" of medication can be administered along with a fixed-schedule regimen, he said. This added dose can be the rapidly acting form of the same drug being used as the long-acting treatment or an entirely separate drug.
Individualization of Doses
Dr. Portenoy called the individualization of the doses used "the most important guideline for success or failure of pain treatment." Dose titration, the monitoring of side effects, the monitoring of analgesia, and the degree of overall comfort of the patient all meld together during treatment, he said. Because of the variability in the response to opioids, there is no one correct dose.
As long as side effects do not become dose-limiting, very high dosages may be needed, he said. "This is not wrong but, rather, it indicates the empirical nature of opioid-based analgesic therapy," he said. And while most patients fare well on opioid therapy, roughly 10% do not. He pointed out four possible strategies for managing this treatment-refractory group.
Strategies for Managing Treatment-Refractory Pain
"Pain continues to be a major public health problem and needs to be continually assessed in all patients," Dr. Portenoy said. Pain and its treatment should also be related to the patients suffering, an issue best addressed through a palliative care approach. "Once pain is an issue for the patient, opioid therapy should be considered," he said. "This is important for all physicians to understand and to communicate to their patients."