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
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
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."