LONDONA prospective survey of cancer patients admitted to a
hospice shows that breakthrough pain is frequent, short
lasting, often unpredictable, and not necessarily related to chronic
pain, making treatment difficult, said Giovambattista
Zeppetella, BSc, MRCGP, of the Palliative Medicine Service, St.
Josephs Hospice, London.
Previous studies have characterized breakthrough pain in patients at
cancer centers, pain clinics, and hospice home care. The current
study explored the prevalence and characteristics of breakthrough
pain in terminally ill cancer patients admitted to a hospice.
For this study, breakthrough pain was defined as a transitory
exacerbation of pain experienced by the patient who has relatively
stable and adequately controlled baseline pain.
During the study period (February to August 1998), there were 432
hospice admissions, and 414 of these were patients with cancer. Of
the cancer patients, 33 (8%) were excluded because they were unable
to answer questions due to dementia, confusion, or final stage of
disease. Another 136 patients did not have chronic pain on admission.
Of the 245 eligible patients with chronic pain, 218 reported
breakthrough pain. Most episodes were tumor related; 11% were
unrelated to the patients reported chronic pain.
The most common sites of breakthrough pain were the abdomen (30%),
lower limb (19%), back (16%), and chest (12%). Patients had an
average of 7 episodes a day of breakthrough pain (range, 1 to 14) (J
Pain Symptom Manage 20:87-92, 2000).
About half of the incidents of breakthrough pain occurred suddenly;
most were unpredictable; and 17% were due to end-of-dose failure of
scheduled analgesics, the investigators reported.
Episodes were generally of short duration, with 73% lasting 30
minutes or less. Neuropathic pains were particularly brief,
with 91% lasting 30 minutes or less, compared with somatic and
visceral pains (69% and 62%, respectively), the authors said.
Patients said their breakthrough pain was best relieved by analgesics
(57%) or lying still (32%), with some patients naming both factors
(17%), but in 14% of episodes, the patient could cite no factors that
relieved the pain.
The patients with breakthrough pain were receiving nonopioid
analgesics (34%), so-called weak opioids (23%), or so-called strong
opioids (64%) for their chronic pain. Of those on strong opioids, 99
were taking long-acting agentsslow-release morphine or
transdermal fentanyl (Duragesic) and of these patients, 43%
were not prescribed rescue medication for breakthrough pain.
Short-Acting Oral Morphine
The investigators emphasized that the medication used to treat
breakthrough pain should be absorbed quickly and produce a
rapid onset of analgesia with minimal adverse events. The
medication should be instantly available, they added,
which may not be possible if the institution keeps controlled drugs
They suggested that because of the rapid onset and short duration of
breakthrough pain, short-acting oral morphine, the most frequently
prescribed rescue medication in this study, may not be appropriate.
It can take up to an hour to produce analgesia, which may then last
for up to 4 hours.
When the patients were asked if they were satisfied with their pain
control, 78% of those with chronic pain but no breakthrough pain said
they were satisfied vs 25% of those with breakthrough pain. The
dissatisfied patients had significantly more occurrences of
breakthrough pain (292 vs 69 among those with breakthrough pain who
were satisfied with their pain control).
This underlines the importance of specifically including an
assessment of breakthrough pain in the overall assessment and
management plan, the researchers noted.
The investigators pointed out that 8% of the original 414 cancer
patients were unable to participate in the survey because they
were too unwell. Most of these patients had been prescribed
opioids, making it likely that at least some of them were having
These patients require careful monitoring to identify
breakthrough pain; clinical signs may be subtle and difficult to
identify, even for experienced hospice staff, they said.
The findings also highlighted the variability in the way researchers
define breakthrough pain. Some studies include only pain of moderate
intensity or greater, but in this study 78% of the 225 patients
reporting mild to moderate pain said they were dissatisfied with
their pain control, suggesting that mild to moderate pain should be
included in the definition of breakthrough pain.
Perhaps an appropriate working definition is that breakthrough
pain, like chronic pain, is whatever the patient says it is and
occurs whenever the patient says it does, the researchers commented.
The other authors of the study, both from St. Josephs Hospice,
were Catherine A. ODoherty, PhD, MRCP, and Silke Collins, MD.