Pain due to cancer may
either be due to the medical interventions for the treatment of the disease or
due to the tumor itself.
Tumors can cause
excruciating pain due to nerve irritation, nerve damage or activation of
specialized pain-sensitive nerve fibres.
chemotherapy or radiotherapy can sometimes cause pain even after the ailment is
Approximately one in
three cancer patients suffer from cancer pain, a condition that adversely
affects their quality of life. Cancer pain is very common in the later stages
of the disease. Generally, proper relief from cancer pain is achievable but
there are certain hindrances to it such as drug shortage, faulty pain
evaluation, addiction concerns, financial problems, etc.
In order to acquire
proper pain control, it is essential to assess the type of pain (somatic,
visceral or neuropathic) and the actual severity of pain. It is also imperative
to recognize and identify the obstacles in the path of alleviation of cancer
pharmacological opioid and nonopioid treatments of cancer pain are discussed:
After examining the
social, behavioral and psychological aspects of an individual, the therapist
can focus on the pharmacologic therapies for the control of pain caused by
The World Health
Organization (WHO) has formulated the analgesic ladder as an accepted guideline
that involves the use of opioids as the chief ingredient of pharmacologic pain
control therapy. It should be used in a stepwise approach depending upon the
pain severity after regular pain assessment and monitoring. Besides opioids,
nonopioid pain killers like acetaminophen and non-steroidal anti-inflammatory
drugs (NSAIDs) are also widely available.
Commonly used opioids
are morphine and codeine. When pain is not relieved by acetaminophen or NSAIDs,
opioids are used to control moderate-to-severe pain.
Since cancer pain is
usually chronic and long lasting in nature, drugs with long half lives are the
preferred choice of treatment.
Cancer pain is
controlled in two steps. The first step involves baseline control while the
second step is to control intermittent phases of pain. Extended-release
formulations such as modified-release morphine, modified-release hydromorphone
and modified-release oxycodone are used to serve the purpose.
The preferred route of
administration is the oral route. For patients who find it difficult to
tolerate morphine, transdermal administration is done.
An overdose of opioids can result in adverse side effects
such as respiratory depression or death. An important point to remember is that
rapid attainment of pain relief should not overshadow the person's safety and
should not pose a potential threat to his life.
Common side-effects of
opioids are nausea, delirium, constipation, sedation, pruritus and respiratory
depression. It is wise to anticipate these adverse effects beforehand and be
careful while using opioid analgesics.
In about 50 percent of
patients seeking opioids analgesics, constipation is reported due to
suppression of intestinal movements and secretions.
administration, prophylactic laxatives should be given to avoid constipation.
sedation is seen in about 23 to 28 percent of patients. It is believed that the
inhibition of sensory input and disturbances in rapid eye movement (REM) are
responsible for sedation. However, tolerance to opioid sedation is achieved in
Nausea is reported in
60 percent cases. Other possible causes of nausea in cancer patients are
uremia, constipation, hypercalcemia, anxiety, infection and chemotherapy.
Nausea can be treated
with thiethylperazine, prochlorperazine, metoclopramide and haloperidol.
Itching or pruritus
caused by opioids is seen in 50 percent patients. Antihistamines such as
promethazine and diphenhydramine are effective in improving the distressing
gabapentin are the preferred choices in patients showing inadequate response to
opioids. According to the Neuropathic Pain Special Interest Group, tramadol and
opioids are the first line of treatment for cancer-related neuropathic pain.
Lidocaine, oxcarbazepine, topiramate, lamotrigine, mexiletine, corticosteroids,
baclofen and clonazepam are other common agents.
The World Health
Organization suggests nonopiods as the first of three crucial steps in cancer
NSAIDs are associated
with hepatic and renal risk; therefore FDA has advocated in 2011 that
acetaminophen amount in a product should not be more than 325 mg per dosage
It was concluded that
with appropriate education and tools, cancer pain can be effectively managed.
Adequate training and proper knowledge are extremely important for providing
Chronic Tumor-Related Pain; Tran et al; US