Many people fear cancer because they associate the disease with pain. While about one-third of people being treated for cancer, and more than half of people with advanced cancer (cancer that has recurred or spread) do suffer from pain, the pain can usually be controlled. There are a variety of medicines, physical treatments and other therapies that can be used to help keep you pain free.
Cancer pain varies in quality (it may be stabbing, sharp, dull or aching) and intensity. The pain may be constant or come and go. It’s important that you let your doctor know when you are in pain, the nature of the pain, and how severe it is so that he or she can determine the cause of the pain and help you manage it effectively.
What causes pain in people with cancer?
Cancer may cause pain where the tumour first started or in areas of the body where the cancer has spread (doctors call these areas metastases). Cancer can cause pain by:
- compressing or invading pain-sensitive tissues such as bones or organs (bone pain is the most common cause of cancer pain);
- expanding in a confined space (e.g. brain tumours growing within the confines of the skull, causing headaches);
- blocking a duct (tube) or organ in the body; or
- invading or damaging nerves, causing those nerves to misfire (this type of pain is called neuropathic pain).
Muscle stiffness, due to tension or inactivity, can also cause pain in people with cancer. Pain may be made worse by tiredness, anxiety or depression.
In addition to the cancer itself, some cancer treatments and procedures can be painful. While surgery, radiotherapy and chemotherapy can be used to cure cancer and treat cancer pain, they can also cause painful side effects. Also, some tests that are used to check on the progress of your treatment, such as bone marrow biopsy, can be painful.
What are some of the medicines used for cancer pain?
Your doctor will recommend different pain relievers depending on the nature of your pain, what’s causing it, and how severe it is. The World Health Organization (WHO) developed guidelines for cancer pain relief in 1986. These guidelines outline a pain relief ‘ladder’.
Doctors often use this 3-step approach when prescribing pain medicines for people with cancer. Milder pain-relief medicines are usually tried first, and if pain persists or gets worse, stronger pain relievers (opioids) are used.
Medicines such as paracetamol, aspirin, and non-steroidal anti-inflammatory drugs (NSAIDs) are often tried first in people with mild pain. In many cases, these medicines can effectively control pain, especially when they are taken regularly. If your pain is already moderate to severe, your doctor may skip these medicines and go straight to opioid medicines (e.g. codeine or morphine).
Opioids are very effective pain relievers, and can be taken by mouth, as skin patches, rectally, or as injections. Opioids can be used on their own, or in combination with non-opioids. Paracetamol used in combination with an opioid often provides more effective pain relief than an opioid alone.
Over time, your body may get used to the opioids, and you may need higher doses to control the pain. This is known as tolerance. It doesn’t affect everyone, but if it does develop, usually small increases in the dose or a change in the type of medication can relieve the pain. Tolerance does not mean that you’ve become addicted to the medication; addiction is, in fact, very rare when an opioid is being used to treat pain.
While opioids are effective pain relievers, they are associated with several troublesome side effects, including:
- nausea and vomiting;
- drowsiness; and
But most side effects can be prevented or controlled. Because constipation affects nearly everyone who takes regular opioids, dietary advice and medicines to prevent constipation are usually given with opioids. Drowsiness and nausea generally resolve after a few days, once your body is used to the opioids. There are also medicines available that can help control these side effects.
How often should I take my pain medicines?
It’s recommended that pain relievers are taken regularly, rather than on an as-needed basis for chronic (persistent or long-lasting) pain, because regular dosing controls pain much more effectively. If you wait until your pain is out of control before taking your pain medicine, it will be much harder to relieve.
In addition to your regular doses of pain reliever, you can take extra doses, or another pain medicine, for so-called ‘breakthrough pain’ (rapid increases in pain that are felt on top of chronic pain).
What are some of the alternative pain medicines?
There are other medicines available that can increase the effectiveness of standard pain relievers and relieve specific types of pain. These include:
A class of antidepressant medicines known as tricyclic antidepressants (tricyclics) has been found to relieve pain. These medicines have a pain-relieving effect that is separate to their antidepressant effect, and may be especially useful in relieving constant, burning pain that is due to nerve damage (neuropathic pain). Nerve damage can result from the cancer itself or cancer therapy (e.g. surgery, radiotherapy or chemotherapy). Tricyclics are the most commonly used medicine for treating burning-type neuropathic pain.
Anticonvulsant medicines — the same medicines that are used to control seizures in people with epilepsy — are also effective in treating neuropathic pain, particularly shooting pain or ‘pins and needles’-type pain.
Corticosteroid medicines can help relieve pain that is due to nerve and spinal cord compression, severe bone pain, and pressure on tissues and organs from swelling.
Bisphosphonates are medicines that can prevent bone loss and reduce pain that is caused by bone tumours.
Medicines that relieve muscle spasm are sometimes used if this is a cause of pain.
Are there any other treatment options?
Nerve blocks are another treatment option, and are usually used in people with localised pain that is not well controlled with other methods. A nerve block involves injecting local anaesthetic into or around a nerve or the space around the spinal cord. The nerve block works by preventing pain signals from travelling along the nerves and reaching your brain, so you don’t feel the pain. Sometimes, the nerves may be surgically cut to block the pain.
What are some of the physical therapies that can help treat cancer pain?
Hot or cold packs are sometimes useful in relieving pain. Heat can soothe sore, tense muscles, and cold packs can numb a painful area. Some people find that alternating use of heat and cold packs can give added relief.
Other treatments that may be used to control pain include:
- massage, which can help relieve muscle tension and spasms;
- acupuncture; and
- transcutaneous electrical nerve stimulation (TENS), which is a therapy that uses mild electrical currents to treat pain.
What about psychological therapies for cancer pain?
Psychological support is an important component of effective pain control. Cognitive behavioural therapy (CBT) can help you change your thought patterns and ways of doing things that reinforce pain. Counselling can also help relieve anxiety and depression, which may make your pain seem worse.
Relaxation therapy can help relieve pain or prevent it from getting worse by reducing muscle tension. It can also help you sleep, reduce anxiety and make other pain relief methods work better. Hypnosis, meditation, support groups and religious counselling can also be effective.
Can treating the cancer help treat cancer pain?
Treating the cancer itself is one of the most effective ways of treating cancer pain. By shrinking the tumour with one or a combination of anti-cancer therapies (surgery, chemotherapy, and radiotherapy), pain can be relieved. Hormonal therapy can also be used to reduce the tumour size and relieve pain from certain types of cancer, such as breast cancer or prostate cancer.
2. World Health Organization (WHO) [website]. WHO s pain ladder. http://www.who.int/cancer/palliative/painladder/en/ (accessed 2009, Nov 5)