Cancer pain doesn’t affect all people who have cancer - whether you have pain will depend on the type of cancer you have, how advanced it is, and the cancer treatment you are having. For those who do have pain, it can usually be controlled.
Adequate pain control is essential to keep you comfortable and be able to do your usual activities. There are a variety of medicines, physical treatments and other therapies that can be used to help keep you pain-free. Talk to your doctor if your cancer pain is not controlled - different options may work at different times, and often, a combination of several treatments works best. Most cancer pain can be relieved when the right treatment is given at the right time.
What causes pain in people with cancer?
Cancer pain varies in quality (it may be stabbing, sharp, dull or aching) and intensity, and 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 to help work out the cause of the pain and help treat it.
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). About 6 out of 10 people being treated for cancer, and more than half of people with advanced cancer (cancer that has recurred or spread) have some pain.
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.
Can treating the cancer help treat cancer pain?
Treating the cancer itself with one or a combination of anti-cancer therapies (surgery, chemotherapy, radiotherapy, hormonal therapy, targeted therapy) is one of the most effective ways of treating cancer pain at any stage of the disease.
What painkillers are used for cancer pain?
Everyone experiences cancer pain differently. If you have pain related to cancer, your doctor will recommend different pain relievers (analgesics) depending on the nature of your pain, what’s causing it, and how severe it is.
Pain relief ladder
The World Health Organization (WHO) has developed guidelines for cancer pain relief in adults. These guidelines outline a pain relief ladder for cancer pain, with the aim of using the most appropriate pain relievers so that the person is free of pain. Doctors often use this 3-step approach when prescribing pain-relievers for people with cancer.
Non-opioid medicines such as paracetamol, aspirin, and non-steroidal anti-inflammatory drugs (NSAIDs) are usually tried first in people with mild pain. In many cases, these medicines can effectively control pain, especially when they are taken regularly.
If pain persists or gets worse (or is already moderate to severe), mild opioids (such as codeine) are used. Opioids can be used either alone or in combination with the non-opioid medications. Paracetamol used in combination with an opioid often provides more effective pain relief than an opioid alone.
If the pain is severe, a strong opioid such as morphine should be the next step. As with mild opioids, this may be combined with non-opioid medicines.
Additional medicines (adjuvants - see below) can be used with the pain relievers, which can help them work more effectively and reduce anxiety.
Non-opioid pain medicines
Non-opioid pain relievers include paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs). Non-opioid painkillers can be taken by mouth, as an injection, or as a suppository that you insert into your rectum.
There are few side effects associated with paracetamol, as long as the recommended dose is not exceeded. Side effects of NSAIDs can include heartburn and stomach ulcers, heart problems and kidney problems.
Opioid pain medicines
Opioids are very effective pain relievers, and can be taken by mouth, as skin patches, rectally (in the form of a suppository), or as injections. Weak opioids include codeine; stronger opioids include morphine, oxycodone, hydromorphone, methadone and fentanyl.
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 cancer pain under medical supervision.
While opioids are effective pain relievers, they are associated with several troublesome side effects, including:
- nausea and vomiting;
- drowsiness; and
- confusion (rare).
However, 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). In people with advanced cancer, taking extra painkillers or anti-anxiety medicines may be recommended before activities that can cause pain (called incident pain).
Other medicines for pain relief
There are other medicines available that can increase the effectiveness of standard pain relievers and relieve specific types of pain. These medicines are called adjuvant analgesics, and include the following.
- Tricyclic antidepressants (tricyclics) 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.
- Antispasmodic and anti-anxiety medicines that relieve muscle spasm are sometimes used if this is a cause of pain.
Nerve blocks and epidurals for cancer pain
Nerve blocks 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, which stops pain signals from travelling along the nerves and reaching your brain, so you don’t feel the pain. Injections of alcohol can give longer-lasting pain relief. Sometimes, a nerve may be surgically cut or destroyed with heat (radiofrequency ablation) to permanently block pain.
Persistent pain can also sometimes be treated by giving pain medicines such as morphine into the space around the spinal cord (epidural or spinal medicines).
Medicinal cannabis (medical marijuana) is another option for some people with cancer pain. It can be used as an adjuvant pain medicine in people who have not responded to conventional treatments. It can be given as a synthetic cannabis product via a mouth spray, which provides pain relief without you feeling any psychological effects (feeling high). Marijuana can also help relieve nausea and vomiting and increase appetite.
Ask your doctor whether medical marijuana may be suitable for you. Your doctor may be able to help you access medicinal cannabis as an unapproved drug through the Special Access Scheme or Authorised Prescriber Scheme, which are programmes that the Australian Government is using to help the appropriate people access these medicines. However, access may still be limited in some states and territories.
What physical therapies 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 thought patterns and ways of doing things that may be reinforcing pain.
- Counselling can help relieve anxiety and depression, which may be making 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.
Hypnotherapy, meditation, support groups and counselling can also be effective.
Palliative care and cancer pain
Palliative care is treatment to relieve symptoms and improve your quality of life, as opposed to treatment to cure your cancer. Palliative care includes, but is not limited to, treatment of cancer pain.
Cancer treatments such as surgery to remove the bulk of a tumour, radiation therapy to relieve pain from bone metastases, chemotherapy to shrink an inoperable tumour, or hormonal therapy to reduce tumour size, are types of palliative care.
Palliative care can be provided by palliative care specialists, GPs, oncologists, pain medicine specialists and other healthcare workers and carers. It can be provided at home, in hospital, and in hospice care. Palliative care can be given at any point during your treatment for cancer - it is not just for end-of-life care.
Remember, if you are feeling that your cancer pain is not adequately controlled, there’s no benefit to suffering in silence - talk to your doctor or specialist about it - they should be able to review your treatment.
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4. Cancer Council NSW. Medical use of cannabis (marijuana) Position statement (Dec 2014). https://www.cancercouncil.com.au/1978/cancer-information/general-information-cancer-information/fact-sheets-and-position-statements/position-statements-fact-sheets-and-position-statements/cancer-council-new-south-wales-medical-use-of-marijuana-fact-sheet/ (accessed Sep 2017).