What is pain?
Pain is felt when special nerve fibres in the body sense something unpleasant, such as a pin prick or extreme pressure, and send a message to the brain, which reads it as pain. Although pain is unpleasant, can be a useful warning sign from our bodies telling us that something is wrong.
Patients and their caregivers are often very concerned and scared about the pain associated with cancer. They may think that if someone has cancer, they are bound to have pain and that nothing can be done to relieve it. But this isn’t true.
Cancer-related pain can be managed. With the help of your child’s health-care team, cancer-related pain can be prevented or reduced so that your child can do the activities that are important to them. Never think that it is “weak” or a burden when asking for help with your child’s pain. Nobody will think you are just complaining. The sooner you speak up about your child’s pain, the easier it is to treat! There are also specialized pain services available to help if needed.
What kind of pain might a child feel with cancer?
Cancer-related pain can come from many sources.
- Pain from the tumour: Your child may feel pain from the tumour pressing on bones, nerves or body organs. This pain usually gets milder or disappears completely as treatment removes the cancer cells from their body.
- Pain from procedures: Cancer treatment means many procedures involving needles, so this may be your child’s most feared part of having cancer.
- Pain from side effects of the cancer treatment: Side effects of cancer treatment can include stomach aches and pain from surgical incisions (cuts).
- Mucositis (say: moo-cus-eye-tis): Some chemotherapies cause painful sores in your child’s mouth and throughout their digestive tract (including the stomach and intestines).
- Neuropathic (say: NOO-roe-path-ik) pain: Sometimes cancer treatment can cause nerve damage. Your child might experience this as pain, burning, tingling, numbness, weakness, clumsiness, trouble walking, or unusual sensations in the hands, arms, legs or feet. Be sure to tell your child’s doctor or nurse practitioner right away if you notice any of these symptoms in your child.
How long might the pain last?
Acute pain
Most commonly, children with cancer-related pain will experience acute pain. Acute pain is what you feel when normal nerves send messages from the injured or affected body tissues to the brain.
Our bodies sense acute pain through specialized nerve cells called nociceptors. These cells are located around the body and sense when organs and tissues receive painful stimulation (for instance a pinprick to the skin).
The nociceptors send messages to the brain through nerve pathways to tell us that there is tissue damage. Because of how nociceptors send messages through the spinal cord, our body can react quickly to acute pain before our brain even knows it exists. For instance, if you accidentally touch a hot stove, your body reacts before your brain has figured out what has happened.
Acute pain is the type of pain you feel from a needle poke for blood work, or from an inflamed joint. This pain is temporary. Acute pain goes away when the healing occurs.
Chronic pain
Chronic pain refers to pain that lasts longer than expected (typically longer than three months). Unlike acute pain, chronic pain persists even after regular healing times for injuries and illness have passed.
Chronic pain can be associated with a disease (such as cancer), but many chronic pains occur even when there is no obvious cause. Sometimes chronic pain is a condition or disease in its own right with specific diagnoses and treatments. Chronic pain may occur in young children with cancer and can take many different forms. Examples include:
- pain in the muscular-skeletal system (bones, muscles and tendons), often described as aching or soreness
- nerve-type pain, often described as tingling, burning or like an electric shock
- abdominal pain
- headaches
Cancer-related pain can occur as acute pain and can sometimes develop into chronic pain. Because pain is invisible, it is very important to let your child know that you believe their pain is real, whether it is acute or chronic pain.
Remember that not all pain your child experiences is related to cancer. There’s no need to fear that every new pain they feel means the cancer is getting worse or has come back. Like all children, your child can get headaches, muscle strains and other aches and pains. However, if they are taking prescription pain medicines, check with your child’s health-care team before giving any over-the-counter pain relief medicines for these aches and pains.
Mechanisms of pain
Pain has different mechanisms:
- nociceptive
- neuropathic
- unclear
Nociceptive
This type of pain occurs when special nerve endings in the body (called nociceptors) are irritated, usually after surgery, radiation therapy or chemotherapy.
Neuropathic
This type of pain occurs when pain nerves send inaccurate signals to the brain. It can happen when there is direct damage to nerves (for example an amputation) or, sometimes, when pain nerves send inaccurate signals even after tissues have healed.
Unclear
Pain may sometimes have a mixed mechanism, for example if it is caused by tissue inflammation and nerve damage. Other times, no clear biological mechanism can be found to explain a child’s chronic pain. However, this does not necessarily mean that the pain is psychogenic.
