The Problem of Pain in Childhood Cancer Survivors

by Dr. Lonnie Zeltzer & Linda Goettina Zame
Source: Fall 2005 CCCF Newsletter

Also see: Stories from Adult and Child Survivors Who Have Suffered with Chronic Pain

What is pain?

This might seem like an unusual question to ask since everyone has experienced pain at one time or another. However, an understanding of pain can help you distinguish between pain that you can take care of, and pain that needs to be evaluated and treated by a doctor. Pain is a complex system of signals that carry messages up to the brain (pain transmission system), and down from the brain (pain inhibitory system) to turn off or reduce the amount of pain. Most importantly, it is in the brain itself where pain perception takes place. There are certain areas in the brain that are responsible for our experience of pain. One part of the cortex, or outer layer of the brain, is responsible for the sensory part of pain. Specifically, this part tells us how much pain we are having, what it feels like, and what part of the body it is coming from. There is another part of the cortex where the perception of "suffering" takes place. This is called the affective pain perception area. An illustration of how these are different is seen in the example of when a patient receives morphine after a surgery. While the sensation of pain may be reduced ("I feel less pain"), the suffering is reduced to a greater extent ("I don't care"). Thus, there are three key concepts about pain: 1) an individual's perception of pain takes place in the brain, 2) there is a sensory and a suffering dimension of pain perception; and 3) pain is caused by an imbalance in the "pain- to- brain" and "brain-to-pain" neural systems, as well as in the brain's pain perception areas.

What makes pain a problem?

When faced with a situation of experiencing acute pain, our pain transmission (pain to brain) and pain control (brain to pain) systems work in balance. Remember the time that you accidentally closed the door on your finger. First it hurt a whole lot (pain transmission). You quickly experienced the pain and noted that the pain was in your finger (sensory pain perception) and were bothered by it (affective pain perception). Eventually, the pain went away (pain control). The pain mechanism worked in balance to reduce and eliminate the pain. Chronic or ongoing pain occurs when the pain system is out of balance. This "dysregulation" can come from many causes. Persistently tense muscles in a certain part of the body, such as the lower back or neck and shoulders, can stimulate sensory nerves from those areas of the body. Hypersensitive areas can develop in those muscles (called "tender points") and you can feel a sensation of pain when you press on them. These tender points are hallmarks of "myofascial" or musculoskeletal pain. Children or adolescents treated for osteosarcoma or other sarcomas who have had spinal changes resulting from radiation to the spine might experience postural distress on muscles. An imbalance in a child or teen's stance that results from one leg being shorter than the other after a limb salvage procedure for bone cancer can also cause postural distress on muscles over time, and especially as the child grows. Such chronic strain on certain muscles can cause chronic myofascial pain to develop. This may be experienced as low back pain, or headaches related to chronic strain on the neck and head muscles. Arthritis can develop as a late-effect of spinal radiation or pelvic radiation. Radiated skin can also become hypersensitive long-term. This is called "neuropathic pain." The sensory nerves in the radiated area of the skin get "turned on" and become more painful when even lightly touched.

There are other types of pain that can develop without an ongoing obvious cause. One example is phantom limb pain after an amputation. Another is called "complex regional pain syndrome type 1" or CRPS. In CRPS a part of the body becomes hypersensitive and painful, often even to light touch, or even wind or water. In these cases, the pain system gets "turned on" so that there is an increased activity in the brain's pain perception, and the pain "turn down" system starts working less and less efficiently and effectively. If pain continues without being effectively turned off or treated, there are neural circuits in the brain called "neural modules" that can keep the pain going. Thus, the usual balance in the body's pain system does not work properly. Similarly, ongoing belly pain, often associated with diarrhea or constipation, or both, and/or nausea and flatulence (lots of gas), is another example of this sensory system dysregulation. In this case it is a dysregulation in the brain to the gut nervous system, called "irritable bowel syndrome." It is important that the cause of pain is evaluated. Often, the way to treat pain is to rebalance the system. Thus, the goal of pain evaluation is to determine the factors that keep the system out of balance, and keep pain perception areas "turned on." The goal of treatment is to rebalance the pain system and turn down hyperactivity in the pain perception areas of the brain, especially the area of pain suffering.

Who is at risk for the development of chronic pain?

The Childhood Cancer Survivor Study, comprising the largest number of survivors of childhood cancer in North America and a large group of their siblings, found that, while the majority of cancer survivors do not have chronic pain, there are certain groups of survivors that are more likely to have pain. These are survivors of bone tumors (osteosarcoma, Ewing's sarcoma), other solid tumors, and Hodgkin disease. The "why" is unknown, although speculation suggests that after-effects of body radiation and the effect that this has on a growing musculoskeletal system may play a role. Headaches were also found to be more prevalent in survivors of child and adolescent cancer than in their siblings, although migraines were found to not be more common.

How to know what kind of pain you have?

Most pain is treatable, and almost all pain and suffering can be reduced to some extent. If you are a survivor of childhood or adolescent cancer and have chronic pain, you do not need to "learn to live with it!" If your physician tells you that, then ask for a referral to see a pain specialist if one is available. I would also encourage you to read more about the different treatments for chronic pain. One source of information is: "Conquering Your Child's Chronic Pain: A pediatrician's Guide to Developing a Normal Childhood" by Lonnie K. Zeltzer MD, and Christina B. Schlank (HarperCollins, 2005). This resource describes all types of pain, as well as mind-body ways of treating pain, much of which can be done without a physician. As discussed above, to get the proper treatment for pain, it is important to understand the most likely reason(s) for the pain. For example, sometimes headaches can be signs of increased intracranial pressure related to a blocked shunt, to tumor growth, to a new tumor in the brain, to head and neck muscle spasm, or just to the central pain perception area being "turned on." Structural and common reasons for the pain will be associated with other clinical signs that can be determined on an examination (e.g. abnormal neurological findings, tender points in the muscles, hypersensitive skin by the head). If no specific likely reason is found for the pain, this does not mean that it is "stress" or the pain is "not real" (often called "non-organic"). Rather, the pain is real and the reason for the pain is related to a nerve signaling imbalance or neural "turn-on," including pain perception areas in the brain.

The symptoms being experienced can also be a clue to the cause of the pain. Neuropathic pain tends to be burning, sharp, stinging, shooting, stabbing. Hollow organ pain (e.g. ureter as in renal stones, uterus, intestines) tends to be crampy in waves. Muscle and bone pain tends to be experienced as a deep aching pain. Headaches that are myofascial tend to feel achy with the head feeling squeezed or as if it is under pressure (which if in the forehead or cheeks could be a sign of sinus infection).

Locating the source of pain can sometimes be difficult because the pain which is being felt in one area of the body is actually coming from another area of the body because of the sensory nerve connections. This is called "referred pain." Examples include hip joint arthritis felt as deep aching pain in the lower thigh above the knee; diaphragm irritation at the base of the lungs felt as sharp pain in the shoulders; pain in the heart related to insufficient blood supply to the heart muscles is felt as shooting pain down the left arm; nerve outlet constriction pain, such as in the lower back is often felt as sciatica or sharp pain down the leg, etc.

How to treat your pain: a mind-body approach to treatment

The approach to most chronic pain involves some active effort on your part in order to receive the best and most longterm gains. The mind and body are connected and our memories, emotions, thoughts, and actions can affect our pain - both positively and negatively. First, it is important to figure out your primary mood. Do you feel depressed much of the time? Depression can be associated with poor appetite, sleep, and energy. The desire to maintain a routine or participate in new activities is low. You may feel that you are in a rut that you can 't seem to get out of. The joy in life is gone. It is important to know that chronic pain can cause depression, which in turn can make chronic pain worse. Chronic pain can reduce the production of needed chemicals (neurotransmitters) that impact mood. In turn, lower levels of those neurotransmitters can reduce the efficiency of the body's pain control system, making it more difficult to turn down pain signals.

Similarly, anxiety or stress can increase the volume of pain transmission, causing more pain. Acute, intermittent pain can become a source of anxiety while waiting for the next pain episode. Since anxiety disorders are rather common, many people do not know that by reducing anxiety they can also reduce their pain.

There are medications and complementary therapies that can be used to reduce depression, anxiety, and/or chronic pain. Medications should be prescribed by a physician and monitored for their effectiveness as well as sideeffects. It is important to report both negative and positive effects to your doctor. It is important to remember that many herbal and other "natural" products can change the metabolism of medications and so all products, whether prescribed or not, should be discussed with the doctor. Complementary therapies for pain include common approaches such as physical therapy, exercise (especially swimming), and good sleep, as well as the less common ones which includes acupuncture, hypnotherapy, Iyengar yoga, biofeedback, craniosacral massage, regular massage, Reiki and other forms of energy therapy, art therapy, music therapy, and other therapies that create homeostasis and balance in your nervous system. Psychotherapy can come in different forms and be valuable if you have depression and/or anxiety. Sometimes the cancer experience can be associated with symptoms of post-traumatic stress disorder (PTSD) in which the central arousal system is chronically "turned on," keeping pain signals on high volume, lowering the "alert system set-point," creating sleep difficulties, as well as other problems. Psychological interventions can be very helpful for many survivors with chronic pain to help learn specific coping skills to be able to function, while the pain begins to diminish. The goal in the treatment of chronic pain is to initially promote increased physical function, followed by a decrease in the intensity of the pain, and subsequent elimination of all pain over time.

Summary

Pain is caused by an imbalance in the pain transmission and control systems of the body. All pain perception (the feeling part and suffering caused by pain) takes place in the brain.The type of pain and location give clues as to what might be causing the pain. Pain that doesn't improve on its own will let you know when to get help.

Remember that all pain can be made worse by stress and lack of sleep, so it is important to find ways to reduce stress and improve sleep patterns. All pain involves both the mind and the body. How we think and feel physically influences pain signals. Treatment for pain can include medication, but should also include at least one physical form of therapy, (e.g. Iyengar yoga, physical therapy, massage, exercise) as well as psychological therapy (e.g. relaxation and breathing techniques, biofeedback, hypnotherapy, psychotherapy). It is the combination of both mind and body treatments that can rebalance the pain neural system and reduce the brain's pain perception to control pain and suffering.

Dr. Zeltzer is a professor of pediatrics, Anesthesiology, Psychiatry and Biobehavioral Sciences at the David Geffen School of Medicine, UCLA; Director of the Pediatric Pain program at UCLA Mattel Children's Hospital and is the Associate Director of the Patients and Survivors Program in the UCLA Jonsson Comprehensive Cancer Center.

Linda Goettina (Zame) D.M.H. is a 30+ year survivor of Hodgkin's disease with a doctorate in mental health from UCSF. In 1998 she founded the first internet discussion group for long term cancer survivors - now with over 400 members. She went on to found Ped-Onc survivors and 4YOUth. In 2005 she was elected to the National Candlelighters board of directors. She has been active as a health advocate for survivors since 1998.