Maastricht University Maastricht, the Netherlands (Spring 2016)
“Can I get you anything to eat sweetie?”
“Sweetie, are you sure?”
“Perhaps I’ll like an apple”, my daughter replies without looking at the nurse.
That was an hour ago. She still hasn’t finished the apple the nurse brought her and I’m worried. It’s early in the evening and my daughter has hardly eaten anything all day. She’s losing weight and if she doesn’t eat, she’ll require tube feeding. I tell her that. I explain to her this means the nurse will push a tube down her throat and into her stomach via one of her nostrils. I know I shouldn’t try and scare her into eating, but I’m desperate.
Childhood cancer is rare and yet it is the primary cause of death by disease in children in industrialized countries. It comes in all kinds of forms and shapes. There’s Ewing’s sarcoma (a form of bone cancer), Wilms’ tumor (a type of kidney cancer), acute lymphatic leukemia (blood cancer),and many more.
My daughter is seven years old when she is diagnosed with cancer. My daughter has neuroblastoma, a type of childhood cancer in which immature neurons from the sympathetic nervous system form a malignancy. It usually presents itself as a large tumor protruding from one of the adrenal glands, as was the case with my daughter. More often than not, the disease is already metastasized when first diagnosed. This was also true of my daughter’s neuroblastoma.
Despite the fact that there are many different types of childhood cancer, treatment is fairly uniform and commonly includes surgery, radiotherapy, and chemotherapy. Decades of research and of intensifying treatment schedules have markedly increased the survival rate for children with cancer. It is a tremendous achievement, but these progressively intensified treatments come with severe burdens. One particular symptom of treatment concerns eating problems. In the context of cancer poor food intake might not appear to be much of a problem, but not eating leads to malnutrition that affects growth and development, and increases the risk of life-threatening complications.
In the case of weight loss, the childhood cancer patient receives complementary feeding—typically nasogastric tube feeding. Placing a nasogastric tube is relatively simple, but it can be a painful procedure and it is highly stressful to a child. Furthermore, tube feeding has been associated with considerable weight gain in children. Like being underweight, being overweight makes cancer treatment less tolerable. It is clearly important to maintain optimal food intake in children undergoing treatment for cancer, but nobody knows how.
Why do childhood cancer patients eat so poorly? A decade ago, Swedish researchers decided to simply ask children with cancer about their eating problems. They also interviewed the children’s parents and nurses at the pediatric oncology ward. They learned that there are three main reasons for decreased “oral intake”: (1) pain; (2) food aversions; (3) taste changes.
Chemotherapy is a nonspecific mode of treatment, meaning it doesn’t just target the cancer and thus entails a lot of adverse side effects. But without chemotherapy no child would stand a chance of surviving cancer. Even with new modes of treatment like immunotherapy, chemotherapy is still indispensable in curing cancer.
One common side effect of chemotherapy is mucositis. Our digestive tract is lined with a protective mucous tissue of epithelial cells from mouth to anus. Chemotherapy damages the mucous membrane, giving way to infections. Painful ulcers may develop in the mouth that turns chewing and swallowing food into a grueling experience.
A second and well-known side effect of chemotherapy is nausea. Such nausea directly affects appetite, but also induces long lasting food aversions. Our brain is wired such that it automatically tries to identify the cause of any gastrointestinal malaise. In finding the cause for nausea, the brain overrides reason and narrows its search to the matter “What did we just eat?” The initial pleasure derived from a food that the brain associates with nausea and vomiting is downgraded to an aversion for that particular food. Any food can become disliked. Some childhood cancer patients even acquire an aversion for chocolate. Understanding that treatment caused the nausea will not dispel the learned dislike for chocolate and these food aversions are not easily unlearned.
Appetite is not necessarily lost because of an acquired aversion or mucositis, but simply because food no longer tastes right. Taste alterations are commonly experienced when treated with chemotherapeutic drugs, but there is surprisingly little research on treatment-induced taste changes. What research there is suggests that chemotherapy has an immediate effect on the taste receptors in the mouth. Taste receptor cells are constantly renewed to maintain a stable sense of taste. Chemotherapy impedes the taste cell turnover .Suddenly fries no longer taste salty, or meat has a strange metallic taste, or everything just tastes bland and slightly bitter. Eating becomes an unpleasant experience when all food tastes and smells different from what is expected.
Poor food intake in childhood cancer patients then is not simply the result of a general loss of appetite, but the outcome of specific treatment side effects. These treatment symptoms are common and often co-occur. But identifying the causes for a problem doesn’t mean the problem is solved. There is very little one can do to prevent mucositis other than maintaining good oral hygiene. Further, nausea can be managed with anti-emetic drugs, but to date there is no drug that completely prevents the occurrence of nausea with chemotherapy. And changes in taste with chemotherapy are still so poorly understood that there really is no way of knowing how to best deal with this treatment symptom.
Children with cancer eat too little. It is clear why this is so, but no more than that. It is time to seriously increase efforts to make treatment more patient-friendly, to manage treatment symptoms more effectively. That’s important too. It’s important for my daughter. It’s important to me. It’s important to all childhood cancer patients and their parents.
My daughter is sleeping. Sitting beside her hospital bed I stare at a piece of paper. Earlier, the nurse asked me to record what my daughter eats and drinks during the day. Today she ate one oatmeal cookie and one apple. She drank one glass of water. I feel utterly powerless.
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Remco Havermans (PhD) is an assistant professor at Maastricht University (Maastricht, the Netherlands) where he teaches undergraduate students at the Faculty of Psychology and Neuroscience and at University College Venlo. He further conducts research with a special interest in addiction and appetite.