Brain Cancer in Childhood

This article relates to We Own the Sky

In Luke Allnutt's novel, We Own the Sky, five-year-old Jack Coates is diagnosed with a glioblastoma brain tumor.

According to the American Cancer Society, brain tumors are "masses of abnormal cells in the brain or spinal cord that have grown out of control." The American Brain Tumor Association estimates that 4,600 children and adolescents are diagnosed with the disease each year. They cite a 2016 study that found cancer of the brain is the most common kind occurring in those younger than 15 and the leading cause of cancer-related deaths in that age group. Even benign brain masses can grow and kill off tissue, impacting an individual's ability to function.

Although about 75% of children with brain cancer survive more than five years after diagnosis, the outlook can vary a great deal based on factors such as the type of cancer and where in the brain it's located. Survival rates per cancer type based on a large number of cases are well documented, but each child's case is different; many defy the odds.

Astrocytomas are a broad category of tumor that start in a type of brain cell called astrocytes; approximately 35% of childhood brain tumors are astrocytomas. Most cancers in this category spread widely throughout the brain and blend with normal cells, often making them inoperable. The highest grade astrocytoma, glioblastoma, is the fastest growing type of tumor there is and the five-year survival rate for those diagnosed with this condition is just 20%. Low-grade types are those which grow very slowly and are less likely to infiltrate surrounding brain tissue, such as pilocytic astrocytoma (survival rate 95%) and fibrillary astrocytoma (80-85%). Other tumor categories include oligodendrogliomas, ependymomas, craniopharyngiomas and primitive neuroectodermal tumors (PNETs).

Some genes control when our cells grow, divide into new cells, and die. Certain genes that help cells grow, divide, and stay alive are called oncogenes. Others that slow down cell division, or cause cells to die at the right time, are called tumor suppressor genes. Cancers can be caused by DNA changes that turn on oncogenes or turn off tumor suppressor genes. These gene changes can be inherited from a parent (as is sometimes the case with childhood cancers), but more often they happen spontaneously during a person's lifetime. While such disruptions can occasionally be genetic, there is no known lifestyle-related or environmental cause of childhood brain tumors. The American Cancer Society states, "Most gene changes are probably just random events that sometimes happen in a cell, without having an external cause."

The earlier a brain tumor is detected, the better the odds of a cure; nevertheless, children aren't generally screened unless symptoms are present. Headaches that get worse over time are a common indicator as are nausea, vomiting, blurred vision, balance problems, behavior changes, seizures and drowsiness. The child's general physician will first run a series of neurological tests which may include checking reflexes, sensation, muscle strength, vision, eye and mouth movement, coordination, balance, alertness and other functions. Should the tests raise concerns, the next step would be to use imaging technology (X-ray, fMRI, CAT scan, etc.) to see if a mass can be detected. A biopsy might follow, although one may not be necessary or possible based on information from the imaging (many astrocytomas can't be biopsied safely).

A child who does have a brain tumor is usually treated by a team of physicians led by a pediatric neurosurgeon. Others taking part could include a pediatric oncologist and a pediatric neurologist, as well as various nurses, psychologists, social workers and/or rehab specialists. Effective treatments for cancers of all types are improving year by year and include surgery, radiation and chemotherapy. A number of newer avenues including targeted therapies such as immunotherapy, also look promising. In the 25% of childhood cancers that can't be cured, physicians will recommend palliative care and hospice services.

Filed under Medicine, Science and Tech

This "beyond the book article" relates to We Own the Sky. It originally ran in May 2018 and has been updated for the February 2019 paperback edition. Go to magazine.

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