Facts About Pediatric Cancer

The Basics:

  • Cancer is the leading cause of death by disease in children younger than 15 years (Stanton & Behrman, 2007).
  • The most common childhood cancer diagnosis is Acute Lymphoblastic Leukemia (ALL), the treatment for which takes approximately 3 years.
  • The second most common are Brain Tumors (Brown, 2006).
  • In the 1960’s, the 5-year survival rate for ALL was 4% (Mannix & Boergers, 2010). Today, it is approaching 90% [70% for Brain Tumors] (Askins & Moore, 2008).  Therefore, families need to prepare for survival.
  • 40% of childhood cancer survivors report neuropsychological late effects (Krull et al., 2008).
  • This makes survivors 10.5 times more likely to have severe cognitive dysfunction than their peers (Oeffinger et al., 2006).

 

What are the most likely neuropsychological effects?

  • Most common primary symptoms are losses in (Butler & Mulhern, 2005):
  1. Attention: ability to focus, concentrate, and shift from one task to another as needed – the cornerstone for executive functioning
  2. Working memory: ability to hold and manipulate information in short term memory
  3. Processing speed: ability to quickly and efficiently perform simple tasks
  • Secondary symptoms are the “real world” results of the primary symptoms The most common secondary symptoms are (Butler & Mulhern, 2005):
  1. IQ loss: often one or more standard deviations (Askins & Moore, 2008)
  2. Academic failure: usually the first indicator of a problem
  3. Vocational and social problems: logical conclusion of #1 and #2
  • In addition to the above, many children experience(Madan-Swain et al., 2010):
  1. Visuospatial deficits
  2. Fine and gross motor difficulties
  3. Fatigue/decreased energy

 

Where do these problems come from?

  • Though brain tumors can certainly cause neuropsychological problems, most late effects result from the cancer treatment.
  • Risk level of cancer treatments (in order from most to least likely to result in cognitive deficits):
  1. Radiation(Mulhern & Butler,  2004)
    1. In short, radiation destroys white matter [the tissue that delivers messages through the brain].
    2. Even localized radiation has been shown to cause problems in non-targeted parts of the brain (Waldrop et al., 1998).
    3. Can cause rapid deterioration of cognitive abilities.
  2. ChemotherapySurgery can cause significant problems, but it depends on where the surgery is occurring. Surgery is a less consistent contributor to late effects than other treatments (Butler & Hasler, 2006).
    1. Many common chemotherapies are toxic to both progenitor cells [a type of stem cell] and myelin-producing cells [myelin enables us to think and act quickly] (Dietrich et al., 2006; Duffner, 2006; Meyers, 2008).
    2. Chemotherapies target quickly growing and dividing cells. The neurons of young children are still growing quickly, which places them at the highest risk (Duffner, 2006). One study found that 90% of children under age 5 who underwent chemotherapy for ALL had resulting neuropsychological deficits (Wilson et al., 1991).
    3. Many chemotherapies actually kill healthy cells even faster than cancer cells (Dietrich et al., 2006).
    4. Deficits tend to be delayed and progressive; and may not be noticed until well after the conclusion of treatment (Meyers, 2008).
    5. Intrathecal (IT) chemotherapies appear to be the worst offenders, causing cognitive impairment in at least 30% of children (Mulhern & Butler, 2004). When combined with radiation, IT chemo becomes even more toxic (Bleyer et al., 1990).