Cognitive Effects of Cancer Therapies
Cognitive Effects of Cancer Therapies
US Oncology Review 2006
Published: October 2008
Published: October 2008
Extraordinary progress has been made in treating childhood leukemia over the past 45 years. Using old and new therapies in ever more effective ways, doctors have been able to increase the five-year relative survival rate for acute lymphocytic leukemia (ALL)— the most common form of childhood leukemia—to 88.4% among patients under the age of five, and 86% among youngsters under the age of 15 in the US.
While leukemia remains the leading cause of death from cancer among children and young adults under the age of 20, the steady increase in survival is striking considering that a patient had only a 14% chance of living five years with the disease in 1960. In fact, pediatric cancer treatments have improved so markedly that experts estimate that one in 900 adults in 2010 will be a childhood cancer survivor, and most will live an average of 60 years from the time of their diagnosis.
Miracle Treatments and Long-term Side Effects
Modern cancer therapies, like all medical interventions, have their share of complications and long-term side-effects; some of these involve the brain. In recent years, with an increasing number of pediatric cancer patients surviving into adolescence and young adulthood, experts have been diagnosing cognitive deficits caused by some of the same therapies that have saved so many. The problem may be becoming less severe as recent treatment protocols have diminished in toxicity. Nonetheless, the rate of cognitive impairment remains high.
As many as 40% of all pediatric ALL patients treated with chemotherapy alone will develop serious learning disabilities within two to three years following treatment. For children who receive cranial radiation, with or without chemotherapy, the percentage is 80–90%.
“The focus up until fairly recently has been on treating the cancers,” explained psychologist Daniel Armstrong, PhD, of the University of Miami, Florida, a noted expert in the cognitive effects of cancer treatments. “Now, we have a real awareness that there is life after cancer.We’re looking at the patient post-treatment, and that often means addressing such issues as serious lifelong cognitive deficits.”
Common late cognitive effects include:
• a marked slowing in thinking (processing) speed;
• attention problems, including daydreaming, ‘spacing out’ and a tendency to distract easily;
• memory difficulties, particularly with tasks that require visual cues, such as remembering numbers and new words;
• fine motor coordination problems;
• difficulty planning and organizing tasks and materials; and
• poor handwriting, reading comprehension, and mathematics skills, particularly in calculations.
Parents soon realize that little things become a major chore for a child with cancer-related cognitive disabilities. Simple homework becomes a six-hour ordeal every night, reading is difficult because of the energy expended to decode the phonetics of a word, making comprehension an afterthought. Handwriting may also be illegible. The emotional costs are also high. Children whose disabilities remain undiagnosed or under-treated sometimes have low self-esteem, which can lead to depression.
