Jul 16, 2004 - 2:30 am
Chemotherapy Impacts Cognitive Functioning Up to Ten Years After Treatment
Standard-dose chemotherapy can negatively impact the cognitive functioning of cancer survivors up to 10 years after treatment, a new study from the Dartmouth-Hitchcock Medical Center finds.
The study -- the first of its kind to compare the neuropsychological effects of chemotherapy and radiation therapy on long-term cancer survivors -- determined that people treated with chemotherapy scored significantly lower on tests for memory, concentration, and psychomotor functioning (ability to integrate different types of information) than patients who received only radiation therapy or surgery. Previous studies have suggested that cancer survivors treated with chemotherapy experience cognitive deficits in the short-term after treatment and up to two years following treatment.
"We wanted to study long-term cancer survivors to see if the secondary effects of chemotherapy on cognitive functioning could be detected many years after treatment and our results suggest that they can," said Tim A. Ahles, Ph.D., lead study author, and Professor of Psychiatry and Program Director of the Center for Psycho-Oncology Research at the Dartmouth-Hitchcock Medical Center. "The cognitive effects of chemotherapy on patients were relatively subtle and most of the scores fell within the normal range of performance. However, patients tell their physicians that these changes are very recognizable."
The 128-person study compared breast cancer and lymphoma survivors treated with chemotherapy (35 breast cancer patients, 36 lymphoma patients) with people who received only radiation therapy or surgery (35 breast cancer patients, 22 lymphoma patients). Study participants were at least five years postdiagnosis, not presently receiving cancer treatment, and disease-free.
Patients were given a standard neuropsychological assessment in nine areas including verbal ability, visual and verbal memory, and motor functioning. Participants also completed questionnaires on anxiety, fatigue, depression, and memory functions.
Results reveal that 85 percent of study participants received only one type of chemotherapy regimen. Survivors who were treated with chemotherapy scored significantly lower on the neuropsychological assessment compared to those treated with only radiation therapy or surgery across multiple domains, particularly in the areas of verbal memory and psychomotor functioning. However, these results, as well as those of other researchers, suggest that only a subgroup of patients experience persistent cognitive deficits post-treatment.
Reports of depression, anxiety, and fatigue, all of which can affect cognitive functioning, did not differ between the groups. This suggests that the differences in performance on the cognitive tests were due to the chemotherapy itself, not to greater levels of depression, anxiety, and fatigue in patients who received chemotherapy.
According to Dr. Ahles, more studies need to be conducted to determine exactly what might be affecting cognitive functioning so researchers can identify types of treatments or cognitive rehabilitation that might help cancer survivors.
Journal of Clinical Oncology