Another genetic factor linked to postchemotherapy cognitive decline is the Val158Met polymorphism of the gene encoding for Catechol-O-methyltransferase (COMT), an enzyme that degrades neurotransmitters such as dopamine. Patients with this polymorphism have rapid dopamine metabolism, resulting in reduced dopamine activity.
These findings point to potential molecular mechanisms for cognitive changes associated with chemotherapy, and suggest that therapies targeted at neurotransmitter systems may ameliorate the effect, Dr. Ahles said.
He noted that animal studies have shown that fluoxetine (Prozac) prevents deficits in behavior and hippocampal function associated with 5-fluourauracil (5-FU), and that nicotine patches have been shown to improve cognitive functioning in patients with mild cognitive impairment.
The symposium was cosponsored by AAHPM, ASCO, ASTRO, and MASCC.