This is a very discouraging study from Wefel and his colleagues at M.D. Anderson, summarized in MedScape. Many women complain of "chemobrain", and there have been a number of studies looking at cognitive changes during or after cancer treatment. It is always impossible to tease out each factor: how much is due to stress, natural aging, diminished estrogen, and how much specifically to the drugs that we take. There are varying opinions about all of this, but I certainly know women who have experienced difficulties with memory, word-finding, and an overall sense of cognitive blunting. It almost always gets better, and there are ways to help yourself along--that can be a topic for another day.
Here's the summary:
Breast cancer chemotherapy linked to cognitive dysfunction
By Laura Dean
Cancer 2010; 116: 3348-3356
MedWire News: US researchers report that chemotherapy for breast cancer is associated with both acute and late onset cognitive dysfunction, with learning and memory, executive function, and processing speed the worst affected domains.
To investigate the growing body of evidence suggesting that cognitive dysfunction is associated with chemotherapy in breast cancer survivors, Jeffrey Wefel ( University of Texas MD Anderson Cancer Center, Houston), and colleagues set up a prospective study of 42 women receiving chemotherapy for T1-3, N0-1, M0 breast cancer.
Patients received standard 5-fluorouracil, doxorubicin, and cyclophosphamide with or without paclitaxel. They also underwent a neuropsychologic evaluation including measures of cognition, mood, and quality of life before chemotherapy, during or shortly after chemotherapy, and 1 year after completion of chemotherapy.
The researchers report that 65% of 37assessed patients demonstrated an acute decline in cognitive function during or shortly after completion of chemotherapy. At the long-term evaluation, 61% 28 assessed patients had evidence of cognitive decline after cessation of treatment. Of these patients, 71% demonstrated continuous decline since the acute interval, whereas 29% demonstrated new onset, delayed cognitive dysfunction that was not present during the acute interval.
The most common cognitive domains affected were learning and memory, executive function, and processing speed. The team found that cognitive decline was not associated with mood or other clinical or demographic characteristics, but there was a trend for baseline cognitive impairment status to be related to late decline.
Wefel and co-authors conclude in the journal Cancer that their findings are "consistent with a developing body of translational animal research demonstrating both acute and delayed structural brain changes as well as functional changes associated with common chemotherapeutic agents such as 5-flouorouracil."
They add: "Clinical and translational research using neuropsychological tests, imaging techniques, biomarkers, and animal models are essential to accelerate our understanding of these toxicities, identify at-risk subgroups, and develop intervention and neuroprotective strategies."