Wednesday, May 19, 2010

New Research from MD Anderson: Delayed Onset of "Chemo Brain" Months After End of Treatment*

Idelle Davidson

In some disturbing findings reported in the April 28, 2010 issue of the journal Cancer, patients may not experience "chemo brain" during treatment but rather months later.  According to the authors, "This is very concerning as clinical lore has suggested that treatment-related cognitive dysfunction should dissipate over time."

The Study
42 patients, all scheduled to undergo a chemotherapy regimen of 5-fluorouracil (5-FU), Adriamycin, and cyclophosphamide (FAC), with or without paclitaxel.

All went through a baseline evaluation prior to beginning chemo.  This included a battery of tests that looked at cognition, mood, and quality of life.

Results: 21% (9 of 42 women) showed cognitive dysfunction on measures of processing speed, executive function, learning and memory.

Patients were given a similar battery of tests during chemo or shortly after completion.

Results: 24 of 37 women (65%) - note, some participants dropped out - demonstrated an acute decline in cognitive functioning

A similar battery of tests 1 year or several months after completing chemo.

Results: 17 of the 28 patients who returned for the late evaluation (61%) showed cognitive decline at end of treatment. The cognitive areas most commonly affected were learning, memory, executive function and processing speed.

Within this group:
12 of those 17 patients (71%) showed a continuous decline since their second evaluation.  5 of those 17 patients (29%) showed a new onset cognitive decline that was not present at their second evaluation.
Previous research from these authors showed that women receiving FAC regimens to treat breast cancer experienced cognitive decline that often did not improve in the year following treatment.  But what's so significant about this study is that they also found a "progressive and delayed cognitive decline that does not appear to be attributable to other interventions."  

In other words, you may feel clear headed during treatment only to experience "chemo brain" months later.  And at least in this study, the fog could get worse after treatment.  Not a happy thought.

*Jeffrey S. Wefel, PhD, et al., "Acute and late onset cognitive dysfunction associated with chemotherapy in women with breast cancer," journal Cancer, 28 Apr 2010.


  1. It would have been interesting to hear what these women had been doing in the mean time. I experienced something like "chemo brain" half a year after treatment, but I can track it down to severe stress, since I was working again. When the stress dissipated, so did the chemo brain.

  2. Juliane, I'm glad that your "chemo brain" dissipated. At least in studies of breast cancer and lymphoma patients, about half of participants report returning to their pre-diagnosis cognitive functioning within one year after end of treatment. We know that stress (and depression) can cloud memory too. In any event, it's great that you're better.