The Prevalence of Mild Cognitive Impairment in Breast Cancer Patients Receiving Chemotherapy According to the Criteria of the National Institute on Aging-Alzheimer's Association (NIA-AA)

Purpose: Breast cancer patients receiving chemotherapy can develop cognitive impairment. There is no gold standard for defining cognitive impairment. We applied the National Institute on Aging-Alzheimer's Association (NIA-AA) criteria for mild cognitive impairment (MCI) to determine its prevalence in breast cancer patients receiving adjuvant chemotherapy and examine differences between patients with and without MCI.

Methods: We used pre-existing cognitive data on 5 neuropsychological test outcomes (verbal memory, processing speed, executive functioning, and verbal fluency) gathered from 240 breast cancer patients who received adjuvant conventional (n = 154) or high-dose chemotherapy (n = 86). Assessments occurred 6 or 12 months post-chemotherapy and results were compared with data from 66 women without cancer. MCI was defined by the following: (i) presence of concern regarding a change in cognition, (ii) impairment in one or more cognitive tests (1.5 standard deviation below a normative mean), (iii) preservation of independence in functional abilities, and (iv) the absence of dementia.

Results: Twenty percent (n = 49) of breast cancer patients who received chemotherapy (conventional therapy n = 29 (12%), high-dose therapy = 20 (8.3%)) met the criteria for MCI, compared with 7.6% (n = 5) of controls. Prevalence was significantly different between patients and controls (P = 0.020, and corrected for IQ P < 0.001). Patients with MCI had significant lower education levels (P < 0.002) and premorbid IQ (P = 0.001) compared with patients without MCI.

Conclusions: Twenty percent of breast cancer patients treated with chemotherapy met NIA-AA criteria for MCI, compared with 7.6% of the controls.

Implications For Cancer Survivors: These criteria, which include formal test performance as well as a person's symptoms and functional status, can be useful in clinical practice and scientific research.