Background: Chemotherapy-induced cognitive dysfunction in patients with breast carcinoma has been described previously. However, those studies only assessed patients' postchemotherapy cognitive functioning and were not able to determine the relation between cognitive function and other treatments, such as surgery and radiotherapy, that often precede systemic chemotherapy.

Methods: Eighty-four women with breast carcinoma underwent a comprehensive neuropsychologic evaluation before receiving adjuvant therapy for nonmetastatic primary breast carcinoma.

Results: Before the start of systemic therapy, 35% of women in the current cohort exhibited cognitive impairment. Verbal learning (18%) and memory function (25%) were impaired significantly more frequently relative to normative expectations. Although the impairments were not significant in the women who were examined, nonverbal memory (17%), psychomotor processing speed and attention (13%), confrontational naming (13%), visuoconstruction (13%), and upper-extremity fine motor dexterity (12%) were impaired more frequently than was expected. Affective distress was related significantly to cognitive impairment (Pearson chi-square = 9.90; P = 0.002). Given the conservative statistical approach employed, extent of surgery, hormone replacement therapy history, and current menopausal status failed to achieve statistical significance, but these variables did exhibit provocative trends with respect to cognitive impairment.

Conclusions: Cognitive impairment frequently is observed before the administration of systemic chemotherapy. Thus, investigations purporting to measure chemotherapy-induced cognitive dysfunction must employ study designs that incorporate prechemotherapy baseline assessments to accurately detect changes in cognitive function that are attributable to chemotherapy.