Effects of High-Dose and Conventional-Dose Adjuvant Chemotherapy on Long-Term Cognitive Sequelae in Patients with Breast Cancer: An Electrophysiologic Study

• Published in: Clinical breast cancer 2006-04, Vol.7 (1), p.67-78
• Main Authors: Kreukels, Baudewijntje P.C., Schagen, Sanne B., Ridderinkhof, K. Richard, Boogerd, Willem, Hamburger, Hans L., Muller, Martin J., van Dam, Frits S.A.M.
• Format: Article
• Language: English
• Subjects: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols - adverse effects; Antineoplastic Combined Chemotherapy Protocols - therapeutic use; Breast Neoplasms - drug therapy; Breast Neoplasms - mortality; Breast Neoplasms - pathology; Breast Neoplasms - surgery; Central Nervous System - drug effects; Chemotherapy, Adjuvant - adverse effects; Cognition Disorders - chemically induced; Cognition Disorders - diagnosis; Cognitive deficits; Cross-Sectional Studies; Dose-Response Relationship, Drug; Drug Administration Schedule; Electrophysiology; Female; Follow-Up Studies; Humans; Information processing; Long-term side effects; Mastectomy, Segmental - methods; Middle Aged; Neoplasm Staging; Neurotoxicity; Probability; Reference Values; Retrospective Studies; Risk Assessment; Survival Rate
• ISSN: 1526-8209; 1938-0666
• DOI: 10.3816/CBC.2006.n.015

The mechanisms underlying cognitive deficits found in a number of patients with breast cancer treated with adjuvant chemotherapy are still unclear. In the current study, we used a combination of measures of brain electric activity and cognitive performance during information processing to elucidate the origin of these cognitive deficits. Twenty-nine patients at high risk with breast cancer treated with adjuvant conventional-dose cyclophosphamide/epirubicin/5-fluorouracil or adjuvant high-dose cyclophosphamide/thiotepa/carboplatin were compared with 23 patients with stage I breast cancer not treated with chemotherapy approximately 4 years after completion of treatment. We studied reaction times and the amplitudes and latencies of the P3, an electrophysiologic index of information processing, in a task with different conditions related to input, central, and output processing of information. The amplitude of the P3 component was significantly reduced in patients with breast cancer treated with high-dose cyclophosphamide/thiotepa/carboplatin compared with patients with breast cancer not treated with chemotherapy. We observed no significant differences in reaction times and P3 latency between the treatment groups. Our data show electrophysiologic alterations in patients with breast cancer treated with high-dose chemotherapy 4 years after completion of treatment. The observed P3 reduction might be a result of suboptimal phasic cortical arousal and problems with the allocation of processing resources in these patients.