Late effects of adjuvant chemotherapy on cognitive function: a follow-up study in breast cancer patients

Background: Neuropsychological examinations have shown an elevated risk for cognitive impairment 2 years after therapy in breast cancer patients randomized to receive adjuvant high-dose cyclophosphamide, thiotepa, carboplatin (CTC) chemotherapy compared with a non-treated control group of stage I breast cancer patients. Patients randomized to receive standard-dose fluorouracil, epirubicin, cyclophosphamide (FEC) chemotherapy showed no elevated risk compared with controls. However, breast cancer patients treated with conventional cyclophosphamide, methotrexate, 5-fluorouracil (CMF) chemotherapy showed a higher risk of cognitive impairment. The present study was designed to obtain a greater insight into these long-term neuropsychological sequelae following chemotherapy and their course in time. Patients and methods: At 4 years post-therapy, 22 of the original 34 CTC patients, 23 of 36 FEC patients, 31 of 39 CMF patients and 27 of 34 control patients were re-examined with neuropsychological tests. Results: Improvement in performance was observed in all chemotherapy groups, whereas in the control group there was a slight deterioration in test results. A differential attrition was observed among the groups, with a relatively high percentage of initially cognitively impaired patients from the CTC group dropping out due to factors related to disease progression. Conclusions: The results suggest that cognitive dysfunction following adjuvant chemotherapy in breast cancer patients may be transient. Additional studies are needed to investigate the differential attrition of patients with cognitive impairment.