NEW YORK (Reuters Health) - As a treatment for high-risk breast cancer patients, chemotherapy with high-dose cyclophosphamide, thiotepa, and carboplatin (CTC) is associated with a drop in cognitive performance over time, new research shows.

Previous reports have shown a drop in cognitive performance among breast cancer survivors treated with certain chemotherapy regimens, the researchers note in the Journal of the National Cancer Institute. However, there was a need to verify this observation in studies and to clarify which regimens produced the greatest cognitive deficits.

Dr. Sanne B. Schagen, from the Netherlands Cancer Institute in Amsterdam, and colleagues used standard tests to compare cognitive function in 28 patients treated with CTC, 39 patients treated with standard-dose 5-FU, epirubicin, and cyclophosphamide, 57 patients who received no chemotherapy, and 60 healthy comparison subjects.

Cognitive function was assessed in cancer patients before and 6 months after treatment (a 12-month interval) and in comparison subjects after a 6-month interval.

At initial testing, cognitive function was comparable in the four groups, the report indicates. At follow-up, however, 25 percent of CTC patients showed worsening cognitive function, while no significant changes occurred in women in the other treatment groups or the healthy subjects.

Executive functions, including skills such as planning, initiating behavior and being able to flexibly change activities, were the cognitive abilities that appeared to be most affected by CTC treatment.

The investigators also note that changes in cognitive function were not influenced by the subjects' menopausal status or reports of fatigue, anxiety or depression.