Cancer treatment and memory loss.

Researchers from the Netherlands have some bad news for women considering very high doses of chemotherapy to combat breast cancer. Frits S.A.M. van Dam of the Netherlands Cancer Institute in Amsterdam and his colleagues report that high doses of toxic chemotherapeutic drugs may raise the risk of cognitive deficits.

Van Dam's team studied 34 breast cancer patients treated with high doses of chemotherapy plus the hormonal drug tamoxifen, 36 patients who received the standard dose of chemotherapy plus tamoxifen, and a control group of 34 breast cancer patients who did not get chemotherapy or tamoxifen. The patients had been assigned at random to these groups.

About 2 years after therapy was completed, the researchers administered a standardized test to assess cognitive functioning. They discovered that 32 percent of women given high-dose chemotherapy had cognitive deficits, including memory lapses and difficulty concentrating. In contrast, 17 percent of the women who had received the standard doses of chemotherapy showed such deficits. Just 9 percent of the control patients had cognitive impairments.

The researchers suspect that chemotherapy is behind the cognitive impairments but say that tamoxifen may play a role as well. None of the women had experienced such lapses before the cancer treatment, they note.

High-dose chemotherapy is being increasingly recommended to women treated for breast cancer. Such treatment aims to rout all the cancer, thus giving patients a better shot at survival. The researchers warn against taking side effects lightly. "Long-term cerebral impairment, even when relatively subtle, may have profound consequences for the daily life of patients," they report in the Feb. 4 Journal of the National Cancer Institute.