Birgit[a]
The Lancet 2002;360:1361-1368.
Brain cancer treatment can impair mental function
Treatments for a certain type of brain tumor may have detrimental effects on patients´ long-term mental functioning, new study findings suggest.
The researchers discovered that patients who received antiepileptic drugs and high doses of radiation therapy to treat their low-grade, or relatively less serious, brain tumors appeared to have more trouble with memory and attention than cancer patients who didn´t receive those treatments.
Patients who had previously been diagnosed with brain tumors also showed greater mental impairments than patients with non-brain tumors. The current study indicates that the majority of mental decline stems from the tumor, and not the treatment, according to Dr. Martin Klein of Vrije Universiteit Medical Centre in Amsterdam, the Netherlands, and his colleagues.
However, Klein´s team notes, patients diagnosed and treated for low-grade brain tumors called gliomas have a strong chance of surviving many years, and the long-term effects of the treatments they are given should be investigated.
"Our findings suggest that the tumour itself has the most deleterious effect on cognitive function and that radiotherapy mainly results in additional long-term cognitive disability when high fraction doses are used," Klein and colleagues write in the November 2nd issue of The Lancet. "Additionally, the effects of other medical factors, especially antiepileptic drug use, on cognitive function in glioma patients deserve attention."
The investigators obtained their findings from tests of mental functioning in 195 patients with a low-grade glioma, of whom more than half had been given radiotherapy up to 22 years earlier. To compare their results to others, the research team also tested 100 patients diagnosed with low-grade blood cancers, and 195 people who had no history of cancer.
All glioma patients--whether they had received radiation or not--performed worse on the tests than other cancer patients, and the discrepancy increased when glioma patients were compared with those who had never had cancer.
However, glioma patients who had never received radiation therapy outperformed those who had, the report indicates--especially those patients who were given relatively high doses. Patients who received antiepileptic drugs to control their seizures also fared less well in the mental functioning tests than those who did not receive the drugs.
Based on these findings, the authors recommend that doctors avoid giving radiotherapy to younger patients in the early stages of glioma, since, at this point, the benefits of the treatment remain unclear. And if radiotherapy is needed, Klein and his team suggest that doctors stick with a relatively low dose.
2002-11-01 (Reuters Health)