(Reuters Health)

"By Will Boggs, MD

NEW YORK (Reuters Health) - Rather than having a harmful effect on brain function, radiotherapy for low-grade glioma brain tumors -- one of the most difficult types of cancer to treat -- can restore cognitive function to its pre-tumor level, a study shows.

"Using modern techniques with moderate total doses, 3-D conformal radiotherapy, and advanced planning imaging and software, the risks of neurocognitive deficits in low-grade glioma patients are quite small and greatly overshadowed by the deficits caused by the tumor itself," Dr. Paul D. Brown from Mayo Clinic, Rochester, Minnesota told Reuters Health.

Brown and colleagues administered a battery of cognitive tests before and after radiotherapy in 20 patients with low-grade glioma. These brain tumors tend to be slow growing but can quickly change into a much more aggressive and deadly tumor.

At baseline, overall cognitive performance was lower than that for age-specific normative standards, the investigators report.

By the second evaluation, a medium 18.3 months after the first, mean test scores were higher than the initial scores for all psychometric measures.

None of the 20 patients experienced significant decline in cognitive function over the follow-up period, regardless of whether they received high-dose or low-dose radiotherapy, the team reports in the International Journal of Radiation Oncology, Biology, Physics.

"Our data is reassuring in that properly administered radiotherapy is well-tolerated and associated with a low risk of cognitive impairment for patients in whom it is indicated," Brown said. "

SOURCE: International Journal of Radiation Oncology, Biology and Physics, November 15, 2005.