MONDAY, March 9 (HealthDay News) -- Treatment with a combination of the chemotherapy drug temozolomide and radiotherapy increases survival for glioblastoma brain tumor patients better than radiotherapy alone, and the improvement persists for up to five years, say Swiss researchers.

Glioblastoma is the most common and aggressive form of primary brain tumor. For more than three decades, surgery followed by radiotherapy was the standard treatment for glioblastoma, but the average life expectancy was just nine to 12 months.

In 2004, a study reported that combined treatment with temozolomide and radiotherapy (TMZ/RT) reduced glioblastoma patients' risk of dying by 37 percent, compared with radiotherapy alone. Two years after treatment, 27 percent of those who had received TMZ/RT were alive, compared with 10 percent who had received radiotherapy alone.

But it wasn't known whether this survival benefit would persist over time.

In the new study, a team at the University of Lausanne Hospitals looked at the long-term outcomes of people in the large international trial. Three years after treatment, 16 percent of those in the TMZ/RT group were still alive, compared with 4 percent of the radiotherapy only group. Survival was 12.1 percent and 3 percent, respectively, after four years, and 9.8 percent and 1.9 percent after five years.

The improvements in survival among people who received TMZ/RT were seen across all subgroups, including people considered to have a poor prognosis, such as more elderly people and those whose tumor could not be surgically removed.

The study was published online and in the May print issue of The Lancet Oncology.

The researchers suggested that testing tumors for the methylation status of the MGMT gene would identify people most likely to benefit from TMZ/RT. Though this combination treatment can prolong survival, it is not a cure, they noted.

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