The results of a large clinical trial show that a drug for treating the most common brain tumor in adults can prolong survival among some patients by several months when given concurrently with radiation.

In the randomized trial, 573 Canadian and European patients with glioblastoma received either radiation plus the drug temozolomide (Temodar) or radiation alone. Patients who received temozolomide lived, on average, 2.5 months longer than those who received radiation alone, according to results reported in the March 10 New England Journal of Medicine.

Glioblastoma kills most patients within a year of diagnosis, and there have been few advances in treatment in recent decades.

"The new approach is a modest but important improvement in the treatment of the disease," says Dr. Gregory Cairncross of the University of Calgary, Canada, a co-leader of the study. "It's a treatment we'll be using until we find something better."

Though the increase in survival is only several months, it represents a "substantial step forward" in the treatment of the disease, says Dr. Lisa DeAngelis, chairman of the Department of Neurology at Memorial Sloan-Kettering Cancer Center in New York.

"This is the first time any drug has shown a significant effect on outcome for this disease," explains Dr. DeAngelis. "But I don't want people to think that we are curing these tumors. I wish that were so, but we're not there yet."

Memorial Sloan-Kettering and some other cancer centers, including the National Cancer Institute (NCI), are already using the experimental strategy. Dr. Howard Fine, chief of NCI's Neuro-Oncology Branch, and his colleagues have used it for several years, and he welcomes the new findings as confirmation of their approach.

"The power of this clinical trial is clear, and it is my hope that this will be the new standard of treatment for this tumor," says Dr. Fine. "The bad news is that the median survival was only increased by 2.5 months and 74 percent of the patients taking temozolomide died within 2 years."

He cautions: "All of our new approaches will build on this new treatment strategy, but we need to keep the results in perspective."

In a related study, also in the March 10 New England Journal of Medicine, European and Canadian researchers, led by Dr. Roger Stupp of University Hospital in Lausanne, Switzerland, identified a gene that may be associated with the responsiveness to temozolomide and could potentially be a biological "marker" to indicate response to the therapy.

The researchers report that patients who benefited from taking temozolomide plus radiation tended to have tumors in which a key gene - called MGMT - had been "silenced" by the addition of a chemical to the gene, a naturally occurring process known as methylation.

If further studies confirm the finding, doctors could one day identify patients who may benefit from the therapy by testing the MGMT gene to learn whether or not it has been silenced. Testing the gene, however, is difficult, and as yet no widely available test exists.

A third study in the March 10 New England Journal of Medicine focused on treating the most common brain tumor in children, medulloblastoma. German researchers found that young children who received chemotherapy alone following surgery for their tumors could achieve long remissions and avoid the radiation therapy that can cause permanent brain damage.

"This study is further confirmation that some very young children can be spared the toxic effects of cerebrospinal radiation, and that a certain percentage of them will be long-term, disease-free survivors," says Dr. Fine.

By Edward R. Winstead