Whole Brain Radiation Doesn't Aid Brain Cancer Survival
But the therapy does prevent new tumors from developing, study finds
TUESDAY, June 6, 2006 (HealthDay News) -- Whole brain radiation therapy along with more targeted radiation therapy doesn't improve survival in patients whose cancer has migrated to the brain, but it may improve their quality of life by preventing the return of tumors and the loss of brain function, Japanese researchers report.
The report appears in the June 7 issue of the Journal of the American Medical Association.
Brain metastases, tumors in the brain due to spread of cancers elsewhere in the body, occur in 20 percent to 40 percent of all patients with cancer and are associated with poor outcomes.
Many physicians believe that, in brain metastases, the entire brain is seeded with micrometastatic disease, even if only a single brain lesion is found. Whole brain radiation therapy (WBRT) has been the recommended treatment. However, the assumption that the entire brain is seeded with micrometastases has been called into question.
For patients who have limited intracranial disease, the potential exists that WBRT could be replaced by targeted treatment, such as surgical resection or stereotactic radiosurgery (SRS), which delivers high-dose, targeted radiation and has less long-term adverse effects than WBRT.
It has been unclear whether adding WBRT to SRS improves survival or neurologic function compared with SRS alone.
"The omission of WBRT has no impact on survival in patients with one to four brain metastases, but intracranial relapse occurs considerably more frequently," said lead researcher Dr. Hidefumi Aoyama, from Hokkaido University Graduate School of Medicine in Sapporo.
However, no significant difference in the frequency of death due to neurologic causes was seen, Aoyama added. "Therefore, SRS alone could be a treatment option, provided that frequent monitoring of brain tumor status is conducted," he said.
To reach this conclusion, Aoyama's team studied 132 patients who were randomly assigned to receive WBRT plus SRS or SRS alone. The researchers found that the median survival time was 7.5 months in patients who received both treatments compared with 8.0 months for patients given SRS alone.
However, at one year, the brain tumor recurrence rate was only 46.8 percent in the WBRT plus SRS group, compared with 76.4 percent for SRS alone group, the researchers found.
"The omission of WBRT obviously increased the risk of intracranial recurrence, therefore, it would be reasonable that the standard treatment would be WBRT with or without SRS," Aoyama said.
The standard treatment is not necessarily the only one, however, Aoyama said.
"We should take into account the patient's background. For example, if the patient does not pursue frequent hospital visits anymore after the treatment, we should recommend WBRT plus SRS," he said. "But, if the patient is afraid of the potential risk of neurocognitive deterioration, SRS alone can be a treatment option. However, in this case, we should explain to the patient the risk of intracranial recurrence and the necessity of frequent MRI scan." \
One expert thinks that the survival data in the study is its least interesting finding.
"We have all been interested in the results of this study," said Dr. Theodore S. Lawrence, the chairman of radiation oncology at the University of Michigan. "This is the first trial that shows what WBRT adds to SRS," he added.
It has been known that the cancer outside the brain, which led to the brain tumors, is the determining factor in survival, Lawrence said. "Most patients die of disease outside the brain," he said. "As treatments for these cancers get better, treatment for brain metastases will also get better, but we are just not at that level yet," he said.
The real concern was whether patients would have a recurrence of brain tumors after treatment, and whether WBRT leads to more neurological problems than SRS alone, Lawrence said. "This study conclusively shows that WBRT decreases the risk of getting new tumors," he said.
The reason that WBRT has been called into question is that it can have severe side effects, Lawrence said. "But, in this paper, there wasn't any clear evidence of important toxicity," he added.
"These findings suggest that the disease is worse than the treatment," he noted. "There was a significant decrease in neurologic function in the group that just got SRS."
"This study suggests that the toxicity of tumors coming back is more important than the toxicity of the WBRT," Lawrence added. "My opinion is the SRS plus WBRT is the best approach, if one is seeking not to have deterioration in brain function."
The American Cancer Society can tell you more about brain cancer.