RATIONALE: Photodynamic therapy uses a drug, such as porfimer sodium, that becomes active
when it is exposed to a certain kind of light. When the drug is active, tumor cells are
killed. Giving photodynamic therapy after surgery may kill any remaining tumor cells.
PURPOSE: This randomized clinical trial is studying two different light doses of photodynamic
therapy using porfimer sodium to compare how well they work in treating patients who are
undergoing surgery for recurrent malignant astrocytoma.