Statistics from the 2008 American Cancer Society Registry show that about 1.4 million people are diagnosed with cancer each year and 40% of those patients may develop brain metastasis in their lifetime. Longer patient life expectancies due to improvements in the treatment of cancer appear to be resulting in an increasein the numbers of patients developing cancer-related brain tumors. Surgical resection of brain metastases followed by whole brain radiation therapy (WBRT) has been the mainstay of treatment for patients with a small number of metastatic lesioins. WBRT can provide excellent tumor control. The problem with WBRT is that it can be associated with cognitive decline and memory loss problems, especially in patients that survive 6 months or more after brain radiation treatment. More focused radiation treatment, known as stereotactic radiosurgery, may lessen the undesirable effects of brain radiation by reducing the amount of brain tissue exposed.
A recent study was performed by a group of physicians at the Departments of Radiation Oncology and Neurosurgery, and the Department of Public Health Sciences at the Henry Ford Hospital in Detroit, Michigan. The study was pursued to learn the outcome of treating metastatic brain lesioins with surgical removal of the tumor followed by radiosurgery focused on the tumor bed.
Eighty five patients with brain metastases were treated with surgical resection of at least one lesion followed by radiosurgery alone to the surgical cavity. Overall local control at 11.2 months was 81.2%.
The 6 month, 1 year and 2 year rates of local control were 88.7%, 81.4% and 75.7%. Each patient was followed closely with clinical examinations and radiographic imaging studies every 2-3 months. If new brain metastases were found, local therapy with surgery or stereotactic radiosurgery was used when possible. For multiple recurrences or when more than 3 new lesions developed, WBRT was used as a salvage treatment.
This study also found that longer longevity was associated with a longer time from inital cancer diagnosis to brain metastasis and a solitary brain metastatic lesion.
WBRT was largely avoided in the patients enrolled in the study and only 1/3 of patients ever received it.
The overall conclusion was that radiosurgery withou WBRT after surgical resection of a metastatic brain tumor achieved excellent control. Close imaging follow up allows for early tratment for any recurrence of metastatic disease. Radiosurgery likely reduces the risk of cognitive decline and memory loss associated with WBRT.