Up to 40 percent of patients diagnosed with cancer will develop one or more metastases to the brain, according to a recent medical journal article quoting data from the American Cancer Society Registry. The standard treatment is whole brain radiation therapy (WBRT). Unfortunately, the median survival time after WBRT alone is about three to six months. Therefore, other treatment options are an active area of research. I found 962 clinical trials currently listed on the web site www.clinicaltrials.gov.
A series of papers in the Journal of Neurooncology reviewed the current information on these treatments:
1. Whole brain radiation therapy
2. Traditional surgery to remove the tumor
3. Chemotherapy, recommended in general only for “exquisitely chemosensitive tumors, such as germinomas”
4. Stereotactic radiotherapy, including Gamma Knife and CyberKnife,
5. Prophylactic anticonvulsants (generally not recommended)
6. Steroids (recommended only to relieve symptoms in some cases)
The results of various treatments and combinations depend on factors including the size of the metastatic tumor, the performance status of the patient, and tumor histology. Good performance status is characterized by independent function and less than 50 percent of the patient's time spent in bed. Tumor histology is determined by where the cancer originated. Small cell lung cancer, leukemia, lymphoma, germ cell tumors, and multiple myeloma are all radiosensitive.
Traditional surgery plus whole brain radiotherapy produced a median survival time of 9.5 months in the studies cited below. Stereotactic radiotherapy produced a median survival time of 10.3 months, which was not significantly different for the number of patients in these studies.
Different primary cancers (breast, lung, kidney, etc.) respond very differently to different treatments. Metastases to the brain are also expected to respond differently, depending on what type of tissue they came from. The authors recommend further studies to address the histology type of the brain tumor.
The median survival time, of course, does not limit the possible survival time for any particular patient.