Patients with cancer can be divided into those with local disease only (ie cancer only in one organ) and those with cancer that has spread to other organs (metastatic). Brain metastases are cancer cells that have spread to the brain from the body and are growing there. They typically occur months after the development of metastases elsewhere in the body although they can be the first site of spread in 15% of patients. While any cancer can spread to the brain, the cancer types that most commonly spread to the brain are lung cancer, breast cancer, melanoma, kidney and colon cancer. More recently, however, there has been an increasing number of patients with gynecological and urological cancers that have also been found to have brain metastases.
Find answers to some frequently asked questions below.
Brain metastases can cause neurological symptoms such as headache, seizures, motor weakness, changes in sensation, or difficulty with thinking, talking, walking or seeing depending on which part of the brain the metastases are growing. Many times, in order to avoid the development of symptoms, MRIs or CT scans of the brain can be performed to try and detect brain metastases when they are small and before they cause symptoms. These scans are called screening tests because they are done to look and see even though patients do not have symptoms. MRI scanning is much more sensitive than CT scan and therefore more likely to detect the metastases when they are smaller.
Because most patients do not undergo routine screening scans, the meaning of finding of something abnormal can be variable. A diagnosis of brain metastasis cannot be made based on MRI or CT scan alone. In the setting of known metastatic cancer elsewhere in the body, however, it would be reasonable to presume that the abnormality in the brain is also related to the cancer.
Because of the uncertainty of diagnosis, all patients with newly found brain lesions should be seen by a Neurosurgeon prior to treatment. In general, if there is more than one lesion or if there was a recent prior scan that did not show the lesion then the diagnosis of brain metastasis is most likely. In the case of a single lesion, in the setting of metastatic cancer in the body, the diagnosis of brain metastasis is still most likely although there is a higher chance of error in diagnosis and biopsy (taking a sample) may be needed to make the right diagnosis.
The treatment of cancer has changed significantly over the last decade. The diagnosis of brain metastases previously predicted an average survival of 6-8 months from diagnosis because it represented the end course of cancer. Today, with many new treatments available, the average survival in some patients can be extended to years and for some, there is even the possibility of remission. The prognosis of patients with brain metastases today is not the same as it was even a decade ago.
The management of brain metastases has changed significantly over the past decade. Options for treatment of brain metastases now include radiosurgery, radiation therapy, surgery, and novel medicines through clinical trials.
Whole Brain Radiation Therapy (WBRT) has been standard of care treatment for brain metastases since the 1970s. It is radiation to the whole brain delivered in small doses each day over a 2-3 week period. It can cause loss of hair, loss of appetite, fatigue and long-term difficulty with memory and dementia-like symptoms. It remains standard of care at many facilities today because it provides comprehensive treatment to all cancer cells in the brain regardless of whether they can be detected by imaging (MRI or CT brain) or not. WBRT however is typically only used once in each patient’s lifetime as the dose delivered is limited by the amount of radiation that the normal brain cells can tolerate.
Radiosurgery is the delivery of radiation focused to the area of the tumors thereby sparing most of the normal brain. Here at Yale we use the Gamma Knife machine to deliver brain radiosurgery. Treatment accuracy is guaranteed by the use of a targeting frame and brain imaging, treatment planning and treatment delivery is achieved all in one day. There is no absolute limit to the number of lesions that can be treated at one time and we routinely treat patients with multiple brain metastases. Because of the ability to limit dose of radiation to the normal brain, higher doses of radiation to the tumor can be delivered compared to WBRT and relatively radio-resistant cancers such as melanoma, renal cell cancer and sarcomas respond well to radiosurgery.
To decide if WBRT or radiosurgery is right for you, a joint consult with our Neurosurgeons and Radiation Oncologists can be set up to discuss your case with you.
Conventional neurosurgery may be required in the following situations:
- There is a single spot in the brain and no other disease in the body is found. Surgery would therefore be done to make a diagnosis.
- The spot in the brain (or one of the spots) is large and causing symptoms and is surgically accessible. Surgery is the fastest and best method for removing cancer and thereby relieving symptoms. Surgery is rarely able to remove all the cancer cells, however, and often needs to be followed by some form of radiation.
- Symptoms develop after radiation therapy or radiosurgery.
- The spot regrows on CT/MR imaging after radiation therapy or radiosurgery. Regrowth of the spot can be due to the cancer re-growing or if it might be related to the effects of radiation (radiation induced inflammation). Standard imaging tests are currently not reliably able to differentiate tumor from radiation necrosis and therefore obtaining tissue is the gold standard for making a diagnosis.
- If the re-growing spot is not easily amenable to standard craniotomy then we offer a unique treatment called Laser Thermal Ablation.
Radiosurgery has become a popular first line treatment for brain metastases. It is usually very effective at stabilizing these tumors in the brain for 6-12 months, but studies here at Yale have shown that if patients survive beyond 9-12 months, it is possible for some of the treated tumors to regrow as seen on follow-up MRI.
Studies here at Yale however have also shown that not all lesions getting bigger on MRI after radiosurgery are tumors regrowing. In about one-third of cases, the enlargement seen on MRI can be a complication of radiation of the normal brain surrounding the original tumor causing an inflammatory reaction that looks like tumor on MRI.
Differentiating tumor regrowth from radiation induced inflammation (also known as radiation necrosis or pseudoprogression) can sometimes be achieved using tests known as FDG-PET and MR spectroscopy. Many times, however, the only means by which to make the diagnosis is surgical biopsy.
If the surgical biopsy shows recurrent tumor then a multidisciplinary plan that could possibly include surgical resection or LTA of the tumor followed by either further radiation or selected chemotherapies could be considered by our Yale multi-disciplinary team.
If the surgical biopsy shows radiation induced inflammation then, in our institutional experience, surgical resection or LTA alone is the most rapid and effective treatment.
LTA is the use of heat emitted from a laser fiber to treat lesions in the brain. It is a cutting edge, minimally invasive technology that allows neurosurgeons to treat lesions inside the skull through a small incision visualized in real time using MRI monitoring. Learn more at MyBrainTumorOptions.com under "Laser Therapy."
As one of the first and longest users of MRI-guided LTA in the USA, Dr Chiang now has 4 years of experience treating a variety of brain tumors and is a national leader in the use of LTA treatment for brain metastases that have regrown following radiosurgery where no other treatment options have been available.
She is currently the lead investigator on a clinical trial studying quality of life in patients with brain metastases regrowing after radiosurgery and the impact of LTA. Dr Chiang also has a significant experience in the use of LTA in conjunction with targeted and immunotherapies especially for lung cancer and melanoma.