NEJM: Stereotactic radiosurgery can help to manage brain metastases
Stereotactic radiosurgery is an appropriate form of therapy for patients who have one to four brain metastases, no larger than 4 cm in diameter, from metastatic cancer, according to an article published March 25 in the New England Journal of Medicine.
John H. Suh, MD, chairman of the department of radiation oncology at the Cleveland Clinic, wrote that stereotactic radiosurgery appears to be effective for all types of primary tumors, even those that have been considered to be resistant to conventional radiation therapy.
The three most common radiation-therapy devices used in stereotactic radiosurgery are cobalt-60–based machines, linear accelerators and cyclotrons, which use gamma rays, x-rays and protons, respectively.
Since the radiation beams are focused on the tumor, shielding to prevent scatter is not required. "In some cases, normal brain structures such as the optic nerves or chiasm should be shielded or avoided to minimize the dose to these sensitive structures," noted Suh.
The doses typically used are 1500 to 2400 cGy, which are biologically equivalent to five to six weeks of daily conventional radiation therapy and depending on the location, number, and size of lesions, the typical treatment time can vary from 30 minutes to three hours, added Suh.
The costs of stereotactic radiosurgery vary on the basis of the technology used, number of lesions treated, and institutional fee for the procedure. “Estimated Medicare costs for stereotactic radiosurgery are $10,000 to $27,000 per procedure, as compared with $2,300 to $7,650 for wholebrain radiation therapy,” said Suh.
Advantages of surgery are:
• Treatment of larger lesions (larger than 4 cm in diameter);
• Rapid resolution of mass effect and edema;
• Removal of cancer, histological confirmation of cancer;
• Rapid tapering of the dose of corticosteroids used to treat symptomatic lesions; and
• Less intensive follow-up and lower risk of radiation necrosis when combined with whole-brain radiation therapy.
Advantages of stereotactic radiosurgery are:
• Treatment of small, deep lesions or eloquent areas;
• Minimally invasive or noninvasive approach;
• Outpatient procedure and general anesthesia is not required;
• Treatment of multiple lesions during same session; and
• Short recovery time (less than one week), potential avoidance of whole-brain radiation therapy and rapid initiation of systemic therapies.
Whole-brain radiation therapy may be administered before or after stereotactic radiosurgery. According to Suh, the most important area of uncertainty in the use of stereotactic radiosurgery concerns whether or not to include whole-brain radiation therapy in the management plan.
The National Comprehensive Cancer Network recommends that stereotactic radiosurgery be considered for patients with a limited number of brain metastases (one to four) who have stable, systemic disease or reasonable systemic treatment options and for patients who have a small number of metastatic lesions in whom whole-brain radiation therapy has failed.
Suh concluded that since institutional practice will help determine treatment approach (surgery vs. no surgery), the best means of management is participation of the patient in a clinical trial. If a patient is not interested in participating in a clinical study, Suh recommended whole-brain radiation therapy followed by stereotactic radiosurgery, rather than stereotactic radiosurgery alone, to minimize the risk of progression of local and distant brain disease.
John H. Suh, MD, chairman of the department of radiation oncology at the Cleveland Clinic, wrote that stereotactic radiosurgery appears to be effective for all types of primary tumors, even those that have been considered to be resistant to conventional radiation therapy.
The three most common radiation-therapy devices used in stereotactic radiosurgery are cobalt-60–based machines, linear accelerators and cyclotrons, which use gamma rays, x-rays and protons, respectively.
Since the radiation beams are focused on the tumor, shielding to prevent scatter is not required. "In some cases, normal brain structures such as the optic nerves or chiasm should be shielded or avoided to minimize the dose to these sensitive structures," noted Suh.
The doses typically used are 1500 to 2400 cGy, which are biologically equivalent to five to six weeks of daily conventional radiation therapy and depending on the location, number, and size of lesions, the typical treatment time can vary from 30 minutes to three hours, added Suh.
The costs of stereotactic radiosurgery vary on the basis of the technology used, number of lesions treated, and institutional fee for the procedure. “Estimated Medicare costs for stereotactic radiosurgery are $10,000 to $27,000 per procedure, as compared with $2,300 to $7,650 for wholebrain radiation therapy,” said Suh.
Advantages of surgery are:
• Treatment of larger lesions (larger than 4 cm in diameter);
• Rapid resolution of mass effect and edema;
• Removal of cancer, histological confirmation of cancer;
• Rapid tapering of the dose of corticosteroids used to treat symptomatic lesions; and
• Less intensive follow-up and lower risk of radiation necrosis when combined with whole-brain radiation therapy.
Advantages of stereotactic radiosurgery are:
• Treatment of small, deep lesions or eloquent areas;
• Minimally invasive or noninvasive approach;
• Outpatient procedure and general anesthesia is not required;
• Treatment of multiple lesions during same session; and
• Short recovery time (less than one week), potential avoidance of whole-brain radiation therapy and rapid initiation of systemic therapies.
Whole-brain radiation therapy may be administered before or after stereotactic radiosurgery. According to Suh, the most important area of uncertainty in the use of stereotactic radiosurgery concerns whether or not to include whole-brain radiation therapy in the management plan.
The National Comprehensive Cancer Network recommends that stereotactic radiosurgery be considered for patients with a limited number of brain metastases (one to four) who have stable, systemic disease or reasonable systemic treatment options and for patients who have a small number of metastatic lesions in whom whole-brain radiation therapy has failed.
Suh concluded that since institutional practice will help determine treatment approach (surgery vs. no surgery), the best means of management is participation of the patient in a clinical trial. If a patient is not interested in participating in a clinical study, Suh recommended whole-brain radiation therapy followed by stereotactic radiosurgery, rather than stereotactic radiosurgery alone, to minimize the risk of progression of local and distant brain disease.