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Treatment of brain malignancies and other brain lesions: Emergence of stereotactic radiosurgery
Al Taira, M.D.Dorothy E. Schneider Cancer CenterWestern Radiation Oncology
Starting point: Surgical resection
Therapeutic and diagnostic
Surgical considerations
Urgency Ambiguity of diagnosis
Invasive Recovery time / perioperative morbidity Caution near eloquent and other critical
brain structures Extent of surgery Patient performance status
The innovator
A neurosurgeon from Sweden, Dr. Lars Leskel, worked for years to develop a non-invasive means for “surgically” treating brain tumors.
Established fundamental premise of radiosurgery
High dose to target with low dose to surrounding normal tissue.
Gamma Knife limitations
• Limited to single fraction treatments• Brain tumors only• Long treatment times and some discomfort
Next step: CyberKnife
Dr. John Adler, another neurosurgeon, pioneered the next breakthrough in stereotactic radiosurgery.
CyberKnife
Advantages (vs Gamma Knife)No head frame requiredCan treat lesions in brain AND rest of body
LimitationsLong treatment timesLimited to only radiosurgery treatments
The newest generation
Mills has just installed a state-of-the- art TrueBeam Varian linear accelerator developed to optimize stereotactic radiosurgery
-frameless -brain and body SRS -dramatically reduced treatment times -optimized to deliver highest quality radiosurgery and IMRT plans
Brain metastases
Approximately 150,000 - 200,000 new cases per year.
~10% of cancer patients will develop symptomatic brain metastases
Primary lung cancers are most common source of brain metastases. Increasing incidence of women with breast cancer developing brain metastases due to improvement in systemic therapy.
With improved identification and treatment of brain metastases, most patients improve after treatment and do not die from these metastatic lesions.
Historic standard: Whole brain radiotherapy
Treat entire brain parenchyma.
Target known lesions and potential micrometastases.
Improved survival versus observation/steroids-alone
Whole brain radiotherapy drawbacks
Fatigue
Hair loss
Risk of decreased cognitive functioning
Risk of decreased overall HRQoL
2-3 weeks of daily treatments
Can we treat initially with SRS instead?
Aoyama (JAMA 2006) SRS +/- WBRTNo difference in overall survival or initial MMSE.
Chang (Lancet Oncology 2009) SRS +/- WBRTInferior neurocognitive outcome and lower OS with WBRT.
Soffietti (JCO 2013) SRS (or surgery) +/- WBRTInferior HRQoL with WBRT. No difference in OS.
WBRT versus SRS dose distribution
Whole brain radiotherapy Stereotactic radiosurgery
2-3 weeks / daily treatments single short treatment
Shifting paradigm
53 year old woman with history breast cancer who completed breast conservation and adjuvant treatment 2.5 years ago. Now with 3 small brain metastases.
Original diagnosis disease-free
interval
Brainmetastases
WBRT
Traditional paradigm
Original diagnosis disease-free
interval
Brainmetastases
SRS
Emerging paradigm
disease-freeinterval
If new brainmetastasis
SRSdisease-freeinterval
If more brainmetastases
SRS or WBRT
Criteria for WBRT versus SRS
• Disease free interval
• Number of new metastases
• Extra-cranial disease control
• Patient performance status
Multidisciplinary decision-making:Brain metastases management
Medical oncologist
Neurosurgeon
Radiation oncologist
Customizedpatient plan
Patient
SRS
WBRT
Surgery
Supportivecare
Mills intracranial radiosugery program
• Program started upon delivery of TrueBeam
• Builds on many years of WRO radiosurgery experience at other cancer centers with wide range of available technologies
• Close collaboration among medical oncologists, neurosurgeons, radiation oncologists and radiologists
• Strong physics capabilities and support
Radiosurgery capabilities
Brain metastases
Schwannomas
Menigniomas
Pituitary adenomas
Vascular disorders
Functional disorders
Other