Phase I Trial of Stereotactic Radiosurgery Following Surgical Resection of Brain Metastases

Brain metastases are the most common adult intracranial tumor, occurring in approximately 10% to 30% of adult cancer patients, and represent an important cause of morbidity and mortality in this population. The standard of care for solitary brain metastasis is surgery followed by whole brain radiation therapy (WBRT). Without WBRT, there are unacceptably high levels of local failure that occur. Local recurrence rates ranged from approximately 45% at 1 year to 60% at 2 years after resection alone. However, aside from improvements in intra-cranial control, it is well documented that WBRT is associated with serious long term side effects, including significant decline in short term recall by as early as 4 months after treatment. Many centers are now offering patients stereotactic radiosurgery (SRS) to the cavity after resection alone to improve local control while avoiding the negative effects of WBRT. There have been several retrospective studies on the use of SRS to the resection cavity alone, from which the 1 year actuarial local control rates range from 35% - 82%. The high rate of in-field local failure suggests that the current dosing regimen used may not be high enough for adequate local control. Currently, the highest local control rates are approximately 80%, but there may be room for improvement with increased dose without significantly increasing the risk of side effects. The investigators propose a trial for patients after surgical resection of solitary brain metastases. The purpose of this trial will be to determine the maximum tolerated dose for single fraction SRS to the resection cavity. There will be three groups based on the resection cavity size. Dose escalation enrollment will be done sequentially within each cohort. You will know which cohort and which specific dose level you are randomized to. After treatment, which will take one day, regardless of cohort, you will be followed closely for treatment outcome and possible side effects. You will be asked to complete three quick surveys at each follow-up appointment regarding quality of life and memory in addition to standard of care surveillance brain MRI and physical exam.

Sex

All

Minimum age

18 Years

Inclusion Criteria:

* Pathologic proven diagnosis of solid tumor malignancy
* Age ≥ 18
* RPA class I or class II
* Mini Mental Status Exam (MMSE) ≥ 18 prior to study entry
* Karnofsky Performance Status ≥ 70%
* Single brain metastasis status post surgical resection with ≤ 1 cc of residual enhancing tumor
* Up to 2 additional intact brain metastases to be treated with stereotactic radiosurgery (SRS) alone
* Resection cavity volume on planning scan of ≤ 35 cc
* First presentation of brain metastases
* Post-operative MRI within 72 hours of surgical resection

Exclusion Criteria:

* Previous brain radiotherapy (SRS or WBRT)
* RPA class III
* Resection cavity volume \> 35 cc
* Radiosensitive or non-solid (eg. small cell lung carcinomas, germ cell tumors, leukemias, or lymphomas) or unknown tumor histologies
* Concurrent chemotherapy (no chemotherapy starting 14 days before start of radiation to 14 days after completion of radiation)
* Evidence of leptomeningeal disease by MRI and/or CSF cytology
* Current pregnancy
* More than 8 weeks between resection and radiosurgical procedure
* No metastases to brain stem, midbrain, pons, or medulla or within 7 mm of the optic apparatus (optic nerves and chiasm)
* Inability to undergo MRI evaluation for treatment planning and follow-up

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