title: Stereotactic irradiation of the postoperative resection cavity for brain metastasis: a frameless linear accelerator-based case series and review of the technique.
abstract: OBJECTIVE
  Whole-brain radiation therapy (WBRT) is the standard of care after resection of a brain metastasis. However, concern regarding possible neurocognitive effects and the lack of survival benefit with this approach has led to the use of stereotactic radiosurgery (SRS) to the resection cavity in place of WBRT. We report our initial experience using an image-guided linear accelerator-based frameless stereotactic system and review the technical issues in applying this technique.
  
  
  METHODS
  We retrospectively reviewed the setup accuracy, treatment outcome, and patterns of failure of the first 18 consecutive cases treated at Brigham and Women's Hospital. The target volume was the resection cavity without a margin excluding the surgical track.
  
  
  RESULTS
  The median number of brain metastases per patient was 1 (range, 1-3). The median planning target volume was 3.49 mL. The median prescribed dose was 18 Gy (range, 15-18 Gy) with normalization ranging from 68% to 85%. In all cases, 99% of the planning target volume was covered by the prescribed dose. The median conformity index was 1.6 (range, 1.41-1.92). The SRS was delivered with submillimeter accuracy. At a median follow-up of 12.7 months, local control was achieved in 16/18 cavities treated. True local recurrence occurred in 2 patients. No marginal failures occurred. Distant recurrence occurred in 6/17 patients. Median time to any failure was 7.4 months. No Grade 3 or higher toxicity was recorded. A long interval between initial cancer diagnosis and the development of brain metastasis was the only factor that trended toward a significant association with the absence of recurrence (local or distant) (log-rank p = 0.097).
  
  
  CONCLUSIONS
  Frameless stereotactic irradiation of the resection cavity after surgery for a brain metastasis is a safe and accurate technique that offers durable local control and defers the use of WBRT in select patients. This technique should be tested in larger prospective studies.
authors.affiliation: Department of Radiation Oncology, Dana-Farber/Brigham and Women's Cancer Center, Boston, MA 02115, USA. pkelly@lroc.harvard.edu
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Kelly
authors.forename: Yijie Brittany
authors.initials: YB
authors.lastname: Lin
authors.forename: Alvin Y
authors.initials: AY
authors.lastname: Yu
authors.forename: Brian M
authors.initials: BM
authors.lastname: Alexander
authors.forename: Fred
authors.initials: F
authors.lastname: Hacker
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Marcus
authors.forename: Stephanie E
authors.initials: SE
authors.lastname: Weiss
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001900:Boston; D001932:Brain Neoplasms / Q000175:diagnosis / Q000401:mortality / Q000473:pathology / Q000556:secondary* / Q000601:surgery*; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis / Q000556:secondary / Q000601:surgery; D016371:Cranial Irradiation / Q000379:methods; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000473:pathology; D008297:Male; D008545:Melanoma / Q000175:diagnosis / Q000556:secondary / Q000601:surgery; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis; D010315:Particle Accelerators; D011182:Postoperative Care / Q000379:methods; D016634:Radiosurgery / Q000295:instrumentation / Q000379:methods*; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D015996:Survival Rate; D013997:Time Factors; D017211:Treatment Failure; D016896:Treatment Outcome; D047368:Tumor Burden