Current dosing paradigm for stereotactic radiosurgery alone after surgical resection of brain metastases needs to be optimized for improved local control

Int J Radiat Oncol Biol Phys. 2012 May 1;83(1):e61-6. doi: 10.1016/j.ijrobp.2011.12.017.


Purpose: To describe the use of radiosurgery (RS) alone to the resection cavity after resection of brain metastases as an alternative to adjuvant whole-brain radiotherapy (WBRT).

Methods and materials: Sixty-two patients with 64 cavities were treated with linear accelerator-based RS alone to the resection cavity after surgical removal of brain metastases between March 2007 and August 2010. Fifty-two patients (81%) had a gross total resection. Median cavity volume was 8.5 cm(3). Forty-four patients (71%) had a single metastasis. Median marginal and maximum doses were 18 Gy and 20.4 Gy, respectively. Sixty-one cavities (95%) had gross tumor volume to planning target volume expansion of ≥1 mm.

Results: Six-month and 1-year actuarial local recurrence rates were 14% and 22%, respectively, with a median follow-up period of 9.7 months. Six-month and 1-year actuarial distant brain recurrence, total intracranial recurrence, and freedom from WBRT rates were 31% and 51%, 41% and 63%, and 91% and 74%, respectively. The symptomatic cavity radiation necrosis rate was 8%, with 2 patients (3%) undergoing surgery. Of the 11 local failures, 8 were in-field, 1 was marginal, and 2 were both (defined as in-field if ≥90% of recurrence within the prescription isodose and marginal if ≥90% outside of the prescription isodose).

Conclusions: The high rate of in-field cavity failure suggests that geographic misses with highly conformal RS are not a major contributor to local recurrence. The current dosing regimen derived from Radiation Therapy Oncology Group protocol 90-05 should be optimized in this patient population before any direct comparison with WBRT.

MeSH terms

  • Adult
  • Aged
  • Analysis of Variance
  • Brain / pathology
  • Brain / radiation effects
  • Brain Neoplasms / mortality
  • Brain Neoplasms / secondary*
  • Brain Neoplasms / surgery*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Necrosis / pathology
  • Neoplasm Recurrence, Local*
  • Postoperative Period
  • Radiation Injuries / pathology
  • Radiosurgery / adverse effects
  • Radiosurgery / methods
  • Radiosurgery / standards*
  • Radiotherapy Dosage / standards*
  • Retrospective Studies
  • Treatment Failure
  • Tumor Burden
  • Young Adult