J Korean Neurosurg Soc.  2009 May;45(5):275-283. 10.3340/jkns.2009.45.5.275.

Radiosurgery for Recurrent Brain Metastases after Whole-Brain Radiotherapy : Factors Affecting Radiation-Induced Neurological Dysfunction

• Gwak HS
• Yoo HJ
• Youn SM
• Lee DH
• Kim MS
• Rhee CH

• KMID: 1495116
• DOI: http://doi.org/10.3340/jkns.2009.45.5.275

Abstract

OBJECTIVE
We retrospectively analyzed survival, local control rate, and incidence of radiation toxicities after radiosurgery for recurrent metastatic brain lesions whose initial metastases were treated with whole-brain radiotherapy. Various radiotherapeutical indices were examined to suggest predictors of radiation-related neurological dysfunction.
METHODS
In 46 patients, total 100 of recurrent metastases (mean 2.2, ranged 1-10) were treated by CyberKnife radiosurgery at average dose of 23.1 Gy in 1 to 3 fractions. The median prior radiation dose was 32.7 Gy, the median time since radiation was 5.0 months, and the mean tumor volume was 12.4 cm3. Side effects were expressed in terms of radiation therapy oncology group (RTOG) neurotoxicity criteria.
RESULTS
Mass reduction was observed in 30 patients (65%) on MRI. After the salvage treatment, one-year progression-free survival rate was 57% and median survival was 10 months. Age (<60 years) and tumor volume affected survival rate (p=0.03, each). Acute (< or =1 month) toxicity was observed in 22% of patients, subacute and chronic (>6 months) toxicity occurred in 21%, respectively. Less acute toxicity was observed with small tumors (<10 cm3, p=0.03), and less chronic toxicity occurred at lower cumulative doses (<100 Gy, p=0.004). "Radiation toxicity factor" (cumulative dose times tumor volume of <1,000 Gyxcm3) was a significant predictor of both acute and chronic CNS toxicities.
CONCLUSION
Salvage CyberKnife radiosurgery is effective for recurrent brain metastases in previously irradiated patients, but careful evaluation is advised in patients with large tumors and high cumulative radiation doses to avoid toxicity.

Keyword

Brain; Metastasis; Radiotherapy; Toxicity; Radiosurgery; Recurrence

MeSH Terms

Brain
Disease-Free Survival
Humans
Incidence
Neoplasm Metastasis
Radiosurgery
Recurrence
Retrospective Studies
Survival Rate
Tumor Burden