title: Factors influencing early complications following Gamma Knife radiosurgery. A prospective study.
abstract: OBJECTIVE
  The factors influencing early complications following Gamma Knife radiosurgery have not been definitely established. We report a prospective study evaluating the incidence of early complications (occurring within 3 months of radiosurgery) and various factors associated with early complications following stereotactic Gamma Knife radiosurgery for intracranial lesions.
  
  
  METHODS
  Seventy-nine previously unirradiated consecutive adult patients (82 lesions: arteriovenous malformations 35, benign tumors 43, metastases 4) treated by Gamma Knife radiosurgery were studied between May 1997 and August 1998. The median target volume was 4.8 cm(3). The median dose of 15 Gy was prescribed to the 50% isodose. Patients were evaluated clinically and radiologically (with CT/MRI/SPECT) at 3-month intervals for the 1st year and 6 monthly thereafter. Complications were further divided as immediate (occurring within 24 h) or acute (occurring from 1 day to 3 months).
  
  
  RESULTS
  Early complications were observed in 19/79 (24.0%) patients. These included immediate in 10 (12.7%) and acute complications in 9 (11.3%) patients and were characterized by headache, nausea/vomiting, vertigo and seizures. No severe early complications were observed. Radiological changes in the form of perilesional edema were seen in 8/82 (9.8%) lesions. Maximum target diameter >25 mm was the only factor significantly associated with early complications by univariate analysis (p = 0.0335). Multivariate analysis revealed maximum target diameter >25 mm and prescribed dose >20 Gy to be significantly associated with early complications (p = 0.0442 and p = 0.0083, respectively).
  
  
  CONCLUSIONS
  Up to one fourth of the patients undergoing Gamma Knife radiosurgery for intracranial lesions can experience self-limiting early toxicity. The selection of targets with small diameter and volume may reduce the risk of early complications following Gamma Knife radiosurgery.
authors: Department of Radiation Oncology, All India Institute of Medical Sciences, New Delhi, India. nsmajhail@hotmail.com
authors: N S
authors: NS
authors: Majhail
authors: S
authors: S
authors: Chander
authors: V S
authors: VS
authors: Mehta
authors: P K
authors: PK
authors: Julka
authors: T
authors: T
authors: Ganesh
authors: G K
authors: GK
authors: Rath
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006261:Headache / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011183:Postoperative Complications / Q000503:physiopathology; D020250:Postoperative Nausea and Vomiting / Q000209:etiology; D016016:Proportional Hazards Models; D011446:Prospective Studies; D016634:Radiosurgery / Q000379:methods / Q000706:statistics & numerical data*; D012640:Seizures / Q000209:etiology; D014717:Vertigo / Q000209:etiology