title: High precision focused irradiation in the form of fractionated stereotactic conformal radiotherapy (SCRT) for benign meningiomas predominantly in the skull base location.
abstract: OBJECTIVE
  To present early clinical results of stereotactic conformal radiotherapy (SCRT) in patients with benign predominantly skull base meningiomas.
  
  
  METHODS
  Between August 1994 and August 1999, 41 patients with benign residual or recurrent meningiomas were treated with SCRT. Thirty-three were histologically verified. All patients were immobilized in a GTC stereotactic relocatable frame, and underwent a post-contrast CT localization scan with additional MRI for fusion in 15 patients. Treatment was delivered on a 6 MV linear accelerator using three (12 patients), or 4 (29 patients) non-coplanar conformal fixed fields to doses of 50-55 Gy in 30-33 daily fractions. Tumours were relatively large with a median gross tumour volume (GTV) of 17.9 cm3 (range 2.5-183 cm3).
  
  
  RESULTS
  At a median follow-up of 21 months (range 6-62 months) none of 41 patients have recurred. The current imaging tumour control rate is 100% at 1 and 3 years. The actuarial survival at 2 years is 100% and 91% at 3 and 5 years. Following SCRT tumour decreased in size in 9 patients. SCRT was well tolerated. Five patients had improvement in vision, and six patients improvement in cranial nerve function. Two patients whose planning target volume (PTV) included the sella developed hypopituitarism during and at 18 months after SCRT. One patient with pre-existing hydrocephalus due to pineal region meningioma developed cognitive impairment 7 months after treatment. One patient with involvement of the optic nerve had visual deterioration at 18 months.
  
  
  CONCLUSIONS
  SCRT is a feasible high precision irradiation technique for residual and recurrent skull base meningiomas including both small and larger tumours with excellent early tumour control and low toxicity. Longer follow-up is necessary to demonstrate sustained tumour control and low morbidity of such high precision localized method of fractionated irradiation.
authors.affiliation: Neuro-Oncology Unit, The Institute of Cancer Research, The Royal Marsden NHS Trust, London, UK.
authors.forename: R
authors.initials: R
authors.lastname: Jalali
authors.forename: C
authors.initials: C
authors.lastname: Loughrey
authors.forename: B
authors.initials: B
authors.lastname: Baumert
authors.forename: J
authors.initials: J
authors.lastname: Perks
authors.forename: A P
authors.initials: AP
authors.lastname: Warrington
authors.forename: D
authors.initials: D
authors.lastname: Traish
authors.forename: S
authors.initials: S
authors.lastname: Ashley
authors.forename: M
authors.initials: M
authors.lastname: Brada
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality / Q000532:radiotherapy*; D008579:Meningioma / Q000000981:diagnostic imaging / Q000401:mortality / Q000532:radiotherapy*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000532:radiotherapy; D018365:Neoplasm, Residual; D011859:Radiography; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal; D019292:Skull Base Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality / Q000532:radiotherapy*; D013238:Stereotaxic Techniques; D015996:Survival Rate