title: Neovascular glaucoma after stereotactic radiotherapy for juxtapapillary choroidal melanoma: histopathologic and dosimetric findings.
abstract: OBJECTIVE
  Enucleation after stereotactic radiotherapy (SRT) for juxtapapillary choroidal melanoma may be required because of tumor progression (TP) or the development of intractable radiation-induced neovascular glaucoma (NVG). We compare pathologic changes and dosimetric findings in those eyes enucleated secondary to NVG as opposed to TP to better understand potential mechanisms.
  
  
  METHODS
  Patients with juxtapapillary choroidal melanoma treated with SRT (70 Gy in 5 fractions, alternate days over a total of 10 days) at the Princess Margaret Hospital, Toronto, Ontario, Canada, who underwent enucleation between 1998 and 2006 were selected. We correlated dosimetric data based on the patient's original SRT treatment plan with histopathologic findings in the retina, optic nerve head, and anterior chamber. A dedicated ocular pathologist reviewed each case in a blinded fashion.
  
  
  RESULTS
  Ten eyes in ten patients were enucleated after SRT. Six were enucleated secondary to NVG and four secondary to because of TP. Aggressive tumor features such as invasion of the sclera and epithelioid cell type were observed predominantly in the TP group. Retinal damage was more predominant in the NVG group, as were findings of radiation-related retinal vascular changes of fibrinoid necrosis and hyalinization. No conclusive radiation-related effects were found in the anterior chamber. The maximum point dose and dose to 0.1 cc were lower for the anterior chamber as compared with the dose to the tumor, retina, and optic nerve head. The mean 0.1-cc doses to the retina were 69.4 Gy and 73.5 Gy and to the anterior chamber were 4.9 Gy and 17.3 Gy for the NVG group and tumor progression group, respectively.
  
  
  CONCLUSIONS
  Our findings suggest that NVG is due to radiation damage to the posterior chamber of the eye rather than primary radiation damage to the anterior segment.
authors.affiliation: Department of Ocular Oncology, Princess Margaret Hospital, University Health Network, Toronto, Ontario, Canada.
authors.forename: Bruno F
authors.initials: BF
authors.lastname: Fernandes
authors.forename: Daniel
authors.initials: D
authors.lastname: Weisbrod
authors.forename: Yeni H
authors.initials: YH
authors.lastname: Yücel
authors.forename: Matthew
authors.initials: M
authors.lastname: Follwell
authors.forename: Hatem
authors.initials: H
authors.lastname: Krema
authors.forename: Mostafa
authors.initials: M
authors.lastname: Heydarian
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.forename: David
authors.initials: D
authors.lastname: Payne
authors.forename: Hugh
authors.initials: H
authors.lastname: McGowan
authors.forename: Ernest R
authors.initials: ER
authors.lastname: Simpson
authors.forename: Normand
authors.initials: N
authors.lastname: Laperriere
authors.forename: Arjun
authors.initials: A
authors.lastname: Sahgal
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002830:Choroid Neoplasms / Q000473:pathology / Q000601:surgery*; D018450:Disease Progression; D005123:Eye / Q000528:radiation effects; D015353:Eye Enucleation / Q000379:methods*; D015355:Glaucoma, Neovascular / Q000209:etiology* / Q000473:pathology; D006801:Humans; D008545:Melanoma / Q000473:pathology / Q000601:surgery; D008875:Middle Aged; D011832:Radiation Injuries / Q000473:pathology; D016634:Radiosurgery / Q000009:adverse effects*; D011879:Radiotherapy Dosage; D014604:Uveal Neoplasms / Q000473:pathology / Q000601:surgery; D000098943:Uveal Melanoma