Title: Radiosurgery with CyberKnife as an organ preserving treatment for small localized choroid melanoma
Authors: KR Prasanna Kumar*, MBBS; Debnarayan Dutta*, MD; Prativa Mishra^, MS; Raghunandhan* MD; P Mahadev * MD, DNB; AN Vaidhyswaran* MD; Sanjay Chandrasekhar* MD; Janos Stumpf *MD, PhD; Rathnadevi* DMRT; V Murali# PhD; PG Kurup# PhD;
*Department of Radiation Oncology, #Medical Physics, Apollo Speciality Hospital, Chennai
^Department of Opthalmology, Apollo Speciality Hospital, Chennai
Aim: To evaluate robotic radiosurgery as an organ preserving treatment for localized choroid melanoma of the eye.
Case report: Thirty six year old female patient had complaint of progressive dimness of vision of right eye for six months. Fundoscopy examination showed small lesion (2.5 x 2.5 mm) in macular region. 320 slices CT scan showed organ confined 2.5 x 2.5 mm nodular lesion in the macular region (3 mm superior and 2.5 mm temporal to the origin of optic nerve at fovea) of right eye and was diagnosed with localized choroid melanoma of right eye (visual acuity 6/18 ). Metastatic workup was normal. She was planned for SRS (CyberKnife) as an organ preserving approach. Planning CT scan and CyberKnife treatment (dose 18 Gy single fraction, prescription isodose 85%; treatment time 22 min, GTV 111.6 mm3, 2mm PTV margin, PTV 403 mm3) were done with retro-bulbar anesthesia. Mean dose to right eye, left eye, right eye lens and pituitary gland was 4.9, 0.4, 0.4 and 1 Gy respectively. Maximum dose to optic chiasm, brainstem, right (2% vol) and left optic nerve were 1.4, 2.1, 15 and 0.4 Gy respectively. Skull tracking method was used as tumour tracking method. She completed treatment without any acute complication and visual acuity was preserved.
Conclusion: Robotic radiosurgery is a feasible, acceptable and an appropriate treatment modality as organ preserving approach in small choroid melanomas.
Keywords: Choroid melanoma, Robotic radiosurgery, Organ preserving approach