Radiosurgery with CyberKnife as an organ preserving treatment for small localized choroid melanoma

1. Radiosurgery with CyberKnife as an organ preserving treatment for small localized choroid melanoma
Debnarayan Dutta MD, KR Prasanna Kumar; *, 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,
^Department of Opthalmology,
Apollo Speciality Hospital, Chennai

2. Aim:Toevaluateroboticradiosurgeryasanorganpreservingtreatmentforlocalizedchoroidmelanomaoftheeye.
Casereport:Thirtysixyearoldfemalepatienthadcomplaintofprogressivedimnessofvisionofrighteyeforsixmonths.Fundoscopyexaminationshowedsmalllesion(2.5x2.5mm)inmacularregion.320slicesCTscanshowedorganconfined2.5x2.5mmnodularlesioninthemacularregion(3mmsuperiorand2.5mmtemporaltotheoriginofopticnerveatfovea)ofrighteyeandwasdiagnosedwithlocalizedchoroidmelanomaofrighteye(visualacuity6/18).Metastaticworkupwasnormal.ShewasplannedforSRS(CyberKnife)asanorganpreservingapproach. PlanningCTscanandCyberKnifetreatment(dose18Gysinglefraction,prescriptionisodose85%; treatmenttime22min,GTV111.6mm3,2mmPTVmargin,PTV403mm3)weredonewithretro- bulbaranesthesia.Meandosetorighteye,lefteye,righteyelensandpituitaryglandwas4.9,0.4,0.4and1Gyrespectively.Maximumdosetoopticchiasm,brainstem,right(2%vol)andleftopticnervewere1.4,2.1,15and0.4Gyrespectively.Skulltrackingmethodwasusedastumourtrackingmethod.Shecompletedtreatmentwithoutanyacutecomplicationandvisualacuitywaspreserved.
Conclusion:Roboticradiosurgeryisafeasible,acceptableandanappropriatetreatmentmodalityasorganpreservingapproachinsmallchoroidmelanomas.
Keywords:Choroidmelanoma,Roboticradiosurgery,Organpreservingapproach
Abstract

3. Case history
36 year old female patient had complaint of progressive dimness of vision of right eye for six months.
Visual acuity of involved eye was 6/18.
Investigations
Fundoscopy examination showed small lesion (2.5 x 2.5 mm) in macular region (Figure 1).
320slicesCTscanshowedorganconfined2.5x2.5mmnodularlesioninthemacularregion(3mmsuperiorand2.5mmtemporaltotheoriginofopticnerveatfovea)ofrighteyeandwasdiagnosedwithlocalizedchoroidmelanomaofrighteye(Figure2).
Metastatic workup was normal (USG abdomen, Chest X-ray).

4. Pre-treatment Fundoscopy (Fig 1)
Fundoscopy examination showed
small lesion (2.5 x 2.5 mm) in macular region.

5. Pre-treatment 320 slice CT scan (Fig 2)
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

6. Treatment history
She was planned for SRS (CyberKnife) as an organ preserving approach .
Planning CT scan done under retro-bulbar anesthesia with thermoplastic mask (Figure 3).
Treatment done under retro-bulbar anesthesia (Figure 6).
Skull tracking method was used as tumour tracking method.
She completed treatment without any acute complication and visual acuity was preserved.

7. Thermoplastic mask (Fig 3)

8. CyberKnife planning (Fig 4)

9. Dose (cGy)
Contours
Min
Mean
Max
PTV
1355
1923
2117
GTV
1720
1965
2104
Left eye
17
43
128
Right eye
25
496
2117
Optic chiasm
22
69
143
Brain stem
18
31
211
Left lens
18
43
114
Right lens
47
94
272
RtOptic nerve
68
620
1781
Lt Optic nerve
21
28
47
Pituitary gland
30
102
229
Dose parameters (Fig 5)
(n=1)
Dose: 18 Gy single fraction
Prescription isodose:85%
Treatment time : 22 min
GTV volume: 111.6 mm3
PTV margin =2mm
PTV volume: 403 mm3

10. Dosimetric parameters (Fig 5)

11. Patient on CyberKnife treatment (Fig 6)

12. DePotter (1)
Summanen(2)
Char (3)
Roberge(4)
Lumbroso(5)
Modorati(6)
Krema(7)
Radiation type
Iodine-125
(85 Gy)
Ru-106
(100 Gy)
Helium (50-80 Gy)
EBRTco-60 (70Gy)
Proton
(60 Gy)
Gamma knife (30-50 Gy)
Stereotactic(70 Gy)
Melanoma location
Juxtapapillary
Not specified
Not specified
Juxtapapillary
Not specified
Not specified
Juxtapapillary
Follow-up
78 ms
31ms
61 ms
60 ms
38 ms
31 ms
37 ms
No of patients
93
100
164
26
1062
78
64
Tumor control
85%
94%
93%
84%
97%
91%
94%
Secondary enucleation
22%
10%
16%
19%
8%
10%
16%
Metastases
12%
-
18%
26%
15%
10%
15%
Radiation cataract
-
26%
41%
8%
22%
6%
53%
Neovascularglaucoma
-
10%
315
27%
15%
19%
42%
Radiation retinopathy
87%
24%
46%
46%
47%
47%
81%
Radiation papillopathy
52%
10%
-
-
15%
16%
64%
Comparison of treatment outcomes & complications of various RT techniques
1.De Potter et al. Arch Opthalmol 1996;114:1357-65
2.Summanen et al. Br J Opthalmol 1996; 80:732-9
3.Char et al. Arch Opthalmol 1990;108:209-14
4.Roberge et al. Radiother Oncol 2005; 74:71-3
5.Lumbroso et al. J Fr Opthalmol 2002; 25:290-7
6.Modorati et al. Br J Opthalmol 2009; 93:40-4
7.Krema et al. Br J Othlalmol 2009,93:1172-76

13. Comparison fSRT, SRS and Proton beam therapy
Sang Yui Choi, Tumori 2009,95:720-725

14. •Roboticradiosurgery(CyberKnife®)isafeasible,acceptableandanappropriatetreatmentmodalityasanorganpreservingapproachinsmallchoroidmelanomas.
•Roboticradiosurgerymaybethepreferredtreatmentoptionespeciallywhereprotonbeamtherapyisnotavailableandtumourthicknessismore(>5mm).
•RoboticradiosurgeryisacosteffectivealternativetoprotonbeamtherapyindevelopingcountriessuchasIndiansubcontinent.
•Prospectivestudieswithmulti-centricco-operationisrequiredforfurtherevaluationofthisuniqueprecisetechnologyinourpatientcohort.
Conclusions