1. MD, MNAMS, DM (Endo) Consultant Endocrinologist Fortis Hospital, Belle Vue Clinic, Kolkata & Research Scientist Dept. of Endocrinology, IPGME&R, Kolkata In Favour of Radiotherapy

2. Orbital fibroblasts in the endomysium & perimysium of extraocular muscles- are the primary target Retroorbital preadepocyte fibroblast-like cell- are the primary target T-cell mediated

3. Immunosuppresion Glucocorticoids Cyclosporine, Cyclophosphamide, Azathioprine, Plasmapheresis External Beam Radiotherapy

4. Mechanism Clonogenic death Apoptotic death Radiation induced death of Inflammatory cells, lymphocytes Reduction in muscle swelling Local Effect (restricted to the orbit only)

5. Stanford- 311 pts 1968-1988- 80% had soft tissue responses, 58% complete response Peterson IA et al. Int J Radiat Oncol Biol Phys 1990; 19:259–264. France- 199 pts 1977-1996- 26% complete response vs 48% partial response Beckendorf V et al. Int J Radiat Oncol Biol Phys 1999; 43:805–815.

6. 56 pts- (vs Prednisone)- Response rate similar (~50%)- Side effects more in Prednisone & Radiotherapy better tolerated Prummel MF, et al. Lancet 1993; 342:949–954. 60 pts (vs placebo- sham radiation)- 60% vs 31% response rate. Motility improved 82% vs 20%. Mourits MP, et al. Lancet 2000; 355:1505–1509.

8. Generalised Effect !! Relapse after withdrawal !! Side effects !!

9. Acne Adrenal insufficiency Arthralgia Avascular necrosis of the hip Cataracts Cushingoid features Diabetes Depression Easy bruisability Fluid retention Glaucoma Headache Hirsutism Hypertension Immunosuppression Increased appetite Irregular heartbeat Loss of libido Menstrual irregularities Mood disturbance Oral rash Osteoporosis Paresthesias Poor wound healing Proximal myopathy Skin rash Stomach ulcers Weakness Weight gain

10. Availability- only in tertiary care centres Expertise- scarce

11. Cataracts (dosimetric errors/ high dose) Retinopathy (DM increased risk) Radiation induced tumor (1.2%) Kinyoun JL, et al. Arch Ophthalmol 1984; 102:1473–1476. Snijders-Keilholz A, et al. Radiother Oncol 1996; 38:69–71.