Abstract
Abstract: :
Purpose: Evaluation of brachytherapy with 106Ru/106Rh–plaques in the therapy of retinoblastoma. Methods: Retrospective non–comparative case observation study to analyse outcome of 106Ru/106Rh–brachytherapy in patients with retinoblastoma. Included were136 patients with 142 affected eyes and 178 retinoblastoma treated between 1979 and 2001. Outcome measures were the eye salvaging rate, local tumor recurrence and complications. Results: Mean age at the treatment was 1.89 years (SD 1.7 years). Brachytherapy was the primary treatment in 60 cases (34%). Insufficient tumor control after laser– and cryocoagulation, brachytherapy, chemotherapy or external beam radiotherapy (EBRT) was the indication in 66%. Mean tumor height was 3.7 mm (SD1.4mm) with a diameter of 5.0 mm (SD 2.8mm) and a mean distance to the optic disk of 4.8 disk diameter (SD: 3.6). Radiation dose values were based on the meanwhile markedly corrected former BEBIG dosimetry. Mean radiation dose at the sclera was 346 Gy (SD 168 Gy) with a mean dose at the apex of 80 Gy (SD 41 Gy). Tumor recurrence occurred in 8 cases (5 year recurrence free: 93%). 15 eyes were finally enucleated (5 year risk: 24.3 %). Radiation retinopathy occurred in 22 eyes (15.5%) and radiation optic neuropathy in 12 eyes (8.5%). Cox regression revealed lower radiation dose at the sclera (risk ratio (RR)=0.99, p=0.014) or vitreous tumor seeding (RR=6.3, p=0.01) as risk factors for tumor recurrence. Risk factors for final enucleation were preceded brachytherapy (RR=91, p=0.0002), EBRT (RR=23.7, p=0.002), chemotherapy (RR=8.9, p=0.009) and larger tumor diameter (RR=1.4, p=0.0004). Predictors for retinopathy were preceded EBRT (RR 4.9, p=0.0005) and retinal detachment (RR=1.3, p=0.02). Optic neuropathy occurred after preceding brachytherapy (RR=16.2 p=0.018) or EBRT (RR=5.6, p=0.015). Conclusions: 106Ru/106Rh–brachytherapy is a save procedure for solitary retinoblastoma with tumor control rates up to 93% at 5 years. Contraindication is a vitreous tumor cell seeding. Preceded irradiation or chemotherapy increases the risk for complications.
Keywords: retinoblastoma • radiation therapy