The first experience of transscleral laser thermotherapy of retinoblastoma

Purpose. To evaluate the efficacy of transscleral thermotherapy (TSTT) in eight patients with retinoblastoma (Rb). Material and methods. In total, 8 patients (9 eyes, 22 tumors) with Rb were treated by TSTT. The average age at the time of treatment was 28 months (from 10 to 45 months). Bilateral Rb was observed in six patients, unilateral – in two. All tumors had preequatorial localization (7 foci – on the mid periphery and 15 – on the far periphery of the fundus). The number of tumors in one eye varied from 1 to 6. The mean tumor thickness was 0.7 mm (from 0.5 to 1.4), the mean basal diameter was 1.5 mm (from 1.0 to 2.9). TSTT was performed transconjunctivally using a diode laser with the following parameters: wavelength – 810 nm, spot diameter – 1000 microns, power from 200 to 500 MW (average – 350 MW), exposure – from 3 to 15 seconds in the scanning mode. Results. Complete tumor regression after TSTT was achieved in 86% of cases (19 tumors). In one case (5%) an incomplete tumor regression was observed and transpupillary thermotherapy was performed. In two cases (9%) continued tumor growth occurred, which required the use of cryotherapy. Overall local tumor control was achieved in all cases (22 tumors). All eyes are preserved, all patients included in the study are alive without distant metastases. No complications from both the anterior and posterior segments, as well as visual signs of scleral damage were not observed in any case. The follow–up period after TSTT ranged from 3 to 11 months (mean – 6 months). Conclusion. First experience of TSTT showed that this method is very promising and can be used to treat small Rb of preequatorial localization in the absence of risk of damage to the iris and equator of the lens, which is the benefit of TSTT compared to transpupillary thermotherapy. Key words: retinoblastoma, transcleral thermotherapy, laser treatment, preequatorial localization, small tumors