[Diode laser thermotherapy and chemothermotherapy in the treatment of retinoblastoma].

Introduction: The use of transpupillary thermotherapy alone or associated with systemic chemotherapy is a therapeutic modality of ocular retinoblastoma that allows ocular preservation without external beam irradiation of the eye. We present our experience with thermotherapy in the treatment of selected cases of retinoblastoma.
Material and Methods: This paper reports a retrospective case series of patients treated for retinoblastoma by thermotherapy or chemothermotherapy (carboplatin IV followed by thermotherapy) in a single institution from October 1994 to December 2000. Data collected include general characteristics of the treated children, tumor characteristics, and the results of the treatments on local tumor control. Transpupillar thermotherapy was delivered with a diode laser through an operating microscope. Each tumor was treated separately and laser intensity, spot size, and duration were adapted to the size of the tumor and the clinical response. Chemothermotherapy consisted in thermotherapy delivered shortly after an intravenous injection of carboplatin (560 mg/m(2)) at day 1, followed by thermotherapy alone at day 8 if the lesion was 6mm or more in diameter. This cycle was administered every 28 days. The choice between thermotherapy and chemothermotherapy depended on the initial size of the lesions. Thermotherapy was used when the lesion measured 3mm or less. Lesions measuring more than 15 mm, or associated with substantial vitreous seeding, retinal detachment, or optic nerve head involvement are not suitable for these techniques.
Results: During the study period, 239 children were treated in our institution and 109 of them (147 eyes, 372 tumors) could be treated conservatively without external beam radiation. The median tumor diameter at the moment of thermotherapy or chemothermotherapy was 2mm (range, 0.2-15.0mm). One hundred and ninety-four tumors were treated by chemothermotherapy and 18 by thermotherapy alone. In 75% of the cases, the treatment was administered after two courses of chemotherapy (etoposide and carboplatin). After a mean follow-up of 55 months (range, 16-89 months), tumor control was obtained in 87.1% of lesions after chemothermotherapy and 77.8% after thermotherapy. Salvage enucleation was necessary for seven lesions (seven eyes) but none in the cases where thermotherapy was used alone. No severe systemic side effects were noted.
Discussion: Diode laser delivers hyperthermia on the tumor bed and its use alone or in association with systemic administration of carboplatin makes it possible to preserve the eye without external beam irradiation, with few side effects and less cumulative doses of chemotherapy.
Conclusion: Thermotherapy and chemothermotherapy provide excellent local tumor control and eye preservation in selected cases of retinoblastoma.