Prior non-irradiative focal therapies do not compromise the efficacy of delayed episcleral plaque brachytherapy in retinoblastoma.

BACKGROUND/AIMS: Non-irradiative local therapies have shown promise in delaying or supplanting external beam radiotherapy (EBRT) and enucleation in patients with retinoblastoma. We hypothesised that prior focal therapy does not compromise the efficacy of delayed episcleral plaque brachytherapy (epBRT).

METHODS

We performed an institutional review board-approved medical record review of patients with retinoblastoma who were treated with I-125 epBRT prior to (primary) or following chemoreduction (delayed), alone and in combination with non-irradiative focal therapy. Clinical and treatment characteristics were retrieved. Treatment failure was defined as the need for subsequent EBRT and/or enucleation. Event-free and ocular survival rates were calculated from the date of plaque placement. The cumulative incidences (CIs) of treatment failure and enucleation were compared across strata using Gray's test.

RESULTS

We identified 50 patients with retinoblastoma (54 eyes), who received a total of 56 plaques between January 1986 and December 2010, with a median follow-up of 8.3 years (range, 0.8-21.2 years). The median time from diagnosis to plaque placement was 12.7 months (range, 0.1-128 months). The CI and 95% CI of treatment failure and enucleation following epBRT at 5 years was 37%±7.2% and42.2%±7.3%, respectively. The lack of prior diode or green laser therapy was predictive of increased risk for treatment failure (p=0.02 and 0.03). International Classification group C or D was predictive of decreased time to enucleation (p=0.004). The use of any focal therapy was not predictive of time to treatment failure (p=0.33).

CONCLUSIONS

The use of non-irradiative focal therapies prior to or following epBRT does not decrease the time to enucleation or treatment failure.