The outcome of chemoreduction treatment in patients with Reese-Ellsworth group V retinoblastoma

Objective: To determine the outcome of chemoreduction treatment in patients with Reese-Ellsworth group V retinoblastoma. Methods: Prospective analysis of 27 eyes in 22 patients with group V retinoblastoma treated with either 2- or 6-cycle chemoreduction and focal treatment methods (argon laser photo coagulation, transpupillary thermotherapy, cryo therapy, and plaque radioth erapy). The need for external beam irradiation and the eventual globe salva ge rate were assessed. Median follow-up was 28 months. Results: There were 16 eyes in the 2-cycle chemoreduction treatment group a nd 11 eyes in the 6-cycle chemoreduction treatment group. No significant di fference was noted between the 2 groups with respect to baseline patient an d eye findings. After chemoreduction treatment, external beam irradiation w as necessary in 12 (75%) of 16 eyes in the 2-cycle chemoreduction treatment group and in 4 (36%) of 11 eyes in the 6-cycle chemoreduction treatment gr oup. There was no statistical difference between the 2- and 6-cycle chemore duction treatment groups with respect to necessity for external beam irradi ation (logistic regression analysis). All 4 eyes in the 2-cycle chemoreduct ion treatment group and 3 of 12 eyes in the 2-cycle chemoreduction treatmen t and irradiation group were eventually enucleated, the globe salvage rates being 0% and 75%, respectively. Two of 7 eyes in the 6-cycle chemoreductio n treatment group and 1 of 4 eyes in the 6-cycle chemoreduction treatment a nd irradiation group were enucleated, the globe salvage rates being 71% and 75%, respectively. Except for the 2-cycle chemoreduction treatment group, in which the globe salvage rate was significantly lower (P =.03), there was no difference among the other 3 groups (2-cycle chemoreduction treatment a nd irradiation; 6-cycle chemoreduction treatment, and 6-cycle chemoreductio n treatment and irradiation) with respect to globe salvage (logistic regres sion analysis). Conclusions: Local tumor control of group V retinoblastoma is possible with 6-cycle chemoreduction and focal therapy when external beam irradiation is not used. A larger sample size is necessary to determine how often externa l beam irradiation can be avoided.