Chemoreduction for retinoblastoma: analysis of tumor control and risks for recurrence in 457 tumors.

PURPOSE To evaluate individual tumor control following chemoreduction for retinoblastoma. METHODS Prospective nonrandomized single-center case series of 457 retinoblastomas managed with six cycles of chemoreduction (vincristine, etoposide, and carboplatin). The tumors were then managed with chemoreduction alone (group A) or chemoreduction combined with thermotherapy (group B), cryotherapy (group C), or both thermotherapy and cryotherapy (group D). The main outcome measure was development of tumor recurrence. RESULTS Of 457 retinoblastomas, 63 (14%) were in group A, 256 (56%) in group B, 127 (28%) in group C, and 11 (2%) in group D. The tumor was located in the macula in 33 (52%) of group A, 109 (43%) of group B, 3 (2%) of group C, and 1 (9%) of group D. Using Kaplan-Meier analysis, recurrence of the individual retinoblastoma at 7 years was found in 45% of group A and in 18% of combined groups B, C, and D. Treatment of the 93 tumor recurrences included thermotherapy, cryotherapy, or plaque radiotherapy in 62 cases (67%) and external beam radiotherapy or enucleation in 31 cases (33%). Risk factors predictive of tumor recurrence by multivariate analysis included macular tumor location for all groups and, additionally, female sex for group A and increasing tumor thickness for groups B, C, and D. CONCLUSIONS Chemoreduction alone or combined with cryotherapy and/or thermotherapy is effective for treatment of retinoblastoma, but tumor recurrence is greatest for those located in the macula and those with greater thickness. Globe salvage is usually achieved despite tumor recurrence.