Purpose: The main purpose of this study was to determine the efficacy of postenucleation adjuvant therapy in preventing metastasis in cases of high-risk retinoblastoma.
Methods: This was a retrospective, nonrandomized comparative study. Of 1020 consecutive patients with retinoblastoma had were managed at a referral center between January 1974 and December 1999, 80 (8%) of those analyzed had unilateral sporadic cases that were treated by primary enucleation and that had high-risk characteristics for metastasis on histopathology reports (anterior chamber seeding, iris infiltration, ciliary body infiltration, massive choroidal infiltration, invasion of optic nerve lamina cribrosa, retrolaminar optic nerve invasion, invasion of optic nerve transection, scleral infiltration, and extrascleral extension). The main outcome measure was the development of metastasis at a minimum follow-up period of 12 months.
Results: There were 44 male and 36 female patients, with age ranging from 1 day to 16 years (median, 33 months). A single histopathologic high-risk characteristic was present in 50 patients (62.5%). Thirty patients (37.5%) manifested 2 or more high-risk characteristics. Forty-six patients (58%) had received postenucleation adjuvant therapy (chemotherapy with or without orbital external beam radiotherapy). Adjuvant therapy was not administered in 34 patients (42%). Metastasis occurred in 10 patients (13%) at a median of 9 months (range, 6-57 months) following enucleation. Eight (80%) of those who developed metastasis had not received adjuvant therapy. A significant difference (P =.02) was found in the incidence of metastasis between the group that had received adjuvant therapy (4%; 2/46) and the group that had not (24%; 8/34). The beneficial effect of adjuvant therapy was statistically significant in subgroups of patients with massive choroidal infiltration (P =.04) or retrolaminar optic nerve invasion (P =.04). There were no adjuvant therapy-related serious systemic complications.
Conclusion: Postenucleation adjuvant therapy is safe and effective in significantly reducing the occurrence of metastasis in patients with retinoblastoma manifesting histopathologic high-risk characteristics.