Evolution in regression patterns following chemoreduction for retinoblastoma.

OBJECTIVE To evaluate the change in regression pattern following chemoreduction and tumor consolidation therapy (thermotherapy or cryotherapy) for retinoblastoma METHODS Retrospective medical record analysis was completed for 557 retinoblastomas (239 eyes of 157 patients) that were treated with chemoreduction and showed regression to 1 of 5 patterns (type 0, no visible remnant; type 1, completely calcified remnant; type 2, completely noncalcified remnant; type 3, partially calcified remnant; and type 4, atrophic chorioretinal flat scar). Evolution of these regression patterns was observed over time. RESULTS Immediately following 6 cycles of chemoreduction, types 0 (2%), 1 (30%), 2 (3%), 3 (33%), and 4 (32%) regression patterns were found. During a mean follow-up period of 56 months (median, 48 months; range, 18-145 months), there was no change in regression patterns classified as type 0, 1, or 4. However, there was evolution of regression pattern types 2 and 3. Over time, type 2 tumor scars either remained stable (41%) or evolved to type 4 (41%), 3 (9%), or 1 (9%) scars. Type 3 tumor scars remained stable (74%) or evolved to type 1 (26%) scars. CONCLUSION Following chemoreduction and tumor consolidation therapy, retinoblastoma regression patterns types 2 and 3 can slowly evolve over time into a slightly different appearance, even without additional treatment. Ophthalmologists should be familiar with these regression patterns and their evolution.