Regression patterns in treated retinoblastoma with chemotherapy plus focal adjuvant therapy

The aim of this study was evaluation of the regression patterns after 3, 6, and 8 months of treatment.

A total of 100 retinoblastoma tumors (57 eyes of 35 patients) were treated with 6 (n = 8) or 8 (n = 92) cycles of systemic chemoreduction and tumor consolidation (transpupillary thermotherapy [TTT] or cryotherapy) during this prospective study.

After 3 months of treatment, type 3 was the predominant pattern (n = 57%, 57%), while after 6 and 8 months of treatment the tumors regressed to type 4 most often (44% and 52%, respectively). Smaller tumors and the peripheral tumors were likely to regress to type 4, whereas larger tumors and those nearer to fovea were more likely to become type 1 pattern. Tumors consolidated with cryotherapy mostly showed type 4 regression (3rd month: 40%, 6th month: 90%, and 8th month: 87.5%). Whereas, those treated with TTT rather regressed to type 3 after 3 months (57.9%) and to type 4 after 6 and 8 months of treatment (51.4% and 59.5%, respectively). Recurrence of the tumor was 40% in our cases with defined correlation with tumor location, size, and subretinal seeds.

We conclude that regression patterns of tumors in patients undergoing systemic chemoreduction with focal adjuvant treatments predominantly changed over time and their changes are dependent on tumor size, location, and type of treatment. It appears that subretinal seeds, tumor size, and location of tumors are the most important factors predicting tumor recurrence.