Treatment Outcomes of Focal Laser Consolidation during Chemoreduction for Group B Retinoblastoma

To evaluate the ocular treatment outcomes of focal laser consolidation during systemic chemoreduction for Group B tumors in the posterior fundus.

Single-institution retrospective chart review from 1995 to 2016.

Patients with Group B retinoblastoma with at least 1 tumor in the posterior fundus.

Evaluation of tumor response to chemotherapy and laser consolidation.

Change in the tumor size with treatment, and the association of timing of laser consolidation to the horizontal and vertical diameter of the final chorioretinal scar.

Forty Group B eyes (22 right eyes and 18 left eyes) were included in the analysis. Mean age at diagnosis was 6.4 months (range 0-24 months). Of the 40 eyes, 35 were treated with both systemic chemotherapy and laser, 4 with chemotherapy only, and 1 eye with laser without chemotherapy. Mean age at initial laser treatment was 7.7 months (standard deviation 5.9 months) and mean number of laser sessions was 6 (standard deviation 5 sessions). The overall globe salvage rate was 95% (38/40 eyes). Mean horizontal and vertical diameters of the tumors in this group showed statistically significant decreases from diagnosis to all subsequent visits (P = 0.0024). The median percent reductions in the horizontal and vertical diameters of the tumors treated with both chemotherapy and laser from diagnosis to the final visit were 13% and 14%, respectively; the overall scar area showed a 13% decrease. For tumors receiving chemotherapy prior to laser therapy, the median reduction in tumor area was 18% from diagnosis to the final examination. Small tumors were found to have a 52% increase in final scar size from diagnosis, whereas larger tumors demonstrated a 37% decrease.

The overall success in treating Group B tumors with chemotherapy and laser was very favorable when considering scar size and globe salvage rates. The size of the chorioretinal scar at the end of treatment was on average 13% smaller than the original tumor size, with greater reductions being noted when chemotherapy preceded laser treatment and when the tumor size at diagnosis was greater than 4.5 mm. A small subset of perifoveal lesions was treated successfully with chemotherapy, alone without laser consolidation.