Outcome, pathologic findings, and compliance in orbital retinoblastoma (International Retinoblastoma Staging System stage III) treated with neoadjuvant chemotherapy: a prospective study

Purpose: The present study prospectively evaluated outcome, pathologic findings, and compliance in orbital retinoblastoma patients (International Retinoblastoma Staging System [IRSS] stage III).

Design: Prospective study and case series.

Participants: Twenty-eight consecutive IRSS stage III retinoblastoma patients were enrolled prospectively in the study after ethics committee approval and written informed consent.

Methods: Planned therapy for patients included treatment with a uniform protocol consisting of neoadjuvant chemotherapy followed by enucleation, adjuvant radiotherapy, and chemotherapy. Prospective computerized data entry and telephone contact were undertaken to improve compliance, a major issue in treatment of orbital retinoblastoma.

Main outcome measures: Event-free survival (EFS) and overall survival (OS) were calculated using Kaplan-Meier survival analysis. The difference between groups was analyzed using the log-rank test.

Results: Median follow-up was 14.75 months (range, 2.23-26.3 months). The OS for all patients was 40.4% and the EFS was 33.33% at a follow-up of 26.3 months. The median EFS and OS were 10.37 months and 15.73 months, respectively. At baseline, bilateral retinoblastoma predicted inferior EFS (P = 0.0006) and OS (P = 0.0081). Twenty-two of 28 patients underwent enucleation, and viable tumor was present in 21 of 22 enucleated specimens (95%). Neoadjuvant chemotherapy prevented orbital exenterations. Presence of tumor in the cut end of the optic nerve significantly correlated with inferior EFS (P = 0.012) and OS (P = 0.0098). Central nervous system metastasis was the most common site of relapse and death. The overall rate of compliance with treatment was 67.8% (19/28), which was twice the compliance rate at the authors' center before initiation of the present study.

Conclusions: There is a paucity of information in the literature on outcomes and pathologic findings after neoadjuvant chemotherapy in IRSS stage III retinoblastoma treated with a uniform treatment protocol, and as far as the authors are aware, there has been no prospective study. Neoadjuvant chemotherapy was able to avoid exenteration in all operated patients; however, residual viable tumor was present in 95% of enucleated specimens. Bilaterality and tumor in the optic nerve cut end after neoadjuvant chemotherapy were associated with inferior outcome. Compliance could be improved with computerized data entry and regular telephone contact.