Tumour angiogenesis as a prognostic factor for disease dissemination in retinoblastoma.

AIM

To evaluate tumour angiogenesis as a predictor of prognosis in retinoblastoma.

METHODS

This was a retrospective, non-randomised comparative clinicopathological study. The histopathology from 24 cases of Reese-Ellsworth (RE) group V unilateral retinoblastoma treated by enucleation alone was reviewed. Group I consisted of five patients (four RE group Vb and one group Va) who developed disseminated disease at a mean of 10.4 months after enucleation. The remaining 19 patients constitute group II (18 RE group Vb and 1 group Va), none of whom had developed metastatic disease with a mean follow up of 54 months. None of the 24 patients had evidence of extraocular disease at enucleation. The surgical specimens from patients with unilateral retinoblastoma treated by enucleation at Hospital do Cancer AC Camargo between January 1992 and December 1995 were identified, reviewed and the clinical data recorded. Two subsequent histological sections were prepared. One stained with haematoxylin and eosin for assessment of choroidal and optic nerve invasion, and the other for immunoreaction with an endothelium specific marker (antibody anti-CD 34). The main outcome measures were choroidal and/or optic nerve invasion and quantification of the tumour's relative vascular area (TRVA) obtained by Chalkley counting.

RESULTS

Choroidal invasion was present in three eyes of group I (all massive) and six eyes of group II (two focal and four massive). Optic nerve invasion was found in two eyes of group I (all post-laminar) and four eyes of group II (three prelaminar and one post-laminar). There was no statistical difference regarding choroidal or optic nerve between the two groups. The TRVA was the only independent variable found to predict disease dissemination (p = 0.008 by Cox analysis). A TRVA equal to or greater than 3.9% had 100% sensitivity and 79% specificity in predicting disease dissemination.

CONCLUSIONS

Quantification of angiogenesis, through measurement of the TRVA, can help to identify patients with retinoblastoma at high risk for disease dissemination after enucleation.