Tumour differentiation and high risk histology features as prognostic factors among patients with retinoblastoma at Kenyatta National Hospital and Presbyterian church of East Africa Kikuyu Hospital.

Abstract

1. BACKGROUND The management protocol for retinoblastoma (RB) post-enucleation, recommends adjuvant treatment for patients exhibiting high risk histopathology features. The degree of tumour differentiation in RB has not been shown to have significant prognostic association in most studies. 2. OBJECTIVES To determine the prognostic value of the degree of tumour differentiation and high risk histopathologic features, and the frequencies of retinoma and histomorphology consistent RB+/+ MYCNA among primarily enucleated RB cases at the KNH and PCEA-KH. 3. DESIGN A retrospective cohort clinical-pathological review of primarily enucleated RB patient from January 2005 to June 2012 at KNH and PCEA-KH. 4. METHODS AND MATERIALS One hundred and forty (140) patients‘ medical records were retrieved from KNH and PCEA-KH. The clinical data obtained included: demographic data, surgical procedure, chemotherapy treatment, and patient outcome which were recorded in a structured questionnaire. Those whose outcome was unknown due loss to follow-up, their next of kin were contacted after seeking verbal consent. Archived specimen eye blocks of these patients were retrieved, processed and microscopically assessed for: retinoma, RB-/-, RB1+/+ MYCNA RB consistent histomorphological features, degree of tumour differentiation, choroidal invasion, scleral invasion and optic nerve invasion which were recording in a structured proforma. Data was then entered into an Access computer program, cleaned and analysed using Statistical Package for Social Scientists (SPSS) version 20.0 Software. xiii 5. RESULTS Of the 140 patients eligible for this study, 106 had a known outcome, 76 (71.7%) being alive while 30 (28.3%) were deceased. The Kaplan-Meier survival probability of the 140 patients was 0.85 at 12 months, 0.78 at 36 months and 0.65 at 60 months. Poorer outcome were noted in patients with bilateral disease (p=0.016), proptosis (p=0.039), not completing adjuvant chemotherapy (p=0.042) and metastasis or recurrence (p=<0.001). Patients with poorly differentiated tumours had also a significantly poorer outcome compared to those with well or moderately differentiated tumours (p=0.037), while the high risk histopathology features were confirmed to confer a significantly poorer outcome; massive choroidal invasion (p=0.002), scleral invasion (p= 0.006) and post-laminar optic nerve invasion (p=<0.001). Multivariate analysis showed a significant association with poor outcome with: proptosis, metastasis, recurrence, poorly differentiated tumours, massive choroidal, sclera and post-laminar optic nerve invasion. The frequency of retinoma was 2.8% among enucleated RB specimens, while no case histomorphologically consistent with RB +/+ MYCNA was noted. 6. CONCLUSION Patients with poorly differentiated tumour were associated with a poorer survival. High risk histopathology features, were confirmed to having a significant poorer survival.The frequency of retinoma in eyes primarily enucleated for RB was low compared to published figures, while no histomorphological consistent RB +/+ MYCNA subtype was identified in this study.