High-risk histopathologic features analysis of Primary enucleated retinoblastoma in tanzania Patients

Abstract

ABSTRACT Introduction: In ocular retinoblastoma; massive choroid infiltration, post-laminar optic nerve invasion, invasion of the optic nerve to the surgical margin, sclera invasion, and extrascleral extension are now accepted as the high-risk factors for local recurrence, metastasis, and indication for adjuvant therapy. The presence of high-risk histopathologic features in enucleated eye specimen is an indication for adjuvant chemotherapy to limit tumor local recurrence and systemic metastasis. Objective: To describe the histopathology of retinoblastoma and determine prevalence of high-risk histopathologic features in primary enucleated eye specimens of retinoblastoma in Tanzania. Methods: This was a retrospective cross-sectional histopathologic review of 132 primary enucleated eyes with retinoblastoma during a 4-year period from January 2013 to December 2016 in the Histopathology Unit at Muhimbili National Hospital. We retrieved patients‟ records, slides and blocks for histology. Demographic, clinical and histopathologic data were collected using excel data collection sheet. Prevalence of high-risk histopathologic features, proportion of the patients that needed adjuvant therapy and proportion of completeness of histopathology reports were determined. Continuous variables were summarized using mean, median, mode, standard deviation and range. Frequency tables, bar charts and pie charts for categorical variables were done by excel. The association between demographic, clinical data, growth pattern and the need for adjuvant therapy was established by univariate and multivariate logistic analyses using Statistics and data (STATA) software, version 13. The association was considered significant for a p-value less than 0.05. Results: Sixty-eight of 132 participants were male. The median age was 33 months, ranging from 3 to 108 months. Bilateral disease was noted in 23/132 participants (17.4%). Leukocoria was the predominant presenting sign. The mean duration of sign to surgery was 11.06 months. Eight two of 132 participants (62.1 %) were in clinical stage group E. One or more high-risk histopathologic features were noted in 62.9% (83/132) participants. Massive choroid infiltration was recorded in (59.8%), post-laminar optic nerve invasion in vi (7.5%), surgical margin optic nerve invasion in (30.3%), scleral invasion in (10.6%) and extrascleral invasion in (31.8%). The combination of surgical margin optic nerve invasion and extrascleral invasion was the overall high-risk feature encountered 30.1% (n=25/83). Statistically significant association was noted between the need for adjuvant therapy and symptoms duration period more than six months, clinical stage group E and both mixed and exophytic tumor growth patterns. Half of the histopathology reports issued for our participants during the study period were found miss complete information about tumor extension and presence or absence of high risk features. Conclusion: The prevalence of retinoblastoma high-risk histopathologic features in Tanzania is high. Though some demographic and clinical factors may predict the presence of high-risk histopathologic features, the histopathology remains the gold standard to determine who need adjuvant therapy in intraocular retinoblastoma after enucleation.