Chemotherapy induced histopathological changes in retinoblastoma, assessment of high risk predictive factors & its correlation with comorbid conditions

BACKGROUND & OBJECTIVES: Retinoblastoma is a malignant intraocular tumor and its treatment requires a multidisciplinary approach. Chemotherapy is an important modality in treatment of retinoblastoma. The purpose of this study was to assess the histopathological changes in retinoblastomas treated with chemotherapy along with correlation of comorbid conditions with high risk histopathological factors (HRF). METHODS: All post-chemotherapy enucleated eye specimens received in the pathology department between 2017 to 2021 were included in the study. Slides were retrieved and reviewed for chemotherapeutic effects, tumor regression, and for assessment of HRF. Patient demographic data, information regarding chemotherapy and co-morbid conditions were retrieved through the hospital database. Chi-square was used to analyze the relation between comorbid conditions and HRF. RESULTS: Chemotherapeutic effects were seen in all eyes with varying degrees of responses. Necrosis, calcification, and gliosis were the most common findings. The majority of eyes showed tumor occupying less than 50% of the eye whereas complete regression was noted in one eye only. Retinal detachment, glaucoma, and buphthalmos were the most common comorbid conditions at the time of diagnosis. Patients with glaucoma were more likely to have ciliary body invasion. Kaplan Meier analysis showed that patients with more than two HRF had decreased survival rates in comparison to those with one or no HRF. CONCLUSION: Histopathological evaluation of chemotherapy-treated eyes shows varying degrees of response to chemotherapy. Post enucleation histopathological evaluation of the globe plays an important role in assessing disease activity and guiding further treatment to prevent metastasis.