Retinoblastoma in Tanzania; Survival and prognostic factors: A retrospective cohort study

Abstract

Objective: To determine the 3-year survival rate and prognostic factors among patients with retinoblastoma diagnosed at Muhimbili National Hospital from January 2016 to December 2018.
Methods: A retrospective cohort study was conducted. Participants were consecutively recruited. Data were collected using a questionnaire. Variables included demographics, clinical presentation, treatment, and survival time. Statistical analysis was performed using Stata version11. Kaplan-Meier survival analysis was used to assess the survival rates, while the log rank test determined statistical significance. The hazard ratios were calculated using Cox regression. A P value < 0.005 was considered statistically significant.
Results: A total of 166 children were studied, with 69.3% having unilateral retinoblastoma and 30.7% bilateral.
Fifty percent of the children were females. The overall mean age at diagnosis was 25.56 ± 15.56 months. The participant’s mean age at diagnosis was 18.7± 11.6 months for bilateral and 31.3± 20.4 months for unilateral retinoblastoma. The most common complaints were leukocoria (90.4%) and eye protrusion (46.4%). The mean duration of symptoms was 7.9±5.3 months, and the mean total delay time was 9.4±5.6 months. At presentation, 51.8% of the study participants had disease stage 3 and 4 according to the International Retinoblastoma Staging System. The 3-year Kaplan-Meier survival rate was 52.3%. Multivariate Cox regression analysis identified age at diagnosis > 24 months (p=0.001), failure to complete treatment (p=<0.001), and extra-ocular disease invasion (p=0.008) as factors associated with lower survival rates.
Conclusion: The 3-year survival rate of patients with retinoblastoma in our setting was 52.3%. Age at diagnosis of >24 months, failure to complete treatment, and extraocular disease invasion were associated with a lower survival rate.