Lag Time between Onset of First Symptom and Treatment of Retinoblastoma: An International Collaborative Study of 692 Patients from 10 Countries

SIMPLE SUMMARY: The authors aimed to determine the lag time between onset of symptoms and diagnosis of retinoblastoma in countries based on their national-income and analyse its effect on the outcomes. Based on analysis of 692 retinoblastoma patients from 11 treatment centres in 10 countries, there was a statistically significant difference in the lag time between onset of symptoms and diagnosis of retinoblastoma based on country income level. This difference in the lag time between different countries results in varied outcomes across patients. Shorter lag time results in better chances of eye and patient survival. ABSTRACT: Background: The relationship between lag time and outcomes in retinoblastoma (RB) is unclear. In this study, we aimed to study the effect of lag time between onset of symptoms and diagnosis of retinoblastoma (RB) in countries based on their national-income and analyse its effect on the outcomes. Methods: We performed a prospective study of 692 patients from 11 RB centres in 10 countries from 1 January 2019 to 31 December 2019. Results: The following factors were significantly different among different countries based on national-income level: age at diagnosis of RB (p = 0.001), distance from home to nearest primary healthcare centre (p = 0.03) and mean lag time between detection of first symptom to visit to RB treatment centre (p = 0.0007). After adjusting for country income, increased lag time between onset of symptoms and diagnosis of RB was associated with higher chances of an advanced tumour at presentation (p < 0.001), higher chances of high-risk histopathology features (p = 0.003), regional lymph node metastasis (p < 0.001), systemic metastasis (p < 0.001) and death (p < 0.001). Conclusions: There is a significant difference in the lag time between onset of signs and symptoms and referral to an RB treatment centre among countries based on national income resulting in significant differences in the presenting features and clinical outcomes.