Time to diagnosis of retinoblastoma in Latin America: A systematic review

Abstract

Retinoblastoma (RB) is the most common intraocular tumor of childhood. In low income countries, Time to diagnosis (TTD: interval between first symptom and diagnosis) has been associated with extraocular disease, metastasis and mortality. However, the relationship between TTD and prognosis is complex and not simply a linear correlation, particularly if TTD is <6 months. This systematic review aims to identify studies reporting TTD of retinoblastoma in Latin America, highlighting factors affecting TTD, alongside proposals and initiatives to obtain shorter intervals. The review also aims to discuss the methodology linked to cancer pathways studies. The study respected PRISMA recommendations, was registered on Prospero, an international database for systematic review registries under number CRD42017076777. MEDLINE/PUBMED, LILACS and SCIELO databases were searched. Studies from Latin America and the Caribbean, published between 1997 and 2017, reporting TTD and age at diagnosis of patients with retinoblastoma were selected. Nine studies were selected, concerning 1560 patients from Argentina, Brazil, Chile, Honduras, Mexico and Peru. The median TTD ranged from 3 to 5 months and the median age at diagnosis ranged from 16.5 to 22.2 months. A prolonged TTD was observed and was associated to damaging results on retinoblastoma outcomes, particularly increasing extraocular disease, and mortality rates. Methodological heterogeneity was observed and reiterates the importance of standardization of TTD studies, allowing more reliable comparisons and greater knowledge about retinoblastoma pathways before diagnosis. Reports on successful initiatives against delayed diagnosis were scarce, emphasizing a need for further studies.

Keywords: Childhood cancer; delayed diagnosis; early detection of cancer; late diagnosis; retinoblastoma.