Epidemiological and Genetic Considerations in Retinoblastoma

Retinoblastoma (Rb) is the most common primary intraocular malignancy of childhood. The incidence of Rb is stable worldwide at one case per 16,000–18,000 live births. It is estimated that 7800–8800 Rb cases were newly diagnosed globally in 2017. Over 80% of these are in low- and middle-income countries (LMICs) in Asia and Africa. So far, there is no validated evidence that retinoblastoma incidence is associated with gender, ethnicity or geographical factors. A link between human papillomavirus (HPV) and Rb is being investigated to establish its role in the pathophysiology of the sporadic form of the disease. Survival rates for Rb vary greatly between countries: while almost all Rb cases from high-income countries survive, cases in LMICs have a mortality rate of up to 70%

Epidemiological and genetic considerations in retinoblastoma

Retinoblastoma is usually initiated by a random mutation of a gene in a retinal cell. It is important to try and recognise if the child has germline retinoblastoma, as this may affect both eyes of the child. Siblings and future children of the child with retinoblastoma are at greater risk of developing this cancer

Sex, gender, and retinoblastoma : analysis of 4351 patients from 153 countries

Objective To investigate in a large global sample of patients with retinoblastoma whether sex predilection exists for this childhood eye cancer. Methods A cross-sectional analysis including 4351 treatment-naive retinoblastoma patients from 153 countries who presented to 278 treatment centers across the world in 2017. The sex ratio (male/female) in the sample was compared to the sex ratio at birth by means of a two-sided proportions test at global level, country economic grouping, continent, and for selected countries. Results For the entire sample, the mean retinoblastoma sex ratio, 1.20, was higher than the weighted global sex ratio at birth, 1.07 (p < 0.001). Analysis at economic grouping, continent, and country-level demonstrated differences in the sex ratio in the sample compared to the ratio at birth in lower-middle-income countries (n = 1940), 1.23 vs. 1.07 (p = 0.019); Asia (n = 2276), 1.28 vs. 1.06 (p < 0.001); and India (n = 558), 1.52 vs. 1.11 (p = 0.008). Sensitivity analysis, excluding data from India, showed that differences remained significant for the remaining sample (chi(2) = 6.925, corrected p = 0.025) and for Asia (chi(2) = 5.084, corrected p = 0.036). Excluding data from Asia, differences for the remaining sample were nonsignificant (chi(2) = 2.205, p = 0.14). Conclusions No proof of sex predilection in retinoblastoma was found in the present study, which is estimated to include over half of new retinoblastoma patients worldwide in 2017. A high male to female ratio in Asian countries, India in specific, which may have had an impact on global-level analysis, is likely due to gender discrimination in access to care in these countries, rather than a biological difference between sexes.Peer reviewe

International travel to obtain medical treatment for primary retinoblastoma : A global cohort study

Early diagnosis and treatment of retinoblastoma (Rb), the most common intraocular malignancy, can save both the child's life and vision. However, access to services and hence chances for survival and preserving the eye and its vision vary widely across the globe. Some families have to, or make a choice to, leave their home country to seek planned medical treatment abroad. We aimed to investigate how frequently this cross-border travel occurs and the factors associated with it. A total of 278 Rb centres in 153 countries were recruited to participate in a global cross-sectional analysis of newly diagnosed Rb patients in 2017. Number and proportions of children who travelled from their home country for treatment were analysed by country, continent, socioeconomic stratum and clinical and demographic features. The cohort included 4351 new patients of whom 223 [5.1%, 95% confidence interval 4.5-5.8] were taken across country borders for planned medical treatment. Independently significant predictors of travelling across borders included: being from a country with a smaller population, being from a country classified as low socioeconomic status, having bilateral Rb and having intraocular disease without extraocular spread. The factors that determine international travel for Rb treatment are complex and deserve further investigation. We may need to rethink the way services are delivered in the light of the threat of severe curtailment of international travel from pandemics like corona virus disease 2019.Peer reviewe

Global retinoblastoma presentation and analysis by national income level

IMPORTANCE : Early diagnosis of retinoblastoma, the most common intraocular cancer, can save both a child’s life and vision. However, anecdotal evidence suggests that many children across the world are diagnosed late. To our knowledge, the clinical presentation of retinoblastoma has never been assessed on a global scale. OBJECTIVES : To report the retinoblastoma stage at diagnosis in patients across the world during a single year, to investigate associations between clinical variables and national income level, and to investigate risk factors for advanced disease at diagnosis. DESIGN, SETTING, AND PARTICIPANTS : A total of 278 retinoblastoma treatment centerswere recruited from June 2017 through December 2018 to participate in a cross-sectional analysis of treatment-naive patients with retinoblastoma who were diagnosed in 2017. MAIN OUTCOMES AND MEASURES : Age at presentation, proportion of familial history of retinoblastoma, and tumor stage and metastasis. RESULTS : The cohort included 4351 new patients from 153 countries; the median age at diagnosis was 30.5 (interquartile range, 18.3-45.9) months, and 1976 patients (45.4%) were female. Most patients (n = 3685 [84.7%]) were from low- and middle-income countries (LMICs). Globally, the most common indication for referral was leukocoria (n = 2638 [62.8%]), followed by strabismus (n = 429 [10.2%]) and proptosis (n = 309 [7.4%]). Patients from high-income countries (HICs) were diagnosed at a median age of 14.1 months, with 656 of 666 (98.5%) patients having intraocular retinoblastoma and 2 (0.3%) having metastasis. Patients from low-income countries were diagnosed at a median age of 30.5 months, with 256 of 521 (49.1%) having extraocular retinoblastoma and 94 of 498 (18.9%) having metastasis. Lower national income level was associated with older presentation age, higher proportion of locally advanced disease and distant metastasis, and smaller proportion of familial history of retinoblastoma. Advanced disease at diagnosis was more common in LMICs even after adjusting for age (odds ratio for low-income countries vs upper-middle–income countries and HICs, 17.92 [95%CI, 12.94-24.80], and for lower-middle–income countries vs upper-middle–income countries and HICs, 5.74 [95%CI, 4.30-7.68]). CONCLUSIONS AND RELEVANCE : This study is estimated to have included more than half of all new retinoblastoma cases worldwide in 2017. Children from LMICs, where the main global retinoblastoma burden lies, presented at an older age with more advanced disease and demonstrated a smaller proportion of familial history of retinoblastoma, likely because many do not reach a childbearing age. Given that retinoblastoma is curable, these data are concerning and mandate intervention at national and international levels. Further studies are needed to investigate factors, other than age at presentation, that may be associated with advanced disease in LMICs.The Queen Elizabeth Diamond Jubilee Trusthttp://oncology.jamanetwork.com/public/About.aspxam2021Paediatrics and Child Healt

Tetrac Delayed the Onset of Ocular Melanoma in an Orthotopic Mouse Model

Ocular melanoma research, the most common primary intraocular malignancy in adults, is hindered by limited in vivo models. In a series of experiments using melanoma cells injected intraocularly into mouse eyes, we developed a model for ocular melanoma. Inoculation of 5 × 105 B16F10 cells led to rapid tumor growth, extensive lung metastasis, and limited animal survival, while injection of 102 cells was sufficient for intraocular tumors to grow with extended survival. In order to improve tumor visualization, 102 melanoma cells (B16F10 or B16LS9) were inoculated into Balb/C albino mouse eyes. These mice developed intraocular tumors that did not metastasize and exhibited extended survival. Next, we studied the therapeutic potential of inhibitor of the thyroid hormones-αvβ3 integrin signaling pathway in ocular melanoma. By utilizing tetraiodothyroacetic acid (tetrac), a thyroid hormone derivative, a delay in tumor onset in the B16F10 (integrin+) arm was observed, compared to the untreated group, while in the B16LS9 cells (integrin–) a similar rate of tumor onset was noticed in both experimental and control groups. In summary, following an optimization process, the mouse ocular melanoma model was developed. The models exhibited an extended therapeutic window and can be utilized as a platform for investigating various drugs and other treatment modalities

Adjuvant use of laser in eyes with macular retinoblastoma treated with primary intravenous chemotherapy

Background Adjuvant use of laser with systemic chemotherapy for treatment of retinoblastoma may reduce recurrence rates while also causing local side effects. Information is lacking on the effect of laser on visual outcomes. Methods A retrospective review of two retinoblastoma centres in the United Kingdom was conducted. Patients were included if there was a macular tumour in at least one eye. Eyes that received chemotherapy alone were compared with eyes that received chemotherapy plus adjuvant laser. Results A total of 76 patients and 91 eyes were included in the study. Systemic chemotherapy alone was used in 71 eyes while chemotherapy plus laser was used in 20 eyes. Demographic characteristics of both groups were similar. Macular relapse rates were similar between groups: 22/71 (31%) eyes in chemotherapy group and 9/20 (45%) eyes in laser group (p=0.29). There was no increase in vitreous relapses in the laser group (2/20 eyes), compared with the chemotherapy group 10/71 eyes (p=0.99). Survival analysis demonstrated similar time to first relapse between groups. Final visual acuity was equal between groups with 6/15 or better present in 31.1% of eyes in the chemotherapy group and 37.5% of eyes in the laser group (p=0.76). Presence of tumour at the fovea was predictive of final visual acuity, regardless of treatment group. Conclusion Adjuvant laser in the treatment of retinoblastoma is safe and does not lead to increased rate of vitreous recurrence. Final visual acuity is determined by the presence of tumour at the fovea and not the use of laser