Retinoblastoma Incidence Trends in Canada: A National Comprehensive Population-Based Study

Nationwide incidence and survival of retinoblastoma in the USA between 1996 and 2018: a review of 5730 cases

BACKGROUND

Retinoblastoma is the most common intraocular cancer in children, with significant variations in incidence and Survival. This study sought to evaluate nationwide retinoblastoma incidences and survival rates in the United States from 1996 to 2018.

METHODS

We extracted data from the North American Association of Central Cancer Registries (NACCR) and the National Program of Cancer Registries between 1996 and 2018. Cases were stratified by sex, age, race, Hispanic origin, urban or rural origin, stage of the disease, and state of residence and compared by laterality. We applied SEER*Stat version 8.4.0.1 software for age-adjusted incidence rates (AAIR) and annual average per cent change (AAPC) and JoinPoint version 4.9.1.0 software to assess incidence trends. Survival trends were evaluated with JPSurv online software.

RESULTS

The study comprised 5730 patients with a crude incidence rate (CIR) of 0.89 per million. The incidence declined from 29.6 per million in the first year of life to 16.5 in the second year. The CIR for unilateral and bilateral diseases were 0.61 and 0.27, respectively. Males had a slightly higher and significant crude incidence of 0.93 versus 0.86 for females. Hispanics had the highest rate of 1.48 in general. Treatment data revealed chemotherapy usage in 39% of unilateral and 78% of bilateral patients. The 5-year cumulative relative Survival did not significantly differ between unilateral (96.8%) and bilateral (97.0%) patients. A slight but significant annual decline in CIR was observed, with a trend toward an increase in the percentage of patients diagnosed in the first year of life.

CONCLUSIONS

This study indicated an overall decrease in incidence but a slight increase in early diagnosis. Findings underscore the need for consistent surveillance, early detection strategies, and personalized care to improve patient outcomes. The changes in the Survival in the unilateral disease require further investigations and mitigation strategies.

Survival and Health Care Burden of Children With Retinoblastoma in Europe

Importance

Studies on the epidemiology of retinoblastoma (RB) could lead to improvement in management.

Objective

To estimate the incidence and survival of RB in European children and the occurrence of second primary tumors (other than RB) in these patients.

Design, Setting, and Participants

This cohort study used population-based data from 81 cancer registries in 31 European countries adhering to the European Cancer Registries (EUROCARE-6) project. Data collection took place between January 2000 and December 2013. European children aged 0 to 14 years diagnosed with RB were included. Data were analyzed from May to November 2023.

Exposures

Diagnosis of RB with International Classification of Diseases for Oncology, Third Edition (ICD-O-3), morphology coded 9510-9514 (retinoblastoma) and malignant behavior (fifth digit of morphology code, 3).

Main Outcome and Measures

Annual incidence (per million children aged 0-14 years), 5-year survival (%), and the standardized incidence ratio (SIR) of subsequent malignant neoplasms.

Results

The study included 3262 patients (mean [SD] age, 1.27 [1.63] years; 1706 [52%] male and 1556 [48%] female) from 81 registries. Of these, 3098 patients were considered in trend analysis after excluding registries with incomplete time coverage: 940 in 2000 to 2003, 703 in 2004 to 2006, 744 in 2007 to 2009, and 856 in 2010 to 2013. The estimated overall European incidence rate was 4.0 (95% CI, 3.9-4.1). Rates among countries varied from less than 2 million to greater than 6 million per year. No time trend of incidence was observed in any area. The overall European 5-year survival was 97.8% (95% CI, 95.5-98.9; 3180 cases). Five-year survival was lower in Estonia and Bulgaria (<80%) and 100% in several countries. Twenty-five subsequent malignant neoplasms were recorded during follow-up (up to 14 years), with an SIR of 8.2 and with cases occurring at mean ages between 1.3 and 8.9 years across different sites. An increased risk was found for hematological tumors (SIR, 5) and bone and soft tissue sarcomas (SIR, 29).

Conclusions and Relevance

This study showed RB incidence remained stable at 4.0 per 1 000 000 European children aged 0 to 14 years from 2000 to 2013, but estimates varied among countries and differences in survival across countries persist. These data might be used to monitor RB management and occurrences of second tumors. The findings suggest future registry studies should aim to collect standardized RB stage at diagnosis and treatment to interpret disparities and potentially improve surveillance.

Advancements in the diagnosis, prognosis, and treatment of retinoblastoma

Retinoblastoma (RB) is a prevalent primitive intraocular malignancy in children, particularly in those younger than age 3 years. RB is caused by mutations in the RB1 gene. In developing countries, mortality rates for this type of cancer are still high, whereas industrialized countries have achieved a survival rate of >95%-98%. Untreated, the condition can be fatal, underscoring the importance of early diagnosis. The existing treatments primarily consist of surgery, radiotherapy, and chemotherapy. The detrimental effects of radiation and chemotherapeutic drugs have been documented as factors that contribute to increased mortality rates and negatively affect the quality of life for patients. MicroRNA (miRNA), a type of noncoding RNA, exerts a substantial influence on RB development and the emergence of treatment resistance by regulating diverse cellular processes. This review highlights recent developments in the involvement of miRNAs in RB. This encompasses the clinical significance of miRNAs in the diagnosis, prognosis, and treatment of RB. Additionally, this paper examines the regulatory mechanisms of miRNAs in RB and explores potential therapeutic interventions. This paper provides an overview of the current and emerging treatment options for RB, focusing on recent studies investigating the application of different types of nanoparticles for the diagnosis and treatment of this condition.

Evaluation of weather and environmental factors and their association with cutaneous melanoma incidence: A national ecological study

Background

Cutaneous melanoma (CM) is a significant contributor to skin cancer-related mortality globally and in Canada. Despite the well-established link between ultraviolet (UV) radiation exposure and skin cancer risk, there remains a gap in population-level interventions and persistent misconceptions about sun exposure and impact of environment on individual behavior.

Objective

The current study provides an ecological analysis using latest available data (2011-2017) to define geographic/environmental contributors to the CM landscape in Canada.

Methods

Utilizing Canadian Cancer Registry and Canadian Urban Environmental Health Research Consortium data, we analyzed 39,605 CM cases occurring in Canada from 2011 to 2017. Environmental data, including UV radiation, greenspace (normalized difference vegetation index), temperature, heat events, and precipitation was used to evaluate the effect of environment on CM incidence rates across Forward Sortation Area postal codes.

Results

Forward Sortation Areas with increased CM incidence were associated with higher annual average temperature, snowfall, heat events, normalized difference vegetation index, and vitamin D-weighted UV exposure. Conversely, factors associated with decreased incidence included an increased annual highest temperature, rain precipitation, and a longer duration of heat events.

Limitations

This study is subject to ecological bias and findings should be interpreted with caution.

Conclusion

This study further substantiates associations between specific environmental factors and CM incidence.

Cutaneous Melanoma Mortality-to-Incidence Ratio and Its Association With Socioeconomic and Healthcare Factors in Canada: A National Ecological Study

INTRODUCTION

The mortality-to-incidence ratio (MIR) can be used to approximate healthcare inequities and is helpful to understand/compare cancer survival between geographic regions/jurisdictions. We investigated cutaneous melanoma (CM) outcomes through MIR analysis in Canadian jurisdictions and census divisions (CDs) between 1992 and 2016.

METHODS

Data were obtained from the national databases from 1992 to 2016 for all Canadian jurisdictions, except Quebec. Age-standardized overall and median MIRs were calculated per province per year, while crude MIRs were calculated for CDs. Generalized linear regression models were conducted to study the effect of province and year on MIR, while a mixed effect regression model was used to determine how healthcare and socioeconomic factors affect MIR, while accounting for possible clustering effects (eg, year and province).

RESULTS

We identified 106,015 CM cases and 20,570 CM deaths between 1992 and 2016. National MIR from 1992 to 2016 demonstrated a significant linear decrease (P value < .0001). The national median MIR was 15.4 (ie, 0.154 × 100), whereby Manitoba (19.9), Ontario (19.5), Saskatchewan (18.5), British Columbia (16.1), and Newfoundland and Labrador (15.9) demonstrated higher MIRs than the Canadian average. CDs with the highest MIRs were commonly identified in the southern regions of provinces. No healthcare or socioeconomic factors were found to be significantly associated with higher MIR at the provincial level.

CONCLUSION

MIRs have decreased at the national and provincial levels in recent decades, which is reassuring. Higher MIRs were noted in select rural CDs and in the Canadian territories, reinforcing the importance of proper dermatological care in all parts of the country.

Updated retinoblastoma incidence and outcome in children in Taiwan from 1980 to 2019: a 40-year nationwide study

BACKGROUND

Retinoblastoma is a potentially fatal disease, and its incidence and mortality varies among different countries and periods.

METHODS

This is a nationwide population-based retrospective study from January 1980 to December 2019 in Taiwan. Patients diagnosed as retinoblastoma were identified from the Taiwan National Cancer Registry. To update the literature on retinoblastoma incidence, mortality and trends in Taiwan, we analysed changes in incidence and survival rates over time according to sex, diagnostic age, laterality and treatment.

RESULTS

During 1980-2019, the incidence of retinoblastoma in Taiwan was 1 per 16 489 live births (95% CI: 13 415-19 564). The diagnostic age decreased from 2.21 ± 0.26 during 1980-1984 to 1.24 ± 0.26 during 1985-2019. Compared with that observed during 1980-1989, the incidence rate observed after 1990 increased significantly in children aged <10 years (RR: 1.62-2.40, P = 0.0049 to < 0.0001). From 1980 to 2019, the incidence rate for the 0-4-year age group increased and that for the 5-9-year age group remained constant. The mean diagnostic age for bilateral retinoblastoma (0.36 ± 0.47 years) was significantly less than that for unilateral retinoblastoma (1.37 ± 0.35 years) during 2007-2019 (P < 0.0001). The 10-year survival rate was highest in the enucleation group (89.8%) compared with radiotherapy (52.2%) and others (70.0%; P < 0.0001).

CONCLUSIONS

During 1980-2019 in Taiwan, the incidence of retinoblastoma increased significantly, and the diagnostic age decreased, which are similar to the ones from other developed countries. However, the survival rate was still lower than that of most developed countries.

Advancements in Nanosystems for Ocular Drug Delivery: A Focus on Pediatric Retinoblastoma

The eye's complex anatomical structures present formidable barriers to effective drug delivery across a range of ocular diseases, from anterior to posterior segment pathologies. Emerging as a promising solution to these challenges, nanotechnology-based platforms-including but not limited to liposomes, dendrimers, and micelles-have shown the potential to revolutionize ophthalmic therapeutics. These nanocarriers enhance drug bioavailability, increase residence time in targeted ocular tissues, and offer precise, localized delivery, minimizing systemic side effects. Focusing on pediatric ophthalmology, particularly on retinoblastoma, this review delves into the recent advancements in functionalized nanosystems for drug delivery. Covering the literature from 2017 to 2023, it comprehensively examines these nanocarriers' potential impact on transforming the treatment landscape for retinoblastoma. The review highlights the critical role of these platforms in overcoming the unique pediatric eye barriers, thus enhancing treatment efficacy. It underscores the necessity for ongoing research to realize the full clinical potential of these innovative drug delivery systems in pediatric ophthalmology.

Retinoblastoma Incidence in Taiwan Over a Recent 20-Year Period: A Comprehensive Nationwide Study

Purpose

Continuous advancements in medical diagnostic technology and the growing availability of resources suggest a potential for fluctuations in the incidence rate of retinoblastoma (Rb). This study aimed to analyze incidence data of Rb patients in Taiwan from 1999 to 2018, utilizing the nationwide Taiwan Cancer Registry (TCR) database. Additionally, we investigated the treatment modalities used for these Rb patients and compared them with those observed in other countries.

Patients and Methods

We conducted a retrospective cohort study utilizing data from the TCR database. The study cohort comprised individuals who were newly diagnosed with Rb between 1999 and 2018. The incidence of Rb was calculated as the number of patients with Rb per million live births, both for the entire population and for different gender groups and time periods. The trends in Rb incidence from 1999 to 2018 across various age groups and sexes were presented with the linear trend test.

Results

From 1999 to 2018, a total of 248 cases of Rb were identified. The overall incidence rate over this 20-year period was 60.20 cases per million live births, corresponding to 1 case per 16,611 live births. Incidence rates for each 5-year period between 1999 and 2018 exhibited no significant differences. The study cohort was predominantly male, with 134 cases (54.03%) being males and 114 cases (45.97%) being females, resulting in an overall male-to-female sex ratio of 1.18. Females had lower relative risk than males (RR: 0.92, 95% CI: 0.72-1.19). Primary surgical intervention was the preferred treatment modality for over 75% of the cases.

Conclusion

This retrospective epidemiology study, using TCR from 1999 to 2018, indicated that no discernible trend of retinoblastoma incidence in Taiwan. Nevertheless, continuous monitoring of incidence rates and exploration of treatment strategies for retinoblastoma within the Taiwanese population are important to address potential changes in developing medical practices.

Incidence and clinical characteristics of pediatric ocular tumors in a Midwestern US population

PURPOSE

To investigate the incidence and clinical characteristics of pediatric ocular tumors in a US Midwestern county population.

METHODS

Retrospective population-based cohort study of all Olmsted County, Minnesota, pediatric patients (<18 years old) diagnosed with any ocular neoplasm from January 1, 2006, to December 31, 2015. Subjects were identified via the Rochester Epidemiology Project, a record-linkage system that captures virtually all medical care provided in this county. Medical records were reviewed to confirm diagnoses. Age- and sex-adjusted incidence rates were calculated and adjusted to the 2010 Olmsted County, Minnesota, pediatric population.

RESULTS

There were 87 incident pediatric ocular tumor diagnoses, yielding an overall age- and sex-adjusted incidence rate of 24.0 per 100,000 per year (95% CI, 19.0-29.1). Females accounted for 46 cases (53%) cases, and 62 (85%) were White. Incidence rate for ocular tumors overall did not differ by patient age (P = 0.08) or sex (P = 0.47). All tumors were benign lesions. The most frequent adnexal/orbital, ocular surface, and intraocular tumors were epidermal inclusion cyst in 18 (21%) cases, conjunctival nevus in 10 (12%), and choroidal nevus in 18 (21%), respectively. The mean follow-up duration was 25.5 months (range, 7 days to 138.6 months), and benign tumor growth occurred in one conjunctival nevus. There were no cases of malignant transformation.

CONCLUSIONS

Pediatric ocular tumors were rare with an estimated incidence of approximately 1 in 4,200 pediatric patients in Olmsted County, Minnesota. All lesions were benign, with benign growth in only 1% of cases, and no tumors underwent malignant transformation.

miRNAs as potential game-changers in retinoblastoma: Future clinical and medicinal uses

Retinoblastoma (RB) is a rare tumor in children, but it is the most common primitive intraocular malignancy in childhood age, especially those below three years old. The RB gene (RB1) undergoes mutations in individuals with RB. Although mortality rates remain high in developing countries, the survival rate for this type of cancer is greater than 95-98% in industrialized countries. However, it is lethal if left untreated, so early diagnosis is essential. As a non-coding RNA, miRNA significantly impacts RB development and treatment resistance because it can control various cellular functions. In this review, we illustrate the recent advances in the role of miRNAs in RB. That includes the clinical importance of miRNAs in RB diagnosis, prognosis, and treatment. Moreover, the regulatory mechanisms of miRNAs in RB and therapeutic interventions are discussed.

Investigation of the Incidence and Geographic Distribution of Bone and Soft Tissue Sarcomas in Canada: A National Population-Based Study

Sarcomas are a heterogeneous group of mesenchymal malignancies with various genetic and environmental risk factors. This study analyzed the epidemiology of sarcomas to gain insight into the incidence and mortality rates of these cancers in Canada, as well as to elucidate their potential environmental risk factors. Data for this study were obtained from le Registre Québécois du Cancer (LRQC) and from the Canadian Cancer Registry (CCR) for the period from 1992 to 2010. Mortality data were obtained from the Canadian Vital Statistics (CVS) database for the period from 1992 to 2010 using the International Classification of Diseases for Oncology, ICD-O-3, ICD-9, or ICD-10 codes, for all subtypes of sarcomas. We found that the overall sarcoma incidence in Canada decreased during the study period. However, there were select subtypes with increasing incidence. Peripherally located sarcomas were found to have lower mortality rates compared to axially located sarcomas, as expected. Clustering of Kaposi sarcoma cases in self-identified LGBTQ+ communities and in postal codes with a higher proportion of African-Canadian and Hispanic populations was observed. Forward Sortation Area (FSA) postal codes with a lower socioeconomic status also had higher Kaposi sarcoma incidence rates.

Investigation of incidence and geographic distribution of gliomas in Canada from 1992 to 2010: a national population-based study highlighting the importance of exposure to airport operations

Background

Gliomas account for over two-thirds of all malignant brain tumors and have few established risk factors beyond family history and exposure to ionizing radiation. Importantly, recent studies highlighted the exposure to ultrafine particles (UFP) as a putative risk factor for malignant brain tumors.

Methods

Clinical and geographic data encompassing all provinces and territories from 1992 to 2010 was obtained from the Canadian Cancer Registry and Le Registre Québécois du Cancer. Linear regression and joinpoint analyses were performed to assess incidence trends. Significantly higher and lower incidence postal codes were then interrogated using Standard Industrial Classification codes to detect significant industrial activity.

Results

In Canada, between 1992 and 2010, there were ~32,360 cases of glioma. Of these, 17,115 (52.9%) were glioblastoma. The overall crude incidence rates of 5.45 and 2.87 cases per 100,000 individuals per year for gliomas and glioblastomas, respectively, were identified. Our findings further revealed increasing crude incidence of gliomas/glioblastomas over time. A male predominance was observed. Provinces leading in glioma incidence included Quebec, Nova Scotia, and New Brunswick. Significantly lower crude incidence of glioma was found in Nunavut, Northwest Territories, Ontario, and Alberta. A putative regional clustering of gliomas was observed, with higher incidence rates in postal code areas correlating with industrial activity related to airport operations.

Conclusion

This study describes the geographic distribution of the glioma disease burden and, potentially, identifies industrial activity related to airport operations as potentially being associated with higher incidence of this cancer.

The role of maternal age & birth order on the development of unilateral and bilateral retinoblastoma: a multicentre study

BACKGROUND/OBJECTIVES

Retinoblastoma is a common childhood intraocular malignancy, the bilateral form of which most commonly results from a de novo germline pathogenic variant in the RB1 gene. Both advanced maternal age and decreasing birth order are known to increase the risk of de novo germline pathogenic variants, while the influence of national wealth is understudied. This cohort study aimed to retrospectively observe whether these factors influence the ratio of bilateral retinoblastoma cases compared to unilateral retinoblastoma, thereby inferring an influence on the development of de novo germline pathogenic variants in RB1.

SUBJECTS/METHODS

Data from 688 patients from 11 centres in 10 countries were analysed using a series of statistical methods.

RESULTS

No associations were found between advanced maternal age, birth order or GDP per capita and the ratio of bilateral to unilateral retinoblastoma cases (p values = 0.534, 0.201, 0.067, respectively), indicating that these factors do not contribute to the development of a de novo pathogenic variant.

CONCLUSIONS

Despite a lack of a definitive control group and genetic testing, this study demonstrates that advanced maternal age, birth order or GDP per capita do not influence the risk of developing a bilateral retinoblastoma.

Uveal melanoma incidence trends in Canada: 1992-2010 vs. 2011-2017

Background/aims

Uveal melanoma is the most common type of non-cutaneous melanoma and the most common ocular malignancy in the adult population, especially affecting Caucasians (98% of cases). Despite its low incidence rate, we have noted increasing incidence trends in recent years.

Methods

We analyzed uveal melanoma incidence data using the Canadian Cancer Registry (CCR) for 2011-2017 years. The data was examined using the International Classification of Diseases for Oncology, Third Edition, codes for all uveal melanoma subtypes. The data for 2011-2017 was then compared to previously published work by our research group for uveal melanoma incidence in Canada between 1992 and 2010 using the same methodology.

Results

Between 2011 and 2017, 1,215 patients were diagnosed with uveal melanoma, 49% of whom were females. The percentage distribution of uveal melanoma between the sexes was similar between 1992-2010 and 2011-2017, whereby of the 2,215 diagnoses of uveal melanoma in 1992-2010, 47.9% were females. The change in the incidence rate for this cancer has doubled between 1992-2010 and 2011-2017, from 0.074 to 0.15 cases per million individuals per year. Our study documents that the Canadian 2011-2017 age-standardized incidence rate (ASIR) for uveal melanoma against the World Health Organization (WHO) 2000-2025 world population standard was 5.09 cases per million individuals per year (95% confidence interval, 4.73-5.44), as compared with the 1992-2010 rate of 3.34 cases per million individuals per year (95% confidence interval, CI 3.20 to 3.47).

Conclusion

This work demonstrates an ongoing, steady increase in uveal melanoma incidence in Canada in recent years.

Anatomo-Clinical Aspects of Retinoblastoma: A Series of 144 Cases

Retinoblastoma (RB) is the most common intraocular primary malignancy for infants and young children. The tumor is bilateral in 40% of cases and unilateral in 60% of cases. The hereditary form is due to a germinal mutation in the RB1 tumor suppressor gene. In developed countries, patients treated for RB have excellent survival, but unfortunately in developing countries delays in diagnosis and lack of human and financial resources are responsible for deaths. We conducted a retrospective study of 144 cases of RB in order to evaluate the clinico-pathological aspect of RB for the national reference center of RB in Morocco. Our study highlighted the indispensable collaboration between the clinician and the pathologist. Besides the diagnostic confirmation, the anatomopathological study gives us information on histopronostic risk factors to guide the treatment.

Population-Based Study Detailing Cutaneous Melanoma Incidence and Mortality Trends in Canada

Background

Cutaneous melanoma (CM) is one of the most fatal types of skin cancer. Alarmingly, increases in incidence and mortality were noted globally for this malignancy, despite increase in understanding of melanoma pathogenesis and enhanced prevention efforts.

Methods

Data was extracted for CM patients for provinces and territories (except Quebec) using two independent, population-based registries. Analysis was performed using both clinical and pathological characteristics: tumor morphologic classification, age, sex, anatomic site affected and place of residence. Mortality trends were assessed over a 7-year period. Results were compared to prior findings for 1992-2010.

Results

During 2011-2017 39,610 patients were diagnosed with CM, with 5,890 reported deaths. National crude CM incidence was 20.75 (age-standardized incidence: 14.12) cases per 100,000 individuals per year. Females accounted for 45.8% of cases and 37.1% of deaths. While CM incidence rates continue to increase in both sexes, since 2013 the CM mortality is declining. We observed important differences across the provinces/territories, where Nova Scotia, Prince Edward Island, southern Ontario/British Columbia and certain coastal communities of New Brunswick demonstrated higher CM incidence and mortality rates. The observed incidence and mortality trends for 2011-2017 validate and extend earlier observations from 1992 to 2010 for CM.

Conclusion

This population-based study highlights that while melanoma's incidence is increasing in Canada, mortality rates are for the first time decreasing since 2013. We detail regional distribution of this cancer highlighting communities in southern/coastal areas, as being most at risk as well as the latest trends of melanoma incidence by age, sex and anatomic site. In males, melanoma is more common on the head/trunk, while in females on the extremities. Notably, Acral Lentiginous Melanoma was the only CM subtype that was more common in females, which primarily affects hands and feet.

Incidence of retinoblastoma in children and adolescents in Brazil: A population-based study

OBJECTIVE

To estimate the incidence of retinoblastoma in children and adolescents in Brazil based on Population-Based Cancer Registry (PBCR), describing temporal trends and some quality indicators of this registry.

METHODS

Based on secondary data from the PBCR of the National Institute of Cancer (INCA) (2000-2018), by selecting the morphological code of retinoblastoma, the annual incidences per million (0-19 years of age) in each local PBCR were estimated by sex and age group, global combined and by region, in addition to the percentage of diagnosis only by death certificate (DC) or not informed (NI), and the male/female ratio (M/F). An annual incidence trend in the five Brazilian geographic regions was also analyzed using the inflection point regression technique.

RESULTS

675 patients were identified in 28 PBCR, 91% between 0 and 4 years of age. The overall combined incidence per million by age group was: 7.02 (0-4 years old), ranging from 5.25 in the Midwest to 11.26 in the Northeast; 0.46 (5-9 years old); 0.05 (10-14 years old) and 0.03 (15-19 years old). The combined incidence per million, adjusted for the world population, was 2.23 (0-14 years old) and 2.24 (0-19 years old). The DC and NI percentages were 13% and 18%, respectively; the M/F ratio was 1.3. The incidence remained stable throughout the study period, except for the city of São Paulo, where there was a significant reduction of 3.4% per year.

CONCLUSIONS

In Brazil, except for the Northeast region, the incidences of retinoblastoma were lower than those reported in several countries worldwide, suggesting possible underreporting, and the time series analysis showed a stable trend. Although this pioneering study brings a recent panel of available data on retinoblastoma in Brazil, more precise estimates are needed and welcome for better planning of onco-ophthalmologic care in the country.

Parental Origin of the RB1 Gene Mutations in Families with Low Penetrance Hereditary Retinoblastoma

Simple Summary

Some families with hereditary retinoblastoma exhibit mild phenotype with low penetrance and variable expressivity, including complete absence of clinical signs of the disease in some carriers of the germline RB1 mutation. The identification of low-penetrance mutations in the RB1 gene and the study of their inheritance in pedigrees is contributing to understanding the mechanisms underlying the development of retinoblastoma with low penetrance. It is important both for further expansion of knowledge in the field of molecular genetics of retinoblastoma, and for competent genetic counseling and subsequent clinical management of families with this form of the disease. Our results support an assumption that parental origin of an RB1 mutation influences the likelihood of developing retinoblastoma. We also revealed a relatively high frequency of asymptomatic carriage of the RB1 mutations among the parents of retinoblastoma patients, highlighting the utmost necessity for molecular analysis among the probands’ relatives irrespective of their clinical status and family history of retinoblastoma.

Abstract

Our aim was to identify RB1 alterations causing hereditary low penetrance retinoblastoma and to evaluate how the parental origin of an RB1 mutation affects its phenotypic expression. By NGS and MLPA, RB1 mutations were found in 191 from 332 unrelated retinoblastoma patients. Among patients with identified RB1 mutations but without clinical family history of retinoblastoma, 7% (12/175) were found to have hereditary disease with one of the parents being an asymptomatic carrier of an RB1 mutation. Additionally, in two families with retinoblastoma history, mutations were inherited by probands from unaffected parents. Overall, nine probands inherited RB1 mutations from clinically unaffected fathers and five, from mothers. Yet, we gained explanations of maternal “unaffectedness” in most cases, either as somatic mosaicism or as clinical presentation of retinomas in involution, rendering the proportion of paternal to maternal truly asymptomatic mutation carriers as 9:1 (p = 0.005). This observation supports an assumption that parental origin of an RB1 mutation influences the likelihood of developing retinoblastoma. Additionally, our study revealed a relatively high frequency of asymptomatic carriage of the RB1 mutations among the parents of retinoblastoma patients, highlighting the utmost necessity of molecular analysis among the probands’ relatives irrespective of their clinical status and family history of retinoblastoma.

Epidemiologic trends and geographic distribution of patients with gallbladder and extrahepatic biliary tract cancers in Canada

BACKGROUND

Gallbladder and biliary tract cancers are rare malignancies that carry a poor prognosis. Research on their epidemiologic trends is scarce.

METHODS

We performed a retrospective analysis of the data in Canada using population-based cancer registries from 1992 to 2010. The incidence and mortality of gallbladder and extrahepatic bile duct cancers were examined at the levels of provinces/territories, cities, and Forward Sortation Area (FSA) postal codes.

RESULTS

The incidence and mortality rates decreased over the study period. The average national incidence rate of gallbladder and biliary tract cancers was 30.92 cases per million individuals per year. Higher than average incidence rates were observed in Manitoba, Saskatchewan and Québec; there were contiguous regions with high incidence in Saskatchewan and Manitoba that suggest an area of putative case clustering. Higher incidence of gallbladder cancer was observed in women, whereas higher incidence of extrahepatic bile duct cancers was noted in men. Lower socioeconomic status and Hispanic race were found to be risk factors for gallbladder and biliary tract cancers.

CONCLUSION

This is the first study to analyze the burden of gallbladder and biliary tract cancers in Canada. The geographic clustering trends present new avenues for research on environmental triggers.

Incidence and Mortality of Prostate Cancer in Canada during 1992-2010

In Canada, prostate cancer is the most common reportable malignancy in men. We assessed the temporal trends of prostate cancer to gain insight into the geographic incidence and mortality trends of this disease. Three independent population-based cancer registries were used to retrospectively analyze demographic data on Canadian men diagnosed with prostate cancer and men who died of prostate cancer between the years of 1992 and 2010. The incidence and mortality rates were calculated at the provincial, city, and forward sortation area (FSA) postal code levels by using population counts that were obtained from the Canadian Census of Population. The Canadian average incidence rate was 113.57 cases per 100,000 males. There has been an overall increasing trend in crude prostate cancer incidence between 1992 and 2010 with three peaks, in 1993, 2001, and 2007. However, age-adjusted incidence rates showed no significant increase over time. The national mortality rate was calculated to be 24.13 deaths per 100,000 males per year. A decrease was noted in crude and age-adjusted mortality rates between 1992 and 2010. Several provinces, cities, and FSAs had higher incidence/mortality rates than the national average. Several of the FSA postal codes with the highest incidence/mortality rates were adjacent to one another. Several Canadian regions of high incidence for prostate cancer have been identified through this study and temporal trends are consistent with those reported in the literature. These results will serve as a foundation for future studies that will seek to identify new regional risk factors and etiologic agents.

Clinicopathological analysis of 719 pediatric and adolescents' ocular tumors and tumor-like lesions: a retrospective study from 2000 to 2018 in China

AIM

To describe the clinicopathologic features and classification of pediatric and adolescent ocular tumors and tumor-like lesions.

METHODS

A total of 719 cases of pathologically confirmed ocular tumors and tumor-like lesions in a pediatric population from two academic institutions over an 18-year period were retrospectively analyzed. The main outcome measures were the clinical and pathological features of the cases.

RESULTS

Benign tumors accounted for 92.1% of all cases while malignant tumors accounted for 7.9%. The most common ocular benign tumors were (epi-)dermoid cysts (19.8%), nevi (15.2%), corneal dermoid tumors (9.8%), and calcified epitheliomas (8.8%). The most common ocular malignant tumors were retinoblastoma (80.8%), and rhabdomyosarcoma (3.9%). Eyelid and ocular surface tumors comprised 73.3% of benign tumors while intraocular and orbital cavity comprised 94.2% of malignant tumors. For tumor site, the upper eyelid was up to 1.79 times more than lower eyelid (P<0.05). Age at surgery and sex also had an association with different lesions (P=0.006, P=0.035, respectively).

CONCLUSION

Most ocular tumors and tumor-like lesions in children and adolescents are benign. Pediatric ocular tumors are distinct from those in adults in terms of histological origin. (Epi-)dermoid cysts are the most common benign tumors while retinoblastomas the most common malignant tumors.

Combined association of massive choroidal and optic nerve invasion as a prognostic relevance in primary retinoblastoma: A 10-year study

PURPOSE

To determine the significance of both massive choroidal invasion and optic nerve invasion (retrolaminar [(RL]+cut end [CE]) as a criterion for classifying high metastatic potential retinoblastoma and their relationship with other known histopathological high-risk features.

METHODS

A retrospective review of 650 eyes diagnosed as retinoblastoma over a 10-year period. In our study, there is male predominance and a higher percentage of the poorly differentiated tumors. The age of most of the patients ranges from 1 month to 8 years with a median age of 2 years.

RESULTS

There were 24% of eyes with massive choroidal invasion and 18% of eyes with optic nerve invasion up to the cut end. On performing Cox-proportional hazard analysis, it was found that massive choroidal invasion in association with optic nerve invasion up to the cut end was an independent prognostic parameter. On Kaplan-Meier analysis, overall survival had reduced in patients having both massive choroidal invasion and an optic nerve cut end invasion along with orbital invasion (P < .05).

CONCLUSION

The presence of massive choroidal invasion in association with optic nerve cut end invasion (RL+CE) could be used as a better prognostic predictor in assessing retinoblastoma patients with high metastatic potential and need to be kept for longer follow up.

High-risk features in primary versus secondary enucleated globes with advanced retinoblastoma: a retrospective histopathological study

PURPOSE

The management of bilateral advanced retinoblastoma (RB) cases is challenging with attempts to use neoadjuvant therapy salvaging of one of the globes. Our aim in this study was to demonstrate the effect of this primary therapy on the histopathological features and risk factors in secondary enucleated compared to primarily enucleated globes with groups D and E RB.

METHODS

We retrospectively reviewed all enucleated globes with advanced RB received in the pathology laboratories over a period of 5 years. Patients were divided into two groups: one with primary enucleations and another with at least one secondary enucleated globe, and their demographic and clinical data were analyzed. The enucleated globes in the two groups were analyzed to compare the general histopathological features including tumor seeding, size, differentiation, growth pattern, mitotic figures, and focality. More importantly, high-risk features: choroidal invasion, optic nerve (ON) invasion, iris/anterior chamber invasion, ciliary body invasion, and scleral and extra-scleral extension, as well as the pathological classification of the tumor (pT) according to the American Joint Committee on Cancer 7th edition were also compared between the two groups.

RESULTS

We had a total of 106 enucleated globes (78 primary and 28 secondary enucleations) from 99 patients with advanced RB (73 patients with primarily and 26 with secondarily enucleated globes). Demographic and clinical profiles of patients were similar in both, but the mean interval from presentation to enucleation was significantly longer in the secondary enucleations (P = 0.015). Rare/occasional mitotic figures were observed in secondary enucleations using multivariate analysis (P = 0.003). Primarily enucleated globes had higher risk of tumor seeding (P = 0.020), post-laminar/surgical margin ON invasion (P = 0.001), and massive choroidal invasion (P = 0.028). Half of the secondary enucleated globes had tumors confined to the globes without invasion (pT1) and statistically significant lower tumor classifications (pT1 or pT2a) compared to primary enucleations (P =0.001). However, 18% of the secondarily enucleated globes in 3 patients had unfavorable outcome with RB-related mortality after a period of 1-4 years.

CONCLUSIONS

Secondary enucleated globes with advanced RB show favorable histopathological findings mainly less mitosis. These eyes have significantly lower chance for harboring choroidal and ON invasion, thus mostly classified as pT1 or pT2a when compared to primarily enucleated globes. The decision for secondary enucleation was observed to be significantly delayed (8.0 months ± 9.8). Prompt decision for needed enucleation based on the response to primary treatment and careful histopathological examination of enucleated globes are essential to prevent disease-related mortality.

Investigating epidemiologic trends and the geographic distribution of patients with anal squamous cell carcinoma throughout Canada

Background

Anal cancer is a rare disease, constituting 0.5% of new cancer cases in the United States. The most common subtype is squamous cell carcinoma (scc). Studies in several developed nations have reported on an increasing incidence of anal cancer in recent decades, and various risk factors pertaining to the pathogenesis of the disease have been identified, including infection with the human papillomavirus, tobacco use, and immunosuppression. The epidemiology and distribution of anal scc throughout Canada remain poorly understood, however.

Methods

Using 3 population-based cancer registries, a retrospective analysis of demographic data across Canada for 1992-2010 was performed. The incidence and mortality for anal scc was examined at the levels of provinces, cities, and the forward sortation area (FSA) component (first 3 characters) of postal codes.

Results

During 1992-2010, 3720 individuals were diagnosed with anal scc in Canada; 64% were women. The overall national incidence rate was 6.3 cases per million population per year, with an average age at diagnosis of 60.4 years. The incidence increased over time, with significantly higher incidence rates documented in British Columbia and Nova Scotia (9.3 cases per million population each). Closer examination revealed clustering of cases in various urban centres and self-identified lgbtq communities in Toronto, Montreal, and Vancouver.

Discussion

This study provides, for the first time, a comprehensive analysis of the burden of anal scc in Canada, identifying susceptible populations and shedding light onto novel avenues of research to lower the incidence of anal cancer throughout the country.

Epidemiology of adult and pediatric Burkitt lymphoma in Canada: sequelae of the HIV epidemic

Background

Although the pathogenesis and epidemiology of endemic Burkitt lymphoma (bl) have been extensively studied, the epidemiologic landscape of sporadic and immunodeficiency-associated bl in North America remains poorly understood.

Methods

We used 3 distinct population-based cancer registries to retrospectively study bl incidence and mortality in Canada. Data for patient sex; age at the time of diagnosis; and reporting province, city, and forward sortation area (fsa, the first three characters of a postal code) were analyzed.

Results

During 1992-2010, 1420 patients with bl in Canada were identified (incidence rate: 2.40 cases per million patient-years), of which 71.1% were male patients. Mean age at diagnosis was 55.5 ± 20.8 years. A bimodal incidence by age distribution was seen in both sexes, with pediatric- and adult-onset peaks. An analysis based on fsas identified select communities with statistically higher rates of adult bl. Several of those fsas were located within the 3 major metropolitan areas (Montreal, Vancouver, Toronto) and within self-identified lgbtq communities. The fsas with a higher socioeconomic status score were associated with lower rates of bl.

Conclusions

Current results highlight the geographic and historic pattern of bl in Canada. The human immunodeficiency virus remains an important risk factor for adult bl.

Epidemiology and Patient Distribution of Oral Cavity and Oropharyngeal SCC in Canada

BACKGROUND

Oral cavity cancers (OCCs) and oropharyngeal cancers (OPCs) continue to be a major source of morbidity and mortality worldwide requiring the shared effort of numerous specialists. Tobacco and alcohol consumption have long been identified as risk factors for both OCC and OPC. In addition, human papilloma virus (HPV) is gaining its position as the main causal agent for OPC.

OBJECTIVE

The objective of this study is to analyze the epidemiology of OCC and OPC in Canada.

METHODS

Data pertaining to the year of diagnosis, the patient's sex, age at the time of diagnosis, province/territory, city and postal code of oral cavity, and oropharyngeal malignancies diagnosed during 1992-2010 were extracted from the Canadian Cancer Registry and Le Registre Québécois du Cancer.

RESULTS

In total, 21 685 OCC cases and 15 965 OPC cases were identified from 1992 to 2010. Of those, 84.97% were oral cavity squamous cell carcinomas (SCCs), 88.10% were oropharyngeal SCCs, and both had a significant male predominance. While oral cavity SCC incidence stabilized over the study period, oropharyngeal SCC continued to increase. Oral cavity SCC incidence increased with age, while oropharyngeal SCC incidence peaked in the 50- to 59-year age group. Detailed geographic distribution analysis of patients at the provincial/territorial, city, and postal code levels identified several patient clusters.

CONCLUSIONS

This work highlights important epidemiological differences in trends between oral and oropharyngeal cancers, identifies high-incidence postal codes for each malignancy, and correlates incidence/mortality with known risk factors including alcohol/tobacco use and HPV infections, therefore providing a comprehensive understanding of epidemiology for these cancers in Canada.

Retinoblastoma in Finland, 1964–2014: incidence and survival

Aims

To determine the incidence of retinoblastoma (Rb) and subsequent survival in the Finnish population during five decades.

Methods

This retrospective observational cohort study comprised all patients with Rb born in Finland during 1964–2014 and diagnosed in 2018 (birth cohort analysis) or diagnosed in 1964–2014 (standard annual analysis), identified from the Finnish Cancer Registry and the national referral centre. We report age-adjusted incidences and survival according to cause of death.

Results

Of children born in 1964–2014, 205 developed Rb, whereas 204 Rbs were diagnosed during these years; 196 belonged to both cohorts. Altogether 80 (38%) of the 213 children had heritable Rb and 19 (9%) had familial disease. The sex ratio was 1.34, suggesting male preponderance. Birth cohort analysis showed a median incidence of 6.2 per 100 000 live births (1:16 130) and less variability as compared with standard annual analysis (12.1, 6.5 and 4.4 per million children 0–4, 0–9 and 0–14 years of age, respectively). The incidence of heritable Rb increased with time, reflecting the increase in familial tumours. Five-year mortality rates from Rb were 6.2% and 7.6% for non-heritable and heritable diseases, respectively, and 35-year mortality rates from second malignancies were 0% and 14.3%, respectively. Family history predicted improved survival, whereas the period of diagnosis did not.

Conclusion

The incidence of familial Rb has increased, along with improvement in survival in Finland in 1964–2014, whereas the overall incidence of Rb was stable. Long-term risk of dying of second malignancies after heritable Rb was in line with other countries.

Epidemiology of invasive ocular surface squamous neoplasia in Canada during 1992-2010

BACKGROUND

Ocular surface squamous neoplasia (OSSN) is the most common non-pigmented ocular surface malignancy. It is classified as invasive OSNN (IOSSN) when the underlying stroma are infiltrated by dysplastic squamous epithelial cells through the basement membrane. Here, we present the descriptive epidemiology and geographical distribution of IOSSN in Canada.

METHODS

We determined the incidence and geographical distribution of IOSSN cases diagnosed between 1992 and 2010 using two independent population-based cancer registries: the Canadian Cancer Registry and Le Registre Québécois du Cancer.

RESULTS

The mean annual age-standardised incidence rate (WHO 2000-2025) of IOSSN for 1992-2010 was 0.45 cases per million individuals per year with an average annual percent increase in incidence of 4.5%. IOSSN localisation to the conjunctiva was documented in at least 57% of the reported cases. IOSSN exhibited a male predilection ratio of 3.3:1.0 with a mean age at diagnosis of 69 years. Incidence rates of IOSSN across Canadian provinces and cities showed no significant differences from the crude national average.

CONCLUSIONS

Our results, particularly concerning IOSSN patient age and male predilection, corroborate with data reported from the USA. Additional studies are needed to determine whether the observed increase in incidence rate over the study period (1992-2010) is significant.

Epidemiology of ophthalmic lymphoma in Canada during 1992-2010

BACKGROUND

Ophthalmic lymphoma (OL) is the most common orbital tumour, particularly in older individuals. Little is known about the epidemiology and geographic distribution of OL in Canada. Descriptive demographic statistics are an important first step in understanding OL burden and are necessary to inform comprehensive national cancer prevention programmes.

METHODS

We determined patterns of incidence and geographical distribution of the three major subtypes of OL: extranodal marginal zone B cell lymphoma, follicular lymphoma (FL) and diffuse large B cell lymphoma. Here, we used cases that were diagnosed during 1992-2010 using two independent population-based cancer registries, the Canadian Cancer Registry and Le Registre Québécois du Cancer (LRQC).

RESULTS

The OL mean annual age-standardised incidence rate for 1992-2010 was 0.65 cases per million people per year with an average annual increase in the incidence rate of 4.5% per year. The mean age of diagnosis was 65 years. OL incidence rate was the highest in the cities located along the heavily industrialised Strait of Georgia in British Columbia.

CONCLUSIONS

Our data on patient age, sex and temporal trends showed similarities with data reported in the USA and Denmark. Additional studies are needed to determine whether the observed increase in OL incidence is genuine or spurious.

Epidemiologic trends and geographic distribution of esophageal cancer in Canada: A national population-based study

Background

Esophageal cancer can be subdivided into two main histological subtypes with significant variability in their etiology and epidemiology. The incidence of esophageal adenocarcinoma (AC) is increasing across the developed countries, whereas the incidence of esophageal squamous cell carcinoma (SCC) is declining. Several risk factors have been identified in the pathogenesis of each subtype, however, their epidemiologic characteristics and distribution throughout Canada remain poorly understood.

Methods

We performed a retrospective analysis of demographic data across Canada from 1992 to 2010 using two independent population‐based cancer registries. The incidence of esophageal cancer, for each subtype, was examined at the levels of provinces/territories, cities, and postal codes.

Results

A total of 19 790 patients were diagnosed with esophageal cancer in Canada between 1992 and 2010; 74% were males. The average national incidence rate was 33.5 cases per million individuals per year. Incidence of esophageal AC increased over time, with notable high‐incidence rates on the Vancouver Island, the coasts of the Great Lakes, and the coasts of the Northumberland Strait in the Maritimes. The overall incidence of esophageal SCC has decreased. However, high incidence of esophageal SCC was detected in the Vancouver city, rural eastern Québec, and in the Maritimes. We also report clustering for each subtype using postal codes, which sheds light onto new avenues of research for potential environmental etiologies.

Conclusions

This study, for the first time, provides a detailed analysis on the burden of esophageal cancer in Canada, revealing important geographic clustering trends.

Analysis of incidence, mortality trends, and geographic distribution of breast cancer patients in Canada

BACKGROUND/PURPOSE

Breast cancer is the malignancy with the highest incidence rate excluding non-melanoma skin cancers, and the second leading cause of cancer-related deaths among Canadian women. Many modifiable risk factors have been linked to the pathogenesis of this disease. The purpose of this study is to analyze the epidemiology of breast cancer in Canada and to examine its geographic distribution to help identify new risk factors for this disease.

METHODS

Three independent population-based cancer registries were used to retrospectively analyze demographic data from Canadian women diagnosed with invasive breast cancer across all provinces and territories between 1992 and 2010. The incidence and mortality rates were assessed at the provincial, city, and forward sortation area (FSA) postal code levels.

RESULTS

The overall age-adjusted incidence rate was 114.4 cases per 100,000 females per year. Six provinces and several groups of FSAs had significantly higher incidence rates. There was a significant increase in incidence and decrease in mortality rates between 1992 and 2010. The overall mortality rate was 31.5 deaths per 100,000 females per year. However, three provinces had significantly higher mortality rates.

CONCLUSION

By identifying high-incidence areas for breast cancer, our study will help identify patient populations that are at higher risk for this malignancy. It will also act as a foundation for future studies to establish novel risk factors for this disease.

Identification of significant geographic clustering of polycythemia vera cases in Montreal, Canada

BACKGROUND

Polycythemia vera (PV) is a chronic myeloproliferative neoplasm associated at times with debilitating symptoms and a significant mortality rate. Understanding the demographics, epidemiology, and geography of this disease may provide further insight into important risk factors associated with its development. The objective of this study was to analyze patient demographics, incidence, and mortality rates, as well as the geographic distribution of PV patients in Canada between 1992 and 2010.

METHODS

This study was achieved by analyzing the Canadian Cancer Registry, Le Registre Québécois du Cancer, and the Canadian Vital Statistics patient databases.

RESULTS

A total of 4645 patients were diagnosed with PV between 1992 and 2010. While the annual incidence rate of this cancer fluctuated in Canada, mortality rate analysis indicated a decreasing trend. Geographically, PV incidence rates were notably elevated in the province of Quebec compared with the Canadian average. Further analysis of high-incidence forward sortation areas indicated a striking clustering of cases in the H4W region encompassing the Côte-Saint-Luc borough of Montreal, with an incidence of 102.97 (95% confidence interval, 75.11-137.79) cases per million per year, which is >13 times the national average.

CONCLUSION

The residential area of Côte-Saint-Luc is an important PV cluster in Canada, with high concentration of retirement homes and geriatric hospices. Also, Jewish residents comprise >60% of the population in this neighborhood. These findings suggest that an older age and, potentially, an inherent genetic predisposition may be implicated in the pathogenesis of this malignancy. This study provides a comprehensive overview of PV burden/geographic distribution of cases in Canada.

Incidence and mortality trends and geographic patterns of follicular lymphoma in Canada

Background

Follicular lymphoma (fl) is the most common indolent lymphoma and the 2nd most common non-Hodgkin lymphoma, accounting for 10%-20% of all lymphomas in the Western world. Epidemiologic and geographic trends of fl in Canada have not been investigated. Our study's objective was to analyze incidence and mortality rates and the geographic distribution of fl patients in Canada for 1992-2010.

Methods

Demographic and geographic patient data for fl cases were obtained using the Canadian Cancer Registry, the Registre québécois du cancer, and the Canadian Vital Statistics database. Incidence and mortality rates and 95% confidence intervals were calculated per year and per geographic area. Rates were plotted using linear regression models to assess trends over time. Overall data were mapped using Microsoft Excel mapping software (Redmond, WA, U.S.A.) to identify case clusters across Canada.

Results

Approximately 22,625 patients were diagnosed with fl during 1992-2010. The age-standardized incidence rate of this malignancy in Canada was 38.3 cases per million individuals per year. Geographic analysis demonstrated that a number of Maritime provinces and Manitoba had the highest incidence rates, and that the provinces of Nova Scotia and Quebec had the highest mortality rates in the nation. Regional data demonstrated clustering of fl within cities or regions with high herbicide use, primary mining, and a strong manufacturing presence.

Conclusions

Our study provides a comprehensive overview of the fl burden and its geographic distribution in Canada. Regional clustering of this disease in concentrated industrial zones strongly suggests that multiple environmental factors might play a crucial role in the development of this lymphoma.

Clinicopathological Findings of Retinoblastoma: A 10-Year Experience from a Tertiary Hospital in Kampala, Uganda

Background

Retinoblastoma (RB) is one of the most common cancers occurring in young children in sub-Saharan Africa. The incidence rate reported in the literature is 9,000 new cases per year, which corresponds to 1 in 15,000 births. This study aimed at analyzing the clinicopathological findings in children with RB in Uganda.

Purpose

The purpose of this study was to describe and analyze the clinicopathological findings in the patients with RB.

Design

This was a cross-sectional analytical study involving 234 eyeball surgical specimens from 214 patients with RB diagnosed between January 2006 and December 2015.

Results

The mean age of the patients was 27.8 months (SD = 21.413, range: 1–132 months). More than half of the cases, 50.9%, presented with leucokoria. Invasion of choroid, sclera, anterior chamber, and optic nerve was found in 26.5% (n = 58), 51.2% (n = 88), 26.2% (n = 45), and 29.2% (n = 49), respectively. Twenty-six percent (n = 56) of the cases with intraocular tumour were at stage I and all patients with metastasis 4.7% (n = 11) had stage IV. The correlation between postlaminar optic nerve invasion and massive choroidal invasion was statistically significant (P = 0.002). Also, there was a statistical significance difference between metastasis and postlaminar invasion (P = 0.004).

Conclusion

The majority of children with RB in Uganda present clinically with leucokoria, and their parents or guardians seek medical intervention at a later stage. Moreover, there was a noticeably significant lag period for the patients to begin treatment after the diagnosis was done.