Stage at diagnosis and survival by stage for the leading childhood cancers in three populations of sub-Saharan Africa

Stage at diagnosis and survival by stage for the leading childhood cancers in Rwanda

BACKGROUND

The lack of accurate population-based information on childhood cancer stage and survival in low-income countries is a barrier to improving childhood cancer outcomes.

METHODS

In this study, data from the Rwanda National Cancer Registry (RNCR) were examined for children aged 0-14 diagnosed in 2013-2017 for the eight most commonly occurring childhood cancers: acute lymphoblastic leukaemia, Hodgkin lymphoma (HL), Burkitt lymphoma (BL), non-Hodgkin lymphoma excluding BL, retinoblastoma, Wilms tumour, osteosarcoma and rhabdomyosarcoma. Utilising the Toronto Childhood Cancer Stage Guidelines Tier 1, the study assigned stage at diagnosis to all, except HL, and conducted active follow-ups to calculate 1-, 3- and 5-year observed and relative survival by cancer type and stage at diagnosis.

RESULTS

The cohort comprised 412 children, of whom 49% (n = 202) died within 5 years of diagnosis. Five-year survival ranged from 28% (95% confidence interval [CI]: 12.5%-45.6%) for BL to 68% (CI: 55%-78%) for retinoblastoma. For the cancers for which staging was carried out, it was assigned for 83% patients (n = 301 of 362), with over half (58%) having limited or localised stage at diagnosis. Stage was a strong predictor of survival; for example, 3-year survival was 70% (95% CI: 45.1%-85.3%) and 11.8% (2.0%-31.2%) for limited and advanced non-HL, respectively (p < .001).

CONCLUSION

This study is only the second to report on stage distribution and stage-specific survival for childhood cancers in sub-Saharan Africa. It demonstrates the feasibility of the Toronto Stage Guidelines in a low-resource setting, and highlights the value of population-based cancer registries in aiding our understanding of the poor outcomes experienced by this population.

Evidence in Focus: The Sparse Landscape of Randomized Trials on Retinoblastoma Treatment

Background

Retinoblastoma, although rare, is one of the most common intraocular malignancies worldwide. Its prognosis has improved significantly in the past few decades, thanks to modern treatments, like systemic, intra-arterial, and intravitreal chemotherapy. However, regarding survival, there are significant differences between high- and low-income countries, eye salvage is still a challenge worldwide, and treatment-related toxicity needs to be carefully and sufficiently managed.

Summary

To appraise the strength of supporting evidence, we performed a systematic review of randomized controlled trials investigating any therapeutic protocol for retinoblastoma. Four trials with 174 participants (188 eyes) were eligible, all pertaining to different intravenous chemotherapy regimens. Vincristine, etoposide, and carboplatin (VEC) appear superior to a 5-drug combination for stage III retinoblastoma. Moreover, etoposide and carboplatin as neoadjuvant chemotherapy followed by thermochemotherapy seem to offer better local control than vincristine and carboplatin. However, increasing carboplatin dose in the VEC protocol failed to improve treatment efficacy.

Key Messages

Retinoblastoma is a success story of modern medicine. However, only intravenous chemotherapy has been studied through randomized trials, while evidence for the most novel retinoblastoma treatments has mainly stemmed from observational studies. International collaborations for multicenter randomized trials could overcome difficulties and increase certainty and precision in the field.

The feasibility of implementing Toronto childhood cancer stage guidelines and estimating the impact on outcome for childhood cancers in seven pediatric oncology units in sub-Saharan Africa. A study from the Franco-African Pediatric Oncology Group

BACKGROUND

The improvement of childhood cancer outcome is determined by early diagnosis, effective treatment, supportive care, and adequate medical follow-up. Stage at diagnosis may reflect timeliness of diagnosis, therefore standardized registration of stage is essential for interpretation of regional differences and time trends in survival. Here, we describe the feasibility of implementing the Toronto Childhood Cancer Stage Guidelines (hereafter Toronto Guidelines [TG]) in the hospital-based cancer registry of the Franco-African Pediatric Oncology Group (GFAOP), and assess the impact of TG stage on outcome in pediatric oncology units (POUs) in seven low- and middle-income countries in sub-Saharan Africa (SSA).

METHODS

All cancer patients diagnosed before 15 years of age with one of the 15 cancer types defined in TG, resident in one of the participating countries, and attending one of the selected POUs in 2017-2019 were included. Stage was assigned according to TG. Patients were followed-up for vital status for at least 12 months post diagnosis. Survival at 3, 6, and 12 months was calculated using Kaplan-Meier method and compared between POUs and tumor groups using log-rank test.

RESULTS

TG stage was assigned to 1772 of 2446 (89%) cases diagnosed with one of 11 cancer types. It was not possible to assign TG stage to acute lymphoblastic leukemia (ALL) and the three types of the central nervous system tumors included in the TG. One-year overall survival (OS) was 58% [95% confidence interval: 55-60] and varied between POUs. Survival declined with increasing stage for four tumor types and was statistically significant for two.

CONCLUSION

Except for ALL and brain tumors, we demonstrated feasibility of TG implementation for childhood solid cancers in participating POUs in SSA, and provided a baseline assessment of childhood cancer outcomes against which future stage distribution and survival can be measured as timelines of diagnosis improve over time within the GFAOP network.

Enhancing information on stage at diagnosis for childhood cancer in Africa

BACKGROUND/PURPOSE

Stage at diagnosis is an important metric in treatment and prognosis of cancer, and also in planning and evaluation of cancer control. In sub-Saharan Africa (SSA), for the latter, the only data source is the population-based cancer registry (PBCR). For childhood cancers, the 'Toronto Staging Guidelines' have been developed to facilitate abstraction of stage by cancer registry personnel. Although the feasibility of staging using this system has been shown, there is limited information on the accuracy of staging.

METHODS

A panel of case records of six common childhood cancers was established. A total of 51 cancer registrars from 20 SSA countries staged these records, using Tier 1 of the Toronto guidelines. The stage that they assigned was compared with that decided by two expert clinicians.

RESULTS

The registrars assigned the correct stage for 53%-83% of cases (71% overall), with the lowest values for acute lymphocytic leukaemia (ALL), retinoblastoma and non-Hodgkin lymphoma (NHL), and the highest for osteosarcoma (81%) and Wilms tumour (83%). For ALL and NHL, many unstageable cases were mis-staged, probably due to confusion over the rules for dealing with missing data; for the cases with adequate information, accuracy was 73%-75%. Some confusion was observed over the precise definition of three stage levels of retinoblastomas.

CONCLUSIONS

A single training in staging resulted in an accuracy, for solid tumours, that was not much inferior to what has been observed in high-income settings. Nevertheless, some lessons were learned on how to improve both the guidelines and the training course.

Temporal changes in childhood cancer incidence and survival by stage at diagnosis in Australia, 2000-2017

BACKGROUND

The Toronto Paediatric Cancer Stage Guidelines are a compendium of staging systems developed to facilitate collection of consistent and comparable data on stage at diagnosis for childhood cancers by cancer registries.

MATERIAL AND METHODS

This retrospective, observational cohort study investigated changes in stage-specific incidence and survival for children diagnosed between 2000-2008 compared to 2009-2017 using the population-based Australian Childhood Cancer Registry. Information on mortality for each patient was available to 31st December 2020. Shifts in incidence by stage were evaluated using chi-square tests, and differences in stage-specific five-year observed survival for all causes of death over time were assessed using flexible parametric models.

RESULTS

Stage was assigned according to the Toronto Guidelines for 96% (n = 7944) of the total study cohort (n = 8292). Changes in the distribution of incidence by stage between the two diagnosis periods were observed for retinoblastoma, with stage 0 increasing from 26% to 37% of cases (p = 0.02), and hepatoblastoma, with metastatic disease increasing from 22% to 39% of cases (p = 0.04). There were large gains in stage-specific survival over time for stage IV rhabdomyosarcoma (five-year adjusted mortality hazard ratio for 2009-2017 compared to 2000-2008 of 0.38, 95% CI 0.19-0.77; p = 0.01), stage M3 for medulloblastoma (HR = 0.41, 95% CI 0.21-0.79; p = 0.01) and metastatic neuroblastoma excluding stage MS (HR = 0.61, 95% CI 0.44-0.84; p < 0.01).

CONCLUSION

These results indicate that improvements in childhood cancer survival in Australia are most likely due to refined management rather than changes in stage at diagnosis, particularly for metastatic solid tumours. Wide international uptake of the Toronto Guidelines will allow comprehensive evaluation of differences in survival between countries.

Childhood and Adolescent Cancer Care at a Tertiary Hospital in Northern Tanzania: A Retrospective Study

PURPOSE

Over 400,000 children are diagnosed with cancer around the world each year, with over 80% of these children residing in low- and middle-income countries. This study aims to summarize the epidemiology and care patterns of newly diagnosed childhood cancer patients in Northern Tanzania.

METHODS

Data from all children and adolescents (age 0-19 years) with newly diagnosed cancers were collected from the Kilimanjaro Cancer Registry located at the Kilimanjaro Christian Medical Centre. Descriptive and inferential analyses were used to compare the demographic and clinical characteristics of the participants over time, stage, and status at last contact. Statistical significance was set at P < .05. Secondary descriptive analysis was conducted on a subset sample with available staging data.

RESULTS

A total of 417 patients were diagnosed with cancer between 2016 and 2021. There was an increase in the rate of patients with newly diagnosed pediatric cancer each year, particularly among children under age 5 years and 10 years. Leukemias and lymphomas were the leading diagnoses and accounted for 183 (43.8%) of all patients. Over 75% of patients were diagnosed at stage III or above. From a subset analysis of patients with available staging data (n = 101), chemotherapy was the most common treatment (87.1%), compared with radiotherapy and surgery.

CONCLUSION

There is a significant burden of children with cancer in Tanzania. Our study fills crucial gaps in the literature related to the large burden of disease and survival for children with cancer in the Kilimanjaro region. Furthermore, our results can be used to understand the regional needs and guide research and strategic interventions to improve childhood cancer survival in Northern Tanzania.

Burkitt lymphoma

Burkitt lymphoma (BL) is an aggressive form of B cell lymphoma that can affect children and adults. The study of BL led to the identification of the first recurrent chromosomal aberration in lymphoma, t(8;14)(q24;q32), and subsequent discovery of the central role of MYC and Epstein-Barr virus (EBV) in tumorigenesis. Most patients with BL are cured with chemotherapy but those with relapsed or refractory disease usually die of lymphoma. Historically, endemic BL, non-endemic sporadic BL and the immunodeficiency-associated BL have been recognized, but differentiation of these epidemiological variants is confounded by the frequency of EBV positivity. Subtyping into EBV⁺ and EBV^- BL might better describe the biological heterogeneity of the disease. Phenotypically resembling germinal centre B cells, all types of BL are characterized by dysregulation of MYC due to enhancer activation via juxtaposition with one of the three immunoglobulin loci. Additional molecular changes commonly affect B cell receptor and sphingosine-1-phosphate signalling, proliferation, survival and SWI-SNF chromatin remodelling. BL is diagnosed on the basis of morphology and high expression of MYC. BL can be effectively treated in children and adolescents with short durations of high dose-intensity multiagent chemotherapy regimens. Adults are more susceptible to toxic effects but are effectively treated with chemotherapy, including modified versions of paediatric regimens. The outcomes in patients with BL are good in high-income countries with low mortality and few late effects, but in low-income and middle-income countries, BL is diagnosed late and is usually treated with less-effective regimens affecting the overall good outcomes in patients with this lymphoma.

The University of Cape Town’s paediatric cancer database: Results from the first years (2019–2021)

Background: The paediatric oncology multidisciplinary team at the University of Cape Town (UCT) developed a research-ready data set.Aim: This study aimed to describe the early results detailing the epidemiological profile of childhood cancer patients and evaluated factors associated with presentation and outcome.Setting: The UCT paediatric oncology platform at the Red Cross War Memorial Children’s Hospital (RCWMCH) and Groote Schuur Hospital (GSH).Methods: A REDCap database was developed with a Cancer Association of South Africa (CANSA) grant. A database administrator consented all new patients and recorded demographic and social information.Results: There were 212 children consented from 2019 to 2021: 109 girls and 103 boys. The age range was from 1 day to 15.98 years, with a median of 5.18 years. Only 32 (15%) of these families had medical insurance, 34 (16%) lived in informal housing and 25 (12%) did not have access to piped water. Seventy-four families (35%) reported a relative with cancer, including seven first degree relatives. With a median follow-up of 12.4 months, the estimated 2-year overall survival (OS) and event-free survival (EFS) was 77% and 72%, respectively. Overall survival was significantly different (p = 0.013) by disease group, varying from 100% for Wilms tumour and germ cell tumours to 52% for rhabdomyosarcoma. Most patients with solid tumours (72%) had advanced disease at diagnosis. Outcomes were poorer for children living in informal housing and without piped water.Conclusion: A real-time database can provide a research-ready data set for interrogating cohort-specific factors impacting childhood cancer outcomes. 

The development of an international childhood cancer hospital register database in 13 African countries. A project of the French African Pediatric Oncology Group (GFAOP)

BACKGROUND AND AIM

The establishment of an international hospital-based register (HBR) for the French African Pediatric Oncology Group (GFAOP) was a necessary step in the group's clinical research program. With help from the Sanofi Espoir Foundation's "My Child Matters" program, the GFAOP resolved to develop an international HBR network to collect quality data on children attending the Pediatric Oncology Units (POUs).

METHODS

All children entering POUs from January 2016 to December 2018 were registered using an online questionnaire. Data collection included information on diagnosis, disease stage, demographics, socioeconomic status, and outcome. An intensive training program was developed to improve both data quality and quantity.

RESULTS

Among the 3348 children registered, 3230 had a suspected cancer, 681 were not confirmed. A diagnosis was confirmed on radiological, clinical, or histological examination for 2549 children including Burkitt lymphoma (516: 20%)-the most frequent diagnosis, Wilms' tumor (459: 18%), retinoblastoma (357: 14%), and acute lymphoblastic leukemia (345: 13%). Of these, 2187 children were treated. Early deaths, abandonment, economic difficulties, and lack of equipment were some of the reasons offered to explain the numbers of undiagnosed and untreated children. Vital status is known for 1994 children: 1187 died and 807 were alive, 551 of these with a follow-up > 12 months.

CONCLUSION

This work has provided reliable data on children attending the POUs, especially clarifying reasons and occasions for care rupture. The data will help to identify material, human resources, and staff training needs, to evaluate progress, and to encourage consideration of pediatric cancer in national cancer plans.

Mapping Pediatric Oncology Clinical Trial Collaborative Groups on the Global Stage

The global pediatric oncology clinical research landscape, particularly in Central and South America, Africa, and Asia, which bear the highest burden of global childhood cancer cases, is less characterized in the literature. Review of how existing pediatric cancer clinical trial groups internationally have been formed and how their research goals have been pursued is critical for building global collaborative research and data-sharing efforts, in line with the WHO Global Initiative for Childhood Cancer.

Local stakeholder engagement is necessary to collaborate with global pediatric cancer trial groups.

Wilms tumour

Wilms tumour (WT) is a childhood embryonal tumour that is paradigmatic of the intersection between disrupted organogenesis and tumorigenesis. Many WT genes play a critical (non-redundant) role in early nephrogenesis. Improving patient outcomes requires advances in understanding and targeting of the multiple genes and cellular control pathways now identified as active in WT development. Decades of clinical and basic research have helped to gradually optimize clinical care. Curative therapy is achievable in 90% of affected children, even those with disseminated disease, yet survival disparities within and between countries exist and deserve commitment to change. Updated epidemiological studies have also provided novel insights into global incidence variations. Introduction of biology-driven approaches to risk stratification and new drug development has been slower in WT than in other childhood tumours. Current prognostic classification for children with WT is grounded in clinical and pathological findings and in dedicated protocols on molecular alterations. Treatment includes conventional cytotoxic chemotherapy and surgery, and radiation therapy in some cases. Advanced imaging to capture tumour composition, optimizing irradiation techniques to reduce target volumes, and evaluation of newer surgical procedures are key areas for future research.