Wilms tumor in Africa: A systematic review of management challenges and outcome in two decades (2000-2019)

Prevention of treatment abandonment remains an important challenge to increase survival of Wilms tumor in sub-Saharan Africa: A report from Wilms Africa-CANCaRe Africa

BACKGROUND

The Wilms Africa studies implemented an adapted Wilm's tumor (WT) treatment protocol in sub-Saharan Africa in two phases. Phase I began with four sites and provided out-of-pocket costs. Phase II expanded the number of sites, but lost funding provision. Objective is to describe the outcomes of Phase II and compare with Phase I.

METHODS

Wilms Africa Phase I (n = 4 sites; 2014-2018) and Phase II (n = 8 sites; 2021-2022) used adapted treatment protocols. Funding for families' out-of-pocket costs was provided during Phase I but not Phase II. Eligibility criteria were age less than 16 years and newly diagnosed unilateral WT. We documented patients' outcome at the end of planned first-line treatment categorized as treatment abandonment, death during treatment, and disease-related events (death before treatment, persistent disease, relapse, or progressive disease). Sensitivity analysis compared outcomes in the same four sites.

RESULTS

We included 431 patients in Phase I (n = 201) and Phase II (n = 230). The proportion alive without evidence of disease decreased from 69% in Phase I to 54% in Phase II at all sites (p = .002) and 58% at the original four sites (p = .04). Treatment abandonment increased overall from 12% to 26% (p < .001), and was 20% (p = .04) at the original four sites. Disease-related events (5% vs. 6% vs. 6%) and deaths during treatment (14% vs. 14% vs. 17%) were similar.

CONCLUSION

Provision of out-of-pocket costs was important to improve patient outcomes at the end of planned first-line treatment in WT. Prevention of treatment abandonment remains an important challenge.

Treatment abandonment in children with Wilms tumor at a national referral hospital in Uganda

INTRODUCTION

The incidence of pediatric Wilms' tumor (WT) is high in Africa, though patients abandon treatment after initial diagnosis. We sought to identify factors associated with WT treatment abandonment in Uganda.

METHODS

A cohort study of patients < 18 years with WT in a Ugandan national referral hospital examined clinical and treatment outcomes data, comparing children whose families adhered to and abandoned treatment. Abandonment was defined as the inability to complete neoadjuvant chemotherapy and surgery for patients with unilateral WT and definitive chemotherapy for patients with bilateral WT. Patient factors were assessed via bivariate logistic regression.

RESULTS

137 WT patients were included from 2012 to 2017. The mean age was 3.9 years, 71% (n = 98) were stage III or higher. After diagnosis, 86% (n = 118) started neoadjuvant chemotherapy, 59% (n = 82) completed neoadjuvant therapy, and 55% (n = 75) adhered to treatment through surgery. Treatment abandonment was associated with poor chemotherapy response (odds ratio [OR] 4.70, 95% confidence interval [CI] 1.30-17.0) and tumor size > 25 cm (OR 2.67, 95% CI 1.05-6.81).

CONCLUSIONS

Children with WT in Uganda frequently abandon care during neoadjuvant therapy, particularly those with large tumors with poor response. Further investigation into the factors that influence treatment abandonment and a deeper understanding of tumor biology are needed to improve treatment adherence of children with WT in Uganda.

Surgical aspects and outcomes after nephrectomy for Wilms tumour in sub-Saharan Africa: A report from Wilms Africa Phase II-CANCaRe Africa

BACKGROUND

Wilms tumour (WT) is one of the common and curable cancer types targeted by the Global Initiative for Childhood Cancer. Tumour excision is essential for cure. This analysis focuses on surgical outcomes of patients with WT in sub-Saharan Africa.

METHODS

We implemented a risk-stratified WT treatment guideline as a multicentre, prospective study across eight hospitals and six countries. Eligibility criteria were age 6 months to 16 years, unilateral WT, surgery performed after preoperative chemotherapy and diagnosed between 1 January 2021 and 31 December 2022. Data collection included a specific surgical case report form (CRF).

RESULTS

The study registered 230 patients, among whom 164 (71.3%) had a nephrectomy. Ninety-eight percent of patients had a completed surgical CRF. Out 164 patients, 50 (30.5%) had distant metastases. Median tumour diameter at surgery was 11.0 cm. Lymph node sampling was done in 122 (74.3%) patients, 34 (20.7%) had intraoperative tumour rupture, and for 18 (10.9%), tumour resection involved en bloc resection of another organ. Tumour size at surgery was significantly correlated with tumour rupture (p < .01). With a median follow-up of 17 months (range: 2-33), 23 (14.0%) patients have relapsed. Twenty-two (13.4%) patients abandoned treatment post nephrectomy. Two-year event-free survival was 60.4% ± 4.7% with treatment abandonment as an event.

CONCLUSION

Survival post nephrectomy is challenged by treatment abandonment, treatment-related mortality and relapse. Large tumours after preoperative chemotherapy were associated with a higher risk of tumour rupture. Earlier diagnosis and access to radiotherapy are expected to improve survival.

Disseminated adult Wilms tumor in pregnancy: Leveraging multidisciplinary care in a low-resource setting

Wilms tumor (WT) occurring in adults is rare and even much more rarely found to coexist with pregnancy. Clinical outcome in adults is worse overall compared with pediatric patients with WT and is often misdiagnosed with no standardized protocols for care guided by high-evidence clinical trials. We present a case of a 23-year-old woman diagnosed with WT who was found to be pregnant immediately following nephrectomy. Workup findings showed that she had disseminated disease but was successfully managed in a multidisciplinary team setting with modified intrapartum chemotherapy followed by postpartum chemotherapy. In low-resource settings, management protocols for adult patients with WT can be individualized by multidisciplinary teams to leverage available resources for best outcomes.

A novel pyroptosis-related gene signature exhibits distinct immune cells infiltration landscape in Wilms' tumor

BACKGROUND

Wilms' tumor (WT) is the most common renal tumor in childhood. Pyroptosis, a type of inflammation-characterized and immune-related programmed cell death, has been extensively studied in multiple tumors. In the current study, we aim to construct a pyroptosis-related gene signature for predicting the prognosis of Wilms' tumor.

METHODS

We acquired RNA-seq data from TARGET kidney tumor projects for constructing a gene signature, and snRNA-seq data from GEO database for validating signature-constructing genes. Pyroptosis-related genes (PRGs) were collected from three online databases. We constructed the gene signature by Lasso Cox regression and then established a nomogram. Underlying mechanisms by which gene signature is related to overall survival states of patients were explored by immune cell infiltration analysis, differential expression analysis, and functional enrichment analysis.

RESULTS

A pyroptosis-related gene signature was constructed with 14 PRGs, which has a moderate to high predicting capacity with 1-, 3-, and 5-year area under the curve (AUC) values of 0.78, 0.80, and 0.83, respectively. A prognosis-predicting nomogram was established by gender, stage, and risk score. Tumor-infiltrating immune cells were quantified by seven algorithms, and the expression of CD8( +) T cells, B cells, Th2 cells, dendritic cells, and type 2 macrophages are positively or negatively correlated with risk score. Two single nuclear RNA-seq samples of different histology were harnessed for validation. The distribution of signature genes was identified in various cell types.

CONCLUSIONS

We have established a pyroptosis-related 14-gene signature in WT. Moreover, the inherent roles of immune cells (CD8( +) T cells, B cells, Th2 cells, dendritic cells, and type 2 macrophages), functions of differentially expressed genes (tissue/organ development and intercellular communication), and status of signaling pathways (proteoglycans in cancer, signaling pathways regulating pluripotent of stem cells, and Wnt signaling pathway) have been elucidated, which might be employed as therapeutic targets in the future.

Prognostic role of primary tumor size in Wilms tumor

Wilms tumor (WT) is the most common childhood malignant kidney tumor. The aim of the present study was to determine the impact of primary tumor size on the survival of patients with WT. The data of 1,523 patients diagnosed with WT between 2000 and 2017 were retrieved from the Surveillance, Epidemiology, and End Results database. Receiver operating characteristic curves were plotted to determine the optimal cut-off value of primary tumor size. Overall survival (OS) and cancer-specific survival (CSS) were analyzed using the Kaplan-Meier method and the Cox proportional hazards regression model. The optimal cut-off value for primary tumor size was found to be 11.15 cm. No significant difference in the distribution of tumor size was detected between male and female patients. However, lymph node metastasis and distant metastasis were significantly more frequent in patients whose tumor was ≥11.15 cm in size compared with those with smaller tumors. In addition, patients with larger tumors exhibited significantly worse OS and CSS rates compared with those with smaller tumors. Furthermore, primary tumor size was identified as an independent prognostic factor for OS and CSS in the multivariate analyses. In summary, the present study indicates that primary tumor size is an independent prognostic factor for patients with WT, and tumors ≥11.15 cm are associated with worse OS and CSS.

Outcomes of Wilms tumor therapy in Lilongwe, Malawi, 2016-2021: Successes and ongoing research priorities

INTRODUCTION

Wilms tumor therapy in low- and middle-income countries (LMICs) relies on treatment protocols adapted to resource limitations, but these protocols have rarely been evaluated in real-world settings. Such evaluations are necessary to identify high-impact research priorities for clinical and implementation trials in LMICs. The purpose of this study was to identify highest priority targets for future clinical and implementation trials in sub-Saharan Africa by assessing outcomes of a resource-adapted treatment protocol in Malawi.

METHODS

We conducted a retrospective cohort study of children treated for Wilms tumor with an adapted SIOP-backbone protocol in Lilongwe, Malawi between 2016 and 2021. Survival analysis assessed variables associated with poor outcome with high potential for future research and intervention.

RESULTS

We identified 136 patients, most commonly with stage III (n = 35; 25.7%) or IV disease (n = 35; 25.7%). Two-year event-free survival (EFS) was 54% for stage I/II, 51% for stage III, and 13% for stage IV. A single patient with stage V disease survived to 1 year. Treatment abandonment occurred in 36 (26.5%) patients. Radiotherapy was indicated for 55 (40.4%), among whom three received it. Of these 55 patients, 2-year EFS was 31%. Of 14 patients with persistent metastatic pulmonary disease at the time of nephrectomy, none survived to 2 years. Notable variables independently associated with survival were severe acute malnutrition (hazard ratio [HR]: 1.9), increasing tumor stage (HR: 1.5), and vena cava involvement (HR: 3.1).

CONCLUSION

High-impact targets for clinical and implementation trials in low-resource settings include treatment abandonment, late presentation, and approaches optimized for healthcare systems with persistently unavailable radiotherapy.

Wilms Tumor in India: A Systematic Review

Shyam SrinivasanBackground  Cure rates of childhood malignancies are inferior in India compared with upper-middle-income countries. There is paucity of quality data addressing outcome of childhood Wilms tumor (WT) from India. This systematic review was conducted to assess the disease trends, treatment strategies, and outcome indicators in WT across India. Materials and Methods  We conducted a systematic search of MEDLINE, Google Scholar, and SCOPUS database, and additionally screened International Society of Pediatric Oncology conference abstracts. Data concerning WT or nephroblastoma published from India were extracted. Results  A total of 17 studies containing 1,170 patients were included in this review. Ninety-four percent of the studies were published after the year 2010. Advanced stage (III and IV) disease was seen in 46% of included patients. In seven studies, patients underwent a pretreatment biopsy before commencement of therapy. A hybrid approach consisting of "surgery first" in a selected subset and "neo-adjuvant chemotherapy" in all others was the most common treatment strategy adopted in half of the studies. The overall survival ranged between 48 and 89%. Key prognostic factors influencing survival across studies included increased tumor volume, metastatic disease, and unfavorable histology. Nonrelapse mortality (2.7-8.5%) was noted to be high. Conclusion  Substantial proportion of children with WT from India present with advanced stages of the disease. Despite several limitations, the current systematic review showed a modest survival among Indian children with WT. Adopting strategies through collaboration to ensure early access to expert care along with involvement of social support team to improve compliance may further improve survival of WT in India.

Cost-effectiveness of running a paediatric oncology unit in Ethiopia

OBJECTIVE

To estimate the cost-effectiveness of running a paediatric oncology unit in Ethiopia to inform the revision of the Ethiopia Essential Health Service Package (EEHSP), which ranks the treatment of childhood cancers at a low and medium priority.

METHODS

We built a decision analytical model-a decision tree-to estimate the cost-effectiveness of running a paediatric oncology unit compared with a do-nothing scenario (no paediatric oncology care) from a healthcare provider perspective. We used the recently (2018-2019) conducted costing estimate for running the paediatric oncology unit at Tikur Anbessa Specialized Hospital (TASH) and employed a mixed costing approach (top-down and bottom-up). We used data on health outcomes from other studies in similar settings to estimate the disability-adjusted life years (DALYs) averted of running a paediatric oncology unit compared with a do-nothing scenario over a lifetime horizon. Both costs and effects were discounted (3%) to the present value. The primary outcome was incremental cost in US dollars (USDs) per DALY averted, and we used a willingness-to-pay (WTP) threshold of 50% of the Ethiopian gross domestic product per capita (USD 477 in 2019). Uncertainty was tested using one-way and probabilistic sensitivity analyses.

RESULTS

The incremental cost and DALYs averted per child treated in the paediatric oncology unit at TASH were USD 876 and 2.4, respectively, compared with no paediatric oncology care. The incremental cost-effectiveness ratio of running a paediatric oncology unit was USD 361 per DALY averted, and it was cost-effective in 90% of 100 000 Monte Carlo iterations at a USD 477 WTP threshold.

CONCLUSIONS

The provision of paediatric cancer services using a specialised oncology unit is most likely cost-effective in Ethiopia, at least for easily treatable cancer types in centres with minimal to moderate capability. We recommend reassessing the priority-level decision of childhood cancer treatment in the current EEHSP.

Evaluating the baseline survival outcomes of the "six Global Initiative for Childhood Cancer index cancers" in Africa

Limited survival data for the six Global Initiative for Childhood Cancer (GICC) priority cancers are available in Africa. Management of pediatric malignancies in Africa is challenging due to lack of resources, setting-specific comorbidities, high rates of late presentation and treatment abandonment. Reporting of outcome data is problematic due to the lack of registries. With the aim of evaluating the feasibility of baseline outcomes for the six index cancers, we present a descriptive analysis of respective survival rates in Africa. The survival rates were between 18% (lower middle-income countries) to 82.3% (upper middle-income countries) for acute lymphoblastic leukemia, between 26.9% (low-income countries) to 77.9% (upper middle-income countries) for nephroblastoma, between 23% (low-income countries) to 100% (upper middle-income countries), for retinoblastoma, 45% (low-income countries) to 95% (upper middle-income countries) for Hodgkin lymphoma and 28% (low-income countries) to 76% (upper middle-income countries) for Burkitt lymphoma. Solutions to improve survival rates and reported outcomes include establishing and funding sustainable registries, training and to actively include all countries in consortia from different African regions.HighlightsContinental differences in childhood cancer management such lack of resources, setting-specific comorbidities, high rates of late presentation and treatment abandonment, present challenges to the achievement of Global Initiative for Childhood Cancer goals.The available data registries do not adequately inform on the true incidences and outcomes of childhood cancers in Africa.The pathophysiology of some childhood cancers in Africa are associated with high-risk prognostic factors.Outcomes can be improved by greater regional collaboration to manage childhood cancer based on local resources and tumor characteristics.Some individual countries have reached the Global Initiative for Childhood Cancer goals for single cancers and it should be possible for more African countries to follow suit.

Wilms’ tumor in low- and middle-income countries: survey of current practices, challenges, and priorities

Purpose

To identify the current practices and priorities in Wilms’ tumor management for surgeons in low- and middle-income countries (LMICs).

Methods

One hundred thirty-seven pediatric surgeons from 44 countries completed surveys on Wilms’ tumor surgical strategy in LMIC. This survey was distributed through the Global Initiative for Children’s Surgery, Pan-African Pediatric Surgical Association, and Latin American Pediatric Surgical Oncology Group.

Results

Ninety-two respondents (67.2%) participated from 19 lower middle-income countries (43.2%). Twenty-one respondents (15.3%) participated from nine lower income countries (20.5%). Nineteen respondents (13.9%) participated from 13 upper middle-income countries (29.5%). Most providers do not obtain biopsy for suspected Wilms’ tumor (79%). Delayed resection after preoperative chemotherapy is the preferred approach (70%), which providers chose due to protocol (45%), to decrease tumor rupture (22%), and to decrease complications (8%). The providers’ goal was to prevent tumor spillage and upstaging (46%) or to prevent bleeding, complication, or other organ resections (21%). Most surgeons believed that upfront resection increased the risk of tumor spillage (72%).

Conclusion

Providers in LMICs prefer delayed resection after preoperative chemotherapy to reduce the incidence of tumor spillage and upstaging of Wilms’ tumor. An evidence-based guideline tailored to the LMIC context can be developed from these findings.

Outcomes of Wilms tumor treatment in western Kenya

BACKGROUND/OBJECTIVES

Wilms tumor (WT) is a curable type of cancer with 5-year survival rates of over 90% in high-income countries, whereas this is less than 50% in low- and middle-income countries. We assessed treatment outcomes of children with WT treated at a large Kenyan teaching and referral hospital.

DESIGN/METHODS

We conducted a retrospective record review of children diagnosed with WT between 2013 and 2016. Treatment protocol consisted of 6 weeks of preoperative chemotherapy and surgery, and 4-18 weeks of postoperative chemotherapy depending on disease stage. Probability of event-free survival (pEFS) and overall survival (pOS) was assessed using Kaplan-Meier method with Cox regression analysis. Competing events were analyzed with cumulative incidences and Fine-Gray regression analysis.

RESULTS

Of the 92 diagnosed patients, 69% presented with high-stage disease. Two-year observed EFS and OS were, respectively, 43.5% and 67%. Twenty-seven percent of children died, 19% abandoned treatment, and 11% suffered from progressive or relapsed disease. Patients who were diagnosed in 2015-2016 compared to 2013-2014 showed higher pEFS. They less often had progressive or relapsed disease (p = .015) and borderline significant less often abandonment of treatment (p = .09). Twenty-nine children received radiotherapy, and 2-year pEFS in this group was 86%.

CONCLUSION

Outcome of children with WT improved over the years despite advanced stage at presentation. Survival probabilities of patients receiving comprehensive therapy including radiation are approaching those of patients in high-income countries. Additional improvement could be achieved by ensuring that patients receive all required treatment and working on earlier diagnosis strategies.

Postchemotherapy tumor volume as a prognostic indicator in Wilms tumor: A single-center experience from South India

BACKGROUND

Optimal risk stratification is the key to minimizing relapse and toxicity in children with Wilms tumor (WT). The study evaluated poor tumor volume response to chemotherapy as a risk factor that predicts relapse.

PROCEDURE

Children with WT who were treated between 2005 and 2020 at the center were analyzed. Tumor volumes at the time of diagnosis and after preoperative chemotherapy were calculated from cross-sectional imaging. The International Society of Paediatric Oncology (SIOP)-WT-2001 protocol was used for treatment. The area under a receiver operating characteristic curve was estimated to ascertain the ability of tumor volume to predict relapse.

RESULTS

Ninety-five patients with a median age of 40 months were included. A postchemotherapy tumor volume cutoff of 270 ml was ascertained to have the best predictive value for relapse. Patients with a tumor volume of <270 ml following preoperative chemotherapy had a better 3-year event-free survival (EFS) than those with a tumor volume of ≥270 ml (89.8% ± 4.0% vs. 57.4% ± 12.5%, p = .001). The data demonstrated that a tumor volume of ≥270 ml after chemotherapy was associated with an increased risk of relapse (hazard ratio [HR]: 5.3, p = .006). The EFS in patients with an epithelial or stromal type of histopathology was not affected by the tumor volume response (p = .437). Conversely, patients with other types of intermediate-risk histopathology who had a poor tumor volume response had an inferior survival (3-year EFS 51.4% ± 18.7%, p = .001).

CONCLUSION

A postchemotherapy tumor volume cutoff of ≥270 ml emerged as a strong predictor of relapse in a low- and middle-income country (LMIC) center study of WT treated with the SIOP protocol.