Purpose Survival from Wilms Tumor (WT) exceeds 90% at 5 years in developed nations, whereas at last report, 2-year event-free survival (EFS) in Kenya reached only 35%. To clarify factors linked to these poor outcomes in Kenya, we established a comprehensive web-based WT registry, comprised of patients from the four primary hospitals treating childhood cancers. Materials and Methods WT patients diagnosed between January 2008 and January 2012 were identified. Files were abstracted for demographic characteristics, treatment regimens, and enrollment in the Kenyan National Hospital Insurance Fund (NHIF). Children under 15 years of age having both a primary kidney tumor on imaging and concordant histology consistent with WT were included. Results Two-year event-free survival (EFS) was 52.7% for all patients (n=133), although loss to follow up (LTFU) was 50%. For the 33 patients who completed all scheduled standard therapy, 2-year EFS was 94%. Patients enrolled in NHIF tended to complete more standard therapy and had a lower hazard of death (Cox 0.192, p <0.001). Conclusion Survival of Kenyan WT patients has increased slightly since last report. Notably, WT patients completing all phases of standard therapy experienced 2-year survival approaching the benchmarks of developed nations. Efforts in Kenya should be made to enhance compliance with WT treatment through NHIF enrollment.

Background Survival from Wilms tumor (WT) in sub-Saharan Africa remains dismal as a result of on-therapy mortality and treatment abandonment. Review of patients diagnosed from 2008–2011 in our Kenyan Wilms Tumor Registry showed a loss to follow up (LTFU) rate approaching 50 percent. The purpose of this study was to trace those LTFU, estimate the survival rate, and identify risk factors for treatment abandonment. Procedure We administered a comprehensive survey to parents of patients with WT at the two largest referral hospitals in Kenya to identify barriers to care. We also telephoned families who had abandoned care to determine vital status and identify risk factors for treatment abandonment. Results Of 136 registered patients, 77 were confirmed dead (56.7%), 38 remained alive (27.9%), and the vital status of 21 patients remains unknown (15.4%). After contacting 33 of the patients who either abandoned curative treatment (n=34) or did not attend off-therapy visits (n=20), the best estimate of 2-year overall survival of patients with WT in Kenya approaches 36%. Sixty-three percent of parents misunderstood treatment plans and 55% encountered financial barriers. When asked how to increase comfort with the child’s treatment, 27% of parents volunteered improving inefficient services and 26% volunteered reducing drug-unavailability. Conclusions Treatment abandonment remains a significant problem contributing to increased mortality from WT in developing countries. This multi-center survey identified the barriers to treatment completion from the parental perspective to be lack of education about WT and treatment, financial constraints, need for quality improvement, and drug-unavailability.

Background Wilms tumor (WT) is thought to arise in children of black African ancestry with greater frequency than whites. To clarify the biological basis for race disparities in WT, we first verified that black children residing in Tennessee have an increased incidence of WT, and second, established molecular profiles in WT that are specific to race. Materials and Methods To assess race disparities in WT epidemiology, the Tennessee Cancer Registry (TCR) was queried for all in-state patients less than 20 years of age and registered between 1999–2008. To explore race disparities in WT biology, six black and four white WT specimens acquired in Tennessee were analyzed using imaging mass spectrometry (IMS). Results TCR data show that black children are overrepresented among WT patients (29%) relative to all other childhood cancers (18.5%; p=0.01). WT ranked the 5th most common cancer diagnosis among blacks, but 9th among whites. The diagnosis of WT occurred 79% more frequently among blacks (n=28) than whites (n=69; p=0.01), and proportionally more blacks tended to present with distant disease. Although overall survival from WT was not statistically different between blacks (92.9%) and whites (94.0%), black males showed the lowest survival (85%; p=0.21). IMS analysis identified peptide spectra from both WT blastema and stroma that independently classify specimens according to race with greater than 80% accuracy. Conclusions In Tennessee, black children appear more susceptible than whites to develop WT. Race-specific molecular profiles can be determined that may help to clarify pathways of Wilms tumorigenesis and the biological basis for race disparities in WT incidence and biology.

Sub-Saharan African children have an increased incidence of Wilms tumor (WT) and experience alarmingly poor outcomes. Although these outcomes are largely due to inadequate therapy, we hypothesized that WT from this region exhibit features of biologic aggressiveness that may warrant broader implementation of high-risk therapeutic protocols. We evaluated 15 Kenyan WT (KWT) for features of aggressive disease (blastemal predominance, Ki67/cellular proliferation) and treatment resistance (anaplasia, p53 immunopositivity). To explore additional biologic features of KWT, we determined the mutational status of the CTNNB1/β-catenin and WT1 genes and performed immunostaining for markers of Wnt pathway activation (β-catenin) and nephronic progenitor cell self-renewal (WT1, CITED1, SIX2). We characterized the proteome of KWT using imaging mass spectrometry (IMS). Results were compared to histology and age-matched North American WT (NAWT) controls. For KWT patients, blastemal predominance was noted in 53.3% and anaplasia in 13%. We detected increased loss to follow up (p=0.028), disease relapse (p=0.044), mortality (p=0.001), and nuclear unrest (p=0.001) in KWT patients compared to controls. KWT and NAWT showed similar Ki67/cellular proliferation. We detected an increased proportion of epithelial nuclear β-catenin in KWT (p=0.013). All 15 KWT were found to harbor wild-type β-catenin, and 1 contained a WT1 nonsense mutation. WT1 was detected by immunostaining in 100% of KWT, CITED1 in 80%, and SIX2 in 80%. IMS revealed a molecular signature unique to KWT that was distinct from NAWT. African WTs appear to express markers of adverse clinical behavior and treatment resistance and may require alternative therapies or implementation of high-risk treatment protocols.