Childhood nephroblastoma in Southern and Eastern Europe and the US: Incidence variations and temporal trends by human development index

Wilms tumor and associated predisposing syndromes and conditions

ABSTRACT

Wilms tumor, also known as nephroblastoma, is relatively rare but is the most common renal malignancy in children, accounting for about 5% of all childhood malignancies and 90% of all childhood renal malignancies. Advances in the understanding of the underlying cause and pathophysiology of Wilms tumor have significantly improved the prognosis and survival rates for children with Wilms tumor, but cases may occur sporadically and certain affected patients face higher rates of relapse and morbidity. The most common clinical presentation involves the identification of an abdominal mass or swelling without other signs or symptoms. The nonspecific nature of symptoms that can present can delay timely diagnosis and treatment. Numerous predisposing syndromes are associated with an increased risk for the development of Wilms tumor. Clinicians who recognize these syndromes and other conditions and understand the increased risk can provide the appropriate level of anticipatory guidance and use the optimal screening plan.

Inter-Ethnic Variations in the Clinical, Pathological, and Molecular Characteristics of Wilms Tumor

Wilms tumor is the commonest primary renal malignancy in children and demonstrates substantial inter-ethnic variation in clinical, pathological, and molecular characteristics. Wilms tumor occurs at a lower incidence and at a younger age in Asians compared to Caucasians and Africans. Asians also present at an earlier stage of disease, with a higher incidence of favorable histology tumors and a lower incidence of perilobar nephrogenic rests compared to Caucasians, while African children present with more advanced disease. Studies have implicated population differences in the incidence of WT1 mutations, loss of imprinting of the IGF2 locus, and loss of heterozygosity of 1p/16q, or 1q gain as possible bases for epidemiological differences in the disease profile of Wilms tumors in various ethnic groups. Yet, evidence to support these associations is confounded by differences in treatment protocols and inequalities in the availability of treatment resources and remains limited by the quality of population-based data, especially in resource-limited settings.

Incidence patterns of childhood non-Wilms renal tumors: Comparing data of the Nationwide Registry of Childhood Hematological Malignancies and Solid Tumors (NARECHEM-ST), Greece, and the Surveillance, Epidemiology, and End Results Program (SEER), USA

BACKGROUND

We used, for the first time, data registered in the Nationwide Registry for Childhood Hematological Malignancies and Solid Tumors (NARECHEM-ST)-Greece to estimate incidence/time trends of the rare childhood (0-14 years) non-Wilms tumors (non-WT), and compared the results of malignant non-WT to those from the Surveillance, Epidemiology, and End Results Program (SEER)-USA.

METHODS

Fifty-five cases (n = 33 malignant-only) were extracted from NARECHEM-ST (2001-2020) and 332 malignant cases from SEER (1990-2017). To allow between-country comparisons, age-standardized incidence rates (AIR) of malignant-only non-WT were calculated, and temporal trends were evaluated using Poisson and joinpoint regressions.

RESULTS

In NARECHEM-ST, malignant and non-malignant non-WT accounted for 22.6% of all renal tumors. Among malignant tumors, the AIR was 1.0/106 children in Greece, similar to that calculated for SEER, USA (AIR=0.9/106). The proportion of infant malignant and non-malignant non-WT was 27% (20% before 6 months) in NARECHEM-ST. Most common non-WT in Greece were congenital mesoblastic nephromas (CMN) diagnosed mainly in infancy (CIR=7.2/106). The proportion of infant malignant non-WT was 20% in SEER (AIRinfancy=2.5/106), mainly attributed to rhabdoid tumors (CIR=1.6/106). The male-to-female (M:F) ratio of malignant non-WT was 0.9 in NARECHEM-ST vs. 1.2 in SEER, whereas boys outnumbered girls with clear cell sarcoma in NARECHEM-ST (M:F=4.0). Lastly, significantly increasing trends in incidence rates were noted in NARECHEM-ST [+ 6.8%, 95% confidence intervals (CI): 0.5, 13.3] and in SEER (+7.3%, 95%CI: 5.6, 9.0).

CONCLUSIONS

Observed incidence, time trends and sociodemographic variations of non-WT may reflect differential registration practices and healthcare delivery patterns including differences regarding surveillance, coding and treatment practices.

The relationship between vascular endothelial growth factor expression and the risk of childhood nephroblastoma: systematic review and meta-analysis

BACKGROUND

This study explores the correlation between vascular endothelial growth factor expression and the risk of childhood nephroblastoma.

METHODS

PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang database were searched to collect independent study data published in China between 2010 and 2021 on the expression and significance of VEGF in childhood nephroblastoma, and literature heterogeneity was tested. The odds ratio (OR) value was used as the effect indicator. Meta-analysis software RevMan 4.2.2 was used, and the original data of each study were statistically processed to calculate the combined OR value and 95% confidence interval (CI).

RESULTS

Twelve studies involving 1,226 cases of pediatric nephroblastoma were included for systematic evaluation. The 12 randomized controlled studies reported the expression of VEGF in childhood nephroblastoma (OR =9.06, 95% CI: 6.97-11.78, P<0.00001). There was a statistically significant difference in expression of VEGF between the unfavorable histology (UH) group and the favorable histology (FH) group (OR =1.17, 95% CI: 1.07-1.27, P=0.0006) and expression of VEGF in different clinical stages of nephroblastoma, including stage I-II and III-IV (OR =0.49, 95% CI: 0.42-0.58, P<0.00001). Positive expression of VEGF showed no significant statistical difference between cases with and without tumor metastasis (OR =1.08, 95% CI: 0.86-1.36, P=0.50).

CONCLUSIONS

The expression of VEGF may play an important role in the occurrence and development of childhood nephroblastoma and could help guide clinicians to judge disease and treatment.

METTL3 polymorphisms and Wilms tumor susceptibility in Chinese children: A five-center case-control study

BACKGROUND

Wilms tumor is a common pediatric tumor worldwide. Methyltransferase like 3 (METTL3) is a core gene of the N6 -methyladenosine (m6 A) modification that widely affects the transcription of tumor-related genes in eukaryotes. METTL3 has been extensively investigated in various tumors but not Wilms tumor.

METHODS

We describe a five-center case-control study with 414 patients and 1199 controls aiming to explore the associations between METTL3 polymorphisms (rs1061026 T>G, rs1061027 C>A, rs1139130 A>G and rs1263801 G>C) and Wilms tumor susceptibility. A TaqMan real-time polymerase chain reaction was performed for genotyping. Odds ratios (ORs) and 95% confidence intervals (CIs) were reported as evaluation indicators to determine any associations.

RESULTS

Referring to the preliminary analysis results, protective genotypes were identified as rs1061026 TG/GG, rs1061027 CA/AA, rs1139130 GG and rs1263801 GC/CC. The children with three protective genotypes were less likely to develop Wilms tumor than children without protective genotypes (adjusted OR = 0.68, 95% CI = 0.46-0.999, p = 0.0496). Similarly, stratified analysis of the subgroup aged > 18 months, carrying 3 or 4 protective genotypes, was a protective factor for Wilms tumor compared to carrying 0-2 protective genotypes (adjusted OR = 0.59 95% CI = 0.39-0.91, p = 0.016). However, we did not observe any other significant results.

CONCLUSIONS

The combined effect of METTL3 polymorphisms reduce Wilms tumor susceptibility in Chinese children. This conclusion requires further verification.

Maternal lifestyle characteristics and Wilms tumor risk in the offspring: A systematic review and meta-analysis

BACKGROUND

Little is known about the etiology of childhood Wilms tumor (WT) and potentially modifiable maternal risk factors, in particular.

METHODS

Unpublished data derived from the hospital-based, case-control study of the Greek Nationwide Registry for Childhood Hematological Malignancies and Solid Tumors (NARECHEM-ST) were included in an ad hoc conducted systematic literature review and meta-analyses examining the association between modifiable maternal lifestyle risk factors and WT. Eligible data were meta-analysed in separate strands regarding the associations of WT with (a) maternal folic acid and/or vitamins supplementation, (b) alcohol consumption and (c) smoking during pregnancy. The quality of eligible studies was evaluated using the Newcastle-Ottawa Scale.

RESULTS

Effect estimates from 72 cases and 72 age- and sex-matched controls contributed by NARECHEM-ST were meta-analysed together with those of another 17, mainly medium size, studies of ecological, case-control and cohort design. Maternal intake of folic acid and/or other vitamins supplements during pregnancy was inversely associated with WT risk (6 studies, OR: 0.78; 95 %CI: 0.69-0.89, I2 = 5.4 %); of similar size was the association for folic acid intake alone (4 studies, OR: 0.79; 95 %CI: 0.69-0.91, I2 = 0.0 %), derived mainly from ecological studies. In the Greek study a positive association (OR: 5.31; 95 %CI: 2.00-14.10) was found for mothers who consumed alcohol only before pregnancy vs. never drinkers whereas in the meta-analysis of the four homogeneous studies examining the effect of alcohol consumption during pregnancy the respective overall result showed an OR: 1.60 (4 studies, 95 %CI: 1.28-2.01, I2 = 0.0 %). Lastly, no association was seen with maternal smoking during pregnancy (14 studies, OR: 0.93; 95 %CI: 0.80-1.09, I2 = 0.0 %).

CONCLUSIONS

In the largest to-date meta-analysis, there was an inverse association of maternal folic acid or vitamins supplementation with WT risk in the offspring, derived mainly from ecological studies. The association with maternal alcohol consumption found in our study needs to be further explored whereas no association with maternal smoking was detected. Given the proven benefits for other health conditions, recommendations regarding folic acid supplementation as well as smoking and alcohol cessation should apply. The maternal alcohol consumption associations, however, should be further explored given the inherent limitations in the assessment of exposures of the published studies.

Wilms tumour event-free and overall survival in Southern and Eastern Europe: Pooled analyses of clinical data from four childhood cancer registries (1999-2017)

BACKGROUND

Wilms tumour (WT) management represents a success story in pediatric oncology. We aimed to assess, for the first time, the event-free survival (EFS) vs. overall survival (OS) in Southern and Eastern Europe (SEE) using harmonised clinical data collected by childhood cancer registries and to identify respective prognostic factors.

METHODS

From 1999 to 2017, data for incident WT cases aged 0-14 years from 3 nationwide (Greece, Belarus and Slovenia) and one regional (Greater Poland) SEE registries were collected following common coding. Kaplan-Meier curves were constructed, and EFS vs. OS values were derived from Cox proportional hazard models by study variables.

RESULTS

A total of 338 WT cases (45.6% males; median age, 3.19 years; age<5 years, 75%) were included in the analyses. Bilateral were 21 tumours (6.2%). Among the 317 unilateral cases, the majority (93.7%) received International Society of Pediatric Oncology-based protocols; EFS5-year was 85.1%, and OS5-year 91.1%; both outcomes were significantly worse in stage IV patients or in those with high-risk/unfavourable histology. Relapse rate among high-risk/unfavourable histology cases was 2.3 times higher than among low-intermediate risk/favourable histology cases, with respective death rate 5.6 times higher. Both relapse and death rates increased significantly in patients with advanced anatomical stage and high-risk/unfavourable histology. Finally, significantly worse was the outcome in bilateral tumours (OS5-year: 76.3%) vs. unilateral non-metastatic tumours (OS5-year: 94.7%).

CONCLUSIONS

Our results delineate the potential of high-quality childhood cancer registration entailing clinical data to assess predictors of WT outcome over and beyond those derived from enrolment into clinical trials. Specifically, outcomes among children with WT residing in the four participating SEE countries were comparable with those reported by major cooperative international groups, albeit somehow inferior. Despite the excellent overall prognosis, however, subgroups of patients with advanced or bilateral disease and/or high-risk histology still suffer poor outcomes.

Survival and mortality rates of Wilms tumour in Southern and Eastern European countries: Socioeconomic differentials compared with the United States of America

BACKGROUND

Despite recent therapeutic advancements, Wilms tumour (WT) presents remarkable survival variations. We explored mortality and survival patterns for children (0-14 years) with WT in 12 Southern and Eastern European (SEE) countries in comparison with the United States of America (USA).

METHODS

A total of 3966 WT cases (0-14 years) were registered by a network of SEE childhood cancer registries (N:1723) during available registration periods circa 1990-2016 and surveillance, epidemiology, and end results program (SEER) (N:2243; 1990-2012); mortality data were provided by the respective national statistical services. Kaplan-Meier curves and Cox proportional hazards models were used to assess the role of age, sex, year of diagnosis, urbanisation and Human Development Index (HDI) on overall survival (OS).

RESULTS

Persisting regional variations shape an overall 78% 5-year OS in the participating SEE countries, lagging behind the USA figure (92%, p=0.001) and also reflected by higher SEE mortality rates. Worth mentioning is the gradually escalating OS in SEE (hazard ratio [HR]5-year increment:0.67, 95% confidence interval [CI]:0.60, 0.75) vs. a non-significant 10% improvement in the SEER data, which had a high starting value. OS differentials [two-fold less favourable among children aged 10-14 years, boys and those living in rural SEE areas (HR:1.37; CI:1.10-1.71) or countries with inferior HDI (2-3-fold)] were minimal in the USA.

CONCLUSIONS

Children with WT residing in SEE countries do not equally enjoy the substantial survival gains, especially for those living in rural areas and in lower HDI countries. Noteworthy are steep and sizeable survival gains in SEE along with the newly presented Greek data pointing to achievable survival goals in SEE despite the financial crisis.