How to improve initial diagnostic accuracy of kidney tumours in childhood?-A non-invasive approach.

Non-invasive differentiation of paediatric kidney tumours is particularly important in the SIOP-RTSG protocols, which recommend pre-operative chemotherapy without histological confirmation. The identification of clinical and tumour-related parameters may enhance diagnostic accuracy. Age, metastases, and tumour volume (TV) were retrospectively analysed in 3306 patients enrolled in SIOP/GPOH 9, 93-01, and 2001 including Wilms tumour (WT), congenital mesoblastic nephroma (CMN), clear cell sarcoma (CCSK), malignant rhabdoid tumour of the kidney (MRTK), and renal cell carcinoma (RCC). WT was diagnosed in 2927 (88.5%) patients followed by CMN 138 (4.2%), CCSK 126 (3.8%), MRTK 58 (1.8%) and RCC 57 (1.7%). CMN, the most common localized tumour (71.6%) in patients younger than 3 months of age, was diagnosed earliest and RCC the latest (median age [months]: 0 and 154, respectively) both associated with significantly smaller TV (median TV [mL]: 67.2 and 45.0, respectively). RCC occurred in >14% of patients older than 120 months or older than 84 months with TV <100 mL. Receiver operating characteristic analyses discriminated WT from CMN, RCC and MRTK regarding age (AUC = 0.976, 0.929 and 0.791) and TV (AUC = 0.768, 0.813 and 0.622). MRTK had the highest risk of metastasis (37.9%) despite young age, whereas the risk of metastasis increased significantly with age in WT. Age and TV at diagnosis can differentiate WT from CMN and RCC. MRTK must be considered for metastatic tumours at young age. Identification of CCSK without histology remains challenging. Combined with MRI-characteristics, including diffusion-weighted imaging, and radiomics and liquid biopsies in the future, our approach allows optimization of biopsy recommendations and prevention of misdiagnosis-based neoadjuvant treatment.

Inpatient Rsv-Management 2016-2022: Epidemiology and Adherence to A Bronchiolitis Treatment Standard at a German University Children's Hospital.

BACKGROUND: This study analyzes the RSV season 2021/2022 in a referral children's hospital, compares the epidemiology and illness severity with RSV-infected inpatients from 2016 to 2020 and audits the adherence to our internal therapy standard for RSV bronchiolitis. MATERIAL AND METHODS: Inpatients with rtPCR-confirmed RSV infection (Jan. 2016 to Jan. 2022). RESULTS: The audit comprises 306 RSV inpatients, on average 50 hospitalizations per year; in 03/2020, a rapid RSV Season-Offset was observed. In the winter season 2020/2021, no patient with RSV was hospitalized. Beginning in July, we noticed a rapid increase of RSV-admissions (most cases in Sept./Oct, duration until Dec. 2021; n=53). In 2021-2022, a significant larger share needed PICU admission (9.4% vs 3.2%, p=0.040). Adherence to the internal guidance was low; only 11.8% (n=36) of all patients received supportive treatment without inhalative or systemic medications, 37% of all patients received antibiotics. CONCLUSIONS: This audit confirms the strong impact of public preventive measures directed against SARS-CoV-2 transmission on RSV epidemiology. Few weeks after easing public COVID-19 restrictions (summer 2021), RSV inpatient cases rapidly increased, lasting until Dec. 2021. The audit of bronchiolitis management revealed surprisingly low adherence to the internal guidance, despite a face-to-face educational session with the attending pediatricians in Oct. 2021. Low adherence resulted in an unnecessary exposure of RSV patients to systemic medications of questionable benefit including antibiotics.

Omission of adjuvant chemotherapy in patients with completely necrotic Wilms tumor stage I and radiotherapy in stage III: The 30-year SIOP-RTSG experience.

BACKGROUND: Completely necrotic Wilms tumor (CN-WT) following preoperative chemotherapy has been regarded as low-risk WT since the International Society of Paediatric Oncology (SIOP) 93-01 study, and patients have been treated with reduced postoperative therapy. The aim of the study was to evaluate whether the omission of adjuvant chemotherapy in patients with localized CN-WT stage I and radiotherapy in stage III was safe. PATIENTS AND METHODS: The retrospective observational study of outcomes of patients diagnosed with localized CN-WT on central pathology review and treated according to the SIOP 93-01 and SIOP-WT-2001 protocols (1993-2022). RESULTS: There were 125 patients with localized CN-WT: 90 with stage I, 10 with stage II, and 25 with stage III. Sixty-two of 125 (49.6%) patients had a discrepant diagnosis and/or staging between the institutional pathologist and central pathology review. In the group of 90 patients with stage I, postoperative chemotherapy was not given to 41 (46%) patients, whereas 49 patients received postoperative chemotherapy-in the latter group, two patients relapsed, and one of them died. One stage I and one stage II patient developed chemotherapy-induced toxicity and died. Nineteen of 25 patients with stage III received no flank radiotherapy. No stage III patient relapsed or died. The overall 5-year event-free survival (EFS) estimate for the entire cohort (stages I-III) was 96.8% [95% confidence interval, CI: 93.6%-99.6%] and the overall survival (OS) was 97.6% [95% CI: 95.0-100%]. The EFS and OS were 97% and 98%, respectively, for stage I, and 100% for stage III. CONCLUSION: Omission of postoperative chemotherapy for patients with CN-WT stage I, and radiotherapy for stage III is safe. Rapid central pathology review is required to assign appropriate treatment and avoid treatment-related side effects.

Redo nephron-sparing surgery in stage V pediatric renal tumors - A report from the SIOP/GPOH study group for renal tumors.

PURPOSE: Nephron-sparing Surgery (NSS) is the surgical treatment of choice in children with bilateral renal tumors or in syndromatic patients. With an increasing role of this surgical approach, there is also an increased number of tumor relapses after NSS. Aim of this study was to evaluate a second ("Redo-") NSS in children with relapsed renal tumors. MATERIALS AND METHODS: We retrospectively analysed patients undergoing Redo-NSS for relapsed kidney tumors between 2009 and 2021 at our institution, which represents a national reference center of the SIOP/GPOH renal tumor study group. RESULTS: Nine patients (5 girls, 4 boys) underwent Redo-NSS with resection of 15 lesions. Mean age at surgery was 58 months (12-137), mean operative time for Redo-NSS was 195 min (137-260). R0 resection status was achieved in all children. Two patients had second relapses, one of them was resected via NSS, the other child underwent tumor nephrectomy. Two patients with anaplastic relapses died from combined second relapses. Thus, 7/9 patients are alive without evidence of disease, an impaired renal function was observed in one child. Mean follow-up after Redo-NSS was 35 months (6-49). CONCLUSIONS: In renal tumor relapses, Redo-NSS can be performed with satisfactory oncological and functional results. Occurrence of diffuse anaplasia should possibly refrain from this approach. Further evaluation in international multicenter analyses are necessary for a definitive determination of Redo-NSS.

TRIM28 inactivation in epithelial nephroblastoma is frequent and often associated with predisposing TRIM28 germline variants.

Wilms tumors (WTs) are histologically diverse childhood cancers with variable contributions of blastema, stroma, and epithelia. A variety of cancer genes operate in WTs, including the tripartite-motif-containing-28 gene (TRIM28). Case reports and small case series suggest that TRIM28 mutations are associated with epithelial morphology and WT predisposition. Here, we systematically investigated the prevalence of TRIM28 inactivation and predisposing mutations in a cohort of 126 WTs with >2/3 epithelial cells, spanning 20 years of biobanking in the German SIOP93-01/GPOH and SIOP2001/GPOH studies. Overall, 44.4% (56/126) cases exhibited loss of TRIM28 by immunohistochemical staining. Of these, 48 could be further analyzed molecularly, revealing TRIM28 sequence variants in each case - either homozygous (~2/3) or heterozygous with epigenetic silencing of the second allele (~1/3). The majority (80%) of the mutations resulted in premature stops and frameshifts. In addition, we detected missense mutations and small deletions predicted to destabilize the protein through interference with folding of key structural elements such as the zinc-binding clusters of the RING, B-box-2, and PHD domains or the central coiled-coil region. TRIM28-mutant tumors otherwise lacked WT-typical IGF2 alterations or driver events, except for rare TP53 progression events that occurred with expected frequency. Expression profiling identified TRIM28-mutant tumors as a homogeneous subset of epithelial WTs that mostly present with stage I disease. There was a high prevalence of perilobar nephrogenic rests, putative precursor lesions, that carried the same biallelic TRIM28 alterations in 7/7 cases tested. Importantly, 46% of the TRIM28 mutations were present in blood cells or normal kidney tissue, suggesting germline events or somatic mosaicism, partly supported by family history. Given the high prevalence of predisposing variants in TRIM28-driven WT, we suggest that immunohistochemical testing of TRIM28 be integrated into diagnostic practice as the management of WT in predisposed children differs from that with sporadic tumors. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

An Observational Case-Control Study on Parental Age and Childhood Renal Tumors.

Despite excellent outcomes, many open questions remain about Wilms tumor (WT). Influences and risk factors for tumorigenesis, as well as tumor aggressiveness and recurrence, are not fully understood. Parental age plays a role in various childhood diseases and is also discussed as a risk factor for childhood cancer. We analyzed both maternal and paternal age at birth as risk factors for the occurrence of Wilms and non-Wilms tumors in children and investigated whether older maternal or paternal age is associated with a higher tumor incidence. During 1990 and 2019 we collected data from 3991 patients from the multicenter studies SIOP9/GPO, SIOP 93-01/GPOH, and SIOP 2001/GPOH, of whom maternal and paternal age was available in 2277 cases. Data from the Federal Statistical Office containing live births in Germany from 1990-2019 served as a comparative database. For maternal age at birth, the control data yielded 22,451,412 cases and for paternal age yielded 19,046,314 cases. Comparing maternal and paternal ages of the study patients with those of the control data, we confirmed that higher parental age is not correlated with the incidence of renal tumors in childhood. Mean ages of fathers and mothers in patients and the control cohort increased between 1991 and 2019 (fathers: 30.28 vs. 34.04; mothers: 27.68 vs. 29.79 in the patient group and 31.29 vs. 34.23 and 28.88 vs. 32.67 in the control group, respectively) without higher numbers of patients with kidney cancer over time. No influence was found for the subtype of cancer nor for syndromes. In addition, overall survival of patients is independent of the year of diagnosis and the age of the parents but depends on histology type and stage in WT.

Impact of Time to Surgery on Outcome in Wilms Tumor Treated with Preoperative Chemotherapy.

(1) Background: Wilms tumor (WT) treated preoperatively is cured in over 90% of cases. However, how long preoperative chemotherapy can be given is unknown. (2) Methods: 2561/3030 patients with WT (age < 18 years) treated between 1989 and 2022 according to SIOP-9/GPOH, SIOP-93-01/GPOH, and SIOP-2001/GPOH are retrospectively analyzed to assess the risk of time to surgery (TTS) for relapse-free survival (RFS) and overall survival (OS). (3) Results: TTS was calculated for all surgeries, with the mean being 39 days (38.5 ± 12.5) for unilateral tumors (UWT) and 70 days (69.9 ± 32.7) for bilateral disease (BWT). Relapse occurred in 347 patients, of which 63 (2.5%) were local, 199 (7.8%) were metastatic, and 85 (3.3%) were combined. Moreover, 184 patients (7.2%) died, 152 (5.9%) due to tumor progression. In UWT, recurrences and mortality are independent of TTS. For BWT without metastases at diagnosis, the incidence of recurrence is less than 18% up to 120 days and increases to 29% after 120 days, and to 60% after 150 days. The risk of relapse (Hazard Ratio) adjusted for age, local stage, and histological risk group increases to 2.87 after 120 days (CI 1.19-7.95, p = 0.022) and to 4.62 after 150 days (CI 1.17-18.26, p = 0.029). In metastatic BWT, no influence of TTS is detected. (4) Conclusions: The length of preoperative chemotherapy has no negative impact on RFS or OS in UWT. In BWT without metastatic disease, surgery should be performed before day 120, as the risk of recurrence increases significantly thereafter.

Stage I epithelial or stromal type Wilms tumors are low risk tumors: An analysis of patients treated on the SIOP-WT-2001 protocol in the UK-CCLG and GPOH studies (2001-2020).

BACKGROUND: Patients treated with preoperative chemotherapy with stage I intermediate-risk Wilms tumor (IR-WT) represent the largest group of patients with Wilms tumor (WT), and they have excellent outcomes. METHODS: The authors performed a retrospective analysis of patients with stage I epithelial (ET-WT) or stromal type WT (ST-WT) treated pre- and postoperatively according to the International Society of Paediatric Oncology-WT-2001 protocol in the UK Children's Cancer and Leukaemia Group and Gesellschaft für Pädiatrische Onkologie und Hämatologie groups' participation in the relevant WT trials and studies (2001-2020). RESULTS: There were 880 patients with stage I IR-WT, including 124 with ET-WT, 156 with ST-WT, and 600 with other IR-WT (oIR-WT). Patients with stage I ET-WT or ST-WT were significantly younger than patients with oIR-WT, represented a large proportion of stage I WTs in their groups, and tumors showed poor histologic response to preoperative chemotherapy. The 5-year event-free survival (EFS) estimates for patients with stage I ET-WT (96.8% ± 1.8 SE) or ST-WT (96.8% ± 1.6 SE) were significantly better than for patients with oIR-WT (90.3% ± 1.3 SE) (p = .014 and p = .009, respectively). A multivariate analysis showed that histologic type (ET-WT or ST-WT) remained a significant factor for EFS when adjusted for age and gender (p = .032 and p = .022, respectively). In both groups, relapses occurred in 3.2% of patients, and the overall survival was 99.2%. CONCLUSIONS: The results suggest that stage I ET-WT or ST-WT could be regarded as low-risk WT, for which omission of postoperative chemotherapy should be considered. PLAIN LANGUAGE SUMMARY: Patients with pretreated intermediate-risk Wilms tumor (WT) represent the largest group of patients with WT. This study reports the outcomes of patients with stage I epithelial type (ET-WT) or stromal type WT (ST-WT). These patients were significantly younger and had a larger proportion of stage I cases than patients with other intermediate-risk WT (oIR-WT). The event-free survival for patients with stage I ET-WT and ST-WT was significantly better than for patients with oIR-WT. Rare relapses were curable resulting in 99.2% overall survival.

Outcomes of patients with Wilms' tumour stage III due to positive resection margins only: An analysis of patients treated on the SIOP-WT-2001 protocol in the UK-CCLG and GPOH studies.

Stage III Wilms' tumour (WT) represents a heterogeneous group which includes different criteria, but all stage III patients are treated according to the same study regiment. The aim of the study was to retrospectively analyse outcomes in patients with stage III due to positive resection margins (RM) only, sub-grouped in RM with viable (RM-v) and nonviable (RM-nv) tumour. Patients were treated pre- and postoperatively according to the SIOP-WT-2001 protocol in the UK-CCLG and GPOH WT trials and studies (2001-2020). There were 197 patients, including 134 with localised, abdominal stage III and 63 with overall stage IV, but abdominal stage III. Stage III due to RM-v had 126 patients, and due to RM-nv 71 patients. The overall 5-year local-relapse-free survival (RFS), event-free (EFS) and overall survival (OS) estimates for all patients with abdominal stage III RM were 95.7% (±SE1.5%), 85.1 (±SE2.6%) and 90.3% (±SE2.2%), respectively. Patients with stage III RM-nv had significantly better RFS and EFS than patients with RM-v (P = .027 and P = .003, respectively). A multivariate analysis showed that RM-v remained a significant factor for EFS when adjusted for age, presence of metastasis at diagnosis, histological risk group and overall stage in Cox regression analysis (P = .006). Patients with stage III due to RM-nv only exhibited no local recurrence and have a significantly better RFS and EFS than patients with RM-v. The results suggest that exclusion of RM-nv as a stage III criterion in the UMBRELLA staging system and consequent treatment reduction is warranted.

Surgical Factors Influencing Local Relapse and Outcome in the Treatment of Unilateral Nephroblastoma.

OBJECTIVE: This study aims to identify factors associated with the occurrence of local relapse (LR) after treatment for unilateral nephroblastoma. BACKGROUND: Despite the fact that LR is rare (~5%) its adverse impact on the need for relapse treatment and outcome (40%-80% overall survival) cannot be neglected. Identifying the causative factors may improve initial treatment to achieve better local control. METHODS: Altogether 2386 patients with unilateral nephroblastoma prospectively enrolled over a period of 32 years (1989-2020) by the German Society for Pediatric Oncology and Hematology (SIOP-9/GPOH, SIOP-93-01/GPOH and SIOP-2001/GPOH) were retrospectively analyzed. Hazard ratios (HR) of LR were calculated for sex, age, size, local staging, histology, type of removal, rupture, lymph node (LN) removal using univariate and multivariate Cox models. RESULTS: Age >48 months, tumor volume >500 mL, histology and LN extent of removal were identified as significant risk factors for LR [HR: 1.68, P =0.018, confidence interval (CI): 1.09-2.58; HR: 1.84, P =0.015, CI: 1.13-3.00; HR: 3.19, P <0.001, CI: 2.03-5.00; HR: 2.26, P =0.002, CI: 1.36-3.576]. LR occur significantly more often in Stage I and II, even if no LN are removed. The risk of metastases is significantly increased after local recurrence (HR: 11.5, P <0.001, CI: 7.11-18.60). LR is associated with a subsequent 18.79-fold increased risk of death (HR: 18.79, P <0.001, CI: 2.07-5.28). CONCLUSIONS: Several factors are responsible for the occurrence of LR. Surgical ones, like LN sampling allow further reduction of LR and consequently a better outcome of patients with unilateral nephroblastoma.

Vena Cava Thrombus in Patients with Wilms Tumor.

(1) Background: Vena cava thrombus (VCT) is rare in Wilms tumor (WT) (4−10%). The aim of this study is to identify factors for an outcome to improve treatment for better survival. (2) Methods: 148/3015 patients with WT (aged < 18 years) and VCT, prospectively enrolled over a period of 32 years (1989−2020) by the German Society for Pediatric Oncology and Hematology (SIOP-9/GPOH, SIOP-93-01/GPOH and SIOP-2001/GPOH), are retrospectively analyzed to describe clinical features, response to preoperative chemotherapy (PC) (142 patients) and surgical interventions and to evaluate risk factors for overall survival (OS). (3) Results: 14 VCT regressed completely with PC and another 12 in parts. The thrombus was completely removed in 111 (85.4%), incompletely in 16 (12.3%), and not removed in 3 (2.3%). The type of removal is unknown in four patients. Patients without VCT have a significantly (p < 0.001) better OS (97.8%) than those with VCT (90.1%). OS after complete resection is (89.9%), after incomplete (93.8%) and with no resection (100%). Patients with anaplasia or stage IV without complete remission (CR) after PC had a significantly worse OS compared to the remaining patients with VCT (77.1% vs. 94.4%; p = 0.002). (4) Conclusions: As a result of our study, two risk factors for poor outcomes in WT patients with VCT emerge: diffuse anaplasia and metastatic disease, especially those with non-CR after PC.

Infants and Newborns with Atypical Teratoid Rhabdoid Tumors (ATRT) and Extracranial Malignant Rhabdoid Tumors (eMRT) in the EU-RHAB Registry: A Unique and Challenging Population.

Introduction: Malignant rhabdoid tumors (MRT) predominantly affect infants and young children. Patients below six months of age represent a particularly therapeutically challenging group. Toxicity to developing organ sites limits intensity of treatment. Information on prognostic factors, genetics, toxicity of treatment and long-term outcomes is sparse. Methods: Clinical, genetic, and treatment data of 100 patients (aged below 6 months at diagnosis) from 13 European countries were analyzed (2005-2020). Tumors and matching blood samples were examined for SMARCB1 mutations using FISH, MLPA and Sanger sequencing. DNA methylation subgroups (ATRT-TYR, ATRT-SHH, and ATRT-MYC) were determined using 450 k / 850 k-profiling. Results: A total of 45 patients presented with ATRT, 29 with extracranial, extrarenal (eMRT) and 9 with renal rhabdoid tumors (RTK). Seventeen patients demonstrated synchronous tumors (SYN). Metastases (M+) were present in 27% (26/97) at diagnosis. A germline mutation (GLM) was detected in 55% (47/86). DNA methylation subgrouping was available in 50% (31 / 62) with ATRT or SYN; for eMRT, methylation-based subgrouping was not performed. The 5-year overall (OS) and event free survival (EFS) rates were 23.5 ± 4.6% and 19 ± 4.1%, respectively. Male sex (11 ± 5% vs. 35.8 ± 7.4%), M+ stage (6.1 ± 5.4% vs. 36.2 ± 7.4%), presence of SYN (7.1 ± 6.9% vs. 26.6 ± 5.3%) and GLM (7.7 ± 4.2% vs. 45.7 ± 8.6%) were significant prognostic factors for 5-year OS. Molecular subgrouping and survival analyses confirm a previously described survival advantage for ATRT-TYR. In an adjusted multivariate model, clinical factors that favorably influence the prognosis were female sex, localized stage, absence of a GLM and maintenance therapy. Conclusions: In this cohort of homogenously treated infants with MRT, significant predictors of outcome were sex, M-stage, GLM and maintenance therapy. We confirm the need to stratify which patient groups benefit from multimodal treatment, and which need novel therapeutic strategies. Biomarker-driven tailored trials may be a key option.

International Comparisons of Clinical Demographics and Outcomes in the International Society of Pediatric Oncology Wilms Tumor 2001 Trial and Study.

PURPOSE: International comparisons of patient demographics, tumor characteristics, and survival can shed light on areas for health care system improvement. The International Society of Pediatric Oncology Wilms Tumor 2001 trial/study registered patients through national clinical study groups in Western Europe and Brazil. This retrospective post hoc analysis of the International Society of Pediatric Oncology Wilms Tumor 2001 database aims to make visible and suggest reasons for any variations in outcomes. METHODS: All patients with unilateral Wilms tumor (WT), age > 6 months, treated with preoperative chemotherapy as per protocol, and registered between 2001 and 2011 were eligible. Countries were grouped to give comparable case numbers and geographical representation. Cox univariable and multivariable (MVA) statistics were applied, with the German collaborative group (Gesellschaft für Pädiatrische Onkologie und Hämatologie-Austria, Germany, and Switzerland) as reference for hazard ratios for event-free survival (EFS) and overall survival (OS). RESULTS: A total of 3,176 eligible patients were registered from 24 countries assigned into six groups. Age and histologic risk group distribution were similar across all groupings. The distribution of WT stage varied by country grouping, with 14.9% (range, 11.1%-18.2%) metastatic at diagnosis. Median follow-up was 78.9 months. For localized WT, 5-year EFS varied from 80% (Brazilian group) to 91% (French group; P < .0001), retaining significance only for Brazil in MVA (P = .001). Five-year OS varied from 89% (Brazilian group) to 98% (French group; P < .0001). In MVA, only superior OS in France was significant (P = .001). Five-year EFS/OS for stage IV did not vary significantly. High-risk histology and tumor volume at surgery were significantly associated with increased risk of death in MVA for metastatic disease. CONCLUSION: International benchmarking of survival rates from WT within a large trial/study database has demonstrated statistically significant differences. Clinical interpretation should take account of variation in tumor stage but also treatment factors.

Immune-mediated thrombotic thrombocytopenic purpura in a Jehovah's Witness - Effectiveness of incorporating extracorporeal immunoadsorption to caplacizumab, steroids and rituximab.

We report the case of a Jehovah's Witness adolescent patient with immune-mediated thrombotic thrombocytopenic purpura after SARS-Cov2 infection successfully treated without therapeutic plasma exchange (TPE) using caplacizumab, corticosteroids, rituximab, and extracorporeal immunoadsorption (EIA). Further patients for whom TPE is not an option might benefit from this approach.

Treatment of patients with stage I focal anaplastic and diffuse anaplastic Wilms tumour: A report from the SIOP-WT-2001 GPOH and UK-CCLG studies.

BACKGROUND: Anaplasia is an unfavourable prognostic histological feature in Wilms tumour (WT). Patients with stage I anaplastic WT (AWT) typically achieve good outcomes, albeit with more treatment than for stage I non-AWT. Since the SIOP-WT-2001 study, patients with focal AWT (FAWT) have been classified as intermediate risk and received less intense treatment than patients with diffuse AWT (DAWT). The aim of the study was to analyse outcomes in these patients. PATIENTS AND METHODS: This was a retrospective analysis of clinicopathological features and outcomes of 59 patients with stage I AWT (19 FAWT, 40 DAWT) from the SIOP-WT-2001 GPOH and UK-CCLG groups. The patients with FAWT were treated as intermediate-risk WT, with 8 weeks of vincristine and actinomycin D (4 weeks pre-operatively, and 4 weeks post-operatively). For comparison, we also assessed outcomes in 818 patients with stage I intermediate-risk non-AWT (IR-non-AWT). The patients with DAWT were treated with vincristine, actinomycin D and doxorubicin for 31 weeks. No group received radiotherapy. RESULTS: Median follow-up was 67.6 months; 4-year event-free survival and overall survival were 87% (95% confidence interval [CI] = 72-100) and 100%, respectively, in the FAWT group, 85% (95% CI = 74-98) and 93% (95% CI 85-100), respectively, in the DAWT group and 91% (95% CI = 89-93) and 98% (95% CI = 97-99), respectively, in the IR-non-AWT group. CONCLUSIONS: Outcomes for patients with stage I FAWT were comparable with those of other, identically treated, patients with stage I IR-non-AWT. Patients with stage I DAWT also showed good outcomes, albeit with more intensive chemotherapy than IR-non-AWT, but without radiotherapy.

Current and Emerging Therapeutic Approaches for Extracranial Malignant Rhabdoid Tumors.

Extracranial malignant rhabdoid tumors (extracranial MRT) are rare, highly aggressive malignancies affecting mainly infants and children younger than 3 years. Common anatomic sites comprise the kidneys (RTK - rhabdoid tumor of kidney) and other soft tissues (eMRT - extracranial, extrarenal malignant rhabdoid tumor). The genetic origin of these diseases is linked to biallelic pathogenic variants in the genes SMARCB1, or rarely SMARCA4, encoding subunits of the SWI/SNF chromatin-remodeling complex. Even if extracranial MRT seem to be quite homogeneous, recent epigenome analyses reveal a certain degree of epigenetic heterogeneity. Use of intensified therapies has modestly improved survival for extracranial MRT. Patients at standard risk profit from conventional therapies; most high-risk patients still experience a dismal course and often therapy resistance. Discoveries of clinical and molecular hallmarks and the exploration of experimental therapeutic approaches open exciting perspectives for clinical and molecularly stratified experimental treatment approaches. To ultimately improve the outcome of patients with extracranial MRTs, they need to be characterized and stratified clinically and molecularly. High-risk patients need novel therapeutic approaches including selective experimental agents in phase I/II clinical trials.

Correction: Welter et al. Characteristics of Nephroblastoma/Nephroblastomatosis in Children with a Clinically Reported Underlying Malformation or Cancer Predisposition Syndrome. Cancers 2021, 13, 5016.

In the original article [...].

Characteristics of Nephroblastoma/Nephroblastomatosis in Children with a Clinically Reported Underlying Malformation or Cancer Predisposition Syndrome.

(1) Background: about 10% of Wilms Tumor (WT) patients have a malformation or cancer predisposition syndrome (CPS) with causative germline genetic or epigenetic variants. Knowledge on CPS is essential for genetic counselling. (2) Methods: this retrospective analysis focused on 2927 consecutive patients with WTs registered between 1989 and 2017 in the SIOP/GPOH studies. (3) Results: Genitourinary malformations (GU, N = 66, 2.3%), Beckwith-Wiedemann spectrum (BWS, N = 32, 1.1%), isolated hemihypertrophy (IHH, N = 29, 1.0%), Denys-Drash syndrome (DDS, N = 24, 0.8%) and WAGR syndrome (N = 20, 0.7%) were reported most frequently. Compared to others, these patients were younger at WT diagnosis (median age 24.5 months vs. 39.0 months), had smaller tumors (349.4 mL vs. 487.5 mL), less often metastasis (8.2% vs. 18%), but more often nephroblastomatosis (12.9% vs. 1.9%). WT with IHH was associated with blastemal WT and DDS with stromal subtype. Bilateral WTs were common in WAGR (30%), DDS (29%) and BWS (31%). Chemotherapy induced reduction in tumor volume was poor in DDS (0.4% increase) and favorable in BWS (86.9% reduction). The event-free survival (EFS) of patients with BWS was significantly (p = 0.002) worse than in others. (4) Conclusions: CPS should be considered in WTs with specific clinical features resulting in referral to a geneticist. Their outcome was not always favorable.

MYCN and MAX alterations in Wilms tumor and identification of novel N-MYC interaction partners as biomarker candidates.

BACKGROUND: Wilms tumor (WT) is the most common renal tumor in childhood. Among others, MYCN copy number gain and MYCN P44L and MAX R60Q mutations have been identified in WT. MYCN encodes a transcription factor that requires dimerization with MAX to activate transcription of numerous target genes. MYCN gain has been associated with adverse prognosis in different childhood tumors including WT. The MYCN P44L and MAX R60Q mutations, located in either the transactivating or basic helix-loop-helix domain, respectively, are predicted to be damaging by different pathogenicity prediction tools, but the functional consequences remain to be characterized. METHODS: We screened a large cohort of unselected WTs for MYCN and MAX alterations. Wild-type and mutant protein function were characterized biochemically, and we analyzed the N-MYC protein interactome by mass spectrometric analysis of N-MYC containing protein complexes. RESULTS: Mutation screening revealed mutation frequencies of 3% for MYCN P44L and 0.9% for MAX R60Q that are associated with a higher risk of relapse. Biochemical characterization identified a reduced transcriptional activation potential for MAX R60Q, while the MYCN P44L mutation did not change activation potential or protein stability. The protein interactome of N-MYC-P44L was likewise not altered as shown by mass spectrometric analyses of purified N-MYC complexes. Nevertheless, we could identify a number of novel N-MYC partner proteins, e.g. PEG10, YEATS2, FOXK1, CBLL1 and MCRS1, whose expression is correlated with MYCN in WT samples and several of these are known for their own oncogenic potential. CONCLUSIONS: The strongly elevated risk of relapse associated with mutant MYCN and MAX or elevated MYCN expression corroborates their role in WT oncogenesis. Together with the newly identified co-expressed interactors they expand the range of potential biomarkers for WT stratification and targeting, especially for high-risk WT.

Prognostic significance of histopathological response to preoperative chemotherapy in unilateral Wilms' tumor: An analysis of 899 patients treated on the SIOP WT 2001 protocol in the UK-CCLG and GPOH studies.

In the SIOP Wilms' tumor (WT) studies, preoperative chemotherapy is used as primary treatment, and tumors are classified thereafter by pathologists. Completely necrotic WTs (CN-WTs) are classified as low-risk tumors. The aim of the study was to evaluate whether a subset of regressive type WTs (RT-WTs) (67%-99% chemotherapy-induced changes [CIC]) showing an exceptionally good response to preoperative chemotherapy had comparably excellent survivals as CN-WTs, and to establish a cut-off point of CIC that could define this subset. The study included 2117 patients with unilateral, nonanaplastic WTs from the UK-CCLG and GPOH-WT studies (2001-2020) treated according to the SIOP-WT-2001 protocol. There were 126 patients with CN-WTs and 773 with RT-WTs, stages I-IV. RT-WTs were subdivided into subtotally necrotic WTs (>95% CIC) (STN-WT96-99) (124 patients) and the remaining of RT-WT (RR-WT67-95) (649 patients). The 5-year event-free survival (EFS) and overall survival (OS) for CN-WTs were 95.3% (±2.1% SE) and 97.3% (±1.5% SE), and for RT-WTs 85.7% (±1.14% SE, P < .01) and 95.2% (±0.01% SE, P = .59), respectively. CN-WT and STN-WT96-99 groups showed significantly better EFS than RR-WT67-95 (P = .003 and P = .02, respectively), which remained significantly superior when adjusted for age, local stage and metastasis at diagnosis, in multivariate analysis, whereas OS were superimposable (97.3 ± 1.5% SE for CN-WT; 97.8 ± 1.5% SE for STN-WT96-99; 94.7 ± 1.0% SE for RR-WT67-95). Patients with STN-WT96-99 share the same excellent EFS and OS as patients with CN-WTs, and although this was achieved by more treatment for patients with STN-WT96-99 than for patients with CN-WT, reduction in postoperative treatment of these patients may be justified.