Anaplasia in Wilms tumor: A critical review

Anaplasia in Wilms tumor is recognized as the most important prognostically unfavorable histological feature. It is subtyped as focal anaplastic Wilms tumor (FAWT) and diffuse anaplastic Wilms tumor (DAWT). Outcomes of patients with DAWT remain poor in patients with stage III and IV tumors. Important issues relevant to anaplasia in Wilms tumor, including prevalence, treatment, outcomes, biomarkers, anaplasia, and chemotherapy, and the concept of tumor aggressiveness, are reviewed and discussed here. We also consider the differences in clinical approaches to anaplasia in Wilms tumor between the two major renal tumor clinical research groups: the International Society of Paediatric Oncology (SIOP) Renal Tumour Study Group and the Children's Oncology Group (COG) Renal Tumor Group. We emphasize the importance and implications of recognizing FAWT and DAWT as separate clinico-pathological entities.

Advances in the clinical management of high-risk Wilms tumors

Outcomes are excellent for the majority of patients with Wilms tumors (WT). However, there remain WT subgroups for which the survival rate is approximately 50% or lower. Acknowledging that the composition of this high-risk group has changed over time reflecting improvements in therapy, we introduce the authors' view of the historical and current approach to the classification and treatment of high-risk WT. For this review, we consider high-risk WT to include patients with newly diagnosed metastatic blastemal-type or diffuse anaplastic histology, those who relapse after having been initially treated with three or more different chemotherapeutics, or those who relapse more than once. In certain low- or low middle-income settings, socio-economic factors expand the definition of what constitutes a high-risk WT. As conventional therapies are inadequate to cure the majority of high-risk WT patients, advancement of laboratory and early-phase clinical investigations to identify active agents is urgently needed.

Advances in the clinical management of high-risk Wilms tumors

Outcomes are excellent for the majority of patients with Wilms tumors (WT). However, there remain WT subgroups for which the survival rate is approximately 50% or lower. Acknowledging that the composition of this high-risk group has changed over time reflecting improvements in therapy, we introduce the authors' view of the historical and current approach to the classification and treatment of high-risk WT. For this review, we consider high-risk WT to include patients with newly diagnosed metastatic blastemal-type or diffuse anaplastic histology, those who relapse after having been initially treated with three or more different chemotherapeutics, or those who relapse more than once. In certain low- or low middle-income settings, socio-economic factors expand the definition of what constitutes a high-risk WT. As conventional therapies are inadequate to cure the majority of high-risk WT patients, advancement of laboratory and early-phase clinical investigations to identify active agents is urgently needed.

Pathology of Wilms' tumour in International Society of Paediatric Oncology (SIOP) and Children's Oncology Group (COG) renal tumour studies: similarities and differences

Excellent outcomes for patients with Wilms' tumour (WT), over 90% for all stages together, have been achieved through researching WT in multicentre and multinational trials and studies in the last 50 years, led by two major groups - International Society of Paediatric Oncology (SIOP) and Children's Oncology Group (COG, previously National Wilms' Tumor Study Group). Despite having different approaches, the survival outcomes in two groups are remarkably similar. In general, in SIOP, which is followed in Europe and most other countries around the world, patients are first treated with pre-operative chemotherapy, followed by surgery and, if necessary, post-operative chemotherapy and radiotherapy. In COG, which is mainly followed in North America, patients are treated with upfront surgery, followed, if necessary, by post-operative chemotherapy and radiotherapy. In both groups, post-operative treatment primarily depends on tumour histological classification and stage, although in recent studies, other prognostic factors have been included, too (tumour volume, response to preoperative chemotherapy, molecular markers). Due to separate initial treatments, there are differences in histological assessment and subtyping of WT, and, more importantly, in staging criteria. In this review, we discuss the similarities and differences between the two groups in order to help pathologists who are dealing with WT to understand and follow the pathological protocol which is appropriate for a particular case since in many centres both approaches may be followed depending on individual case's / patient's circumstances.

Pediatric cancer care in Africa: SIOP Global Mapping process

In November 2018, theInternational Society of Paediatric Oncology (SIOP) launched a project to map African facilities providing pediatric oncology treatment. A 55-item digital survey was created in English, piloted in India, translated to French and Portuguese, and distributed by email, social media, or personal contacts. December 2019, 48/54 African countries responded (72% surveys completed and analyzed). Issues included incomplete responses, multiple entries for one facility with conflicting data for key services, and repeated entries with varied answers by the same respondent. The facility mapping project, now on-going program will serve as a global registry of global pediatric cancer centers.

Wilms' Tumor in Adults-Conventional and Unconventional Presentations of a Rare Entity with a Review of Literature

Wilms' tumor (WT) in adults is a rare neoplasm. Only a few reports are available in the literature. The tumor often masquerades as renal cell carcinoma (RCC). For accurate reporting, histopathological examination (HPE) plays a vital role in early diagnosis and prompt administration of multimodality treatment helps to improve the prognosis. We comprehensively analyzed five cases of adult WT presenting in the third to fifth decade with flank pain, hematuria, fever, and palpable lump. After complete clinical, biochemical, radiological, and HPE evaluation, tumor was staged and treatment was planned accordingly. Patients with low-stage WT were treated with open radical nephrectomy and chemotherapy. One of the patients diagnosed with inferior vena cava (IVC) thrombus apart from the above treatment also underwent IVC thrombectomy. Another young male presenting with distant metastasis (stage IV) and focal anaplasia on histology received preoperative chemotherapy and then planned for surgery. Unfortunately, the tumor being unresectable, second-line chemotherapy was given but he ultimately succumbed to death. All other patients are on regular follow-up and disease-free. Adult nephroblastoma is a rare clinical entity with hostile behavior. The presence of IVC thrombus is not a contraindication to surgery. Although the management strategy as per pediatric protocol by the inclusion of multimodality approach improves survival, still the overall prognosis in adults is dismal. There is a need for a standardized treatment protocol to encourage a homogenous approach for this rare disease and thereby improve survival.

Non-rhabdomyosarcoma soft-tissue sarcoma

Non-rhabdomyosarcoma soft-tissue sarcomas (NRSTS) comprise 4% of childhood cancers and consist of numerous histologic subtypes. Prognostic factors associated with poor outcome include high histologic grade, large tumor size, presence of metastases, and unresectability. Complete surgical resection is critical for the best oncologic outcomes and is prioritized in treatment algorithms. The use of radiation therapy (RT) and chemotherapy is based upon factors such as resectability, histologic grade, tumor size, and stage. North American and European trials are defining a risk-based approach to NRSTS to limit treatment-related toxicity and to maximize therapeutic efficacy. In this paper, we summarize the current roles of surgery, RT, and chemotherapy in NRSTS and describe ongoing research that is advancing the care of NRSTS patients.

Advances in radiotherapy technology for pediatric cancer patients and roles of medical physicists: COG and SIOP Europe perspectives

Over the last two decades, rapid technological advances have dramatically changed radiation delivery to children with cancer, enabling improved normal-tissue sparing. This article describes recent advances in photon and proton therapy technologies, image-guided patient positioning, motion management, and adaptive therapy that are relevant to pediatric cancer patients. For medical physicists who are at the forefront of realizing the promise of technology, challenges remain with respect to ensuring patient safety as new technologies are implemented with increasing treatment complexity. The contributions of medical physicists to meeting these challenges in daily practice, in the conduct of clinical trials, and in pediatric oncology cooperative groups are highlighted. Representing the perspective of the physics committees of the Children's Oncology Group (COG) and the European Society for Paediatric Oncology (SIOP Europe), this paper provides recommendations regarding the safe delivery of pediatric radiotherapy. Emerging innovations are highlighted to encourage pediatric applications with a view to maximizing the therapeutic ratio.

The role of twinning in sustainable care for children with cancer: A TIPPing point? SIOP PODC Working Group on Twinning, Collaboration, and Support

With the World Health Organization (WHO) Global Initiative for Childhood Cancer, there is renewed interest in sustainable interventions to improve childhood cancer care in low-/middle-income countries (LMICs). Practitioners in LMICs have traditionally practiced "twinning," i.e., targeted international pediatric oncology partnerships (TIPPs) between one or more institutions in a high-income country (HIC) and an LMIC, to improve care for children with cancer in the latter. The International Society of Paediatric Oncology Committee for Paediatric Oncology in Developing Countries Working Group on Twinning, Collaboration, and Support reviewed guidelines from https://cancerpointe.com and the current literature, gathered input from practitioners in LMICs, and in this article discuss the role of TIPPs in the WHO initiative.

Wilms tumour in children: 18 years of experience at Vilnius University Hospital Santaros Klinikos, Lithuania

Introduction

Wilms tumour (WT) is the most common childhood abdominal malignancy, with an average annual incidence of 1 in 10,000 children. The study published in 2002 reported lower survival rates of WT in Lithuania in comparison to the data of SIOP-9 study and the European Organization for Research and Treatment of Cancer (EORTC). We aimed to assess current diagnostic approach and treatment results of patients with WT treated at our institution and to compare the results with the previously published study.

Materials and methods

A retrospective single-centre study was performed. 48 patients with WT registered at the institutional data-base from 2000 to 2018 were enrolled. An estimated 5-year overall survival (OS_5y) and 2-year event-free survival (EFS_2y) by stage and risk groups was calculated using IBM SPSS. A comparative analysis of two time periods - 2000-2008 and 2009-2018 - was carried out.

Results

Forty-two (87.5%) patients presented with localised disease and 6 (12.5%) with primary metastatic disease. The majority of cases were of the intermediate-risk group (77%). The OS_5yof all analysed children was 86.4%. The EFS_2y was 88.9% in stage I, 91.7% in stage II, 83.3% in stage III, and 50% in stage IV. The EFS_2y was 100% in the low-risk group, 86.5% in the intermediate-risk group, and 25% in the high-risk group. Improvement of outcomes was observed over the analysed period: OS_5y changed from 81.0% in 2000-2008 to 92.6% in 2009-2018. Among 48 cases, ten patients showed recurrence: eight - early relapse and two - late relapse. Six patients died.

Conclusions

WT was diagnosed at early stages in most cases. The  survival was better among the  patients diagnosed in earlier stages and with favourable risk group. Better survival rates were observed in patients treated in 2009-2018 compared to the 2000-2008 period.

The role of TCF3 as potential master regulator in blastemal Wilms tumors

Wilms tumors are the most common type of pediatric kidney tumors. While the overall prognosis for patients is favorable, especially tumors that exhibit a blastemal subtype after preoperative chemotherapy have a poor prognosis. For an improved risk assessment and therapy stratification, it is essential to identify the driving factors that are distinctive for this aggressive subtype. In our study, we compared gene expression profiles of 33 tumor biopsies (17 blastemal and 16 other tumors) after neoadjuvant chemotherapy. The analysis of this dataset using the Regulator Gene Association Enrichment algorithm successfully identified several biomarkers and associated molecular mechanisms that distinguish between blastemal and nonblastemal Wilms tumors. Specifically, regulators involved in embryonic development and epigenetic processes like chromatin remodeling and histone modification play an essential role in blastemal tumors. In this context, we especially identified TCF3 as the central regulatory element. Furthermore, the comparison of ChIP-Seq data of Wilms tumor cell cultures from a blastemal mouse xenograft and a stromal tumor provided further evidence that the chromatin states of blastemal cells share characteristics with embryonic stem cells that are not present in the stromal tumor cell line. These stem-cell like characteristics could potentially add to the increased malignancy and chemoresistance of the blastemal subtype. Along with TCF3, we detected several additional biomarkers that are distinctive for blastemal Wilms tumors after neoadjuvant chemotherapy and that may provide leads for new therapeutic regimens.

ETV6-NTRK3 in congenital mesoblastic nephroma: A report of the SIOP/GPOH nephroblastoma study

BACKGROUND

Congenital mesoblastic nephroma (MN) is a rare pediatric renal tumor representing approximately 5% of all pediatric renal tumors. Three different types of MN are distinguished histologically: classical, cellular, and mixed. A frequent genetic alteration is the translocation t(12;15) resulting in a fusion of the ETV6 gene on 12p13 and the NTRK3 gene on 15p15 that occurs almost exclusively in cellular MN. The aim of this study was to determine translocation status of a large cohort of MN with respect to tumor subtype and outcome.

PROCEDURE

In total, clinical data from 111 patients were available. Sixty-seven tumors were classical MN (51%), 29 cellular MN (31%), and 15 were mixed MN (18%). From these 111 cases, 79 were analyzed by FISH and RT-PCR.

RESULTS

All classical and mixed MN were translocation negative. Seventeen out of 29 (58%) cellular MN harbored the ETV6-NTRK3 translocation. Five-year relapse-free survival (RFS) and overall survival (OS) were 93.2% and 96.8% for the complete cohort. All seven relapses occurred in translocation negative tumors. Five-year RFS was significantly inferior for cellular and mixed MN compared to classic MN (89%, 80%, and 98%), whereas 5-year OS was similar (93%, 96%, and 98%). Within the group of cellular MN, patients having translocation-positive tumors had a significantly superior RFS (5-year RFS: 100% vs. 73%).

CONCLUSION

The majority of cellular MNs harbor the ETV6-NTKR3 gene fusion, whereas all classic- and mixed-type MNs were translocation negative. Within the cellular subgroup, patients having translocation-positive tumors had a significantly superior RFS.

High-dose treatment for malignant rhabdoid tumor of the kidney: No evidence for improved survival-The Gesellschaft für Pädiatrische Onkologie und Hämatologie (GPOH) experience

BACKGROUND

Malignant rhabdoid tumor of the kidney (MRTK) is the most aggressive childhood renal tumor with overall survival (OS) rates ranging from 22% to 42%. Whether high-dose chemotherapy with autologous stem-cell transplantation (HDSCT) in an intensive first-line treatment offers additional benefit is an ongoing discussion.

METHODS

A retrospective analysis of all 58 patients with MRTK from Austria, Switzerland, and Germany treated in the framework of consecutive, prospective renal/rhabdoid tumor studies SIOP9/GPO, SIOP93-01/GPOH (where SIOP is International Society of Pediatric Oncology and GPOH is German Society of Pediatric Oncology and Hematology), SIOP2001/GPOH, and European Rhabdoid Tumor Registry from 1991 to 2014.

RESULTS

Median age at diagnosis was 11 months. Fifty percent of patients had metastases or multifocal disease at diagnosis (Stage IV). Local stage distribution was as follows: not done/I/II/III-1/6/11/40. Fifteen (26%) patients underwent upfront surgery. Thirty-seven (64%) patients achieved a complete remission, 17 (29%) relapsed, 34 (59%) died of disease progression, and two (3%) died of treatment-related complication. Mean time to the first event was 3.5 months. Two-year EFS/OS (where EFS is event-free survival) for the whole group was 37 ± 6%/38 ± 6%. Metastases/multifocal disease, younger age, and local stage III were associated with significantly inferior survival. Eleven (19%) patients underwent HDSCT (carboplatin + thiotepa, n = 6; carboplatin + etoposide + melphalan, n = 4; others, n = 1); 2-year OS in this group was 60 ± 15% compared to 34 ± 8% in the non-HDSCT group (P = 0.064). However, the time needed from radiologic to histologic diagnosis, stem-cell harvest, and HDSCT must also be taken into account to avoid selection bias by excluding the highest risk group with early progression (<90 days). Thus, 2-year EFS only for patients without progression until day 90 was 60 ± 16% consolidated by HDSCT compared to 62 ± 11% without (P = 0.8).

CONCLUSION

Our retrospective analysis suggests comparable outcomes for patients with and without HDSCT, if adjusted for early disease progression.

A framework to develop adapted treatment regimens to manage pediatric cancer in low- and middle-income countries: The Pediatric Oncology in Developing Countries (PODC) Committee of the International Pediatric Oncology Society (SIOP)

Many children with cancer in low- and middle-income countries are treated in hospitals lacking key infrastructure, including diagnostic capabilities, imaging modalities, treatment components, supportive care, and personnel. Childhood cancer treatment regimens adapted to local conditions provide an opportunity to cure as many children as possible with the available resources, while working to improve services and supportive care. This paper from the Adapted Treatment Regimens Working Group of the Pediatric Oncology in Developing Countries committee of the International Society of Pediatric Oncology outlines the design, development, implementation, and evaluation of adapted regimens and specifies levels of services needed to deliver them.

Efficacy of Different Protocols in Treatment of Nephroblastoma: A revisit

BACKGROUND

Management of Nephroblastoma (NB) remains a subject of debate despite the fact that it ranked first among primary childhood's renal neoplasm. We have previously discussed this issue 13, 14, yet, the sample size was limited.

AIM

The aim of this study was to further evaluate the efficacy of initial surgery in the treatment of stage II and III pediatric NB as a part of the short administration schedule as in National Wilms' Tumor Study (NWTS)-4 and to evaluate its effectiveness compared to the long administration schedule.

PATIENTS AND METHODS

The study included 50 children who were primarily diagnosed as stage II and III NB. They were divided into 2 equal groups. Group I (n = 25) included children who have undergone neoadjuvant chemotherapy followed by surgery and postoperative chemotherapy, while group II (n = 25) included children who have undergone primary surgery as an initial management followed by chemotherapy. After a mean postoperative follow-up period of 20±6 months, clinical and radiological evaluation was performed to all patients.

RESULTS

In group I, 15 patients were preoperatively diagnosed as stage II and 10 patients as stage III while in group II, 16 patients were proved to be stage II and 9 patients were stage III. After a follow up period, clinical and radiological evaluation using CT was performed to all patients. In patients with stage II, evidence of recurrence was noted in 5 patients of group I whereas no patient showed any evidence of recurrence in group II. In patients with stage III, rebound increase in size was seen in 3 patients in group I and only one patient in group II.

CONCLUSIONS

This study confirmed our previous conclusions that initial surgical intervention with appropriate adjuvant therapy has a better outcome than the neoadjuvant chemotherapy and delayed surgery for children primarily diagnosed as stage II and III NB. Moreover, it may also act as a short administration schedule for the treatment as it is not less effective than the long administration schedule and can be administered at a substantially lower total treatment cost.

Image based feasibility of renal sparing surgery for very low risk unilateral Wilms tumors: a report from the Children's Oncology Group

PURPOSE

Nephrectomy with lymph node sampling is the recommended treatment for children with unilateral Wilms tumor under the Children's Oncology Group protocols. Using radiological assessment, we determined the feasibility of performing partial nephrectomy in a select group of patients with very low risk unilateral Wilms tumor.

MATERIALS AND METHODS

We reviewed imaging studies of 60 patients with a mean age of less than 2 years with very low risk unilateral Wilms tumor (mean weight less than 550 gm) to assess the feasibility of partial nephrectomy. We evaluated percentage of salvageable parenchyma, tumor location and anatomical features preventing a nephron sparing approach.

RESULTS

A linear relationship exists between tumor weight and computerized tomography estimated tumor volume. Mean tumor weight in the study population was 315 gm. Partial nephrectomy was deemed feasible in only 5 of 60 patients (8%).

CONCLUSIONS

When considering a select population with very low risk unilateral Wilms tumor (lower volume tumor), only a small percentage of nonpretreated patients are candidates for nephron sparing surgery.