Management and outcome of pediatric Wilms tumor with malignant inferior Vena cava thrombus: largest cohort of single-center experience

Wilms Tumor with Vena Caval Intravascular Extension: A Surgical Perspective

Wilms tumor (WT) is the most common kidney tumor in pediatric patients. Intravascular extension of WT above the level of the renal veins is a rare manifestation that complicates surgical management. Patients with intravascular extension are frequently asymptomatic at diagnosis, and tumor thrombus extension is usually diagnosed by imaging. Neoadjuvant chemotherapy is indicated for thrombus extension above the level of the hepatic veins and often leads to thrombus regression, obviating the need for cardiopulmonary bypass in cases of cardiac thrombus at diagnosis. In cases of tumor extension to the retrohepatic cava, neoadjuvant therapy is not strictly indicated, but it may facilitate the regression of tumor thrombi, making resection safer. Hepatic vascular isolation and cardiopulmonary bypass increase the risk of bleeding and other complications when utilized for tumor thrombectomy. Fortunately, WT patients with vena caval with or with intracardiac extension have similar overall and event-free survival when compared to patients with WT without intravascular extension when thrombectomy is successfully performed. Still, patients with metastatic disease at presentation or unfavorable histology suffer relatively poor outcomes. Dedicated pediatric surgical oncology and pediatric cardiothoracic surgery teams, in conjunction with multimodal therapy directed by a multidisciplinary team, are preferred for optimized outcomes in this patient population.

Robotic-assisted laparoscopic surgery for the treatment of Wilms' tumor in children: single-center experience and medium-term outcomes

To report our institutional experience and the medium-term outcomes of utilizing robotic-assisted laparoscopic surgery (RALS) in patients with Wilms' tumor (WT). The robotic surgical interventions include nephron-sparing surgery (RAL-NSS), radical nephrectomy (RAL-RN), and nephrectomy with inferior vena cava thrombectomy (RAL-N-IVCT). We retrospectively collected medical records of WT patients who underwent RALS in our center between August 2019 and February 2022. Patients' baseline demographics, preoperative parameters, and perioperative/postoperative data were recorded and analyzed. Follow-up results were collected to evaluate the oncological outcomes. A total of 12 patients (13 sides) with a median age of 30 (IQR: 19.5-45.5) months were included. All operations were successfully completed without conversion. Seven patients received preoperative chemotherapy. Distribution of surgical interventions was as follows: five patients underwent RAL-RN, five received RAL-NSS, one with bilateral WT underwent concurrent RAL-RN and RAL-NSS, and one received RAL-RN-IVCT post preoperative chemotherapy. Postoperative chemotherapy was conducted in ten patients. The estimated intraoperative blood loss was 27 ± 4.0 ml for the RAL-NSS group, 41.67 ± 12.13 ml for the RAL-RN group, and 350 ml for the RAL-RN-IVCT groups, respectively. The median perioperative serum creatinine levels were 32.5 (IQR: 30.75-39.5) μmol/l preoperatively and 35 (IQR: 31.75-38.5) μmol/l postoperatively, which showed no significant difference. No positive lymph nodes were detected. Postoperative chemotherapy was performed according to the tumor volume and pathological findings. The median follow-up time was 17.5 (15.8-22.3) months. During this interval, neither distant metastasis nor recurrence was identified. Based on our medium-term follow-up observations, RAL-NSS, RAL-RN, and RAL-RN-IVCT exhibit promising feasibility and safety profiles in the therapeutic landscape of WT.

Critical elements of radical nephroureterectomy for pediatric unilateral renal tumor

Children with renal masses require surgical management to provide accurate surgical staging and skilled resection of the tumor. This document includes evidence-based recommendations for pediatric surgeons regarding the resection, staging, and proper nodal basin evaluation.

Breaking down tumor thrombus: Current strategies for medical management

Tumor thrombus, the intravascular extension of tumor into adjacent blood vessels, is frequently encountered in patients with renal cell carcinoma and hepatocellular carcinoma, and often involves the abdominal vasculature including the renal vein, portal vein, and the inferior vena cava. While a bland thrombus is composed of platelets and fibrin, in contrast, a tumor thrombus refers to an organized collection of tumor cells. Though oftentimes detected incidentally on imaging, tumor thrombus may have significant clinical implications and can be challenging to differentiate from bland thrombus. Additionally, the optimal management of tumor thrombus, including the use of anticoagulation, remains poorly described. This review summarizes common causes of tumor thrombus, as well as its impact on staging, prognosis, and treatment.

Response to Neoadjuvant Chemotherapy and Outcomes in Children With Wilms Tumor With Caval Thrombus: A Single Center Experience

AIM

The aim of our study is to present our experience in the management and outcome of Wilms tumor with intracaval thrombus.

MATERIALS AND METHODS

All children with Wilms tumor with intracaval thrombus who presented to us from July 2000 to December 2017 were reviewed retrospectively. We evaluated the tumor stage, management, and outcomes in these patients.

RESULTS

Thirty-four patients were included in the study. The median age of presentation was 48 months (11 to 84 mo). Preoperative chemotherapy was given in 32 (94%), with a median duration of 8 weeks. Intracaval thrombus completely resolved in 9 (26%) children after neoadjuvant chemotherapy. Surgical intervention for residual inferior vena cava (IVC) thrombus was performed in 32 patients. The median follow-up was 30 months (5 to 150 mo). At the last follow-up, 24 patients (70%) were alive and disease free. The 5-year overall survival (OS) and event-free survival were 67% (95% confidence interval, 50% to 84%) and 59% (95% confidence interval, 42% to 76%). The OS in children with nonmetastatic disease (94%) was significantly higher than those with metastases (29%; P <0.01). The OS in children with complete resolution of IVC thrombus (100%) was significantly higher than those with persistent thrombus (48%; P =0.025). Analysis of survival outcomes in children with nonmetastatic disease (stage III) revealed no significant difference on comparison with cohort with stage III disease with absence of IVC thrombus. The P -value was 0.224 and 0.53 for 5-year OS and event-free survival, respectively.

CONCLUSION

The management of Wilms tumor can be complicated by the presence of caval thrombus. Patients with metastasis have a significantly poor outcome. Patients in whom, there is complete resolution of intracaval thrombus on neoadjuvant chemotherapy have a significantly higher OS.

Wilms tumor in children: A multivariate analysis of prognostic factors, with emphasis on inferior vena cava/right atrium extension. Results from a single-center study

BACKGROUND

To identify prognostic factors for overall survival through the analysis of 132 patients with Wilms tumor followed at a single center, with emphasis on the inferior vena cava/right atrium extension.

METHODS

Retrospective analysis of overall survival using logistic regression models and including age, sex, clinical features, associated syndromes, comorbidities, tumor size before chemotherapy, stage, presence of metastatic disease and its site, invasion of adjacent structures, inferior vena cava/right atrium extension, laterality, tumor histology, chemotherapy protocol, and radiotherapy as potential risk factors.

RESULTS

From January 2000 through November 2021, 132 patients met the inclusion criteria, 64 females and 68 males; 15 (11.4%) patients presented with tumoral extension to inferior vena cava/right atrium and 44 had metastatic disease (33.3%). Based on logistic regression, the factors correlating to a fatal outcome were male sex (p = 0.046), high risk histology (p = 0.036), and the presence of metastatic disease (p = 0.003). None of the patients presenting inferior vena cava/right atrium extension died (p = 0.992). In a specific analysis of metastatic sites, hepatic metastasis alone showed correlation with a fatal outcome (p = 0.001).

CONCLUSION

These results underline the importance of identifying and treating metastatic disease and high-risk tumors. The female gender as a potential driver for a less aggressive disease is a new finding that deserves further investigation. The accurate identification of inferior vena cava/right atrium extension, subsequent preoperative chemotherapy, and resection with a skilled team promoted survival rates of all patients.

LEVEL OF EVIDENCE

II.

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.

Multimodality Imaging of Pleuropulmonary Blastoma: Pearls, Pitfalls, and Differential Diagnosis

Pleuropulmonary blastomas are rare, potentially aggressive embryonal cancers of the lung parenchyma and pleural surfaces that account for 0.25%-0.5% of primary pulmonary malignancies in children. Pleuropulmonary blastomas are classified as cystic (type I), mixed cystic and solid (type II), and solid (type III). Pleuropulmonary blastoma occurs in the same age group (0-6 years) as other more common solid tumors such as neuroblastoma and Wilms tumor. Differential diagnosis includes metastasis from Wilms tumor and macrocystic congenital pulmonary airway malformation (CPAM). A key pathologic and genetic discriminator is the DICER1 germline mutation found in patients with pleuropulmonary blastoma. Imaging, histopathologic, and clinical data are important to use in conjunction in order to determine the diagnosis and risk stratification of pleuropulmonary blastomas. Survival varies from poor to good, depending on type. However, the spectrum of pleuropulmonary blastoma is insufficiently understood due to the variable presentation of this rare disease. We present a current review of the literature regarding pleuropulmonary blastomas in this article.

Multidisciplinary Treatment Strategies for Wilms Tumor: Recent Advances, Technical Innovations and Future Directions

Significant progress has been made in the management of Wilms tumor (WT) in recent years, mostly as a result of collaborative efforts and the implementation of protocol-driven, multimodal therapy. This article offers a comprehensive overview of current multidisciplinary treatment strategies for WT, whilst also addressing recent technical innovations including nephron-sparing surgery (NSS) and minimally invasive approaches. In addition, surgical concepts for the treatment of metastatic disease, advances in tumor imaging technology and potentially prognostic biomarkers will be discussed. Current evidence suggests that, in experienced hands and selected cases, laparoscopic radical nephrectomy and laparoscopic-assisted partial nephrectomy for WT may offer the same outcome as the traditional open approach. While NSS is the standard procedure for bilateral WT, NSS has evolved as an alternative technique in patients with smaller unilateral WT and in cases with imminent renal failure. Metastatic disease of the lung or liver that is associated with WT is preferably treated with a three-drug chemotherapy and local radiation therapy. However, surgical sampling of lung nodules may be advisable in persistent nodules before whole lung irradiation is commenced. Several tumor markers such as loss of heterozygosity of chromosomes 1p/16q, 11p15 and gain of function at 1q are associated with an increased risk of recurrence or a decreased risk of overall survival in patients with WT. In summary, complete resection with tumor-free margins remains the primary surgical aim in WT, while NSS and minimally invasive approaches are only suitable in a subset of patients with smaller WT and low-risk disease. In the future, advances in tumor imaging technology may assist the surgeon in defining surgical resection margins and additional biomarkers may emerge as targets for development of new diagnostic tests and potential therapies.

Impact of neoadjuvant chemotherapy on thrombus viability in patients with Wilms tumour and caval extension: systematic review with meta-analysis

BACKGROUND

Inferior vena cava (IVC) tumour thrombus in children with Wilms tumour is typically managed with neoadjuvant chemotherapy with the intention of achieving thrombus regression in order to minimize the risks associated with complex vascular surgery.

METHODS

A systematic review of Medline and Embase databases was undertaken to identify all eligible studies with reference to thrombus viability in Wilms tumour index cases with caval/cardiac extension. A meta-analysis of proportions was utilized for pooled thrombus viability data across studies. Logistic regression was used to analyse the relationship between thrombus viability and duration of chemotherapy.

RESULTS

Thirty-five eligible observational studies and case reports met inclusion criteria describing a total of 236 patients with thrombus viability data. The pooled proportion of patients with viable tumour thrombus after neoadjuvant chemotherapy was 0.53 (0.43-0.63). Logistic regression analysis of 54 patients receiving either a standard (4-6 weeks) or extended (more than 6 weeks) course of neoadjuvant chemotherapy resulted in an odds ratio of 3.14 (95 per cent c.i. 0.97 to 10.16), P = 0.056, with extended course therapy trending towards viable tumour thrombus.

CONCLUSION

Preoperative chemotherapy is successful in achieving non-viability of caval and cardiac thrombi in around 50 per cent of children, without added benefit from extended cycles of neoadjuvant chemotherapy. Risks versus benefits of extirpative vascular surgery must be considered, therefore, for these high-risk patients.

Management of Pediatric Tumors With Vascular Extension

Background: Pediatric tumors can present with vascular extension to the inferior vena cava and right atrium, which impacts the surgical strategy and can be challenging during surgical treatment. Wilms tumor (WT) is the most common retroperitoneal tumor that can present with vascular extension, but also adrenal tumors, clear cell tumors from the kidney, and hepatoblastomas can present with this situation. Surgical aims include obtaining complete tumor resection without risk for patients, to avoid severe bleeding, cardiac arrest, and embolization, and to avoid cardiac bypass if possible. Objective: To describe and discuss the surgical strategies to deal with pediatric tumors with vascular extension and propose a protocol. Method: Retrospectivly review the experience of treating patients with vascular extension in a single institution, describing different scenarios and a decision making fluxogram based on the preoperative evaluation regarding the surgical techniques and the need for cardiac bypass that are adequate for each situation. Image studies are important to guide the surgical strategy. Depending on the quality of image available, computerized tomography (CT) or magnetic resonance imaging (MRI) can be enough to give the information needed for surgical decisions. Ultrasonography (US) with Doppler is helpful to confirm diagnosis and describes factors to guide the adequate surgical strategy, like the upper level extension and presence or absence of blood flow around the thrombus. Neoadjuvant chemotherapy is indicated in most cases, in order to reduce the upper level of extension (and avoid the need for cardiac bypass) and to lower the risk of embolization. The approach is based on the upper level of the thrombus and can include cavotomy or cavectomy, sometimes with cardiac bypass and cardiac arrest with hypothermia, when the thrombus reaches the diaphragmatic level or above. Pathology analysis of the thrombus can guide staging and the need for radiotherapy postoperatively. Results: A decision making fluxogram protocol is presented focusing on the surgical treatment of such condition. Conclusion: Surgery strategy is highly impacted by the presence of vascular extension in pediatric tumors. Surgeons should be aware of potential complications and how to prevent them. Such cases should be treated in reference centers.

Resection of Inferior Vena Cava Without Reconstruction for Intravascular Intrusion of Wilms Tumor

Persistent inferior vena cava (IVC) tumor thrombus in Wilms tumor patients represents a management challenge. We describe three pediatric cases with preoperative evaluation documenting complete IVC occlusion and well-developed collaterals. They underwent nephrectomy and tumor thrombus removal accomplished with circumferential resection of the retrohepatic IVC without vascular reconstruction. All patients are asymptomatic and disease-free at 9, 2.5, and 2 years after stopping therapy. Cavectomy without reconstruction is safe and well tolerated in Wilms tumor patients with completely occlusive IVC tumor thrombus. Additionally, when performed en bloc with nephrectomy and with clear margins, cavectomy obviates the need for radiotherapy per protocol.