Minimally invasive and robotic-assisted approaches applied to pediatric surgical oncology.

The management of pediatric tumors is complex, with surgery, chemotherapy, and radiotherapy being cornerstones in their treatment. Tumor removal is increasingly performed by a minimally invasive approach, which allows for quicker postoperative recovery and less postoperative pain. The goal of this report is to give an overview of minimally invasive surgical approaches for common pediatric tumors, with a focus on technical considerations and postoperative outcomes.

Disease Control and Toxicity Outcomes after Stereotactic Ablative Radiation Therapy for Recurrent and/or Metastatic Cancers in Young-Adult and Pediatric Patients.

BACKGROUND: Pediatric patients with metastatic and/or recurrent solid tumors have poor survival outcomes despite standard-of-care systemic therapy. Stereotactic ablative radiation therapy (SABR) may improve tumor control. We report the outcomes with the use of SABR in our pediatric solid tumor population. METHODS: This was a single-institutional study in patients < 30 years treated with SABR. The primary endpoint was local control (LC), while the secondary endpoints were progression-free survival (PFS), overall survival (OS), and toxicity. The survival analysis was performed using Kaplan-Meier estimates in R v4.2.3. RESULTS: In total, 48 patients receiving 135 SABR courses were included. The median age was 15.6 years (interquartile range, IQR 14-23 y) and the median follow-up was 18.1 months (IQR: 7.7-29.1). The median SABR dose was 30 Gy (IQR 25-35 Gy). The most common primary histologies were Ewing sarcoma (25%), rhabdomyosarcoma (17%), osteosarcoma (13%), and central nervous system (CNS) gliomas (13%). Furthermore, 57% of patients had oligometastatic disease (≤5 lesions) at the time of SABR. The one-year LC, PFS, and OS rates were 94%, 22%, and 70%, respectively. No grade 4 or higher toxicities were observed, while the rates of any grade 1, 2, and 3 toxicities were 11.8%, 3.7%, and 4.4%, respectively. Patients with oligometastatic disease, lung, or brain metastases and those who underwent surgery for a metastatic site had a significantly longer PFS. LC at 1-year was significantly higher for patients with a sarcoma histology (95.7% vs. 86.5%, p = 0.01) and for those who received a biological equivalent dose (BED10) > 48 Gy (100% vs. 91.2%, p = 0.001). CONCLUSIONS: SABR is well tolerated in pediatric patients with 1-year local failure and OS rates of <10% and 70%, respectively. Future studies evaluating SABR in combination with systemic therapy are needed to address progression outside of the irradiated field.

Bilateral Wilms tumor with anaplasia: A report from the Children's Oncology Group Study AREN0534.

INTRODUCTION: The purpose of this study is to examine the outcomes in children with anaplastic bilateral Wilms tumor (BWT) from study AREN0534 in order to define potential prognostic factors and areas to target in future clinical trials. METHODS: Demographic and clinical data from AREN0534 study patients with anaplasia (focal anaplasia [FA], or diffuse anaplasia [DA]) were compared. Event-free survival (EFS) and overall survival (OS) were reported using Kaplan-Meier estimation with 95% confidence bands, and differences in outcomes between FA and DA compared using log-rank tests. The impact of margin status was analyzed. RESULTS: Twenty-seven children who enrolled on AREN0534 had evidence of anaplasia (17 DA, 10 FA) in at least one kidney and were included in this analysis. Twenty-six (96%) had BWT. Nineteen percent had anaplastic histology in both kidneys (four of 17 DA, and one of 10 FA). Forty-six percent with BWT had bilateral nephron-sparing surgery (NSS); one child who went off protocol therapy, eventually required bilateral completion nephrectomies. Median follow-up for EFS and OS was 8.6 and 8.7 years from enrollment. Four- and 8-year EFS was 53% [95% confidence interval (CI): 34%-83%] for DA; 4-year EFS was 80% [95% CI: 59%-100%], and 8-year EFS 70% [95% CI: 47%-100%] for FA. Three out of 10 children with FA and eight out of 17 children with DA had events. EFS did not differ statistically by margin status (p = .79; HR = 0.88). Among the six children who died (five DA, one FA), all experienced prior relapse or progression within 18 months. CONCLUSION: Events in children with DA/FA in the setting of BWT occurred early. Caution should be taken about interpreting the impact of margin status outcomes in the context of contemporary multimodal therapy. Future targeted investigations in children with BWT and DA/FA are needed.

Survival outcomes in pediatric patients with metastatic Ewing sarcoma who achieve a rapid complete response of pulmonary metastases.

PURPOSE: Our objectives were to compare overall survival (OS) and pulmonary relapse between patients with metastatic Ewing sarcoma (EWS) at diagnosis who achieve rapid complete response (RCR) and those with residual pulmonary nodules after induction chemotherapy (non-RCR). PATIENTS AND METHODS: This retrospective cohort study included children under 20 years with metastatic EWS treated from 2007 to 2020 at 19 institutions in the Pediatric Surgical Oncology Research Collaborative. Chi-square tests were conducted for differences among groups. Kaplan-Meier curves were generated for OS and pulmonary relapse. RESULTS: Among 148 patients with metastatic EWS at diagnosis, 61 (41.2%) achieved RCR. Five-year OS was 71.2% for patients who achieved RCR, and 50.2% for those without RCR (p = .04), and in multivariable regression among patients with isolated pulmonary metastases, RCR (hazards ratio [HR] 0.42; 95% confidence interval [CI]: 0.17-0.99) and whole lung irradiation (WLI) (HR 0.35; 95% CI: 0.16-0.77) were associated with improved survival. Pulmonary relapse occurred in 57 (37%) patients, including 18 (29%) in the RCR and 36 (41%) in the non-RCR groups (p = .14). Five-year pulmonary relapse rates did not significantly differ based on RCR (33.0%) versus non-RCR (47.0%, p = .13), or WLI (38.8%) versus no WLI (46.0%, p = .32). DISCUSSION: Patients with EWS who had isolated pulmonary metastases at diagnosis had improved OS if they achieved RCR and received WLI, despite having no significant differences in rates of pulmonary relapse.

Day to Day Advocacy by Pediatric Health Care Providers.

This manuscript highlights the impressive advocacy work that members of the American Academy of Pediatrics have achieved and serves to inspire pediatric health care providers of all specialties to pursue such efforts beyond the acute physical need of the child. This article represents one of the Symposia presented at the 2023 American Academy of Pediatrics Section on Surgery.

Updates From the Other Side of the Drape: Recent Advances in Multimodal Pain Management and Opioid Reduction Among Pediatric Surgical Patients.

As the management of acute pain for children undergoing surgical procedures as well as recognition of the short and long term risks of exposure to opioids has evolved, multimodal and multidisciplinary approaches using organized pathways has resulted in improved perioperative outcomes and patient satisfaction. In this 2023 symposium held at the American Academy of Pediatrics on Surgery meeting, a multidisciplinary discussion on current enhanced recovery after surgery pathways, alternate methods of effective pain control and education and advocacy efforts for opioid reduction were discussed, and highlights are included in this article.

The Shared Ovary: A Multidisciplinary Discussion With Pediatric and Adolescent Gynecology.

Pediatric and adolescent ovarian lesions are common and are frequently managed by both pediatric surgeons and pediatric and adolescent gynecologists. During the 2023 American Academy of Pediatric Section on Surgery meeting, an educational symposium was delivered focusing on various aspects of management of pediatric and adolescent benign and malignant masses, borderline lesions, and fertility options for children and adolescents undergoing cancer therapies. This article highlights the discussion during this symposium.

Central Venous Catheter Consideration in Pediatric Oncology: A Systematic Review and Meta-analysis From the American Pediatric Surgical Association Cancer Committee.

BACKGROUND: Tunneled central venous catheters (CVCs) are the cornerstone of modern oncologic practice. Establishing best practices for catheter management in children with cancer is essential to optimize care, but few guidelines exist to guide placement and management. OBJECTIVES: To address four questions: 1) Does catheter composition influence the incidence of complications; 2) Is there a platelet count below which catheter placement poses an increased risk of complications; 3) Is there an absolute neutrophil count (ANC) below which catheter placement poses an increased risk of complications; and 4) Are there best practices for the management of a central line associated bloodstream infection (CLABSI)? METHODS: Data Sources: English language articles in Ovid Medline, PubMed, Embase, Web of Science, and Cochrane Databases. STUDY SELECTION: Independently performed by 2 reviewers, disagreements resolved by a third reviewer. DATA EXTRACTION: Performed by 4 reviewers on forms designed by consensus, quality assessed by GRADE methodology. RESULTS: Data were extracted from 110 manuscripts. There was no significant difference in fracture rate, venous thrombosis, catheter occlusion or infection by catheter composition. Thrombocytopenia with minimum thresholds of 30,000-50,000 platelets/mcl was not associated with major hematoma. Limited evidence suggests a platelet count <30,000/mcL was associated with small increased risk of hematoma. While few studies found a significant increase in CLABSI in CVCs placed in neutropenic patients with ANC<500Kcells/dl, meta-analysis suggests a small increase in this population. Catheter removal remains recommended in complicated or persistent infections. Limited evidence supports antibiotic, ethanol, or hydrochloric lock therapy in definitive catheter salvage. No high-quality data were available to answer any of the proposed questions. CONCLUSIONS: Although over 15,000 tunneled catheters are placed annually in North America into children with cancer, there is a paucity of evidence to guide practice, suggesting multiple opportunities to improve care. LEVEL OF EVIDENCE: III. This study was registered as PROSPERO 2019 CRD42019124077.

Robotic-assisted Pediatric Thoracic and Abdominal Tumor Resection: An Initial Multi-center Review.

INTRODUCTION: Robotic-assisted minimally invasive surgery (RA-MIS) for tumor resection is an emerging technology in the pediatric population with significant promise but unproven safety and feasibility. METHODS: A multi-center retrospective review of patients ≤18 years undergoing RA-MIS tumor resection from December 2015-March 2023 was performed. Patient demographics, perioperative variables, and complication rates were analyzed. RESULTS: Thirty-nine procedures were performed on 38 patients (17 thoracic, 22 abdominal); 37% female and 68% non-Hispanic White. Median age at surgery was 8.3 years (IQR 5.7, 15.7); the youngest was 1.7 years-old. Thoracic operations included resections of neuroblastic tumors (n = 16) and a single paraganglioma. The most common abdominal operations included resections of neuroblastic tumors (n = 5), pheochromocytomas (n = 3), and angiomyolipomas (n = 3). Six patients underwent retroperitoneal lymph node dissection (RPLND) for paratesticular tumors. Median operating time for the cohort was 2:52 h (IQR 2:04, 4:31). Two thoracic cases required open conversion due to poor visualization and lack of working domain. All patients underwent complete tumor resection; one had tumor spillage from a positive margin (Wilms tumor). Median LOS was 1.5 days (IQR 1.1, 3.0). Postoperatively, one patient developed a chyle leak requiring interventional radiology drainage, but none required a return to the operating room. CONCLUSIONS: Robotic-assisted surgery is safe and feasible for tumor resection in carefully selected pediatric patients, achieving complete resection with minimal morbidity and short LOS. Resection should be performed by those with robotic expertise for optimal outcomes. LEVEL OF EVIDENCE: IV. TYPE OF STUDY: Original Clinical Research.

Does preoperative calcium and 1, 25 OH vitamin D supplementation impact postoperative hypocalcemia and length of stay following pediatric thyroidectomy?

OBJECTIVE: To investigate whether perioperative calcium and 1,25 OH vitamin D supplementation (PCDS) influences the rates of postoperative hypocalcemia and length of stay (LOS) following pediatric thyroidectomy. STUDY DESIGN: Retrospective Cohort Review. SETTING: Tertiary children's hospital. METHODS: 94 patients who underwent completion or total thyroidectomy with or without concomitant neck dissection from 2010 to 2020 at a single institution were included. Patients with pre-existing hypocalcemia or preoperative vitamin D insufficiency were excluded. Rates of postoperative hypocalcemia and LOS were compared for patients receiving PCDS to those receiving no supplementation. RESULTS: Thirty percent of patients with PCDS had documented postoperative hypocalcemia compared to 64% of patients without PCDS (p = 0.01). Patients with PCDS had a median LOS of 30 h compared to 36 h (p = 0.002). Multivariable analyses confirmed that patients with PCDS had lower odds of postoperative hypocalcemia (OR: 0.32, CI: 0.11, 0.89) and shorter LOS by 17 h (SE: 8, p = 0.04) after adjustment for confounders. CONCLUSION: PCDS is associated with significantly lower risk of hypocalcemia and shorter LOS. Standardizing preoperative care for pediatric patients undergoing thyroidectomy may decrease variability and improve outcomes following surgery.

Quality Improvement Methodology to Improve Standardized Reporting of Pediatric Thyroid Ultrasounds Using TI-RADS.

BACKGROUND/PURPOSE: The process of evaluating pediatric thyroid nodules at our institution was inconsistent with a high rate of negative biopsies raising concern of appropriate patient selection for biopsy. Our aim was to institute a standardized risk stratification reporting system for thyroid nodules to increase utilization and agreement of TI-RADS reporting at our institution. METHODS: Radiology report data were collected and analyzed as part of a quality improvement project. A standardized TI-RADS dictation template was created, ultrasound technicians were trained, a multi-disciplinary conference initiated, and education provided for radiologists and clinicians. Control charts were used to track utilization and agreement of scoring of TI-RADS reporting based upon review by a radiologist trained in TI-RADS scoring. RESULTS: From January 2019 to January 2021, 218 patients with a thyroid nodule had a thyroid ultrasound performed at our institution. TI-RADS was utilized in 0 % (0 of 57) of children in the four months prior to project initiation. Following creation of the template, utilization increased to 65 % (39 of 60) over 5 months. Utilization further increased after the first training conference and was maintained above 90 % for 13 months. Ultrasound reports were in agreement in 46.7 % (28 of 60) of children initially. Agreement in reporting improved to 71.4 % (10 of 14) in the 3 months following the first training and to 78.4 % (58 of 74) over 12 months. Agreement in reporting was maintained at 80 % in the following 6 months. CONCLUSIONS: A quality improvement initiative can improve utilization and agreement of scoring using the TI-RADS system in pediatrics. This may ultimately reduce unnecessary biopsies and sedation in children. LEVEL OF EVIDENCE: Level III. TYPE OF STUDY: Quality Improvement.

Robotic-Assisted Surgery in Patients Less than 15 kg: A Single Center Review.

Introduction: Robotic-assisted surgery (RAS) is an increasingly utilized tool in children. However, utilization of RAS among infants and small children has not been well established. The purpose of this study was to review and characterize RAS procedures for children ≤15 kg. Methods: We performed a single institution retrospective descriptive analysis including all patients ≤15 kg undergoing RAS between January 2013 and July 2021. Data collection included procedure type, age, weight, gender, and surgical complications. Cases were further categorized according to surgical specialty: pediatric urology (PU), pediatric surgery (PS), and multiple specialties (MS). t-Tests were used for statistical analyses. Results: Since 2013, a total of 976 RAS were identified: 492 (50.4%) were performed by PU, 466 (47.8%) by PS, and 18 (1.8%) by MS. One hundred eighteen (12.1%) were performed on children ≤15 kg, consisting of 110 (93.2%) PU cases, 6 (5.1%) PS cases, and 2 (1.7%) MS cases. Procedures were significantly more common in the PU subgroup, mean of 12 cases/year, compared to PS subgroup, mean of 0.63 cases/year, (P < .01). The mean weight of PU patients (10.5 kg) was significantly less than PS patients (13.9 kg) (P < .01). Mean age was also significantly lower among PU patients (18.6 months) compared to PS (34.2 months) (P < .01). Conclusion: RAS among patients ≤15 kg is safe and feasible across pediatric surgical subspecialties. RAS was performed significantly more frequently by pediatric urologists in younger and smaller patients compared to pediatric surgeons. Further refinement of robotic technology and instrumentation should enhance the applicability of these procedures in this young group.

Comparison of Outcomes Between Surveillance Ultrasound and Completion Lymph Node Dissection in Children and Adolescents With Sentinel Lymph Node-Positive Cutaneous Melanoma.

OBJECTIVE: To determine the impact of nodal basin ultrasound (US) surveillance versus completion lymph node dissection (CLND) in children and adolescents with sentinel lymph node (SLN) positive melanoma. BACKGROUND: Treatment for children and adolescents with melanoma are extrapolated from adult trials. However, there is increasing evidence that important clinical and biological differences exist between pediatric and adult melanoma. METHODS: Patients ≤18 years diagnosed with cutaneous melanoma between 2010 and 2020 from 14 pediatric hospitals were included. Data extracted included demographics, histopathology, nodal basin strategies, surveillance intervals, and survival information. RESULTS: Of 252 patients, 90.1% (n=227) underwent SLN biopsy (SLNB), 50.9% (n=115) had at least 1 positive node. A total of 67 patients underwent CLND with 97.0% (n=65/67) performed after a positive SLNB. In contrast, 46 total patients underwent US observation of nodal basins with 78.3% (n=36/46) of these occurring after positive SLNB. Younger patients were more likely to undergo US surveillance (median age 8.5 y) than CLND (median age 11.3 y; P =0.0103). Overall, 8.9% (n=21/235) experienced disease recurrence: 6 primary, 6 nodal, and 9 distant. There was no difference in recurrence (11.1% vs 18.8%; P =0.28) or death from disease (2.2% vs 9.7%; P =0.36) for those who underwent US versus CLND, respectively. CONCLUSIONS: Children and adolescents with cutaneous melanoma frequently have nodal metastases identified by SLN. Recurrence was more common among patients with thicker primary lesions and positive SLN. No significant differences in oncologic outcomes were observed with US surveillance and CLND following the identification of a positive SLN.

Management and Outcomes of Wilms Tumor With Suprarenal Intravascular Extension: A Pediatric Surgical Oncology Research Collaborative Study.

OBJECTIVE: The purpose of this study was to describe management and outcomes from a contemporary cohort of children with Wilms tumor complicated by inferior vena caval thrombus. BACKGROUND: The largest series of these patients was published almost 2 decades ago. Since then, neoadjuvant chemotherapy has been commonly used to manage these patients, and outcomes have not been reported. METHODS: Retrospective review of 19 North American centers between 2009 and 2019. Patient and disease characteristics, management, and outcomes were investigated and analyzed. RESULTS: Of 124 patients, 81% had favorable histology (FH), and 52% were stage IV. IVC thrombus level was infrahepatic in 53 (43%), intrahepatic in 32 (26%), suprahepatic in 14 (11%), and cardiac in 24 (19%). Neoadjuvant chemotherapy using a 3-drug regimen was administered in 82% and postresection radiation in 90%. Thrombus level regression was 45% overall, with suprahepatic level showing the best response (62%). Cardiopulmonary bypass (CPB) was potentially avoided in 67%. The perioperative complication rate was significantly lower after neoadjuvant chemotherapy [(25%) vs upfront surgery (55%); P =0.005]. CPB was not associated with higher complications [CPB (50%) vs no CPB (27%); P =0.08]. Two-year event-free survival was 93% and overall survival was 96%, higher in FH cases (FH 98% vs unfavorable histology/anaplastic 82%; P =0.73). Neither incomplete resection nor viable thrombus cells affected event-free survival or overall survival. CONCLUSIONS: Multimodal therapy resulted in excellent outcomes, even with advanced-stage disease and cardiac extension. Neoadjuvant chemotherapy decreased the need for CPB to facilitate resection. Complete thrombectomy may not always be necessary.

Variability in Surveillance Strategies Following Resection of Sacrococcygeal Teratoma.

INTRODUCTION: Surveillance following sacrococcygeal teratoma (SCT) resection varies. The purpose of this study was to describe the clinical characteristics and outcomes of patients undergoing SCT resection and examine current institutional practices to detect recurrence. METHODS: A single-institution retrospective review of children who underwent resection of an SCT from January 1, 2010 to December 31, 2020 was performed. Data were summarized and surveillance strategies compared between histopathologic subtypes using nonparametric methods. RESULTS: Thirty six patients (75.0% female) underwent SCT removal at a median age of 8 d. Histopathology revealed 27 mature teratomas (75.0%), eight immature teratomas (22.2%), and one malignant germ cell tumor (2.8%). Median postoperative follow-up was 3.17 y (interquartile range [IQR]: 2.31-4.38 y). Patients had a median of 2.32 clinic visits per year (IQR: 2.00-2.70), alpha-fetoprotein levels were obtained at a median of 2.01 times per year (IQR: 0-1.66), and surveillance imaging was performed at a median of 2.31 times per year (IQR: 0-2.84). Patients with immature teratomas had alpha-fetoprotein laboratories obtained more frequently than patients with mature teratomas (3.10 times/year versus 0.93 times/year, P = 0.001). There was no significant difference in the number of imaging studies obtained between groups. Two patients (5.6%) developed recurrence, which were identified on magnetic resonance imaging at 191 and 104 d postresection, respectively. CONCLUSIONS: Postoperative surveillance practices varied widely. Recurrence was noted in a single malignant case in the first year following resection. Multi-institutional studies are needed to determine the optimal surveillance strategy to detect recurrence of SCT.

Diagnostic Performance of Magnetic Resonance Imaging for Pediatric Ovarian Neoplasms: A Multi-Institutional Review.

STUDY OBJECTIVE: To assess the diagnostic performance of MRI to predict ovarian malignancy alone and compared with other diagnostic studies. METHODS: A retrospective analysis was conducted of patients aged 2-21 years who underwent ovarian mass resection between 2009 and 2021 at 11 pediatric hospitals. Sociodemographic information, clinical and imaging findings, tumor markers, and operative and pathology details were collected. Diagnostic performance for detecting malignancy was assessed by calculating sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for MRI with other diagnostic modalities. RESULTS: One thousand and fifty-three patients, with a median age of 14.6 years, underwent resection of an ovarian mass; 10% (110/1053) had malignant disease on pathology, and 13% (136/1053) underwent preoperative MRI. MRI sensitivity, specificity, PPV, and NPV were 60%, 94%, 60%, and 94%. Ultrasound sensitivity, specificity, PPV, and NPV were 31%, 99%, 73%, and 95%. Tumor marker sensitivity, specificity, PPV, and NPV were 90%, 46%, 22%, and 96%. MRI and ultrasound concordance was 88%, with sensitivity, specificity, PPV, and NPV of 33%, 99%, 75%, and 94%. MRI sensitivity in ultrasound-discordant cases was 100%. MRI and tumor marker concordance was 88% with sensitivity, specificity, PPV, and NPV of 100%, 86%, 64%, and 100%. MRI specificity in tumor marker-discordant cases was 100%. CONCLUSION: Diagnostic modalities used to assess ovarian neoplasms in pediatric patients typically agree. In cases of disagreement, MRI is more sensitive for malignancy than ultrasound and more specific than tumor markers. Selective use of MRI with preoperative ultrasound and tumor markers may be beneficial when the risk of malignancy is uncertain. CONCISE ABSTRACT: This retrospective review of 1053 patients aged 2-21 years who underwent ovarian mass resection between 2009 and 2021 at 11 pediatric hospitals found that ultrasound, tumor markers, and MRI tend to agree on benign vs malignant, but in cases of disagreement, MRI is more sensitive for malignancy than ultrasound.

Critical elements of pediatric neuroblastoma surgery.

Neuroblastoma (NB) is the most common solid extracranial malignancy of childhood with an incidence of 1 per 100,000 in the United States compromising approximately 10 % of childhood cancer. Unfortunately, patients with high-risk NG continue to have long-term survival less than 50 %. Both Children's Oncology Group and the International Society of Paediatric Oncology have demonstrated the important role of surgery in the treatment of high-risk NB. Herein, we compose the results of an extensive literature review as well as expert opinion from leaders in pediatric surgical oncology, to present the critical elements of effective surgery for high-risk neuroblastoma.

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.

Unwrapping Nephrogenic Rests and Nephroblastomatosis for Pediatric Surgeons: A Systematic Review Utilizing the PICO Model by the APSA Cancer Committee.

BACKGROUND: Nephrogenic rests (NR) may represent precursor lesions for Wilms tumor (WT), but their clinical course is not fully understood and no guidelines for treatment exist. This study sought to evaluate the outcomes of pediatric patients with NRs related to traditional chemotherapy and surgery. METHODS: A PRISMA-P-compliant literature search was conducted in MEDLINE, Embase, CINAHL, Web of Science, COCHRANE, and SCOPUS from inception to June 2021. Clinical questions regarding the treatment of NRs, including chemotherapy and surgery, were developed in the population, intervention, comparison, and outcome format. RESULTS: Twenty-five studies including 1445 patients met inclusion criteria for evaluating chemotherapy compared to observation for NRs. Eighteen studies including 1392 patients met inclusion criteria for evaluating the role of surgery for NRs. Patients with isolated NRs who underwent observation progressed to WT 33% of the time; chemotherapy reduced the rate of WT to 3.9%. Observation of multiple NRs and diffuse hyperplastic perilobar nephroblastomatosis (DHPLN) led to progression to WT 50% and 100% of the time, respectively. Chemotherapy reduced the rate of WT to 34% for multiple NRs and 46% for DHPLN. Surgery for isolated NRs reduced the risk of WT development from 23.7% in patients with incomplete excision to 3.3% with complete excision; however, 96% of patients with incompletely excised NRs had bilateral disease. CONCLUSIONS: Observation with close surveillance for isolated NRs is safe. Treatment with chemotherapy is recommended for patients with multiple NRs and DHPLN. Surgical management of NRs should focus on renal function preservation. LEVEL OF EVIDENCE: Treatment study, Level III.