Surgical Management of Wilms Tumors with Intravenous Extension: A Multicenter Analysis of Clinical Management with Technical Insights.

BACKGROUND: About 5% of Wilms tumors present with vascular extension, which sometimes extends to the right atrium. Vascular extension does not affect the prognosis, but impacts the surgical strategy, which is complex and not fully standardized. Our goal is to identify elements of successful surgical management of Wilms tumors with vascular extensions. PATIENTS AND METHODS: A retrospective study of pediatric Wilms tumors treated at three sites (January 1999-June 2019) was conducted. The inclusion criterion was the presence of a renal vein and vena cava thrombus at diagnosis. Tumor stage, pre and postoperative treatment, preoperative imaging, operative report, pathology, operative complications, and follow-up data were reviewed. RESULTS: Of the 696 pediatric patients with Wilms tumors, 69 (9.9%) met the inclusion criterion. In total, 24 patients (37.5%) had a right atrial extension and two presented with Budd-Chiari syndrome at diagnosis. Two died at diagnosis owing to pulmonary embolism. All patients received neoadjuvant chemotherapy and thrombus regressed in 35.6% of cases. Overall, 14 patients had persistent intra-atrial thrombus extension (58%) and underwent cardiopulmonary bypass. Most thrombi (72%) were removed intact with nephrectomy. Massive intraoperative bleeding occurred during three procedures. Postoperative renal insufficiency was identified as a risk factor for patient survival (p = 0.01). With a median follow-up of 9 years (range: 0.5-20 years), overall survival was 89% and event-free survival was 78%. CONCLUSIONS: Neoadjuvant chemotherapy with proper surgical strategy resulted in a survival rate comparable to that of children with Wilms tumors without intravascular extension. Clinicians should be aware that postoperative renal insufficiency is associated with worse survival outcomes.

Lung biopsies in infants and children in critical care situation.

INTRODUCTION: Lung biopsy is considered as the last step investigation for diagnosing lung diseases; however, its indication must be carefully balanced with its invasiveness. The present study aims to evaluate the diagnostic yield of lung biopsy in critically ill patients hospitalized in the pediatric intensive care unit (ICU). MATERIAL AND METHODS: Children who underwent a lung biopsy in the ICU between 1995 and 2022 were included. Biopsies performed in the operating room and post-mortem biopsies were excluded. RESULTS: Thirty-one patients were included, with a median age of 18 days (2 days to 10.8 years); 21 (67.7%) were newborns. All patients required invasive mechanical ventilation, 26 (89.7%) had a pulmonary hypertension, and 22 (70.9%) were placed under extracorporeal membrane oxygenation (ECMO). The lung biopsy led to a diagnosis in 81% of the patients. The diagnostic reliability seemed to decrease with age (95% in newborns, 71% in 1 month to 2 years and 0/3 patients aged over 2 years old). Diffuse developmental disorders of the lung accounted for 15 (49%) patients, primarily alveolar capillary dysplasia, followed by surfactant disorders in 5 (16%) patients. Complications occurred in 9/31 (29%) patients including eight under ECMO, with massive hemorrhages in seven cases. DISCUSSION AND CONCLUSION: In critical situations, lung biopsy should be performed. Lung biopsy is a reliable diagnostic procedure for neonates in critical situation when a diffuse developmental disorder of the lung is suspected. The majority of lung biopsy complication was associated with the use of ECMO. The prospective evaluation of the complications of such procedure under ECMO, and particularly over 10 days of ECMO and in children over 2-year-old remains to be ascertained.

A 10-year experience in testicular tissue cryopreservation for boys under 18 years of age: What can be learned from 350 cases?

BACKGROUND: A growing number of centers worldwide are preserving testicular tissue (TT) of young boys at risk of fertility loss to preserve their fertility. Data in this regard are scarce and experience sharing is essential to the optimization of the process. OBJECTIVES: This report of our 10-year activity of pediatric fertility preservation (FP) has the objective to (1) improve knowledge regarding the feasibility, acceptability, safety, and potential usefulness of the procedure; (2) analyze the impact of chemotherapy on spermatogonia in the cryopreserved TT. MATERIALS AND METHODS: For this retrospective study of data prospectively recorded, we included all boys under 18 years of age referred to the FP consultation of our academic network between October 2009 and December 2019. Characteristics of patients and cryopreservation of testicular tissue (CTT) were extracted from the clinical database. Univariate and multivariate analyses were used to assess factors associated with the risk of absence of spermatogonia in the TT. RESULTS: Three hundred and sixty-nine patients (7.2 years; 0.5-17.0) were referred to the FP consultation for malignant (70%) or non-malignant (30%) disease, of whom 88% were candidates for CTT, after a previous chemotherapy exposure (78%). The rate of recorded immediate adverse events was 3.5%, with painful episodes dominating. Spermatogonia were detected in the majority of TTs: 91.1% of those exposed to chemotherapy and 92.3% of those not exposed (p = 0.962). In multivariate analysis, the risk of absence of spermatogonia was almost three-fold higher in boys > 10 years of age ([OR] 2.74, 95% CI 1.09-7.26, p = 0.035) and four-fold higher in boys exposed to alkylating agents prior to CTT ([OR] 4.09, 95% CI 1.32-17.94, p = 0.028). DISCUSSION/CONCLUSION: This large series of pediatric FP shows that this procedure is well accepted, feasible, and safe in the short term, strengthening its place in the clinical care pathway of young patients requiring a highly gonadotoxic treatment. Our results demonstrate that CTT post-chemotherapy does not impair the chance to preserve spermatogonia in the TT except when the treatment includes alkylating agents. More data on post-CTT follow-up are still required to ensure the long-term safety and usefulness of the procedure.

Nephrometry Scoring Systems for Nephron Sparing Surgery in Children.

The surgical decision to attempt nephron-sparing surgery (NSS) in children with renal tumors can be difficult. In adults, nephrometric tools are used for decision-making. More than 90% of low-complexity tumors are eligible for NSS, and high-complexity tumors often require total nephrectomy. We retrospectively applied those nephrometric tools [Radius, Exophytic, Nearness to the sinus or collecting system, Anterior/posterior, Location relative to polar lines (RENAL), Preoperative Aspects and Dimensions Used for an Anatomical classification (PADUA), and Renal Tumor Invasion Index (RTII) scoring systems] to the preoperative imaging of children operated for renal tumors in our institution from 2015 to 2019 and correlated them with the type of surgery. The scores were assessed by 2 independent surgeons and 1 radiologist. Forty-four tumors were removed, including 16 NSS, 38 after neo-adjuvant chemotherapy, and 6 upfront surgeries, in 30 children. More than 50% of patients in the low and medium-risk population for RENAL, PADUA, and RTII scores, and ~15% in the high-complexity categories underwent NSS. Tumors removed through NSS were significantly less complex according to each score. Interobserver reliability was good for 3 scores. The application of the RENAL, PADUA, and RTII was able to accurately classify most of the pediatric tumors, according to their complexity. These scores could help increase the indications of NSS in renal tumor surgery.

Delineating the interplay between oncogenic pathways and immunity in anaplastic Wilms tumors.

Wilms tumors are highly curable in up to 90% of cases with a combination of surgery and radio-chemotherapy, but treatment-resistant types such as diffuse anaplastic Wilms tumors pose significant therapeutic challenges. Our multi-omics profiling unveils a distinct desert-like diffuse anaplastic Wilms tumor subtype marked by immune/stromal cell depletion, TP53 alterations, and cGAS-STING pathway downregulation, accounting for one-third of all diffuse anaplastic cases. This subtype, also characterized by reduced CD8 and CD3 infiltration and active oncogenic pathways involving histone deacetylase and DNA repair, correlates with poor clinical outcomes. These oncogenic pathways are found to be conserved in anaplastic Wilms tumor cell models. We identify histone deacetylase and/or WEE1 inhibitors as potential therapeutic vulnerabilities in these tumors, which might also restore tumor immunogenicity and potentially enhance the effects of immunotherapy. These insights offer a foundation for predicting outcomes and personalizing treatment strategies for aggressive pediatric Wilms tumors, tailored to individual immunological landscapes.

Thoracoscopy for Pediatric Thoracic Neurogenic Tumors-A European Multi-Center Study.

OBJECTIVES: To assess the efficacy of thoracoscopy and the outcome for children with thoracic neurogenic tumors. METHODS: We performed a retrospective review of 15 European centers between 2000 and 2020 with patients who underwent thoracoscopy for a neurogenic mediastinal tumor. We assessed preoperative data, complications, and outcomes. Results were expressed with the median and range values. RESULTS: We identified 119 patients with a median age of 4 years old (3 months-17 years). The diameter was 5.7 cm (1.1-15). INRG stage was L1 n = 46, L2 n = 56, MS n = 5, M n = 12. Of 69 patients with image-defined risk factors (IDRF), 29 had only (T9-T12) locations. Twenty-three out of 34 patients with preoperative chemotherapy had an 18 mm (7-24) decrease in diameter. Seven out of 31 patients lost their IDRF after chemotherapy. Fourteen had a conversion to thoracotomy. The length of the hospital stay was 4 days (0-46). The main complications included chylothorax (n = 7) and pneumothorax (n = 5). Long-term complications included Horner's syndrome (n = 5), back pain, and scoliosis (n = 5). Pathology was 53 neuroblastomas, 36 ganglioneuromas, and 30 ganglioneuroblastomas. Fourteen had a postoperative residue. With a median follow-up of 21 months (4-195), 9 patients had a recurrence, and 5 died of disease. Relapses were associated with tumor biology, histology, and the need for chemotherapy (p = 0.034, <0.001, and 0.015, respectively). Residues were associated with preoperative IDRF (excluding T9-T12 only) and the need for preoperative chemotherapy (p = 0.04 and 0.020). CONCLUSION: Our results show that thoracoscopy is safe, with good outcomes for thoracic neurogenic tumors in selected cases. Surgical outcomes are related to the IDRFs, whereas oncologic outcomes are related to tumor histology and biology.

Combined esophageal and duodenal atresia: A review of the literature from 1950 to 2020.

The combination of duodenal atresia (DA) and esophageal atresia (EA) is very rare. With improvements in prenatal sonography and the use of fetal magnetic resonance imaging (MRI), these malformations can be diagnosed in a more accurate and timely manner; polyhydramnios remains the most common sign despite having a low specificity. The high rate of associated anomalies (in 85% of cases) can also impact neonatal management and increase the morbidity rate; thus, it is of paramount importance to look for every possible associated malformation, such as VACTERL and chromosomic anomalies. The surgical management of this combination of atresias is not well defined and changes according to the patient's clinical status, the type of EA, and the other associated malformations. Management ranges from a primary approach for one of the atresias with delayed correction of the other (56.8%) to a simultaneous repair of both atresias (33.8%) with or without gastrostomy, or total abstention (9.4%). We suggest that a simultaneous approach can be safely performed on patients in good physical condition, with a birth weight over 1500 g, and with no major respiratory distress; this method begins by closing the tracheoesophageal fistula to protect the lung and then repairing the DA. The mortality rate has decreased over the years, dropping from 71% before 1980 to 24% after 2001. In this review, we present the available evidence on these conditions, focusing mostly on the epidemiology, prenatal diagnosis, neonatal management strategies, and outcome, with the aim of determining how the different clinical features and surgical approaches may impact on morbidity and mortality.

Usefulness of routine early œsophagogram after primary repair of œsophageal atresia: a multicenter study.

BACKGROUND: Advances in surgical and neonatal care have led to improved survival of patients with œsophageal atresia (OA) over time. Morbidity remains significant, with one-third of patients being affected by a postoperative complication. Several aspects of management are not consensual, such as the use of œsophagogram before starting oral feeding. METHODS: We conducted a multicenter retrospective study, including all children with OA that underwent a primary anastomosis in the first days of life, between 2012 and 2018 in five French centers, to determine the usefulness of postoperative œsophagogram during the 10 days after early primary repair of OA to diagnose the anastomotic leak and congenital œsophageal stenosis. RESULTS: Among 225 included children, 90 (40%) had a routine œsophagogram and 25 (11%) had an anastomotic leak, clinically diagnosed before the scheduled œsophagogram in 24/25 (96%) children at median postoperative day 4. Ten patients had associated congenital œsophageal stenosis diagnosed on the œsophagogram in only 30% of cases. CONCLUSION: Early œsophagogram is rarely useful in the diagnosis of an anastomotic leak, which is clinically diagnosed before performing an œsophagogram in the majority of cases. The need for a postoperative œsophagogram should be evaluated on a case-by-case basis. IMPACT: Early œsophagogram is not helpful in the diagnosis of an anastomotic leak in the majority of cases. An anastomotic leak is most often diagnosed clinically before performing an œsophagogram. Early postoperative œsophagogram could be helpful for the diagnosis of congenital œsophageal stenosis. However, dysphagia occurs later and early diagnosis of congenital œsophageal stenosis has no impact on the management and outcome of asymptomatic children. Indication of postoperative œsophagogram has to be evaluated on a case-by-case basis.

Technical advances in the surgical management of Wilms tumors in children.

Surgery is one of the cornerstones of Wilms tumor treatment. In this article, we present technical advancements that are finding their way into the armamentarium of pediatric cancer surgeons. We discuss the current approaches, challenges, opportunities, and future directions of minimally invasive surgery (laparoscopic and robotics), image-guided surgery, and fluorescence-guided surgery. Furthermore, we discuss the use of intraoperative ultrasonography, as well as the use of new techniques to improve the quality of lymph node sampling.

Number of lymph nodes sampled in SFCE/SIOP 2001 patients with Wilms tumour: Is the goal of more than six achievable?

AIM: The number of lymph nodes (LN) that should be sampled during nephrectomy for Wilms tumour (WT) remains controversial but of utmost importance for staging purposes. The aim of this French national retrospective study of patients enrolled in SIOPWT2001 trial was to analyse the number of LN sampled according to their site and to determine if the number of six asked by the International Society of Paediatric Oncology - Renal Tumour Study Group (SIOP-RTSG) UMBRELLA protocol is achievable. METHODS: We reviewed the data collected on central pathology review forms from 2002 to 2014 for only unilateral WT. LN were divided whether they were clearly identified by surgeons at nephrectomy or only found by pathologists on the nephrectomy specimen. RESULTS: A total of 539 patients (240 male/299 female) were included (458 localized/81 metastatic). Median age at surgery was 41.3 months [0-189]. The number of LN sampled was 0, 1-6, ≥7 and unknown in 69 (12.8%), 293 (54.3%), 160 (29.7%) and 17 (3.2%) cases, respectively. The number of patients with sampled LN were higher if LN were identified by both the pathologist and the surgeon (n = 231, 42.8%) (p = < .001). At least one invaded LN (LN+) was found in 66 patients (12.2%), more than half being found among patients having LN sampled by both pathologist and surgeon (p < .001). The mean number of identified LN was six if no LN+ was detected on final histological analysis, while it was 11 in case of LN+ (p < .001). CONCLUSIONS: The aim of sampling more than six LN is achievable, but only with the active collaboration of both surgeons and pathologists.

Outcome of long gap esophageal atresia at 6 years: A prospective case control cohort study.

BACKGROUND DATA: EA is the most frequent congenital esophageal malformation. Long gap EA remains a therapeutic challenge for pediatric surgeons. A case case-control prospective study from a multi-institutional national French data base was performed to assess the outcome, at age of 1 and 6 years, of long gap esophageal atresia (EA) compared with non-long gap EA/tracheo-esophageal fistula (TEF). The secondary aim was to assess whether initial treatment (delayed primary anastomosis of native esophagus vs. esophageal replacement) influenced mortality and morbidity at ages 1 and 6 years. METHODS: A multicentric population-based prospective study was performed and included all patients who underwent EA surgery in France from January 1, 2008 to December 31, 2010. A comparative study was performed with non-long gap EA/TEF patients. Morbidity at birth, 1 year, and 6 years was assessed. RESULTS: Thirty-one patients with long gap EA were compared with 62 non-long gap EA/TEF patients. At age 1 year, the long gap EA group had longer parenteral nutrition support and longer hospital stay and were significantly more likely to have complications both early post-operatively and before age 1 year compared with the non-long gap EA/TEF group. At 6 years, digestive complications were more frequent in long gap compared to non-long gap EA/TEF patients. Tracheomalacia was the only respiratory complication that differed between the groups. Spine deformation was less frequent in the long gap group. There were no differences between conservative and replacement groups at ages 1 and 6 years except feeding difficulties that were more common in the native esophagus group. CONCLUSIONS: Long gap strongly influenced digestive morbidity at age 6 years.

Nutritional status at age 1 year in patients born with esophageal atresia: A population-based, prospective cohort study.

Objective: Despite recent progress in caring for patients born with esophageal atresia (EA), undernutrition and stunting remain common. Our study objective was to assess nutritional status in the first year after birth with EA and to identify factors associated with growth failure. Study design: We conducted a population-based study of all infants born in France with EA between 2010 and 2016. Through the national EA register, we collected prenatal to 1 year follow-up data. We used body mass index and length-for-age ratio Z scores to define patients who were undernourished and stunted, respectively. Factors with P < 0.20 in univariate analyses were retained in a logistic regression model. Results: Among 1,154 patients born with EA, body mass index and length-for-age ratio Z scores at 1 year were available for about 61%. Among these, 15.2% were undernourished and 19% were stunted at the age of 1 year. There was no significant catch-up between ages 6 months and 1 year. Patients born preterm (41%), small for gestational age (17%), or with associated abnormalities (55%) were at higher risk of undernutrition and stunting at age 1 year (P < 0.05). Neither EA type nor surgical treatment was associated with growth failure. Conclusion: Undernutrition and stunting are common during the first year after birth in patients born with EA. These outcomes are significantly influenced by early factors, regardless of EA type or surgical management. Identifying high-risk patient groups with EA (i.e., those born preterm, small for gestational age, and/or with associated abnormalities) may guide early nutritional support strategies.

Imaging of Pediatric Testicular and Para-Testicular Tumors: A Pictural Review.

Pre- and post-pubertal testicular tumors are two distinct entities in terms of epidemiology, diagnosis and treatment. Most pre-pubertal tumors are benign; the most frequent are teratomas, and the most common malignant tumors are yolk-sac tumors. Post-pubertal tumors are similar to those found in adults and are more likely to be malignant. Imaging plays a pivotal role in the diagnosis, staging and follow-up. The appearance on ultrasonography (US) is especially helpful to differentiate benign lesions that could be candidates for testis-sparing surgery from malignant ones that require radical orchidectomy. Some specific imaging patterns are described for benign lesions: epidermoid cysts, mature cystic teratomas and Leydig-cell tumors. Benign tumors tend to be well-circumscribed, with decreased Doppler flow on US, but malignancy should be suspected when US shows an inhomogeneous, not-well-described lesion with internal blood flow. Imaging features should always be interpreted in combination with clinical and biological data including serum levels of tumor markers and even intra-operative frozen sections in case of conservative surgery to raise any concerns of malignity. This review provides an overview of imaging features of the most frequent testicular and para-testicular tumor types in children and the value of imaging in disease staging and monitoring children with testicular tumors or risk factors for testicular tumors.

Long-Term Functional Outcomes of an Anorectal Malformation French National Cohort.

OBJECTIVES: The present study aimed to assess long-term functional outcomes of children with anorectal malformations (ARMs) across a network of expert centers in France. METHODS: Retrospective cross-sectional study of patients ages 6-30 years that had been surgically treated for ARM. Patient and ARM characteristics (eg, level, surgical approach) and functional outcomes were assessed in the different age groups. RESULTS: Among 367 patients, there were 155 females (42.2%) and 212 males (57.8%), 188 (51.2%) cases with, and 179 (48.8%) higher forms without, perineal fistula. Univariate and multivariate statistical analyses with logistic regression showed correlation between the level of the rectal blind pouch and voluntary bowel movements (odds ratio [OR] = 1.84 [1.31-2.57], P < 0.001), or soiling (OR = 1.72 [1.31-2.25], P < 0.001), which was also associated with the inability to discriminate between stool and gas (OR = 2.45 [1.28-4.67], P = 0.007) and the presence of constipation (OR = 2.97 [1.74-5.08], P < 0.001). Risk factors for constipation were sacral abnormalities [OR = 2.26 [1.23-4.25], P = 0.01) and surgical procedures without an abdominal approach (OR = 2.98 [1.29-6.87], P = 0.01). Only the holding of voluntary bowel movements and soiling rates improved with age. CONCLUSION: This cross-sectional study confirms a strong association between anatomical status and functional outcomes in patients surgically treated for ARM. It specifically highlights the need for long-term follow-up of all patients to help them with supportive care.

The clinical impact of observer variability in lung nodule classification in children with Wilms tumour.

OBJECTIVES: To investigate the extent to which observer variability of computed tomography (CT) lung nodule assessment may affect clinical treatment stratification in Wilms tumour (WT) patients, according to the recent Société Internationale d'Oncologie Pédiatrique Renal Tumour Study Group (SIOP-RTSG) UMBRELLA protocol. METHODS: I: CT thoraces of children with WT submitted for central review were used to estimate size distribution of lung metastases. II: Scans were selected for blinded review by five radiologists to determine intra- and inter-observer variability. They assessed identical scans on two occasions 6 months apart. III: Monte Carlo simulation (MCMC) was used to predict the clinical impact of observer variation when applying the UMBRELLA protocol size criteria. RESULTS: Lung nodules were found in 84 out of 360 (23%) children with WT. For 21 identified lung nodules, inter-observer limits of agreement (LOA) for the five readers were ±2.4 and ±1.4 mm (AP diameter), ±1.9 and ±1.8 mm (TS diameter) and ±2.0 and ±2.4 mm (LS diameter) at assessments 1 and 2. Intra-observer LOA across the three dimensions were ±1.5, ±2.2, ±3.5, ±3.1 and ±2.6 mm (readers 1-5). MCMC demonstrated that 17% of the patients with a 'true' nodule size of ≥3 mm will be scored as <3 mm, and 21% of the patients with a 'true' nodule size of <3 mm will be scored as being ≥3 mm. CONCLUSION: A significant intra-inter observer variation was found when measuring lung nodules on CT for patients with WT. This may have significant implications on treatment stratification, and thereby outcome, when applying a threshold of ≥3 mm for a lung nodule to dictate metastatic status.

How we approach paediatric renal tumour core needle biopsy in the setting of preoperative chemotherapy: A Review from the SIOP Renal Tumour Study Group.

The International Society of Paediatric Oncology Renal Tumour Study Group (SIOP-RTSG) advocate treating children with Wilms tumour (WT) with preoperative chemotherapy, whereas the Renal Tumor Committee of the Children's Oncology Group (COG) advocates primary nephrectomy (without biopsy) when feasible. Successive SIOP-RTSG trial protocols recommended pretreatment biopsy of children with unilateral tumours only where there were features to suggest an increased probability of a non-WT requiring a change in management. The UK experience in the SIOP WT 2001 trial showed that an alternate approach of performing biopsies on all children with renal tumour masses to determine histology at diagnosis rarely changes management, and can result in misdiagnosis (particularly patients in the age range typical for WT). Although a more selective approach to biopsy has been routine practice in all other countries participating in SIOP-RTSG trials, there was variation between national groups. To address this variation and provide evidence-based recommendations for the indications and recommended approach to renal tumour biopsy within the SIOP paradigm, an international, multidisciplinary working group of SIOP-RTSG members was convened. We describe the resulting recommendations of this group, which are to be incorporated in the ongoing SIOP-RTSG UMBRELLA study.

Prognostic impact of pulmonary nodules diagnosed at initial presentation in patients with osteosarcoma.

BACKGROUND: Resection of all lung metastases in patients with osteosarcoma improves survival. The increased computed tomography (CT) scan quality allows detecting smaller nodules. We aimed to evaluate the prognostic impact of those nodules that do not meet the classical criteria for lung metastases. METHODS: A central radiology review (CRR) on lung CT scans performed during the treatment of patients included in OS2006 trial and treated with a high-dose methotrexate-based chemotherapy from 2007 to 2013 was realized in three centers. RESULTS: At trial enrollment, among 77 patients, six (8%) had nodules meeting the trial's criteria for metastatic disease, 46 (60%) were classified as having localized disease, and 25 (32%) as having doubtful nodules. After CRR, 218 nodules were found at diagnosis (all in patients classified as "metastatic or doubtful" and 13 patients classified as "localized") (median two nodules per patient [1-52]). The 5-year event-free survival/overall survival (EFS/OS) of patients with at least one nodule versus no nodule were similar (67.7%/79.2% vs. 81.8%/91%). After histological analysis, two of 46 (4.3%) "localized" and eight of 25 (32.0%) "doubtful" patients were re-classified as "metastatic," whereas there was no change in patients initially "metastatic." The 5-year OS of confirmed histological metastatic versus nonmetastatic patients were different (56% vs. 92%, p < .01). CONCLUSION: Central review of lung CT scan increased the detection of nodules in osteosarcoma. Patients with small lung nodules classified as doubtful had a quite similar outcome as those with a localized disease. However, patients with confirmed metastatic nodules have a poorer prognosis, even if considered as "localized" at diagnosis.

Brachytherapy for Pediatric Patients at Gustave Roussy Cancer Campus: A Model of International Cooperation for Highly Specialized Treatments.

PURPOSE: Childhood cancer is rare, and treatment is frequently associated with long-term morbidity. Disparities in survival and long-term side effects encourage the establishment of networks to increase access to complex organ-conservative strategies, such as brachytherapy. We report our experience of an international cooperation model in childhood cancers. METHODS AND MATERIALS: We examined the outcome of all children referred to our center from national or international networks to be treated according to a multimodal organ-conservative approach, including brachytherapy. RESULTS: We identified 305 patients whose median age at diagnosis was 2.2 years (range, 1.4 months to 17.2 years). Among these patients, 99 (32.4%) were treated between 2015 and 2020; 172 (56.4%) were referred from national centers; and 133 (43.6%) were international patients from 31 countries (mainly Europe). Also, 263 patients were referred for primary treatment and 42 patients were referred for salvage treatment. Genitourinary tumors were the most frequent sites, with 56.4% bladder/prostate rhabdomyosarcoma and 28.5% gynecologic tumors. In addition to brachytherapy, local treatment consisted of partial tumor resection in 207 patients (67.9%), and 39 patients (13%) had additional external radiation therapy. Median follow-up was 58 months (range, 1 month to 48 years), 93 months for national patients, and 37 months for international patients (P < .0001). Five-year local control, disease-free survival, and overall survival rates were 90.8% (95% confidence interval [CI], 87.3%-94.4%), 84.4% (95% CI, 80.1%-89.0%), and 93.3% (95% CI, 90.1%-96.5%), respectively. Patients referred for salvage treatment had poorer disease-free survival (P < .01). Implementation of image guided pulse-dose-rate brachytherapy was associated with better local control among patients with rhabdomyosarcoma referred for primary treatment (hazard ratio, 9.72; 95% CI, 1.24-71.0). At last follow-up, 16.7% patients had long-term severe treatment-related complications, and 2 patients (0.7%) had developed second malignancy. CONCLUSIONS: This retrospective series shows the feasibility of a multinational referral network for brachytherapy allowing high patient numbers in rare pediatric cancers. High local control probability and acceptable late severe complication probability could be achieved despite very challenging situations. This cooperation model could serve as a basis for generating international reference networks for high-tech radiation such as brachytherapy to increase treatment care opportunities and cure probability.