Management of undifferentiated embryonal sarcoma of the liver: A Pediatric Surgical Oncology Research Collaborative study.

BACKGROUND: Undifferentiated embryonal sarcoma of the liver (UESL) is a rare tumor for which there are few evidence-based guidelines. The aim of this study was to define current management strategies and outcomes for these patients using a multi-institutional dataset curated by the Pediatric Surgical Oncology Research Collaborative. METHODS: Data were collected retrospectively for patients with UESL treated across 17 children's hospitals in North America from 1989 to 2019. Factors analyzed included patient and tumor characteristics, PRETEXT group, operative details, and neoadjuvant/adjuvant regimens. Event-free and overall survival (EFS, OS) were the primary and secondary outcomes, respectively. RESULTS: Seventy-eight patients were identified with a median age of 9.9 years [interquartile range [IQR): 7-12]. Twenty-seven patients underwent resection at diagnosis, and 47 patients underwent delayed resection, including eight liver transplants. Neoadjuvant chemotherapy led to a median change in maximum tumor diameter of 1.6 cm [IQR: 0.0-4.4] and greater than 90% tumor necrosis in 79% of the patients undergoing delayed resection. R0 resections were accomplished in 63 patients (81%). Univariate analysis found that metastatic disease impacted OS, and completeness of resection impacted both EFS and OS, while multivariate analysis revealed that R0 resection was associated with decreased expected hazards of experiencing an event [hazard ratio (HR): 0.14, 95% confidence interval (CI): 0.04-0.6]. At a median follow-up of 4 years [IQR: 2-8], the EFS was 70.0% [95% CI: 60%-82%] and OS was 83% [95% CI: 75%-93%]. CONCLUSION: Complete resection is associated with improved survival for patients with UESL. Neoadjuvant chemotherapy causes minimal radiographic response, but significant tumor necrosis.

The metabolic and lipidomic profiling of the effects of tracheal occlusion in a rabbit model of congenital diaphragmatic hernia.

PURPOSE: Fetal tracheal occlusion (TO) reverses the pulmonary hypoplasia associated with congenital diaphragmatic hernia (CDH), but its mechanism of action remains poorly understood. 'Omic' readouts capture metabolic and lipid processing function, which aid in understanding CDH and TO metabolic mechanisms. METHODS: CDH was created in fetal rabbits at 23 days, TO at 28 days and lung collection at 31 days (Term ∼32 days). Lung-body weight ratio (LBWR) and mean terminal bronchiole density (MTBD) were determined. In a cohort, left and right lungs were collected, weighed, and samples homogenized, and extracts collected for non-targeted metabolomic and lipidomic profiling via LC-MS and LC-MS/MS, respectively. RESULTS: LBWR was significantly lower in CDH while CDH + TO was similar to controls (p = 0.003). MTBD was significantly higher in CDH fetuses and restored to control and sham levels in CDH + TO (p < 0.001). CDH and CDH + TO resulted in significant differences in metabolome and lipidome profiles compared to sham controls. A significant number of altered metabolites and lipids between the controls and CDH groups and the CDH and CDH + TO fetuses were identified. Significant changes in the ubiquinone and other terpenoid-quinone biosynthesis pathway and the tyrosine metabolism pathway were observed in CDH + TO. CONCLUSION: CDH + TO reverses pulmonary hypoplasia in the CDH rabbit, in association with a specific metabolic and lipid signature. A synergistic untargeted 'omics' approach provides a global signature for CDH and CDH + TO, highlighting cellular mechanisms among lipids and other metabolites, enabling comprehensive network analysis to identify critical metabolic drivers in disease pathology and recovery. TYPE OF STUDY: Basic Science, Prospective. LEVEL OF EVIDENCE: II.

Gender trends in applicants to general surgery residency programs in Canada.

BACKGROUND: Surgical disciplines lag behind non-surgical disciplines in attracting female trainees. Female representation of Canadian General Surgeons has not been evaluated in recent years in the literature. The objectives of this study were to assess gender trends in applicants to Canadian General Surgery residency programs and practicing general surgeons and subspecialists. METHODS: This retrospective cross-sectional study analyzed gender data for residency applicants ranking General Surgery as their first-choice discipline from publicly-available annual Canadian Residency Matching Service (CaRMS) R-1 match reports from 1998 to 2021. Aggregate gender data for practicing female physicians in General Surgery and related subspecialties, including Pediatric Surgery, obtained from annual Canadian Medical Association (CMA) census from 2000 to 2019 was also analysed. RESULTS: There was a significant increase in the proportion of female applicants from 34% in 1998 to 67% in 2021 (p < 0.001) and of successfully matched candidates from 39% to 68% (p = 0.002) from 1998 to 2021. Success rates between male and female candidates were significantly different in 1998 (p < 0.001), but not in 2021 (p = 0.29). The proportion of practicing female General Surgeons also significantly increased from 10.1% in 2000 to 27.9% in 2019 (p = 0.0013), with variable trends in subspecialties. CONCLUSION: Gender inequality in General Surgery residency matches has normalized since 1998. Despite females representing more than 40% of applicants and successfully matched candidates to General Surgery since 2008, a gender gap still exists amongst practicing General Surgeons and subspecialists. This suggests the need for further cultural and systemic change to mitigate gender disparities. TYPE OF STUDY: Original research article, clinical research. LEVEL OF EVIDENCE: Level III (Retrospective cross-sectional study).

The influence of surgical and procedural rotations and interest in a surgical discipline on medical students' suturing ability during clerkship.

BACKGROUND: Although suturing is an essential competency for medical students, there has been limited research into the skills acquisition process over the course of medical school curriculum. This study aimed to determine whether suturing ability improved over the course of clerkship and whether an interest in a surgical discipline was associated with improved skill acquisition. METHODS: The suturing ability of third-year medical students at a large Canadian medical school was assessed at the beginning of clerkship (August 2018) as well as before and after their surgery rotation by 2 expert reviewers using a validated, objective scoring system as well as a qualitative assessment, both in person and via blinded video recordings. Students were randomly allocated to 4 groups for their clerkship year by the medical school. RESULTS: Of 133 eligible students, 115 (86.5%) completed the study. Median suturing assessment scores improved significantly after the surgery rotation (214.5 [interquartile range (IQR) 191.1-235.0] v. 238.0 [IQR 223.5-255.0], p = 0.001). Groups that had completed a procedural rotation (emergency medicine, obstetrics and gynecology) between clerkship and starting their surgery rotation had improved scores between these time points (p < 0.05), whereas scores decreased for groups that did not have a procedural rotation between assessments. Regardless of previous rotations, suturing scores were similar between groups after the surgery rotation. The 21 students (18.3%) who were interested in a surgical discipline had higher suturing scores than students who were not interested in surgery at the beginning of clerkship (229.1 [IQR 220.2-253.0] v. 208.0 [IQR 185.0-228.0], p < 0.001) and after the surgery rotation (252.0 [IQR 227.0-268.0] v. 235.8 [IQR 220.5-251.2], p = 0.02). CONCLUSION: Medical students' suturing ability improved during the surgery rotation but was also influenced by other procedural rotations and students' interest in procedure specialties. Skill acquisition by medical students is complex and requires additional investigation.

Histologic type predicts disparate outcomes in pediatric hepatocellular neoplasms: A Pediatric Surgical Oncology Research Collaborative study.

BACKGROUND: Hepatocellular carcinoma (HCC) is a rare cancer in children, with various histologic subtypes and a paucity of data to guide clinical management and predict prognosis. METHODS: A multi-institutional review of children with hepatocellular neoplasms was performed, including demographic, staging, treatment, and outcomes data. Patients were categorized as having conventional HCC (cHCC) with or without underlying liver disease, fibrolamellar carcinoma (FLC), and hepatoblastoma with HCC features (HB-HCC). Univariate and multivariate analyses identified predictors of mortality and relapse. RESULTS: In total, 262 children were identified; and an institutional histologic review revealed 110 cHCCs (42%; 69 normal background liver, 34 inflammatory/cirrhotic, 7 unknown), 119 FLCs (45%), and 33 HB-HCCs (12%). The authors observed notable differences in presentation and behavior among tumor subtypes, including increased lymph node involvement in FLC and higher stage in cHCC. Factors associated with mortality included cHCC (hazard ratio [HR], 1.63; P = .038), elevated α-fetoprotein (HR, 3.1; P = .014), multifocality (HR, 2.4; P < .001), and PRETEXT (pretreatment extent of disease) stage IV (HR, 5.76; P < .001). Multivariate analysis identified increased mortality in cHCC versus FLC (HR, 2.2; P = .004) and in unresectable tumors (HR, 3.4; P < .001). Disease-free status at any point predicted survival. CONCLUSIONS: This multi-institutional, detailed data set allowed a comprehensive analysis of outcomes for children with these rare hepatocellular neoplasms. The current data demonstrated that pediatric HCC subtypes are not equivalent entities because FLC and cHCC have distinct anatomic patterns and outcomes in concert with their known molecular differences. This data set will be further used to elucidate the impact of histology on specific treatment responses, with the goal of designing risk-stratified algorithms for children with HCC. LAY SUMMARY: This is the largest reported granular data set on children with hepatocellular carcinoma. The study evaluates different subtypes of hepatocellular carcinoma and identifies key differences between subtypes. This information is pivotal in improving understanding of these rare cancers and may be used to improve clinical management and subsequent outcome in children with these rare malignancies.

Inflammatory myofibroblastic tumor: A multi-institutional study from the Pediatric Surgical Oncology Research Collaborative.

Inflammatory myofibroblastic tumor (IMT) is a mesenchymal neoplasm of intermediate malignancy. We describe the largest cohort of IMT patients to date, aiming to further characterize this rare, poorly understood tumor. This is a multi-institutional review of IMT patients ≤39 years, from 2000 to 2018, at 18 hospitals in the Pediatric Surgical Oncology Research Collaborative. One hundred and eighty-two patients were identified with median age of 11 years. Thirty-three percent of tumors were thoracic in origin. Presenting signs/symptoms included pain (29%), respiratory symptoms (25%) and constitutional symptoms (20%). Median tumor size was 3.9 cm. Anaplastic lymphoma kinase (ALK) overexpression was identified in 53% of patients. Seven percent of patients had distant disease at diagnosis. Ninety-one percent of patients underwent resection: 14% received neoadjuvant treatment and 22% adjuvant treatment. Twelve percent of patients received an ALK inhibitor. Sixty-six percent of surgical patients had complete resection, with 20% positive microscopic margins and 14% gross residual disease. Approximately 40% had en bloc resection of involved organs. Median follow-up time was 36 months. Overall 5-year survival was 95% and 5-year event-free survival was 80%. Predictors of recurrence included respiratory symptoms, tumor size and distant disease. Gross or microscopic margins were not associated with recurrence, suggesting that aggressive attempts at resection may not be warranted.

Differentiating congenital ovarian cysts from other abdominal cystic lesions in female infants: A study by the Canadian Consortium for Research in Pediatric Surgery (CanCORPS).

PURPOSE: The origin of congenital abdominal cysts in the female fetus often dictates management. While most arise from the ovary and are often managed non-operatively, some are non-ovarian and are frequently removed. We analyzed a national sample of female infants with congenital abdominal cysts to elucidate prenatal and postnatal factors associated with the diagnosis of a non-ovarian cyst. METHODS: A retrospective cohort study of female infants who were prenatally diagnosed with abdominal cysts between 2013 and 2017 at 10 Canadian pediatric surgical centres was performed. Clinical characteristics, pre- and postnatal sonographic findings, and cyst trajectories were compared between patients with proven ovarian etiology and those with cysts arising from other organs. RESULTS: Of 185 infants with prenatally diagnosed abdominal cysts, 22 (12%) were non-ovarian, five of which had clear non-ovarian organ of origin on prenatal ultrasound. Comparison of the other 17 cysts with 163 congenital ovarian cysts showed the following factors to be associated with a non-ovarian origin: earlier gestational age at diagnosis (23.5 vs 33.5 weeks, p <0.001), smaller diameter on first prenatal ultrasound (15.8 vs. 39.7 mm, p <0.001), change in sonographic character from simple to complex (87% vs 22%, p <0.001), and postnatal sonographic characteristics of complex cyst (87% vs. 48%, p = 0.004). CONCLUSION: Clear organ of origin, diagnosis earlier in gestation, smaller initial prenatal cyst diameter, and sonographic cyst character change differentiate congenital non-ovarian cysts from their ovarian counterparts. These characteristics may be used to guide diagnosis and management.

Implications of Tumor Characteristics and Treatment Modality on Local Recurrence and Functional Outcomes in Children With Chest Wall Sarcoma: A Pediatric Surgical Oncology Research Collaborative Study.

OBJECTIVE: To determine the impact of tumor characteristics and treatment approach on (1) local recurrence, (2) scoliosis development, and (3) patient-reported quality of life in children with sarcoma of the chest wall. SUMMARY OF BACKGROUND DATA: Children with chest wall sarcoma require multimodal therapy including chemotherapy, surgery, and/or radiation. Despite aggressive therapy which places them at risk for functional impairment and scoliosis, these patients are also at significant risk for local recurrence. METHODS: A multi-institutional review of 175 children (median age 13 years) with chest wall sarcoma treated at seventeen Pediatric Surgical Oncology Research Collaborative institutions between 2008 and 2017 was performed. Patient-reported quality of life was assessed prospectively using PROMIS surveys. RESULTS: The most common diagnoses were Ewing sarcoma (67%) and osteosarcoma (9%). Surgical resection was performed in 85% and radiation in 55%. A median of 2 ribs were resected (interquartile range = 1-3), and number of ribs resected did not correlate with margin status ( P = 0.36). Local recurrence occurred in 23% and margin status was the only predictive factor(HR 2.24, P = 0.039). With a median follow-up of 5 years, 13% developed scoliosis (median Cobb angle 26) and 5% required corrective spine surgery. Scoliosis was associated with posteriorrib resection (HR 8.43; P= 0.003) and increased number of ribs resected (HR 1.78; P = 0.02). Overall, patient-reported quality of life is not impaired after chest wall tumor resection. CONCLUSIONS: Local recurrence occurs in one-quarter of children with chest wall sarcoma and is independent of tumor type. Scoliosis occurs in 13% of patients, but patient-reported quality of life is excellent.

Appendectomy Versus Observation for Appendicitis in Neutropenic Children With Cancer.

BACKGROUND: Optimal management of neutropenic appendicitis (NA) in children undergoing cancer therapy remains undefined. Management strategies include upfront appendectomy or initial nonoperative management. We aimed to characterize the effect of management strategy on complications and length of stay (LOS) and describe implications for chemotherapy delay or alteration. METHODS: Sites from the Pediatric Surgery Oncology Research Collaborative performed a retrospective review of children with NA over a 6-year period. RESULTS: Sixty-six children, with a median age of 11 years (range 1-17), were identified with NA while undergoing cancer treatment. The most common cancer diagnoses were leukemia (62%) and brain tumor (12%). Upfront appendectomy was performed in 41% of patients; the remainder had initial nonoperative management. Rates of abscess or perforation at diagnosis were equivalent in the groups (30% vs 24%; P = .23). Of patients who had initial nonoperative management, 46% (17 of 37) underwent delayed appendectomy during the same hospitalization. Delayed appendectomy was due to failure of initial nonoperative management in 65% (n = 11) and count recovery in 35% (n = 6). Cancer therapy was delayed in 35% (n = 23). Initial nonoperative management was associated with a delay in cancer treatment (46% vs. 22%, P = .05) and longer LOS (29 vs 12 days; P = .01). Patients who had initial nonoperative management and delayed appendectomy had a higher rate of postoperative complications (P < .01). CONCLUSIONS: In pediatric patients with NA from oncologic treatment, upfront appendectomy resulted in lower complication rates, reduced LOS, and fewer alterations in chemotherapy regimens compared to initial nonoperative management.

Thoracoscopy vs thoracotomy for the management of metastatic osteosarcoma: A Pediatric Surgical Oncology Research Collaborative Study.

Complete surgical resection of pulmonary metastatic disease in patients with osteosarcoma is crucial to long-term survival. Open thoracotomy allows palpation of nodules not identified on imaging but the impact on survival is unknown. The objective of this study was to compare overall survival (OS) and pulmonary disease-free survival (DFS) in children who underwent thoracotomy vs thoracoscopic surgery for pulmonary metastasectomy. A multi-institutional collaborative group retrospectively reviewed 202 pediatric patients with osteosarcoma who underwent pulmonary metastasectomy by thoracotomy (n = 154) or thoracoscopy (n = 48). Results were analyzed by Kaplan-Meier survival estimates and multivariate Cox proportional hazard regression models. With median follow-up of 45 months, 135 (67.5%) patients had a pulmonary relapse and 95 (47%) patients were deceased. Kaplan-Meier analysis showed no significant difference in 5-year pulmonary DFS (25% vs 38%; P = .18) or OS (49% vs 42%, P = .37) between the surgical approaches of thoracotomy and thoracoscopy. In Cox regression analysis controlling for other factors impacting outcome, there was a significantly increased risk of mortality (HR 2.11; P = .027; 95% CI 1.09-4.09) but not pulmonary recurrence (HR 0.96; P = .90; 95% CI 0.52-1.79) with a thoracoscopic approach. However, in the subset analysis limited to patients with oligometastatic disease, thoracoscopy had no increased risk of mortality (HR 1.16; P = .62; 0.64-2.11). In conclusion, patients with metastatic osteosarcoma and limited pulmonary disease burden demonstrate comparable outcomes after thoracotomy and thoracoscopy for metastasectomy. While significant selection bias in these surgical cohorts limits the generalizability of the conclusions, clinical equipoise for a randomized clinical trial in patients with oligometastatic disease is supported.