EPCT-12. NATIONAL MULTICENTERED RETROSPECTIVE REVIEW OF DEMOGRAPHIC, TUMOUR AND INTRAOPERATIVE FEATURES ASSOCIATED WITH THE DEVELOPMENT OF CEREBELLAR MUTISM AFTER PEDIATRIC POSTERIOR FOSSA TUMOUR RESECTION

Background Cerebellar mutism (CM) is a condition characterized by a significant lack or loss of speech in children following posterior fossa (PF) surgery. The biological origin of CM remains largely unclear and remains the subject of ongoing debate. Despite multidisciplinary rehabilitative interventions, the outcome is less favorable than initially described. Given the treatment refractory nature of CM, central to its management is prevention. Methods A national multi-centered retrospective review of all the children undergoing posterior fossa resection at 4 Canadian academic pediatric institutions was undertaken. Patient, tumour, surgical features suggested to be associated with the post-operative development of CM were reviewed to identify pre-operative and intra-operative factors that may predict post-operative CM occurrence. Results 258 pediatric patients were identified after posterior fossa lesion resection. Mean age at surgery was 6.74 years (SD 4.60) and 42.2% were female. Frozen section was available in 90.3% of cases. The majority of final tumour histology was medulloblastoma (35.7%), pilocytic astrocytoma (32.6%), ependymoma (17.1%) and exophytic glioma (1.2%). Intra-operative impression of adherence to the floor of the 4th ventricle was negative in 47.7%, positive in 36.8% of cases. The extent of resection assessed intraoperatively as gross total resection was 69.8% of cases. Intra-operative abrupt changes in blood pressure and/or heart rate was identified in 19.4% and 17.8% of cases. CM was experienced in 19.5% of patients (N=50), with the majority of cases identified by post-operative day 7. The clinical resolution of CM as mainly assessed by a neurosurgeon (86%) and was complete, significantly resolved, slight improvement, no improvement or deterioration in 56.0%, 8.0%, 20.0%, 14.0%, 2.0% respectively. Conclusion As a devastating surgical complication, identifying and understanding the biological origin of CM is the first step to complication avoidance. Maximal safe resection irrespective of intra-operative pathology remains the goal to avoid the devastating complication of CM.

48 Chyle Leak Following Pancreaticoduodenectomy: A Tertiary HPB Unit 14-year Experience and a Proposed Management Algorithm

Introduction Chyle leak (CL) is an uncommon complication of pancreaticoduodenectomy (PD). Its incidence, risk factors, and effect on prognosis are not well described and optimum management remains debated. This study aims to calculate the incidence of CL, identify risk factors, consider effect on patient outcome, and propose a simple management algorithm. Method This is a retrospective review of all patients who developed CL following PD between January 2006 and April 2020. The following details were obtained from a prospectively maintained database: age, ASA grade, BMI, details of operation, tumour histology, length of stay, and mortality. Results A total of 560 patients underwent PD and 17 (3.04%) developed CL. These patients had significantly higher BMI (P < 0.01) and significantly longer operation times (P < 0.05). CL patients had a higher rate of portal vein (PV) tumour adherence, PV resection, and intra-operative blood transfusion although this was not statistically significant. Sixteen CL patients (94.1%) were managed successfully with a non-operative approach. Conclusions 3.04% of patients who underwent PD developed CL. CL was associated with higher BMI and longer operation time. CL did not affect length of stay. The vast majority of CL cases can be managed successfully with a non-operative approach.

Significance of spermatic cord invasion in radical inguinal orchidectomy: Will a modified subinguinal orchidectomy suffice?

Introduction and objectives: Radical inguinal orchidectomy with ligation and division of the spermatic cord at the deep inguinal ring is the treatment of choice for testicular mass suspicious of cancer. In the era of organ preserving and minimally invasive surgery, it may be possible to propose a less radical sub-inguinal orchidectomy that may avoid the morbidity associated with opening the inguinal canal. The effect of this approach on oncological margins is not known. The aim of this article was to investigate the presence of spermatic cord involvement after a radical inguinal orchidectomy with a view to test feasibility of a modified sub-inguinal approach for testicular tumour excision. Materials and methods: A retrospective study on all orchidectomies performed for suspected testicular cancer was performed at a single hospital from over an 8-year period from January 2005 to December 2013. Non-cancerous lesions were excluded after histopathological review. All testicular malignancies were included and detailed histopathological review was performed. Results: A total of 121 orchidectomies were performed over the 8-year period. Three patients had spermatic cord involvement. Spermatic cord involvement did not adversely affect the outcome in these patients after a median follow-up of 5 years irrespective of tumour histology. The proximal spermatic cord was not involved in any testicular germ cell tumours on further cord sectioning, the only patient with proximal cord involvement had a B-cell lymphoma. Conclusion: We postulate that a sub-inguinal modified orchidectomy may be a less invasive alternative to radical inguinal orchidectomy, with comparable oncological outcomes based on low risk of spermatic cord involvement, which in itself is not a prognostic factor. We require further long-term follow-up studies on patients who have undergone this approach to validate the oncological outcomes and report the possible advantage of lower post-operative complications with this technique.

Expression of E-Cadherin/Beta-Catenin in Epithelial Carcinomas of the Thyroid Gland

BACKGROUND: The aberrant activation of Wnt signalling pathway may be a common denominator for the development of thyroid tumorigenesis. It was announced that the loss of E-cadherin rather than β-catenin mutation represents a crucial event in determining the degree of differentiation of thyroid carcinomas.AIM: The aim of the study was to evaluate the expression of E-cadherin and β-catenin in the thyroid cancer tissue and to correlate these data with some histological and clinical parameters of the tumours.MATERIAL AND METHODS: We investigated 112 patients, having thyroid tumours – papillary, follicular, anaplastic and oncocytic carcinomas immunohistochemically with antibodies against E-cadherin and β-catenin. Survival analyses were done.RESULTS: E-cadherin expression was focally retained in the tumour cell membranes and the tumour cell cytoplasm of the papillary, follicular and oncocytic thyroid cancers, weather in anaplastic cancers it was almost lost (p = 0.0042, and р = 0.019, respectively, Fisher's Exact Test). The expression of β-catenin in tumour cytoplasm and membrane in papillary cancers was higher as compared to that in the other tumours (p = 0.111, and р = 0.0104, respectively).CONCLUSION: Not surprisingly, the presence of aberrant expression of E-cadherin and β-catenin in thyroid cancer has been associated with better patients' prognosis and better differentiated tumour histology.