Stage Discrepancy Research Articles

Clinical and Pathological Staging Discrepancies in Laryngeal Cancer: A Systematic Review

Background/Objectives: Laryngeal squamous cell carcinoma (LSCC) is one of the most prevalent and challenging malignancies of the head and neck. Clinical staging (cTNM) plays a pivotal role in therapeutic decision-making. However, current imaging modalities often fall short, resulting in discrepancies between cTNM and pathological staging (pTNM). This systematic review aimed to critically evaluate the existing literature on the concordance between clinical and pathological staging of LSCC, quantifying staging inaccuracies and highlighting the prevalence of both under- and overstaging at diagnosis. Methods: A comprehensive search of the English-language literature was conducted across multiple databases, including PubMed, Embase, Scopus, the Cochrane Library, and Web of Science. Eligibility was limited to retrospective case series and observational studies reporting sufficient data to directly correlate individual patients’ cTNM and pTNM classifications. Results: Thirty-one studies comprising 7939 patients met the inclusion criteria. The overall concordance rate between cT and pT was approximately 86.43%. The concordance rates between cT and pT were 82.41%, 82.03%, 78.14%, and 89.64% for cT1, cT2, cT3, and cT4, respectively. Most discordant cases in cT2 and cT3 involved understaging at clinical diagnosis. Conclusions: The limited accuracy of clinical staging in reflecting the true extent of disease remains a critical challenge in the management of LSCC. The inability of current imaging techniques to reliably detect the subtle invasion of key anatomical structures contributes to both under- and overstaging, with significant clinical implications. For patients undergoing non-surgical organ-preservation strategies, these inaccuracies may adversely affect oncologic outcomes.

Effect of Blade Number on Internal Flow and Performance Characteristics in Low-Head Cross-Flow Turbines

Cross-flow turbines are widely used in microhydropower systems because of their cost-effectiveness, environmental sustainability, adaptability, and robust design. However, their relatively lower efficiency than other turbine types limit their application in large-scale projects. Previous studies have identified poor flow profiles as a significant factor contributing to inefficiency, with the number of blades playing a critical role in the flow behavior, efficiency, and structural stability. This study employed numerical simulations to analyze how varying the number of blades affects the internal flow characteristics and performance of the turbine at, and off, its best operating points. Configurations with 16, 20, 24, 28, 32, 36, 40, and 44 blades were investigated under constant low-head conditions, fully open valve settings, and varying runner speeds. Simulations were performed using ANSYS CFX, incorporating steady-state conditions, a two-phase flow model with a movable free surface, and a shear stress turbulence model. The results indicate that the 28-blade configuration achieved a maximum hydraulic efficiency of 83%, outperforming the preset 24-blade setup by 6%. Flow profiles were examined using pressure and velocity gradients to identify regions of adverse pressure. Due to the impulse nature of the turbine, the flow profile is more sensitive to changes in the flow speed than to pressure. The flow trajectory showed stability in the first stage but exhibited discrepancies in the second stage, which were attributed to turbulence, recirculation, and shaft flow impingement. The observed performance improvements were linked to reduced hydraulic losses due to flow separation and friction, emphasizing the significance of the number of blades and the regions of optimal efficiency under low-head conditions.

OGC SO15 - Utility of radiological re-staging following neo-adjuvant chemotherapy and its impact on oncological outcomes in resectable gastric adenocarcinoma

Abstract Background The current perioperative chemotherapy regimen that comprises the multimodal treatment strategy for gastric cancer consists of Fluorouracil, Leucovorin, Oxaliplatin, and Docetaxel. Despite improvement in outcomes at a population level, real-world data suggests that ≤40% of patients show a poor/no response to the neoadjuvant phase of treatment. Identification of these poor/non-responders may facilitate a re-evaluation of their treatment strategy and prevent potentially futile surgery. Radiological re-staging following neoadjuvant treatment is routinely performed despite its debatable accuracy and benefits. This study aimed to define the accuracy of radiological re-staging and its impact on survival following neoadjuvant treatment for resectable GC. Method Patients with resectable gastric cancer who completed 4 cycles of neoadjuvant FLOT and underwent resectional surgery with curative intent between 2018 and 2022 were retrospectively identified. All patients were clinically staged with gastroscopy, CT and staging laparoscopy. The index radiological/clinical stage at diagnosis was compared to the radiological re-staging following neoadjuvant treatment. Patient were re-staged with either a CT or PET-CT. Both were then compared with the final pathological stage to assess for correlation between the radiological and pathological stage. A survival analysis was then performed to evaluate the impact of radiological-pathological staging discrepancy on overall survival Results A total of 65 consecutive patients met the inclusion criteria of this study. On comparison of the index clinical stage with the radiological re-stage post-neoadjuvant treatment, 71% had concordant stages, 25% were downstaged, and 4% were upstaged. On comparison of the index clinical stage with the final pathological stage, 35% had concordant stages, 38% were upstaged and 27% were down staged (Cohen kappa = -0.224, 95% CI -0.390, -0.058). Discrepancy between clinical stage and radiological re-stage did not influence survival. However, discrepancy between clinical and pathological stage highlighted survival differences where upstaged patients had reduced survival (p = 0.018). Conclusion The accuracy of clinical staging compared to final pathological staging in the setting of aggressive tumour biology remains undefined. Radiological re-staging following neoadjuvant treatment proves to be an unreliable tool for assessing treatment response and does not predict long-term survival outcomes. These findings highlight the importance of accurate staging and the need for more precise methods of evaluating treatment response. This may enhance decision-making, individualise treatment regimens, and improve patient outcomes.

CapeOX as neoadjuvant chemotherapy for locally advanced rectal cancer: might less be more?

BackgroundLocally advanced rectal cancer (LARC) poses unique challenges in treatment, with current neoadjuvant chemoradiotherapy (NA-CRT) showing limitations. The CapeOX regimen emerges as a potential less aggressive neoadjuvant chemotherapy (NAC) for LARC.MethodsWe conducted a retrospective study involving treatment-naïve patients with LARC from March 2014 to March 2021 who received 2–4 cycles of CapeOX NAC followed by radical surgery. Treatment response was evaluated using tumor regression grade (TRG), MRI-based TRG (MRI-TRG), and Neoadjuvant Rectal (NAR) score.Results94.7% of patients experienced symptom improvement and 96.4% achieved sphincter-preserving surgery. Post-NAC showed significant tumor regression and MRI confirmed a tumor length reduction (P < 0.001). Clinical and pathological staging discrepancies post-NAC suggest broader therapeutic advantages. 5-year overall and disease-free survival rates were 78.4% and 73.4%. NAR scores provided better prognostic accuracy than MRI-TRG.ConclusionCapeOX NAC presents notable benefits for LARC patients and its clinical significance may be underestimated. The NAR score demonstrates superior prognostic value over MRI-TRG.

Impact of the FIGO2023 staging system on endometrial cancer in Japan: differences between next-generation sequencing and simplified surrogate marker analysis.

The International Federation of Gynecology and Obstetrics (FIGO) revised the staging system of endometrial cancer in 2023. In this study, we aimed to determine stage transitions and prognosis of endometrial cancer using FIGO2008, FIGO2023 without molecular classification (FIGO2023), and FIGO2023 with molecular classification (FIGO2023m). Eighty-three patients diagnosed with endometrial cancer who underwent surgery and next-generation sequencing (NGS) molecular profiling as part of the Project HOPE cohort study were enrolled. Each case was staged according to the FIGO2008 and FIGO2023 criteria, and we evaluated changes in stage and disease-specific survival (DSS). Molecular classification based on NGS was performed to evaluate FIGO2023m, and the concordance rate with immunohistochemical marker analysis was assessed. Transitioning from FIGO2008 to FIGO2023 resulted in the restaging of 18 cases. Conversely, transitioning from FIGO2008 to FIGO2023m led to the restaging of 15 cases. The concordance rate between FIGO2023 and FIGO2023m staging was 96.4%. With FIGO2023m, the 5-year DSS was 97.6% for stage I (95% confidence interval [CI] 83.9-99.7), 83.3% for stage II (95% CI 56.8-94.3), 100% for stage III (95% CI NA), and 25.0% for stage IV (95% CI 0.9-66.5). Discrepancies in disease staging due to discordance between simplified surrogate marker analysis and NGS evaluation occurred in two cases. The revision of the staging system from FIGO2008 to FIGO2023 and FIGO2023m resulted in the restaging of several cases, with significant changes between stages I and II.

Evaluasi Implementasi Blended Learning pada Mata Kuliah Fisika Modern dengan Model Diskrepansi

The purpose of this paper is to describe the essence that occurs at each stage in the discrepancy evaluation model which consists of the Design, Installation, Process and Product stages related to the Blended Learning method in the modern spectacles course at the Muslim University of Maros. Based on the type of research used, this research is included in program evaluation research using the discrepancy evaluation model. The research sample consisted of 14 people plus 1 modern physics lecturer. Data collection was carried out using a mixed method with data collection instruments using, (1) interview guidelines, (2) questionnaires with a Likert scale model and (3) documentation. The data analysis technique used for qualitative data is data analysis using the Miles and Huberman model. This data analysis technique consists of data collection, data reduction and drawing conclusions. As for the quantitative data, the data analysis technique used is quantitative descriptive analysis and the calculation of the coefficient of determination. The results showed that (1) there was no discrepancy in the design stage (2) there was a discrepancy in the installation stage of 0.04 (3) there was a discrepancy in the Process stage of 0.23 (4) there was a discrepancy in the Product stage of 0. 78. So that the Blended Learning lectures can be continued with suggestions for improvement, namely (1) Lecturers continue to carry out their obligations to carry out face-to-face lectures, (2) Require students to study material in Google Classroom, (3) Uploaded material has various forms.

Predictive Value of Magnetic Resonance Imaging in Risk Stratification and Molecular Classification of Endometrial Cancer.

This study evaluated the magnetic resonance imaging (MRI) findings of endometrial cancer (EC) patients and identified differences based on risk group and molecular classification. The study involved a total of 175 EC patients. The MRI data were retrospectively reviewed and compared based on the risk of recurrence. Additionally, the associations between imaging phenotypes and genomic signatures were assessed. The low-risk and non-low-risk groups (intermediate, high-intermediate, high, metastatic) showed significant differences in tumor diameter (p < 0.001), signal intensity and heterogeneity on diffusion-weighted imaging (DWI) (p = 0.003), deep myometrial invasion (involvement of more than 50% of the myometrium), cervical invasion (p < 0.001), extrauterine extension (p = 0.002), and lymphadenopathy (p = 0.003). Greater diffusion restriction and more heterogeneity on DWI were exhibited in the non-low-risk group than in the low-risk group. Deep myometrial invasion, cervical invasion, extrauterine extension, lymphadenopathy, recurrence, and stage discrepancy were more common in the non-low-risk group (p < 0.001). A significant difference in microsatellite stability status was observed in the heterogeneity of the contrast-enhanced T1-weighted images (p = 0.027). However, no significant differences were found in MRI parameters related to TP53 mutation. MRI features can be valuable predictors for differentiating risk groups in patients with EC. However, further investigations are needed to explore the imaging markers based on molecular classification.

Discrepancies in staging and perioperative classification of pelvic endometriosis according to #Enzian 2021.

The aim of this study is to compare the extent of ovarian endometriosis diagnosed at preoperative staging with subsequent perioperative findings. Definition of discrepancies observed according to the #Enzian 2021 classification. The cohort includes 62 patients of reproductive age with preoperative findings of ovarian endometrioma. Patients were divided according to the #Enzian 2021 classification into subgroups (O1, O2 + O3) with unilateral and bilateral findings. The percentage concordance of preoperative and perioperative findings was evaluated. In the evaluation of ovarian involvement, the preoperative ultrasound diagnosis shows almost 100% agreement with the findings on the ovaries during surgery. Periadnexal adhesions were predicted preoperatively in only half of the cases. The difference in laterality was confirmed with T3 involvement in the O2 + O3 subgroup. In the bilateral involvement, the finding of the presence of grade 3 adhesions was doubled. An association of ovarian form of endometriosis (O2-O3) with deep infiltrating endometriosis of the small pelvis was observed in 50% of the cohort. The ovarian form of endometriosis is associated with the occurrence of other endometriosis lesions in the small pelvis. In this study, it was confirmed that preoperative staging underestimates the extent of endometriosis in the small pelvis. In the surgical management of ovarian endometriosis, extensive adhesive process should be expected.

Discrepancy between clinical and pathological staging of laryngeal carcinoma: a dilemma to be solved

ObjectivesThe aim of this study was to investigate the degree of discrepancy between the clinical and pathological staging of laryngeal carcinoma, and the potential impact of this discrepancy on the outcomes and prognosis.MethodsThis study was conducted on 127 patients who underwent total laryngectomy over five years (October 2016–October 2021). Data collected from pretherapeutic clinical staging regarding the extent of the tumor affection of different laryngeal subsites was compared to the postsurgical pathological assessment.ResultsOverall, 12 out of 127 patients (9.4%) in the current study, were clinically over-staged from T3 to T4 due to radiological diagnosis of tumor infiltration of laryngeal cartilages that proved pathologically to be free of tumor. Additionally, discordance in the N stage was found in 12.6% (n = 16). However, stage discrepancy did not have a significant impact on the prognosis and survival.ConclusionDiscordance between clinical and pathological TNM staging of laryngeal carcinoma may affect the decision making and the choice of the treatment options. Some improvement can be probably achieved with advancements and higher accuracy of the preoperative diagnostic tools.

OGC P21 Discrepancy between the clinical and final histopathological staging of locally advanced oesophageal adenocarcinoma

Abstract Background Accurate staging of locally advanced oesophageal cancer plays a pivotal role in treatment planning and prognostic counselling for the patients. Clinical staging employs various imaging modalities to guide treatment decisions and predict outcomes. This study aimed to compare clinical staging (post neoadjuvant chemotherapy) with the final histopathological staging in patients with locally advanced oesophageal adenocarcinoma undergoing oesophagectomy at Belfast Health and Social Care Trust. Methods A retrospective analysis was conducted on a cohort of 81 patients diagnosed with locally advanced oesophageal adenocarcinoma who underwent neo-adjuvant chemotherapy followed by oesophagectomy at Belfast Trust between March 2020 and March 2022. Patients with squamous cell carcinoma, those who proceeded directly to surgery and those treated with salvage oesophagectomy following previous radical chemo-radiotherapy were excluded from the study to minimise heterogeneity. Two independent radiologists reviewed the restaging PETCT scans and validated the clinical staging. The post neoadjuvant clinical staging was subsequently compared to the final histopathological staging obtained from surgical resection specimens. Results Among the 81 patients included in this study, a significant proportion of patients were upstaged (53%) or downstaged (31%). The combined T&amp;N staging accuracy was observed in only 13 patients (16%). 21 patients (26.3%) had their T staging downstaged on final assessments. Nodal staging discrepancies were observed in 35 cases (43.2%) upon final histopathological assessment. These isolated nodal discrepancies primarily involved nodal upstaging, with 14 patients upstaged from N0 to N1 and 13 patients upstaged from N0 to N2. Conclusions The accuracy of clinical staging for oesophageal adenocarcinoma remains poor. Our study revealed notable discrepancies in nodal staging between clinical and final histopathological staging. Approximately 43.2% of patients had isolated nodal discrepancies, primarily involving nodal upstaging. These findings emphasize the challenges in accurately assessing nodal involvement and highlight the need for improved staging methods to guide optimal treatment for locally advanced oesophageal adenocarcinoma. The topic of whether the routine use of EUS is justified for evaluating regional lymphnodes and enhancing staging remains a subject of debate, notwithstanding the limitations and challenges inherent to EUS.

ThTP4.13 Discrepancy between preoperative MRI staging and post-operative histopathology staging in rectal cancer patients who had primary surgery. A retrospective study at a District General Hospital

Abstract Aim The aim of this retrospective study was to analyse the discrepancy between preoperative MRI staging and post-operative histopathology staging of rectal cancer patients who had primary surgery. Methods A retrospective cohort study analysed the records of 47 patients with histology confirmed rectal cancer over the period of 5 years from 2017 to 2022. Data was collected from the hospital database. Results Forty-seven patients were evaluated. The mean age of presentation was 72 years. Out of 47 patients 65.95% (n=31/47) were men; 34.05 % (n=16/47) were women. Discrepancy in T staging and N staging were found in 44% (n=21/47) and 49% (n=22/45) patients respectively. Two patients had inconclusive N staging on preoperative MRI. In T stage discrepancy, 86 % ( n=18/21) were upstaged and 14% (n=3/21) were downstaged. In N stage discrepancy, 73%(n=16/22) were upstaged and 27% (n=6/22) were downstaged. Conclusion There was significant discrepancy in preoperative MRI staging and post-operative histopathology staging in our study. Discrepancy in rectal cancer staging has critical effects on management, outcomes, and survival rates of patients. Appropriate and accurate clinical radiological staging enables multi-disciplinary teams to plan optimal management approaches.

Comparison Between Clinical and Pathological Staging After Elective Neck Dissection in Head and Neck Cancer.

Head and neck squamous cell carcinomas (HNSCC) are the most common malignancies in the head and neck. Previous studies have shown discrepancies in clinical and pathological staging, with a significant number of head and neck cancer patients who were not correctly staged. This has important implications regarding the treatment and prognosis of these patients. The aim of this study was to analyze potential disagreements in clinical and pathological staging in patients with head and neck cancer who underwent elective neck dissection. A retrospective study of patients with squamous cell carcinoma of the head and neck, who underwent elective neck dissection, between January 2018 and December 2020. We analyzed 87 patients, with an average age of 64 ± 10.05 years, of whom 96.6% were male. The primary tumor location was the glottis (31%), oropharynx (26.4%), hypopharynx (19.5%), supraglottis (11.5%), and oral cavity (11.5%). In 87.3% there was a history of smoking and/or drinking. Pathological N (pN) staging was higher than clinical staging in 34.3% of patients (N1 in 22.9%; N2 in 8%; N3 in 3.4%). There were no significant differences between the number of nodes removed and the pN staging. However, there was a significant survival difference in patients with>15 nodes removed (p=0.05). There was also a significant difference in patients with pN up-staging regarding survival (p=0.005).Pathological T staging was different from clinical T staging (p<0.05), with an up-staging in 18.4% of the patients and a down-staging in 14.9%, without significant differences regarding survival or recurrence (p>0.05).Adjuvant treatment with radiotherapy was performed in 41.4% and with chemo-radiotherapy in 13.8% of the patients. Locoregional recurrence occurred in 17.5%. This study revealed that clinical and pathological N staging after elective neck dissection disagreed in a substantial number of patients, with pathological upstaging and significant differences regarding survival. With relation to T staging, there were no significant differences regarding survival. We should be aware of staging disagreements since they can have significant implications on the treatment and prognosis of cancer patients.

Discrepancies in Embryonic Staging: Towards a Gold Standard.

For over half a century, the Carnegie staging system has been used for the unification of chronology in human embryo development. Despite the system's establishment as a "universal" system, Carnegie staging reference charts display a high level of variation. To establish a clear understanding for embryologists and medical professionals, we aimed to answer the following question: does a gold standard of Carnegie staging exist, and if so, which set of proposed measures/characteristics would it include? We aimed to provide a clear overview of the variations in published Carnegie staging charts to compare and analyze these differences and propose potential explanatory factors. A review of the literature was performed, wherein 113 publications were identified and screened based on title and abstract. Twenty-six relevant titles and abstracts were assessed based on the full text. After exclusion, nine remaining publications were critically appraised. We observed consistent variations in data sets, especially regarding embryonic age, varying as large as 11 days between publications. Similarly, for embryonic length, large variations were present. These large variations are possibly attributable to sampling differences, developing technology, and differences in data collection. Based on the reviewed studies, we propose the Carnegie staging system of Prof. Hill as a gold standard amongst the available data sets in the literature.

Statistical Mistakes Commonly Made When Writing Medical Articles

Statistical analysis is an essential component of the medical writing process for research-related articles. Although the importance of statistical testing is emphasized, statistical mistakes continue to appear in journal articles. Major statistical mistakes can occur in any of the three different stages of medical writing, including in the design stage, analysis stage, and interpretation stage. In the design stage, mistakes occur if there is a lack of specificity regarding the research hypothesis or data collection and analysis plans. Discrepancies in the analysis stage occur if the purpose of the study and characteristics of the data are not sufficiently considered, or when an inappropriate analytic procedure is followed. After performing the analysis, the results are interpreted, and an article is written. Statistical analysis mistakes can occur if the underlying methods are incorrectly written or if the results are misinterpreted. In this paper, we describe the statistical mistakes that commonly occur in medical research-related articles and provide advice with the aim to help readers reduce, resolve, and avoid these mistakes in the future.

Accuracy of germ cell tumor histology and stage within a Canadian cancer registry.

Cancer registries are the mainstay for Canadian population-based cancer statistics. Data are collected in provincial and territorial registries, including the Nova Scotia Cancer Registry (NS CR). The goal of this study was to determine the accuracy of NS CR data for germ cell tumors (GCT). This analysis included all NS CR patients diagnosed with GCT from 2006-2015. The date and method of diagnosis, primary site, histology, and stage were recorded from the NS CR and compared to each patient's chart. Any discrepancies between the two sources were reviewed and reasons behind the discrepancies recorded. A total of 229 patients made up the study cohort. Using NS CR data, 57.6% had seminoma, 34.5% non-seminoma (NSG CT), and 7.9% other. Discrepancies in pathology were noted in 16 patients (7.0%). Using NS CR staging data (available in 185 cases), 71.9% had stage I, 12.4% stage II, 11.9% stage III, and 3.8% other. Discrepancies in stage were noted in 32 patients (17.3%) with NS CR data downstaging eight patients (4.3%) and upstaging 21 patients (11.4%). The site of the primary GCT was discrepant in 12 patients (5.2%). The date of diagnosis was accurate within one week for all patients except one. Higher-level NS CR data, such as date of diagnosis and overall pathological diagnosis, appear relatively accurate; however, there are inaccuracies in histological subtype and stage. This study raises awareness of these gaps and highlights key areas for improvement in educating registry personnel who interpret and enter data about the uniqueness of GCT pathology, staging, and interpretation of tumor markers.

Is the Number of National Database Research Studies in Musculoskeletal Sarcoma Increasing, and Are These Studies Reliable?

Is the Number of National Database Research Studies in Musculoskeletal Sarcoma Increasing, and Are These Studies Reliable?

The impact of multimodality integrated positron emission tomography-computed tomography on improving the staging and management of head and neck malignancy: a cross- sectional study.

Clinical assessment of head and neck cancers is highly challenging owing to the complexity of regional anatomy and wide range of lesions. The diagnostic evaluation includes detailed physical examination, biopsy and imaging modalities for disease extent and staging. Appropriate imaging is done to enable determination of precise tumor extent and involvement of lymph nodes, and detection of distant metastases and second primary tumors. To evaluate the initial staging discrepancy between conventional contrasted computed tomography (CT) and 18F-fluorodeoxy-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) and its impact on management plans for head and neck malignancies. Prospective cross-sectional study in two tertiary-level hospitals. This study included 30 patients with primary head and neck malignant tumors who underwent contrasted computed tomography and whole-body 18F-FDG PET/CT assessments. The staging and treatment plans were compared with the incremental information obtained after 18F-FDG PET/CT. 18F-FDG PET/CT was found to raise the stage in 33.3% of the cases and the treatment intent was altered in 43.3% of them, while there was no management change in the remaining 56.7%. 18F-FDG PET/CT had higher sensitivity (96% versus 89.2%) and accuracy (93% versus 86.7%) than conventional contrast-enhanced computed tomography. Our study demonstrated that 18F-FDG PET/CT had higher sensitivity and accuracy for detecting head and neck malignancy, in comparison with conventional contrast-enhanced computed tomography. 18F-FDG PET/CT improved the initial staging and substantially impacted the management strategy for head and neck malignancies.

Real‐world staging computed tomography scanning technique and important reporting discrepancies in pancreatic ductal adenocarcinoma

BackgroundComputed tomography (CT) is the first‐line staging imaging modality for pancreatic ductal adenocarcinoma (PDAC) which determines resectability and treatment pathways.MethodsBetween January 2016 and December 2019, prospectively collated data from two Australian cancer centres was extracted from the PURPLE Pancreatic Cancer registry. Real‐world staging CTs and corresponding reports were blindly reviewed by a sub‐specialist radiologist and compared to initial reports.ResultsOf 131 patients assessed, 117 (89.3%) presented with symptoms, 74 (56.5%) CTs included slices ≤3 mm thickness and CT pancreas protocol was applied in 69 (52.7%) patients. Initial reports lacked synoptic reporting in 131 (100%), tumour identification in 2 (1.6%) and tumour measurement in 13 (9.9%) cases. Tumour‐vascular relationship reporting was missing in 69–109 (52.7–83.2%) for regarding the key arterial and venous structures that is required to assess resectability. Initial reports had no comment on venous thrombus or venous collaterals in 80 (61.1%) and 109 (83.2%) and lacked locoregional lymphadenopathy interpretation in 13 (9.9%) cases. Complete initial staging report was present in 72 (55.0%) patients. Sub‐specialist radiological review resulted in down‐staging in 16 (22.2%) and up‐staging in 1 (1.4%) patient. Staging discrepancies were mainly regarding metastatic disease (12, 70.6%) and tumour‐vascular relationship (5, 29.4%).ConclusionReal‐world staging imaging in PDAC patients show low proportion of dedicated CT pancreas protocol, high proportion of incomplete staging reports and no synoptic reporting. The most common discrepancy between initial and sub‐specialist reporting was regarding metastases and tumour‐vascular relationship assessment resulting in sub‐specialist down‐staging in almost every fifth case.

Accuracy of germ cell tumor histological subtype and stage within the Canadian cancer registry.

411 Background: Cancer registries are the mainstay for Canadian population-based cancer statistics and research. Data is collected in provincial and territorial registries including the Nova Scotia Cancer Registry (NSCR). The goal of this study was to determine the accuracy of the NSCR data regarding the diagnosis, primary site, histological subtype, and stage of germ cell tumors (GCT) when compared to the individual pathology reports and staging investigations from the chart. Methods: This analysis included all NSCR patients diagnosed with GCT from 2006-2015. From the NSCR, the date and method of diagnosis, primary site, histology, and stage were recorded. This data was also extracted from each patient’s chart record. Any discrepancies between the two sources were reviewed and reasons behind the discrepancies were recorded. Results: 239 unique patients were identified in the NSCR during the specified time period. Ten were excluded as no chart records were available to confirm accuracy. 229 patients make up the study cohort. Using NSCR data 57.6% had seminoma, 34.5% nonseminoma (NSGCT), and 7.9% other. Discrepancies in pathology were noted in 29 patients (12.7%) for a number of reasons including no appropriate coding option in the NSCR, multiple tumors, biopsy only specimens with misinterpretation of tumor marker elevation, and true coding error. Using NSCR staging data (available in 185 cases) 71.9% had stage I, 12.4% stage II, 11.9% stage III, and 3.8% other. Discrepancies in stage were noted in 33 patients (17.9%) with NSCR data downstaging 10 patients (5.4%) and upstaging 19 patients (10.3%) predominantly due to miscoding patients as stage IS. The site of the primary GCT was discrepant in 12 patients (5.2%) due primarily to difficulty coding post chemotherapy orchiectomy specimens and burnt out primary testicular lesions. The date of diagnosis was accurate within 1 week for all patients except one which differed by several months. Conclusions: Canadian cancer registry data is population based and used for many purposes including policy decisions and research. The NSCR higher level data such as date of diagnosis and overall pathological diagnosis appears relatively accurate. However, there are inaccuracies in more detailed information like histological subtype and stage. This study raises awareness of these gaps. It also highlights key areas for improvement in educating registry personnel who interpret and enter data about the uniqueness of GCT pathology, staging and interpretation of tumor markers.

The influence of gas pore pressure in dense granular flows: numerical simulations versus experiments and implications for pyroclastic density currents

We investigate the influence of gas pore pressure in granular flows through numerical simulations on horizontal and low-angle inclined surfaces. We present a two-phase formulation that allows a description of dam-break experiments considering high-aspect-ratio collapsing columns and depth-dependent variations of flow properties. The model is confirmed by comparing its results with data from analogue experiments. The results suggest that a constant, effective pore pressure diffusion coefficient can be determined in order to reproduce reasonably well the dynamics of the studied dam-break experiments, with values of the diffusion coefficient consistent with experimental estimates from defluidizing static columns. The discrepancies between simulations performed using different effective pore pressure diffusion coefficients are mainly observed during the early acceleration stage, while the final deceleration rate, once pore pressure has been dissipated, is similar in all the studied numerical experiments. However, these short-lasting discrepancies in the acceleration stage can be manifested in large differences in the resulting run-out distance. We also analyze the pore pressure at different distances along the channel. Although our model is not able to simulate the under-pressure phase generated by the sliding head of the flows in experiments and measured beneath the flow-substrate interface, the spatio-temporal characteristics of the subsequent over-pressure phase are compatible with experimental data. Additionally, we studied the deposition dynamics of the granular material, showing that the timescale of deposition is much smaller than that of the granular flow, while the time of the deposition onset varies as a function of the distance from the reservoir, being strongly controlled by the surface slope angle. The simulations reveal that an increment of the surface slope angle from 0° to 10° is able to increase significantly the flow run-out distance (by a factor between 2.05 and 2.25, depending on the fluidization conditions). This has major implications for pyroclastic density currents, which typically propagate at such gentle slope angles.