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Dive into the research topics where Corwyn Rowsell is active.

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Featured researches published by Corwyn Rowsell.


Gastric Cancer | 2012

A systematic review of the accuracy and utility of peritoneal cytology in patients with gastric cancer

Pierre-Anthony Leake; Roberta Cardoso; Rajini Seevaratnam; Laércio Gomes Lourenço; Lucy Helyer; Alyson L. Mahar; Corwyn Rowsell; Natalie G. Coburn

BackgroundThere is lack of uniformity in the utilization of peritoneal cytology in gastric cancer management. The identification of intraperitoneal free cancer cells (IFCCs) is believed to confer poor prognosis. However, while some of these patients are palliated, others may undergo more aggressive therapies. In this review, we aimed to identify and synthesize findings on the use of peritoneal cytology in predicting peritoneal recurrence and overall survival in curative gastric cancer patients.MethodsElectronic literature searches were conducted using Medline, EMBASE, and the Cochrane Central Register of Controlled Trials from January 1, 1998 to December 31, 2009. We determined the accuracy, sensitivity, and specificity of peritoneal cytology in predicting peritoneal recurrence based on four techniques—conventional cytology, immunoassay, immunohistochemistry, and reverse transcriptase-polymerase chain reaction. Recurrence rates and overall survival rates for curative patients were determined, based on positivity or negativity for IFCCs.ResultsTwenty-eight articles were included. All four techniques showed wide variations in accuracy, sensitivity, and specificity in predicting peritoneal recurrence. Recurrence rates for patients positive for IFCCs ranged from 11.1 to 100%, while those negative for IFCCs had recurrence rates of 0–51%. Overall survival was significantly reduced for patients with positive IFCCs. Short follow-up periods and possible duplication of results may limit result interpretation.ConclusionThe presence of IFCCs appears to increase the risk of peritoneal recurrence and is associated with worse overall survival in gastric cancer patients. Further incorporation of peritoneal cytology in clinical decision-making in gastric cancer depends on the development of a consistently accurate and rapid IFCC detection method.


Human Pathology | 2012

International study group on rectal cancer regression grading : interobserver variability with commonly used regression grading systems

Runjan Chetty; Pelvender Gill; Dhirendra Govender; Adrian C Bateman; Hee Jin Chang; Vikram Deshpande; David K. Driman; Marisa Gomez; Godman Greywoode; Eleanor Jaynes; C. Soon Lee; Michael Locketz; Corwyn Rowsell; Anne Rullier; Stefano Serra; Neil A. Shepherd; Eva Szentgyorgyi; Rajkumar Vajpeyi; Lai Mun Wang; Andrew Bateman

The aim of this study was to ascertain the level of concordance among gastrointestinal pathologists for regression grading in rectal cancers treated with neoadjuvant chemoradiation. Seventeen gastrointestinal pathologists participated using the Mandard, Dworak, and modified rectal cancer regression grading systems to grade 10 representative slides that were selected from 10 cases of rectal cancer treated with long-course neoadjuvant chemoradiation. The slides were scanned with a whole-slide scanner generating dynamic digitized images. The results showed very little concordance across the 3 grading systems, with κ values of 0.28, 0.35, and 0.38 for the Mandard, Dworak, and modified rectal cancer regression grading systems, respectively. In only 1 of 10 study cases was there unanimous grading concordance using the modified rectal cancer regression grading system. It was felt that these systems lacked precision and clarity for reproducible, accurate regression grading. The study concluded that there was a need for a simple, reproducible regression grading system with clear criteria, a cumulative or composite score taking into account all sections of the tumor bed that is sampled rather than the worst section (highest grade), and there should be a uniform method of sampling of these specimens.


Catheterization and Cardiovascular Interventions | 2013

Hybrid intravascular ultrasound and optical coherence tomography catheter for imaging of coronary atherosclerosis.

Brian Li; Annie S.O. Leung; Alan Soong; Chelsea Munding; Hyunggyun Lee; Amandeep Thind; Nigel R. Munce; Graham A. Wright; Corwyn Rowsell; Victor X. D. Yang; Bradley H. Strauss; F. Stuart Foster; Brian Courtney

To demonstrate the feasibility of imaging human coronary atherosclerosis using a novel hybrid intravascular ultrasound (IVUS) and optical coherence tomography (OCT) imaging catheter.


Applied Immunohistochemistry & Molecular Morphology | 2009

CDX2, cytokeratins 7 and 20 immunoreactivity in rectal adenocarcinoma.

Reda S. Saad; Jan F. Silverman; Mahmoud A. Khalifa; Corwyn Rowsell

There are limited data regarding CDX2 expression in rectal carcinoma. The CK20/CK7 immunoprofile of colorectal adenocarcinoma has been described in studies, which have mostly lumped colonic and rectal tumors together. In this study, we investigated the diagnostic utility of immunohistochemical stains for CK7, CK20, and CDX2 in a series of rectal adenocarcinoma. Fifty-five specimens of rectal adenocarcinomas were retrieved and immunostained for CK7 (Dako-M7018), CK20 (NovoCastra NCL-L-CK20), and CDX2 (NovoCastra NCL-CDX2). Thirty cases of pancreatic adenocarcinoma and 15 cholangiocarcinomas were also studied as a comparison group. CK7 was expressed in 12/55 (22%) and CK20 in 48/55 (87%) cases of rectal adenocarcinoma. The CK7−/CK20+ immunophenotype was identified in 36/55 (65%), CK7+/CK20+ in 12/55 (22%), and CK7−/CK20− in 7/55 (13%) rectal adenocarcinoma. CDX2 showed moderate-strong positivity in all cases and was not related to tumor differentiation. Benign rectal mucosa was available in 37 cases and showed the following results: CK7−/CK20+ in 25/37 (67%), CK7+/CK20+ in 8/37 (22%) and CK7−/CK20− in 4/37 (11%) cases. In pancreatic adenocarcinomas and cholangiocarcinomas, 29/45 (64%) were CK7+/CK20+ and 16/45 (36%) were CK7+/CK20−. CDX2 was positive in only 3/45 (7%) of these cases; all were pancreatic adenocarcinomas. In conclusion, CK7 can be expressed in rectal adenocarcinoma, and should not be used as the sole basis for excluding a rectal primary. CDX2 is a sensitive marker for rectal origin of adenocarcinoma. It can be helpful in cases with metastatic rectal carcinoma, especially those with CK7+/CK20+ or CK20−/CK7− immunophenotype. In this study, CDX2 expression was not influenced by the grade (differentiation) of rectal adenocarcinoma.


Annals of Surgical Oncology | 2015

Consensus Recommendations for the Diagnosis and Management of Pancreatic Neuroendocrine Tumors: Guidelines from a Canadian National Expert Group

Simron Singh; Chris Dey; Hagen F. Kennecke; Walter Kocha; J. Maroun; Peter Metrakos; Tariq Mukhtar; Janice L. Pasieka; Daniel Rayson; Corwyn Rowsell; Lucas Sideris; Ralph Wong; Calvin Law

Pancreatic neuroendocrine tumors (pNETs) are rare heterogeneous tumors that have been steadily increasing in both incidence and prevalence during the past few decades. Pancreatic NETs are categorized as functional (F) or nonfunctional (NF) based on their ability to secrete hormones that elicit clinically relevant symptoms. Specialized diagnostic tests are required for diagnosis. Treatment options are diverse and include surgical resection, intraarterial hepatic therapy, and peptide receptor radionuclide therapy (PRRT). Systemic therapy options include targeted agents as well as chemotherapy when indicated. Diagnosis and management should occur through a collaborative team of health care practitioners well-experienced in managing pNETs. Recent advances in pNET treatment options have led to the development of the Canadian consensus document described in this report. The discussion includes the epidemiology, classification, pathology, clinical presentation and prognosis, imaging and laboratory testing, medical and surgical management, and recommended treatment algorithms for pancreatic neuroendocrine cancers.


Ejso | 2014

Variability of Ki67 labeling index in multiple neuroendocrine tumors specimens over the course of the disease.

Simron Singh; Julie Hallet; Corwyn Rowsell; Calvin Law

BACKGROUND The Ki67-LI is a valid surrogate for biologic behavior of neuroendocrine tumors (NETs), with higher levels associated with aggressive behavior. The World Health Organization (WHO) classifies NETs according to Ki67-LI (G1: <3%; G2 : 3-20%; G3: >20%). Little is known about the evolution of NETs histologic characteristics over the disease course. We sought to evaluate variations in Ki67-LI throughout NETs disease course. METHODS We retrospectively reviewed the Sunnybrook Odette Cancer Center NET database for patients with multiple pathology specimens. Primary outcome was the WHO NET class based on Ki67-LI for each specimen. We assessed change in WHO class between specimens. RESULTS Forty-three patients were retrieved, of which 39 had specimens from the primary tumor and a metastatic focus, and 4 had specimens from multiple metastatic foci. Sixteen (37.0%) were identified with Ki67-LI falling in different WHO classes on distinct biopsies. For 12 (75.0%) of those 16 patients, Ki67-LI showed enough variability for WHO class to be upstaged: 5 (31%) from G1 to G2, 2 (13%) from G2 to G3, and 5 (31%) from G1 to G3. CONCLUSION When multiple pathology specimens were available, Ki67-LI varied throughout NETs disease course, with a majority of cases upgraded to a higher WHO class. If confirmed, this finding may have implications in how neuroendocrine tumors are monitored and treated. Further research is warranted to confirm these findings, understand better the underlying mechanisms of Ki67 variability, and define its relationship to prognosis.


Virchows Archiv | 2009

Retroperitoneal margin of the pancreaticoduodenectomy specimen: anatomic mapping for the surgical pathologist

Mahmoud A. Khalifa; Vlad Maksymov; Corwyn Rowsell

Surgical margin status of the pancreaticoduodenectomy specimen is an independent predictor of survival in patients with pancreatic head cancer. Although most surgical pathologists are familiar with the protocols for grossing and evaluation of the various margins of the specimen, the currently prevailing definitions of the retroperitoneal surgical margin minimize the fact that this margin is actually a combination of surfaces of different anatomical structures. The unfamiliarity with its detailed anatomy often creates communication gaps when the pathologic findings are presented to other members of the multidisciplinary team. The following discussion is the collective opinion of hepato-pancreato-biliary pathologists in two tertiary care Canadian medical centers in this field. It describes the authors’ proposed nomenclature and landmarks for anatomic mapping of the retroperitoneal margin of the pancreaticoduodenectomy resected specimen. Increasing familiarity with the subtleties of the retroperitoneal margin is expected to improve communication and sets the stage for future quality improvement initiatives and translational research in the multidisciplinary setting.


Journal of Clinical Pathology | 2006

Papillary renal cell carcinoma within a renal oncocytoma: case report of an incidental finding of a tumour within a tumour.

Corwyn Rowsell; Neil Fleshner; Paula Marrano; Jeremy A. Squire; Andrew Evans

The most common renal tumours are clear cell, papillary, chromophobe and collecting duct renal cell carcinomas (RCCs), and benign oncocytomas and angiomyolipomas. Tumours with hybrid features between some of these entities have been recognised; in particular, tumours with features of both chromophobe RCC and oncocytoma. Case reports describing one distinct type of primary renal tumour actually within another are very rare. The incidental finding of a papillary RCC located in an oncocytoma in a nephrectomy specimen from a 75-year-old man is described. Morphological criteria for each tumour type were completely satisfied and fluorescence in situ hybridisation detected the expected number of copies of chromosome 7 in the cells of each tumour type. The cells in the papillary tumour contained three copies, whereas the oncocytoma cells contained only two per nucleus. To our knowledge, this is the first report of a papillary RCC being identified within an oncocytoma.


Virchows Archiv | 2005

Primary chordoid meningioma of lung

Corwyn Rowsell; Jane Sirbovan; Marc K. Rosenblum; Bayardo Perez-Ordonez

Primary meningiomas of the lung are rare. Most pulmonary meningiomas are typical syncytial or transitional meningiomas with smaller numbers of fibrous-type tumors. Herein, we report an unusual pulmonary tumor with the microscopic, immunohistochemical, and ultrastructural characteristics of a chordoid meningioma. The tumor was composed of cords and fascicles of small- to medium-sized spindle and epithelioid cells with eosinophilic cytoplasm and round nuclei with finely dispersed chromatin. The tumor cells were surrounded by an abundant mucoid, vacuolated stroma. The periphery of the tumor was enveloped by a significant lymphoplasmacytic infiltrate. The neoplastic cells were positive for vimentin and epithelial membrane antigen only. The unusual morphology of the tumor caused significant diagnostic difficulties. The differential diagnosis included inflammatory myofibroblastic tumor, spindle cell myoepithelioma, and extraskeletal myxoid chondrosarcoma. To the best of our knowledge, this is possibly the first description of an extracranial or intrapulmonary chordoid meningioma.


Virchows Archiv | 2012

A multi-centre pathologist survey on pathological processing and regression grading of colorectal cancer resection specimens treated by neoadjuvant chemoradiation

Runjan Chetty; Pelvender Gill; Dhirendra Govender; Adrian C Bateman; Hee Jin Chang; David K. Driman; Fraser Duthie; Marisa Gomez; Eleanor Jaynes; Cheok Soon Lee; Michael Locketz; Claudia Mescoli; Corwyn Rowsell; Anne Rullier; Stefano Serra; Neil A. Shepherd; Eva Szentgyorgyi; Rajkumar Vajpeyi; Lai Mun Wang

To ascertain the approach and degree of consensus of pathologists in the handling and regression grading of colorectal cancer resection specimens treated with neoadjuvant chemoradiation, a ten-part questionnaire was circulated to 18 gastrointestinal pathologists in eight countries. The questions were specific and addressed pertinent issues related to colorectal cancer with neoadjuvant chemoradiation. There is a lack of consensus on how to handle the specimen, number of sections taken, correlation with pre- and post-operative radiological imaging, and especially, regression grading schema employed. Consensus in the form of guidelines is required so that the pathological assessment of these specimens will provide clinically relevant information for patient management, irrespective of location.

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Calvin Law

Sunnybrook Health Sciences Centre

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Simron Singh

Sunnybrook Health Sciences Centre

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Stefano Serra

University Health Network

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Adrian C Bateman

University Hospital Southampton NHS Foundation Trust

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Eleanor Jaynes

University Hospital Southampton NHS Foundation Trust

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David K. Driman

London Health Sciences Centre

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