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Dive into the research topics where D A Stewart is active.

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Featured researches published by D A Stewart.


Bone Marrow Transplantation | 2003

High-dose thiotepa, busulfan, cyclophosphamide and ASCT without whole-brain radiotherapy for poor prognosis primary CNS lymphoma

Tina Cheng; P Forsyth; Ahsan Chaudhry; Don Morris; S Glück; James A. Russell; D A Stewart

Summary:Treatment of primary central nervous system lymphoma (PCNSL) with combined high-dose methotrexate (HD-MTX)-based chemotherapy and whole-brain radiotherapy (WBRT) is associated with severe neurotoxicity, but high relapse rates are associated with the use of either modality alone. In an attempt to improve upon these dismal results, we treated seven PCNSL patients with HD-MTX-based induction therapy followed by thiotepa, busulfan, cyclophosphamide (TBC), and autologous stem cell transplant (ASCT), without WBRT. Six of these patients had at least one of the following poor prognostic features: Karnofsky performance status (KPS) ⩽50%, age >60 years, or relapsed disease. All but one patient tolerated the treatment well and experienced improvements in neurological function and overall performance status post-transplant. No treatment-induced neurotoxicity (dementia, ataxia, and incontinence) was observed although the follow-up is short. One early treatment-related death occurred in a patient with multiple comorbid medical conditions. The other six patients achieved a complete response (CR) after TBC and ASCT. Five patients are currently alive and relapse-free at 5, 8, 24, 36, and 42 months from diagnosis. One additional patient relapsed and died 33 months after diagnosis. Two of the seven patients received TBC/ASCT as the only treatment after disease progression following their initial chemotherapy and both remain relapse-free at the time of this report, 22 and 31 months post-TBC/ASCT. In conclusion, prolonged CR can be attained after chemotherapy-only treatment of poor prognosis PCNSL. Furthermore, this small series suggests that high-dose chemotherapy for PCNSL should include drugs that penetrate the CNS such as busulfan and thiotepa rather than standard lymphoma regimens such as BEAM.


Cancer | 2010

Interim report of a phase 2 clinical trial of lenalidomide for T-cell non-Hodgkin lymphoma.

Greg Dueck; Neil Chua; Angeli Prasad; Daygen Finch; D A Stewart; Darrell White; Richard H. van der Jagt; James B. Johnston; Andrew R. Belch; Tony Reiman

Novel therapies are needed to improve outcomes in T‐cell lymphomas. The authors report the interim results of a prospective multicenter trial evaluating lenalidomide in T‐cell lymphomas.


Bone Marrow Transplantation | 1999

Superior autologous blood stem cell mobilization from dose-intensive cyclophosphamide, etoposide, cisplatin plus G-CSF than from less intensive chemotherapy regimens

D A Stewart; D Guo; Don Morris; Man-Chiu Poon; B. A. Ruether; A. R. Jones; Klassen J; Iwona A. Auer; Joanne Luider; Ahsan Chaudhry; Chris W. Brown; James A. Russell

The study purpose was to determine if G-CSF plus dose-intensive cyclophosphamide 5.25 g/m2, etoposide 1.05 g/m2 and cisplatin 105 mg/m2 (DICEP) results in superior autologous blood stem cell mobilization (BSCM) than less intensive chemotherapy. From January 1993 until May 1997, 152 consecutive patients with non-Hodgkin’s lymphoma (n = 55), breast cancer (n = 47), Hodgkin’s disease (n = 14), multiple myeloma (n = 9), AML (n = 9), or other cancers (n = 18) initially underwent BSCM by one of three methods: Group 1: G-CSF alone × 4 days (n = 30). Group 2: disease-oriented chemotherapy, dosed to avoid blood transfusions, followed by G-CSF starting day 7 or 8, and apheresis day 13 or 14 (n = 82). Group 3: DICEP days 1–3, G-CSF starting day 14, and apheresis planned day 19, 20 or 21 (n = 40). A multivariate analysis was performed to determine which factors independently predicted BSCM. The median peripheral blood CD34+ (PB CD34+) cell count the morning of apheresis linearly correlated with the number of CD34+ cells removed per litre of apheresis that day. The median PB CD34+ cell count and median CD34+ cells × 106 removed per litre of apheresis were highest for Group 3, intermediate for Group 2, and lowest for Group 1. By multivariate analysis, mobilization group (3 > 2 > 1), disease other than AML, no prior melphalan or mitomycin-C, and less than two prior chemotherapy regimens predicted better BSCM. Out of 15 Group 3 patients who had infiltrated marrows, 11 had no detectable cancer in marrow and apheresis products after DICEP. These data suggest that DICEP results in superior BSCM than less intensive chemotherapy regimens.


The Journal of Urology | 1998

COMPLIANCE OF CLINICAL STAGE I NONSEMINOMATOUS GERM CELL TUMOR PATIENTS WITH SURVEILLANCE

D. Hao; J. Seidel; Rollin Brant; F. Alexander; D.S. Ernst; N. Summers; James A. Russell; D A Stewart

PURPOSE We evaluate compliance and its effect on the outcome of patients with clinical stage I nonseminomatous germ cell tumor who underwent post-orchiectomy surveillance at the Tom Baker Cancer Centre. MATERIALS AND METHODS From 1980 to 1994, 76 evaluable patients underwent surveillance at the Tom Baker Cancer Centre. The surveillance protocol consisted of clinical evaluation, chest x-ray and serum tumor marker measurements monthly in year 1, every 2 months in year 2, every 6 months in years 3 to 5 and yearly in years 6 to 10. Abdomen and pelvic computerized tomography (CT) were scheduled every 2 months in year 1 and every 4 months in year 2. Noncompliance was defined as missing 2 or more consecutive clinic visits, tumor marker measurements or chest x-rays or 1 or more CT scans. RESULTS Compliance with clinical evaluations was 61.5% in year 1 and 35.5% in year 2, whereas compliance with CT was only 25% and 11.8% in years 1 and 2, respectively. By univariate analysis diagnosis before 1990 predicted noncompliance, while age, marital status and distance from the center did not. Recurrent disease was detected in 28 patients (37%) at a median of 5.5 months after orchiectomy (range 1 to 49.5). Among the 47 compliant patients 23 had relapse and none died. Among the 29 noncompliant patients 5 had relapse and 2 died with central nervous system disease. CONCLUSIONS Overall compliance with this surveillance program was poor but this study was too small to demonstrate whether poor compliance adversely affects overall survival.


Bone Marrow Transplantation | 1999

Factors predicting engraftment of autologous blood stem cells : CD34+ subsets inferior to the total CD34+ cell dose

D A Stewart; D Guo; Joanne Luider; Iwona A. Auer; Klassen J; E Ching; Don Morris; Ahsan Chaudhry; Chris W. Brown; James A. Russell

Data were analyzed on 178 consecutive patients (median age 43 years) who underwent autologous blood stem cell transplantation (ABSCT) at a single institution to determine if CD34+subsets (CD34+38−, CD34+33−, CD34+33+, CD34+41+) or various clinical factors affect hematopoietic engraftment independent of the total CD34+ cell dose/kg. Using Cox proportional hazards models, the factors independently associated with rapid neutrophil engraftment were higher CD34+ dose/kg, use of G-CSF post-ABSCT, and conditioning regimen (single-agent melphalan ± TBI slower). Factors independently associated with rapid platelet engraftment were higher CD34+ cell dose/kg, higher ratio of CD34+33−/total CD34+ cells infused, conditioning regimen (mitoxantrone, vinblastine, cyclophosphamide faster), and no CD34+ cell selection of the autograft. The CD34+ cell selection process seemed to deplete CD34+41+ cells to a greater extent than total CD34+cells which may explain our observation that it resulted in slower platelet engraftment. In conclusion, the total CD34+ dose/kg was a better predictor of hematopoietic engraftment following ABSCT than the dose of any CD34+ subset. Platelet engraftment, however, was also influenced by the ratio of CD34+33−/total CD34+cells for unmanipulated autografts, and possibly by the CD34+41+dose for autografts manipulated by CD34+ selection. The use of CD34+ subsets requires further investigation in predicting engraftment of autografts which undergo ex vivo manipulation.


Cancer | 2015

Final report of a phase 2 clinical trial of lenalidomide monotherapy for patients with T‐cell lymphoma

Ethan Toumishey; Angeli Prasad; Greg Dueck; Neil Chua; Daygen L. Finch; James B. Johnston; Richard H. van der Jagt; D A Stewart; Darrell White; Andrew R. Belch; Tony Reiman

Patients with T‐cell lymphomas face a poorer prognosis compared with patients with B‐cell lymphomas. New therapeutic approaches need to be developed to improve outcomes for these patients.


Bone Marrow Transplantation | 2002

Possible benefits of high-dose chemotherapy and autologous stem cell transplantation for adults with recurrent medulloblastoma

Mi Zia; P Forsyth; Ahsan Chaudhry; James A. Russell; D A Stewart

In an attempt to improve the dismal prognosis of adults with recurrent medulloblastoma, six patients were treated with aggressive salvage therapy including high-dose chemotherapy (HDCT) and autologous stem cell transplantation (ASCT). At relapse, all patients underwent surgical debulking followed by HDCT/ASCT and then radiotherapy when possible. The treatment plan included two cycles of HDCT/ASCT; first with cyclophosphamide, etoposide and carboplatin (CECb) and then 2 months later with cyclophosphamide and thiotepa (CT). Three of the six patients received the planned therapy. One patient experienced severe toxicity requiring life-sustaining therapy. This patient developed multi-organ dysfunction including multiple enhancing lesions in both cerebral hemispheres that slowly resolved over several months. Two other patients did not mobilize sufficient stem cells for two ASCT procedures. They received one ASCT conditioned with cyclophosphamide, thiotepa and carboplatin (CTCb). Three of six patients had a complete response (CR); the other three had a partial response (PR). Following the first ASCT, median duration of response was 13.5 months (range 9–29 months) and median survival was 21.5 months (range 12–42 months). There was no treatment-related mortality. We conclude that HDCT/ASCT with CECb-CT or CTCb is active against recurrent medulloblastoma in adults and may be associated with prolonged remissions. Multiple enhancing cerebral lesions on brain MRI early post-HDCT/ASCT may be a consequence of the treatment rather than metastatic disease.


Autophagy | 2013

Reovirus modulates autophagy during oncolysis of multiple myeloma

Chandini M. Thirukkumaran; Zhong Qiao Shi; Joanne Luider; Karen Kopciuk; He Gao; Nizar J. Bahlis; Paola Neri; Mark Pho; D A Stewart; Adnan Mansoor; Don Morris

Multiple myeloma (MM) is a clonal plasma cell malignancy that accounts for 10–15% of newly diagnosed hematological cancers. Although significant advances have been made in the treatment of MM the disease still remains incurable. The oncolytic potential of reovirus has previously been demonstrated by others and us and is currently in phase III clinical trials for solid tumors. In addition a phase I clinical trial has recently been initiated for MM. Despite the clinical activity, the mechanism(s) of cell death caused by reovirus in MM is yet not well elucidated. A comprehensive understanding of reovirus-mediated histology-specific cell death mechanisms is imperative if this therapeutic is to become a standard of care for patients. Previously we have shown that reovirus-mediated cell death of breast and prostate cancer is orchestrated via apoptosis. The present study demonstrates for the first time that in addition to inducing apoptosis reovirus also upregulates autophagy during oncolysis of MM.


Bone Marrow Transplantation | 2000

Predictive factors for long-term engraftment of autologous blood stem cells

Peter Duggan; D Guo; Joanne Luider; Iwona A. Auer; Klassen J; Ahsan Chaudhry; Don Morris; S Glück; Christopher B. Brown; James A. Russell; D A Stewart

Data from 170 consecutive patients aged 19–66 years (median age 46 years) who underwent unmanipulated autologous blood stem cell transplant (ASCT) were analyzed to determine if total CD34+ cells/kg infused, CD34+ subsets (CD34+41+, CD34+90+, CD34+33−, CD34+38−, CD34+38−DR−), peripheral blood CD34+ cell (PBCD34+) count on first apheresis day, or various clinical factors were associated with low blood counts 6 months post ASCT. Thirty-four patients were excluded from analysis either because of death (n = 17) or re-induction chemotherapy prior to 6 months post ASCT (n = 13), or because of lack of follow-up data (n = 4). Of the remaining 136 patients, 46% had low WBC (<4 × 109/l), 41% low platelets (<150 × 109/l), and 34% low hemoglobin (<120 g/l) at a median of 6 months following ASCT. By Spearmans rank correlation, both the total CD34+ cell dose/kg and the PBCD34+ count correlated with 6 month blood counts better than any subset of CD34+ cells or any clinical factor. The PBCD34+ count was overall a stronger predictor of 6 month blood counts than was the total CD34+ cells/kg infused. Both factors retained their significance in multivariate analysis, controlling for clinical factors. In conclusion, subsets of CD34+ cells and clinical factors are inferior to the total CD34+ cell dose/kg and PBCD34+ count in predicting 6 month blood counts following ASCT. Bone Marrow Transplantation (2000) 26, 1299–1304.


Bone Marrow Transplantation | 2011

High incidence of post transplant lymphoproliferative disorder after antithymocyte globulin-based conditioning and ineffective prediction by day 28 EBV-specific T lymphocyte counts

Mette Hoegh-Petersen; D Goodyear; Michelle Geddes; S Liu; Alejandra Ugarte-Torres; Yichuan Liu; J T Walker; Kevin Fonseca; Andrew Daly; Peter Duggan; D A Stewart; James A. Russell; Jan Storek

The largest study on post-allogeneic hematopoietic cell transplant lymphoproliferative disorder (PTLD) epidemiology showed a cumulative incidence of 1.7% in patients receiving antithymocyte globulin (ATG). We had noted an apparently higher incidence in our transplant recipients whose conditioning included ATG. Therefore, we formally determined the incidence of PTLD through chart review. We also evaluated whether counts of EBV-specific T lymphocytes measured by cytokine flow cytometry could identify patients at risk of developing PTLD. Among 307 allogeneic transplant recipients, 25 (8.1%) developed PTLD. This was biopsy proven in 11 patients, and was fatal in seven patients. Patient age, EBV serostatus, donor type/match or GVHD did not influence PTLD risk significantly. Median onset of PTLD was 55 (range, 28–770) days post transplant. Day 28 EBV-specific T lymphocyte counts were not significantly different in 11 patients who developed PTLD and 31 non-PTLD patients matched for published risk factors for PTLD. In summary, when using conditioning with thymoglobulin 4.5 mg/kg, the incidence of PTLD is relatively high and cannot be predicted by day 28 cytokine flow cytometry-determined EBV-specific T lymphocyte counts. Thus, in this scenario PTLD prevention may be warranted, for example, using EBV DNAemia monitoring with preemptive therapy.

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James A. Russell

University of British Columbia

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Klassen J

Tom Baker Cancer Centre

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Chris W. Brown

National Oceanic and Atmospheric Administration

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S Glück

Tom Baker Cancer Centre

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D Guo

Tom Baker Cancer Centre

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Iwona A. Auer

Foothills Medical Centre

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