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Dive into the research topics where Sameer Parpia is active.

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Featured researches published by Sameer Parpia.


The New England Journal of Medicine | 2010

Long-Term Results of Hypofractionated Radiation Therapy for Breast Cancer

Timothy J. Whelan; Jean-Philippe Pignol; Mark N. Levine; Jim A. Julian; Robert MacKenzie; Sameer Parpia; Wendy Shelley; Laval Grimard; Julie Bowen; Francisco Perera; Anthony Fyles; Ken Schneider; Sunil P.P. Gulavita; Carolyn R. Freeman

BACKGROUND The optimal fractionation schedule for whole-breast irradiation after breast-conserving surgery is unknown. METHODS We conducted a study to determine whether a hypofractionated 3-week schedule of whole-breast irradiation is as effective as a 5-week schedule. Women with invasive breast cancer who had undergone breast-conserving surgery and in whom resection margins were clear and axillary lymph nodes were negative were randomly assigned to receive whole-breast irradiation either at a standard dose of 50.0 Gy in 25 fractions over a period of 35 days (the control group) or at a dose of 42.5 Gy in 16 fractions over a period of 22 days (the hypofractionated-radiation group). RESULTS The risk of local recurrence at 10 years was 6.7% among the 612 women assigned to standard irradiation as compared with 6.2% among the 622 women assigned to the hypofractionated regimen (absolute difference, 0.5 percentage points; 95% confidence interval [CI], -2.5 to 3.5). At 10 years, 71.3% of women in the control group as compared with 69.8% of the women in the hypofractionated-radiation group had a good or excellent cosmetic outcome (absolute difference, 1.5 percentage points; 95% CI, -6.9 to 9.8). CONCLUSIONS Ten years after treatment, accelerated, hypofractionated whole-breast irradiation was not inferior to standard radiation treatment in women who had undergone breast-conserving surgery for invasive breast cancer with clear surgical margins and negative axillary nodes. (ClinicalTrials.gov number, NCT00156052.)


Journal of Clinical Oncology | 2013

Interim Cosmetic and Toxicity Results From RAPID: A Randomized Trial of Accelerated Partial Breast Irradiation Using Three-Dimensional Conformal External Beam Radiation Therapy

Ivo A. Olivotto; Timothy J. Whelan; Sameer Parpia; Do-Hoon Kim; Tanya Berrang; Pauline T. Truong; Iwa Kong; Brandy Cochrane; Alan Nichol; Isabelle Roy; Isabelle Germain; Mohamed Akra; Melanie Reed; Anthony Fyles; Theresa Trotter; Francisco Perera; W. Beckham; Mark N. Levine; Jim A. Julian

PURPOSE To report interim cosmetic and toxicity results of a multicenter randomized trial comparing accelerated partial-breast irradiation (APBI) using three-dimensional conformal external beam radiation therapy (3D-CRT) with whole-breast irradiation (WBI). PATIENTS AND METHODS Women age > 40 years with invasive or in situ breast cancer ≤ 3 cm were randomly assigned after breast-conserving surgery to 3D-CRT APBI (38.5 Gy in 10 fractions twice daily) or WBI (42.5 Gy in 16 or 50 Gy in 25 daily fractions ± boost irradiation). The primary outcome was ipsilateral breast tumor recurrence (IBTR). Secondary outcomes were cosmesis and toxicity. Adverse cosmesis was defined as a fair or poor global cosmetic score. After a planned interim cosmetic analysis, the data, safety, and monitoring committee recommended release of results. There have been too few IBTR events to trigger an efficacy analysis. RESULTS Between 2006 and 2011, 2,135 women were randomly assigned to 3D-CRT APBI or WBI. Median follow-up was 36 months. Adverse cosmesis at 3 years was increased among those treated with APBI compared with WBI as assessed by trained nurses (29% v 17%; P < .001), by patients (26% v 18%; P = .0022), and by physicians reviewing digital photographs (35% v 17%; P < .001). Grade 3 toxicities were rare in both treatment arms (1.4% v 0%), but grade 1 and 2 toxicities were increased among those who received APBI compared with WBI (P < .001). CONCLUSION 3D-CRT APBI increased rates of adverse cosmesis and late radiation toxicity compared with standard WBI. Clinicians and patients are cautioned against the use of 3D-CRT APBI outside the context of a controlled trial.


Journal of Clinical Oncology | 2013

Randomized Trial of Decongestive Lymphatic Therapy for the Treatment of Lymphedema in Women With Breast Cancer

Ian S. Dayes; Timothy J. Whelan; Jim A. Julian; Sameer Parpia; Kathleen I. Pritchard; David D'Souza; Lyn Kligman; Donna Reise; Linda LeBlanc; Margaret L. McNeely; L. Manchul; Jennifer Wiernikowski; Mark N. Levine

PURPOSE Because of its morbidity and chronicity, arm lymphedema remains a concerning complication of breast cancer treatment. Although massage-based decongestive therapy is often recommended, randomized trials have not consistently demonstrated benefit over more conservative measures. PATIENTS AND METHODS Women previously treated for breast cancer with lymphedema were enrolled from six institutions. Volumes were calculated from circumference measurements. Patients with a minimum of 10% volume difference between their arms were randomly assigned to either compression garments (control) or daily manual lymphatic drainage and bandaging followed by compression garments (experimental). The primary outcome was percent reduction in excess arm volume from baseline to 6 weeks. RESULTS A total of 103 women were randomly assigned, and 95 were evaluable. Mean reduction of excess arm volume was 29.0% in the experimental group and 22.6% in the control group (difference, 6.4%; 95% CI, -6.8% to 20.5%; P = .34). Absolute volume loss was 250 mL and 143 mL in the experimental and control groups, respectively (difference, 107 mL; 95% CI, 13 to 203 mL; P = .03). There was no difference between groups in the proportion of patients losing 50% or greater excess arm volume. Quality of life (Short Form-36 Health Survey) and arm function were not different between groups. CONCLUSION This trial was unable to demonstrate a significant improvement in lymphedema with decongestive therapy compared with a more conservative approach. The failure to detect a difference may have been a result of the relatively small size of our trial.


Annals of Internal Medicine | 2015

D-dimer testing to select patients with a first unprovoked venous thromboembolism who can stop anticoagulant therapy: a cohort study.

Clive Kearon; Frederick A. Spencer; Denis O'Keeffe; Sameer Parpia; Sam Schulman; Trevor Baglin; Scott M. Stevens; Scott Kaatz; Kenneth A. Bauer; James D. Douketis; Steven R. Lentz; Craig M. Kessler; Stephan Moll; Jean M. Connors; Jeffrey S. Ginsberg; Luciana Spadafora; Jim A. Julian

BACKGROUND Normal D-dimer levels after withdrawal of anticoagulant therapy are associated with a reduced risk for recurrence in patients with unprovoked venous thromboembolism (VTE) and may justify stopping treatment. OBJECTIVE To determine whether patients with a first unprovoked VTE and negative D-dimer test result who stop anticoagulant therapy have a low risk for recurrence. DESIGN Prospective management study with blinded outcome assessment. (ClinicalTrials.gov: NCT00720915). SETTING 13 university-affiliated clinical centers. PATIENTS 410 adults aged 75 years or younger with a first unprovoked proximal deep venous thrombosis or pulmonary embolism who had completed 3 to 7 months of anticoagulant therapy. INTERVENTION Anticoagulant therapy was stopped if D-dimer test results were negative and was not restarted if results were still negative after 1 month. MEASUREMENTS Recurrent VTE during an average follow-up of 2.2 years. RESULTS In 319 patients (78%) who had 2 negative D-dimer results and did not restart anticoagulant therapy, rates of recurrent VTE were 6.7% (95% CI, 4.8% to 9.0%) per patient-year overall (42 of 319), 9.7% (CI, 6.7% to 13.7%) per patient-year in men (33 of 180), 5.4% (CI, 2.5% to 10.2%) per patient-year in women with VTE not associated with estrogen therapy (9 of 81), and 0.0% (CI, 0.0% to 3.0%) per patient-year in women with VTE associated with estrogen therapy (0 of 58) (P = 0.001 for the 3-group comparison). LIMITATIONS Imprecision in female subgroups. Results may not be generalizable to different D-dimer assays from the one used in the study. CONCLUSION The risk for recurrence in patients with a first unprovoked VTE who have negative D-dimer results is not low enough to justify stopping anticoagulant therapy in men but may be low enough to justify stopping therapy in women. PRIMARY FUNDING SOURCE Canadian Institutes of Health Research.


Annals of Internal Medicine | 2013

Selective d-Dimer Testing for Diagnosis of a First Suspected Episode of Deep Venous Thrombosis: A Randomized Trial

Lori-Ann Linkins; Shannon M. Bates; Eddy Lang; Susan R. Kahn; James D. Douketis; Jim A. Julian; Sameer Parpia; Peter Gross; Jeffrey I. Weitz; Frederick A. Spencer; Agnes Y.Y. Lee; Martin O'Donnell; Mark Crowther; Howard H.W. Chan; Wendy Lim; Sam Schulman; Jeffrey S. Ginsberg; Clive Kearon

BACKGROUND D-Dimer testing is sensitive but not specific for diagnosing deep venous thrombosis (DVT). Changing the use of testing and the threshold level for a positive test result on the basis of risk for DVT might improve the tradeoff between sensitivity and specificity and reduce the need for testing. OBJECTIVE To determine whether using a selective D-dimer testing strategy based on clinical pretest probability (C-PTP) for DVT is safe and reduces diagnostic testing compared with using a single D-dimer threshold for all patients. DESIGN Randomized, multicenter, controlled trial. Patients were allocated using a central automated system. Ultrasonographers and study adjudicators but not other study personnel were blinded to trial allocation. (ClinicalTrials.gov: NCT00157677) SETTING 5 Canadian hospitals. PATIENTS Consecutive symptomatic patients with a first episode of suspected DVT. INTERVENTION Selective testing (n = 860), defined as D-dimer testing for outpatients with low or moderate C-PTP (DVT excluded at D-dimer levels <1.0 µg/mL [low C-PTP] or <0.5 µg/mL [moderate C-PTP]) and venous ultrasonography without D-dimer testing for outpatients with high C-PTP and inpatients, or uniform testing (n = 863), defined as D-dimer testing for all participants (DVT excluded at D-dimer levels <0.5 µg/mL). MEASUREMENTS The proportion of patients not diagnosed with DVT during initial testing who had symptomatic venous thromboembolism during 3-month follow-up and the proportion of patients undergoing D-dimer testing and ultrasonography. RESULTS The incidence of symptomatic venous thromboembolism at 3 months was 0.5% in both study groups (difference, 0.0 percentage point [95% CI, -0.8 to 0.8 percentage points]). Selective testing reduced the proportion of patients who required D-dimer testing by 21.8 percentage points (CI, 19.1 to 24.8 percentage points). It reduced the proportion who required ultrasonography by 7.6 percentage points (CI, 2.9 to 12.2 percentage points) overall and by 21.0 percentage points (CI, 14.2 to 27.6 percentage points) in outpatients with low C-PTP. LIMITATION Results may not be generalizable to all D-dimer assays or patients with previous DVT, study personnel were not blinded, and the trial was stopped prematurely. CONCLUSION A selective D-dimer testing strategy seems as safe as and more efficient than having everyone undergo D-dimer testing when diagnosing a first episode of suspected DVT. PRIMARY FUNDING SOURCE Heart and Stroke Foundation of Ontario.


Annals of Oncology | 2014

Tumor factors predictive of response to hypofractionated radiotherapy in a randomized trial following breast conserving therapy

A. L. Bane; Timothy J. Whelan; Gregory R. Pond; Sameer Parpia; G. Gohla; Anthony Fyles; J.-P. Pignol; K. I. Pritchard; S. Chambers; Mark N. Levine

PURPOSE To determine whether tumor grade, molecular subtype and hypoxia predict response to hypofractionated versus standard radiotherapy (RT) following breast-conserving surgery (BCS) for node-negative breast cancer in a randomized controlled trial (RCT). PATIENTS AND METHODS Formalin-fixed paraffin-embedded (FFPE) tumor blocks were available on 989 of 1234 patients enrolled in the Hypofractionation Whole Breast Irradiation (HWBI) Trial. A central pathology review and assessment of tumor grade using the Nottingham grading system was carried out. Tumors were classified by molecular subtype as luminal A, luminal B, HER2 enriched, basal-like or unclassified using a six-biomarker panel; ER, PR, HER-2, Ki67, CK5/6 and EGFR. Tumors were also classified as hypoxic based on the expression of HIF1α, CAIX or GLUT-1. The primary end point was local recurrence (LR). RESULTS Median follow-up was 12 years. In the multivariable Cox model, molecular subtype was the only factor predictive of LR, the 10-year cumulative incidence was 4.5% for luminal A and basal-like, 7.9% for luminal B and 16.9% for HER-2 enriched tumors (P < 0.01). Tumor grade, molecular subtype or hypoxia did not predict response to hypofractionation. CONCLUSIONS In women enrolled in the HWBI trial following BCS tumor molecular subtype predicted LR. However tumor grade, molecular subtype and hypoxia did not predict response to hypofractionation suggesting that patients with node-negative breast tumors of all grades and molecular subtypes may be safely treated with hypofractionated RT regimens.


Contemporary Clinical Trials | 2014

Improvement in the quality of abstracts in major clinical journals since CONSORT extension for abstracts: A systematic review

Lawrence Mbuagbaw; Michael Thabane; Thuva Vanniyasingam; Victoria Borg Debono; Sarah Daisy Kosa; Shiyuan Zhang; Chenglin Ye; Sameer Parpia; Brittany B. Dennis; Lehana Thabane

BACKGROUND We sought to determine if the publication of the Consolidated Standards of Reporting Trials (CONSORT)(1) extension for abstracts in 2008 had led to an improvement in reporting abstracts of randomized controlled trials (RCTs).(2) METHODS: We searched PubMed for RCTs published in 2007 and 2012 in top-tier general medicine journals. A random selection of 100 trial abstracts was obtained for each year. Data were extracted in duplicate on the adherence to the CONSORT extension for abstracts. The primary outcome was the mean number of items reported and the secondary outcome was the odds of reporting each item. We also estimated incidence rate ratios (IRRs).(3) RESULTS: Significantly more checklist items were reported in 2012 than in 2007: adjusted mean difference was 2.91 (95% confidence interval [CI](4) 2.35, 3.41; p<0.001). In 2012 there were significant improvements in reporting the study as randomized in the title, describing the trial design, the participants, and objectives and blinding. In the Results section, trial status and numbers analyzed were also reported better. The IRRs were significantly higher for 2012 (IRR 1.32; 95% CI 1.25, 1.39; p<0.001) and in multisite studies compared to single site studies (IRR 1.08; 95% CI 1.03, 1.15; p=0.006). CONCLUSIONS There was a significant improvement in the reporting of abstracts of RCTs in 2012 compared to 2007. However, there is still room for improvement as some items remain under-reported.


British Journal of Sports Medicine | 2016

The prevalence and significance of a short QT interval in 18 825 low-risk individuals including athletes

Harshil Dhutia; Aneil Malhotra; Sameer Parpia; Vincent Gabus; Gherardo Finocchiaro; Greg Mellor; Ahmed Merghani; Lynne Millar; Rajay Narain; Nabeel Sheikh; Elijah R. Behr; Michael Papadakis; Sanjay Sharma

Objectives The short QT syndrome is a cardiac channelopathy characterised by accelerated repolarisation which manifests as a short QT interval on the ECG. The definition of a short QT interval is debated, ranging from <390 to ≤320 ms, and its clinical significance in healthy young individuals is unknown. We assessed the prevalence and medium-term significance of an isolated short QT interval in a diverse young British population. Methods Between 2005 and 2013, 18 825 apparently healthy people aged 14–35 years underwent cardiovascular evaluation with history, physical examination and ECG. QT intervals were measured by cardiologists using 4 recommended guidelines (Seattle 2013, Heart Rhythm Society 2013, European Society of Cardiology 2010 and American Heart Association 2009). Results The prevalence of a short QT interval was 0.1% (26 patients, ≤320 ms), 0.2% (44 patients, ≤330 ms), 7.9% (1478 patients, <380 ms), 15.8% (2973 patients, <390 ms). Male gender and Afro-Caribbean ethnicity had the strongest association with short QT intervals. Athletes had shorter QT intervals than non-athletes but athletic status did not predict short QT intervals. Individuals with short QT intervals ≤320 ms did not report syncope or a sinister family history, and during a follow-up period of 5.3±1.2 years, there were no deaths in this group. Conclusions The prevalence of a short QT interval depends on the recommended cut-off value. Even at values ≤320 ms, there was an excellent medium-term prognosis among 14 people followed. We conclude that a definition of ≤320 ms is realistic to prevent overdiagnosis and excessive investigations.


Contemporary Clinical Trials | 2011

Competing events in patients with malignant disease who are at risk for recurrent venous thromboembolism

Sameer Parpia; Jim A. Julian; Lehana Thabane; Agnes Y.Y. Lee; Frederick R. Rickles; Mark N. Levine

Patients with malignant disease enrolled in trials of thrombotic disorders may experience competing events such as death. The occurrence of a competing event may prevent the thrombotic event from being observed. Standard survival analysis techniques ignore competing risks, resulting in possible bias and distorted inferences. To assess the impact of competing events on the results of a previously reported trial comparing low molecular weight heparin (LMWH) with oral anticoagulant (OAC) therapy for the prevention of recurrent venous thromboembolism (VTE) in patients with advanced cancer, we compare the results from standard survival analysis with those from competing risk techniques which are based on the cumulative incidence function (CIF) and Grays test. The Kaplan-Meier method overestimates the risk of recurrent VTE (17.2% in the OAC group and 8.7% in the LMWH group). Risk of recurrence using the CIF is 12.0% and 6.0% in the OAC and LMWH groups, respectively. Both the log-rank test (p=0.002) and Grays test (p=0.006) suggest evidence in favor of LMWH. The overestimation of risk is 30% in each treatment group, resulting in a similar relative treatment effect; using the Cox model the hazard ratio (HR) is 0.48 (95% confidence interval [CI], 0.30 to 0.78) and HR=0.47 (95% CI, 0.29 to 0.74) using the CIF model. Failing to account for competing risks may lead to incorrect interpretations of the probability of recurrent VTE. However, when the distribution of competing risks is similar within each treatment group, standard and competing risk methods yield comparable relative treatment effects.


Vascular Medicine | 2016

Endovascular therapy for advanced post-thrombotic syndrome: Proceedings from a multidisciplinary consensus panel.

Suresh Vedantham; Susan R. Kahn; Samuel Z. Goldhaber; Anthony J. Comerota; Sameer Parpia; Sreelatha Meleth; Diane Earp; Rick L. Williams; Akhilesh K. Sista; William A. Marston; Suman Rathbun; Elizabeth A. Magnuson; Mahmood K. Razavi; Michael R. Jaff; Clive Kearon

Patients with advanced post-thrombotic syndrome (PTS) and chronic iliac vein obstruction suffer major physical limitations and impairment of health-related quality of life. Currently there is a lack of evidence-based treatment options for these patients. Early studies suggest that imaging-guided, catheter-based endovascular therapy can eliminate iliac vein obstruction and saphenous venous valvular reflux, resulting in reduced PTS severity; however, these observations have not been rigorously validated. A multidisciplinary expert panel meeting was convened to plan a multicenter randomized controlled clinical trial to evaluate endovascular therapy for the treatment of advanced PTS. This article summarizes the findings of the panel, and is expected to assist in developing a National Institutes of Health-sponsored clinical trial and other studies to improve the care of patients with advanced PTS.

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Agnes Y.Y. Lee

University of British Columbia

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