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Featured researches published by Clement Ma.


Journal of Clinical Oncology | 2011

Comparison of Health-Related Quality of Life 5 Years After SPIRIT: Surgical Prostatectomy Versus Interstitial Radiation Intervention Trial

Juanita Crook; A. Gomez-Iturriaga; Kris Wallace; Clement Ma; Sharon Fung; Shabbir M.H. Alibhai; Michael A.S. Jewett; Neil Fleshner

PURPOSE The American College of Surgeons Oncology Group phase III Surgical Prostatectomy Versus Interstitial Radiation Intervention Trial comparing radical prostatectomy (RP) and brachytherapy (BT) closed after 2 years due to poor accrual. We report health-related quality of life (HRQOL) at a mean of 5.3 years for 168 trial-eligible men who either chose or were randomly assigned to RP or BT following a multidisciplinary educational session. PATIENTS AND METHODS After initial lack of accrual, a multidisciplinary educational session was introduced for eligible patients. In all, 263 men attended 47 sessions. Of those, 34 consented to random assignment, 62 chose RP, and 94 chose BT. Five years later, these 190 men underwent HRQOL evaluation by using the cancer-specific 50-item Expanded Prostate Cancer Index Composite, the Short Form 12 Physical Component Score, and Short Form 12 Mental Component Score. Response rate was 88.4%. The Wilcoxon rank sum test was used to compare summary scores between the two interventions. RESULTS Of 168 survey responders, 60.7% had BT (9.5% randomly assigned) and 39.3% had RP (9.5% randomly assigned). Median age was 61.4 years for BT and 59.4 for RP (P = .05). Median follow-up was 5.2 years (range, 3.2 to 6.5 years). For BT versus RP, there was no difference in bowel or hormonal domains, but men treated with BT scored better in urinary (91.8 v 88.1; P = .02) and sexual (52.5 v 39.2; P = .001) domains, and in patient satisfaction (93.6 v 76.9; P < .001). CONCLUSION Although treatment allocation was random in only 19%, all patients received identical information in a multidisciplinary setting before selecting RP, BT, or random assignment. HRQOL evaluated 3.2 to 6.5 years after treatment showed an advantage for BT in urinary and sexual domains and in patient satisfaction.


International Journal of Radiation Oncology Biology Physics | 2011

10-year experience with I-125 prostate brachytherapy at the Princess Margaret Hospital: results for 1,100 patients.

Juanita Crook; Jette Borg; Andrew Evans; Ants Toi; Elantholi P. Saibishkumar; Sharon Fung; Clement Ma

PURPOSE To report outcomes for 1,111 men treated with iodine-125 brachytherapy (BT) at a single institution. METHODS AND MATERIALS A total of 1,111 men (median age, 63) were treated with iodine-125 prostate BT for low- or intermediate-risk prostate cancer between March 1999 and November 2008. Median prostate-specific antigen (PSA) level was 5.4 ng/ml (range, 0.9-26.1). T stage was T1c in 66% and T2 in 34% of patients. Gleason score was 6 in 90.1% and 7 or 8 in 9.9% of patients. Neoadjuvant hormonal therapy (2-6 months course) was used in 10.1% of patients and combined external radiotherapy (45 Gy) with BT (110 Gy) in 4.1% (n = 46) of patients. Univariate and multivariate Cox proportional hazards were used to determine predictors of failure. RESULTS Median follow-up was 42 months (range, 6-114), but for biochemical freedom from relapse, a minimum PSA test follow-up of 30 months was required (median 54; n = 776). There were 27 failures, yielding an actuarial 7-year disease-free survival rate of 95.2% (96 at risk beyond 84 months). All failures underwent repeat 12-core transrectal ultrasound -guided biopsies, confirming 8 local failures. On multivariate analysis, Gleason score was the only independent predictor of failure (p = 0.001; hazard ratio, 4.8 (1.9-12.4). Median International Prostate Symptom score from 12 to 108 months ranged between 3 and 9. Of the men reporting baseline potency, 82.8% retained satisfactory erectile function beyond 5 years. CONCLUSION Iodine-125 prostate BT is a highly effective treatment option for favorable- and intermediate-risk prostate cancer and is associated with maintenance of good urinary and erectile functions.


Journal of Clinical Oncology | 2010

Soluble Mesothelin-Related Peptide and Osteopontin As Markers of Response in Malignant Mesothelioma

Paul Wheatley-Price; Boming Yang; Demetris Patsios; Devalben Patel; Clement Ma; Wei Xu; Natasha B. Leighl; Ronald Feld; B.C. John Cho; Brenda O'Sullivan; Heidi C. Roberts; Ming-Sound Tsao; Martin C. Tammemagi; Masaki Anraku; Zhuo Chen; Marc de Perrot; Geoffrey Liu

PURPOSE In malignant mesothelioma (MM), radiologic assessment of disease status is difficult. Both soluble mesothelin-related peptide (SMRP) and osteopontin (OP) have utility in distinguishing MM from benign pleural disease. We evaluated whether SMRP and OP also correlated with the disease course of MM. PATIENTS AND METHODS Serial plasma samples from patients with MM were prospectively collected, and SMRP and OP levels were measured. Radiologic tests across time periods showing disease progression, stability, or shrinkage were compared with corresponding changes in SMRP/OP levels. RESULTS From 41 patients, 165 samples were collected (range, 2 to 10; median 4). At study entry, 37 of 41 patients had measurable disease, of whom 92% (34 of 37) had elevated baseline SMRP levels; four of 41 patients had no evidence of recurrence and each had normal baseline SMRP levels. In 21 patients receiving systemic therapy, percentage change in SMRP more than 10% correlated with the radiologic assessment by a trained thoracic radiologist (P < .001), by formal Response Evaluation Criteria in Solid Tumors (RECIST; P = .008), or by modified RECIST (P < .001). All seven patients who underwent surgical resection with negative margins had elevated preoperative SMRP levels that fell to normal postoperatively. Rising SMRP was observed in all patients with radiologic disease progression. No associations were found with OP. CONCLUSION Percentage changes in SMRP levels, but not changes in OP levels, are a potentially useful marker of disease course. These findings should be validated prospectively for a role as an objective adjunctive measure of disease course in both clinical trials and clinical practice.


Journal of Clinical Oncology | 2009

Phase II Study of Preoperative Gefitinib in Clinical Stage I Non–Small-Cell Lung Cancer

Humberto Lara-Guerra; Thomas K. Waddell; Maria A. Salvarrey; Anthony M. Joshua; Catherine T. Chung; Narinder Paul; Scott L. Boerner; Akira Sakurada; Olga Ludkovski; Clement Ma; Jeremy A. Squire; Geoffrey Liu; Frances A. Shepherd; Ming-Sound Tsao; Natasha B. Leighl

PURPOSE Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have proven efficacy in advanced non-small-cell lung cancer (NSCLC). Their role in early-stage NSCLC has not been established. Our purpose was to explore the use of preoperative gefitinib in clinical stage I NSCLC to assess tumor response, toxicity, and clinical and molecular predictors of response. PATIENTS AND METHODS Patients received gefitinib 250 mg/d for up to 28 days, followed by mediastinoscopy and surgical resection in an open-label, single-arm study. Tumor response was evaluated by Response Evaluation Criteria in Solid Tumors. Blood samples and tumor biopsies were collected and analyzed for transforming growth factor alpha level, EGFR protein expression, EGFR gene copy number, and EGFR (exon 19 to 21) and KRAS mutations. RESULTS Thirty-six patients completed preoperative treatment (median duration, 28 days; range, 27 to 30 days). Median follow-up time is 2.1 years (range, 0.86 to 3.46 years). Three patients experienced grade 3 toxicities (rash, diarrhea, and elevated ALT). Tumors demonstrated EGFR-positive protein expression in 83%, high gene copy number in 59%, EGFR mutations in 17%, and KRAS mutations in 17%. Tumor shrinkage was more frequent among women and nonsmokers. Partial response was seen in four patients (11%), and disease progression was seen in three patients (9%). The strongest predictor of response was EGFR mutation. CONCLUSION Preoperative window therapy with gefitinib is a safe and feasible regimen in early NSCLC and provides a trial design that may better inform predictors of treatment response or sensitivity.


Pharmacogenetics and Genomics | 2009

Cisplatin pharmacogenetics, DNA repair polymorphisms, and esophageal cancer outcomes

Penelope Ann Bradbury; Matthew H. Kulke; Rebecca S. Heist; Wei Zhou; Clement Ma; Wei Xu; Ariela L. Marshall; Rihong Zhai; Susanne M. Hooshmand; Kofi Asomaning; Li Su; Frances A. Shepherd; Thomas J. Lynch; John Wain; David C. Christiani; Geoffrey Liu

Objectives Genetic variations or polymorphisms within genes of the nucleotide excision repair (NER) pathway alter DNA repair capacity. Reduced DNA repair (NER) capacity may result in tumors that are more susceptible to cisplatin chemotherapy, which functions by causing DNA damage. We investigated the potential predictive significance of functional NER single nucleotide polymorphisms in esophageal cancer patients treated with (n = 262) or without (n = 108) cisplatin. Methods Four NER polymorphisms XPD Asp312Asn; XPD Lys751Gln, ERCC1 8092C/A, and ERCC1 codon 118C/T were each assessed in polymorphism–cisplatin treatment interactions for overall survival (OS), with progression-free survival (PFS) as a secondary endpoint. Results No associations with ERCC1 118 were found. Polymorphism–cisplatin interactions were highly significant in both OS (P = 0.002, P = 0.0001, and P<0.0001) and PFS (P = 0.006, P = 0.008, and P = 0.0007) for XPD 312, XPD 751, and ERCC1 8092, respectively. In cisplatin-treated patients, variant alleles of XPD 312, XPD 751, and ERCC1 8092 were each associated with significantly improved OS (and PFS): adjusted hazard ratios of homozygous variants versus wild-type ranged from 0.22 [95% confidence interval (CI): 0.1–0.5] to 0.31 (95% CI: 0.1–0.7). In contrast, in patients who did not receive cisplatin, variant alleles of XPD 751 and ERCC1 8092 had significantly worse survival, with adjusted hazard ratios of homozygous variants ranging from 2.47 (95% CI: 1.1–5.5) to 3.73 (95% CI: 1.6–8.7). Haplotype analyses affirmed these results. Conclusion DNA repair polymorphisms are associated with OS and PFS, and if validated may predict for benefit from cisplatin therapy in patients with esophageal cancer.


European Urology | 2011

Non–Risk-Adapted Surveillance in Clinical Stage I Nonseminomatous Germ Cell Tumors: The Princess Margaret Hospital’s Experience

Jeremy Sturgeon; Malcolm J. Moore; D. Kakiashvili; Ignacio Duran; Lynn Anson-Cartwright; Dominik R. Berthold; Padraig Warde; Mary K. Gospodarowicz; Ruth E. Alison; Justin Liu; Clement Ma; Greg Pond; Michael A.S. Jewett

BACKGROUND Since 1981 Princess Margaret Hospital has used initial active surveillance (AS) with delayed treatment at relapse as the preferred management for all patients with clinical stage I nonseminomatous germ cell tumors (NSGCT). OBJECTIVE Our aim was to report our overall AS experience and compare outcomes over different periods using this non-risk-adapted approach. DESIGN, SETTING, AND PARTICIPANTS Three hundred and seventy-one patients with stage I NSGCT were managed by AS from 1981 to 2005. For analysis by time period, patients were divided into two cohorts by diagnosis date: initial cohort, 1981-1992 (n=157), and recent cohort, 1993-2005 (n=214). INTERVENTION Patients were followed at regular intervals, and treatment was only given for relapse. MEASUREMENTS Recurrence rates, time to relapse, risk factors for recurrence, disease-specific survival, and overall survival were determined. RESULTS AND LIMITATIONS With a median follow-up of 6.3 yr, 104 patients (28%) relapsed: 53 of 157 (33.8%) in the initial group and 51 of 214 (23.8%) in the recent group. Median time to relapse was 7 mo. Lymphovascular invasion (p<0.0001) and pure embryonal carcinoma (p=0.02) were independent predictors of recurrence; 125 patients (33.7%) were designated as high risk based on the presence of one or both factors. In the initial cohort, 66 of 157 patients (42.0%) were high risk and 36 of 66 patients (54.5%) relapsed versus 17 of 91 low-risk patients (18.7%) (p<0.0001). In the recent cohort, 59 of 214 patients (27.6%) were high risk and 29 of 59 had a recurrence (49.2%) versus 22 of 155 low-risk patients (14.2%) (p<0.0001). Three patients (0.8%) died from testis cancer. The estimated 5-yr disease-specific survival was 99.3% in the initial group and 98.9% in the recent one. CONCLUSIONS Non-risk-adapted surveillance is an effective, simple strategy for the management of all stage I NSGCT.


Genetic Epidemiology | 2013

Recommended joint and meta-analysis strategies for case-control association testing of single low-count variants.

Clement Ma; Thomas W. Blackwell; Michael Boehnke; Laura J. Scott

In genome‐wide association studies of binary traits, investigators typically use logistic regression to test common variants for disease association within studies, and combine association results across studies using meta‐analysis. For common variants, logistic regression tests are well calibrated, and meta‐analysis of study‐specific association results is only slightly less powerful than joint analysis of the combined individual‐level data. In recent sequencing and dense chip based association studies, investigators increasingly test low‐frequency variants for disease association. In this paper, we seek to (1) identify the association test with maximal power among tests with well controlled type I error rate and (2) compare the relative power of joint and meta‐analysis tests. We use analytic calculation and simulation to compare the empirical type I error rate and power of four logistic regression based tests: Wald, score, likelihood ratio, and Firth bias‐corrected. We demonstrate for low‐count variants (roughly minor allele count [MAC] < 400) that: (1) for joint analysis, the Firth test has the best combination of type I error and power; (2) for meta‐analysis of balanced studies (equal numbers of cases and controls), the score test is best, but is less powerful than Firth test based joint analysis; and (3) for meta‐analysis of sufficiently unbalanced studies, all four tests can be anti‐conservative, particularly the score test. We also establish MAC as the key parameter determining test calibration for joint and meta‐analysis.


Head and Neck-journal for The Sciences and Specialties of The Head and Neck | 2009

NODAL RATIO AS AN INDEPENDENT PREDICTOR OF SURVIVAL IN SQUAMOUS CELL CARCINOMA OF THE ORAL CAVITY

Mark G. Shrime; Gideon Bachar; Jane Lea; Cheryl Volling; Clement Ma; Patrick J. Gullane; Ralph W. Gilbert; Jonathan C. Irish; Dale H. Brown; David P. Goldstein

The association between nodal ratio and survival in oral cavity carcinomas has recently been proposed, but no prospective evaluations exist.


Clinical Cancer Research | 2009

Vascular Endothelial Growth Factor Polymorphisms and Esophageal Cancer Prognosis

Penelope Ann Bradbury; Rihong Zhai; Clement Ma; Wei Xu; Jessica Hopkins; Matthew J. Kulke; Kofi Asomaning; Zhaoxi Wang; Li Su; Rebecca S. Heist; Thomas J. Lynch; John Wain; David C. Christiani; Geoffrey Liu

Purpose: Vascular endothelial growth factor (VEGF) promotes angiogenesis and vascular permeability. The VEGF gene is polymorphic. We investigated the prognostic significance of three VEGF single nucleotide polymorphisms (SNP) in esophageal cancer. Experimental Design: Three hundred sixty-one patients were genotyped for three VEGF SNPs (−460T/C, 405G/C, and 936C/T) using DNA extracted from prospectively collected blood samples. The association of each individual SNP, and haplotypes of the three SNPs, on overall survival (OS) was investigated. Results: The variant allele of 936C/T was associated with improved OS compared with the wild-type genotype (log-rank P < 0.001). This association remained significant for OS after adjustments for age, gender, performance status, and disease stage [VEGF 936C/T: adjusted hazard ratio (AHR), 0.70; 95% confidence interval (95% CI), 0.49-0.99; P = 0.04; VEGF 936T/T: AHR, 0.11; 95% CI, 0.02-0.82; P = 0.03]. No independent associations were found for VEGF −460T/C and VEGF 405G/C. The CGC haplotype of the three VEGF SNPs (−460T/C, 405G/C, and 936C/T) combined was associated with reduced OS compared with all other patients (CGC/CGC: AHR, 1.51; 95% CI, 1.00-2.30; P = 0.05). Conclusions:VEGF 936C/T, and a haplotype of 460T/C, 405G/C, and 936C/T combined, has potential prognostic significance in esophageal cancer.


Cancer Epidemiology, Biomarkers & Prevention | 2008

Genetic Polymorphisms and Head and Neck Cancer Outcomes: A Review

Jessica Hopkins; David W. Cescon; Darren Tse; Penelope Ann Bradbury; Wei Xu; Clement Ma; Paul Wheatley-Price; John Waldron; David Goldstein; François Meyer; Isabelle Bairati; Geoffrey Liu

Head and neck cancer (HNC) patients have variable prognoses even within the same clinical stage and while receiving similar treatments. The number of studies of genetic polymorphisms as prognostic factors of HNC outcomes is growing. Candidate polymorphisms have been evaluated in DNA repair, cell cycle, xenobiotic metabolism, and growth factor pathways. Polymorphisms of XRCC1, FGFR, and CCND1 have been consistently associated with HNC survival in at least two studies, whereas most of the other polymorphisms have either conflicting data or were from single studies. Heterogeneity and lack of description of patient populations and lack of accounting for multiple comparisons were common problems in a significant proportion of studies. Despite a large number of exploratory studies, large replication studies in well-characterized HNC populations are warranted. (Cancer Epidemiol Biomarkers Prev 2008;17(3):490–9)

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Geoffrey Liu

Princess Margaret Cancer Centre

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Juanita Crook

University of British Columbia

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Wei Xu

Nanjing Normal University

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Jette Borg

University Health Network

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Li Su

Harvard University

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