Harvey Quon

University of Manitoba, Winnipeg, Manitoba, Canada

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Publications (8)21.78 Total impact

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    ABSTRACT: Introduction To examine the impact of published randomized controlled trial (RCT) data on referrals for adjuvant radiotherapy (RT) in patients who had high-risk pathologic features after radical prostatectomy (RP). Methods In this population-based, retrospective Canadian study, all patients who received a diagnosis of prostate adenocarcinoma and underwent RP from 2003-2008 were identified through the Manitoba Cancer Registry. Manual review of pathology reports was performed, and patients who had high-risk pathologic features of extracapsular extension, seminal vesicle invasion, or positive surgical margins were included. Referrals for adjuvant RT were examined before and after publication of RCT data to determine their influence on practice. Multivariable logistic regression was used to identify factors related to referral. Results Of the 1080 identified patients, 546 (50.6%) had ≥ 1 high-risk pathologic feature. Only 78 (14.3%) of the 546 patients were referred for adjuvant RT within 6 months of RP. Year of diagnosis, in relation to the publication of the RCT, was not significantly associated with referral (P = .60). Higher pT stage (P < .0001), Gleason score (P = .035), and increased distance from cancer center (P = .004) were associated with referral. Conclusion In patients who had high-risk pathologic features after RP, referral rates for adjuvant RT were low and did not increase after presentation of RCT. Men who had higher pT stage, Gleason score, and rural residence were more likely to be referred.
    Clinical Genitourinary Cancer 01/2014; 12(1):e1–e5. · 1.43 Impact Factor
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    ABSTRACT: BACKGROUND AND PURPOSE: Biological dose escalation through stereotactic ablative radiotherapy (SABR) holds promise of improved patient convenience, system capacity and tumor control with decreased cost and side effects. The objectives are to report the toxicities, biochemical and pathologic outcomes of this prospective study. MATERIALS AND METHODS: A phase I/II study was performed where low risk localized prostate cancer received SABR 35Gy in 5 fractions, once weekly on standard linear accelerators. Common Terminology Criteria for Adverse Events v3.0 and Radiation Therapy Oncology Group late morbidity scores were used to assess acute and late toxicities, respectively. Biochemical control (BC) was defined by the Phoenix definition. RESULTS: As of May 2012, 84 patients have completed treatment with a median follow-up of 55months (range 13-68months). Median age was 67years and median PSA was 5.3ng/ml. The following toxicities were observed: acute grade 3+: 0% gastrointestinal (GI), 1% genitourinary (GU), 0% fatigue; late grade 3+: 1% GI, 1% GU. Ninety-six percent were biopsy negative post-treatment. The 5-year BC was 98%. CONCLUSIONS: This novel technique employing standard linear accelerators to deliver an extreme hypofractionated schedule of radiotherapy is feasible, well tolerated and shows excellent pathologic and biochemical control.
    Radiotherapy and Oncology 05/2013; · 4.52 Impact Factor
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    ABSTRACT: To estimate the out-of-pocket costs for patients undergoing external beam radiotherapy (EBRT) for prostate cancer and calculate the patient-related savings of being treated with a 5-fraction versus a standard 39-fraction approach. Seventy patients accrued to the pHART3 (n = 84) study were analyzed for out-of-pocket patient costs as a result of undergoing treatment. All costs are in Canadian dollars. Using the postal code of the patient's residence, the distance between the hospital and patient home was found using Google Maps. The Canada Revenue Agency automobile allowance rate was then applied to determine the cost per kilometer driven. The average cost of travel from the hospital and pHART3 patient's residence was $246 per person after five trips. In a standard fractionation regimen, pHART3 patients would have incurred an average cost of $1921 after 39 visits. The patients receiving hypofractionated radiotherapy would have paid an average of $38 in parking while those receiving conventional treatment would have paid $293. The difference in out-of-pocket costs for the patients receiving a standard versus hypofractionated treatment was $1930. Medium term prospective data shows that hypofractionated radiotherapy is an effective treatment method for localized prostate cancer. Compared to standard EBRT, hypofractionated radiotherapy requires significantly fewer visits. Due to the long distance patients may have to travel to the cancer center and the expense of parking, the short course treatment saves each patient an average of $1900. A randomized study of standard versus hypofractionated accelerated radiotherapy should be conducted to confirm a favorable efficacy and tolerability profile of the shorter fractionation scheme.
    The Canadian Journal of Urology 04/2012; 19(2):6165-9. · 0.74 Impact Factor
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    ABSTRACT: To determine intra-fraction displacement of the prostate during extreme hypofractionated radiotherapy using pre- and post-treatment orthogonal images with three implanted gold seed fiducial markers. In total, 265 image pairs were obtained from 53 patients who underwent extreme hypofractionated radiotherapy to a dose of 35 Gy in five fractions on standard linear accelerators. Position verification was obtained with orthogonal X-rays before and after treatment and were used to determine intra-fraction prostate displacement. The mean intra-fraction prostate displacements were -0.03 ± 0.61 mm (one standard deviation), 0.21 ± 1.50 mm and -0.86 ± 1.73 mm in the left-right, superior-inferior and anterior-posterior directions, respectively. The mean intra-fraction displacement during the first two fractions was moderately correlated with the displacement in the remaining three fractions, with correlation coefficients of 0.63 (95% confidence interval 0.43-0.77) and 0.47 (95% confidence interval 0.22-0.65) in the superior-inferior and anterior-posterior directions, respectively. There was no significant correlation in the left-right direction with a coefficient of -0.04 (95% confidence interval -0.31-0.23). The mean intra-fraction prostate displacement during a course of extreme hypofractionated radiotherapy is small. A strategy using the first two fractions to predict future displacements >5 mm warrants further validation.
    Clinical Oncology 01/2012; 24(9):640-5. · 2.86 Impact Factor
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    ABSTRACT: To evaluate the change in health-related quality of life (QOL) of patients with high-risk prostate cancer treated using hypofractionated radiotherapy combined with long-term androgen deprivation therapy. A prospective Phase I-II study enrolled patients with any of the following: clinical Stage T3 disease, prostate-specific antigen level ≥20 ng/mL, or Gleason score 8-10. Radiotherapy consisted of 45 Gy (1.8 Gy per fraction) to the pelvic lymph nodes with a concomitant 22.5 Gy intensity-modulated radiotherapy boost to the prostate, for a total of 67.5 Gy (2.7 Gy per fraction) in 25 fractions over 5 weeks. Daily image guidance was performed using three gold seed fiducials. Quality of life was measured using the Expanded Prostate Cancer Index Composite (EPIC), a validated tool that assesses four primary domains (urinary, bowel, sexual, and hormonal). From 2004 to 2007, 97 patients were treated. Median follow-up was 39 months. Compared with baseline, at 24 months there was no statistically significant change in the mean urinary domain score (p = 0.99), whereas there were decreases in the bowel (p < 0.01), sexual (p < 0.01), and hormonal (p < 0.01) domains. The proportion of patients reporting a clinically significant difference in EPIC urinary, bowel, sexual, and hormonal scores at 24 months was 27%, 31%, 55%, and 60%, respectively. However, moderate and severe distress related to these symptoms was minimal, with increases of only 3% and 5% in the urinary and bowel domains, respectively. Hypofractionated radiotherapy combined with long-term androgen deprivation therapy was well tolerated. Although there were modest rates of clinically significant patient-reported urinary and bowel toxicity, most of this caused only mild distress, and moderate and severe effects on QOL were limited. Additional follow-up is ongoing to characterize long-term QOL.
    International journal of radiation oncology, biology, physics 11/2011; 83(2):617-23. · 4.59 Impact Factor
  • Harvey Quon, Andrew Loblaw, Robert Nam
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    ABSTRACT: What's known on the subject? and What does the study add? Estimates of prostate cancer cases are often based solely on changes in the age distribution of the population or on historical trends. This study also incorporates changes in screening prevalence, sensitivity screening maneuvers and lowering threshold for biopsies. • To estimate the magnitude of increase in prostate cancer cases diagnosed in Canada by the year 2021. • Using available evidence, the number of new prostate cancer cases expected in 2021 was estimated based on the effects of four major factors: aging population, increased prevalence of PSA screening, lowered PSA cutoff to recommend biopsy, and improved sensitivity of prostate biopsy. • These effects were combined with population data from Statistics Canada and the Canadian Cancer Statistics to estimate new prostate cancer cases. • The two factors with the largest effect on estimated new prostate cancers in 2021 compared with 2009 were: aging population (increase of 39%), and lowering the PSA threshold to 2.6 ng/mL before prostate biopsy (increase of 200%). • In the 'best-case' scenario, the number of new prostate cancers will only be affected by the aging population and will increase by 39% to 35,121 new cases. • In the 'most-likely' scenario, all four factors will have a combined effect to increase new cases by 201% to 76,379. • The aging population and lowering PSA threshold to 2.6 ng/mL have the most significant impact on estimated new prostate cancer cases in 2021. At that time, the number of new cases may triple to 76,379 cases in Canada. • Significant planning will be required to manage this considerable increase in new prostate cancers. .
    BJU International 04/2011; 108(11):1734-8. · 3.05 Impact Factor
  • Radiotherapy and Oncology - RADIOTHER ONCOL. 01/2011; 99.
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    ABSTRACT: To report the acute and late toxicities of patients with high-risk localized prostate cancer treated using a concomitant hypofractionated, intensity-modulated radiotherapy boost combined with long-term androgen deprivation therapy. A prospective Phase I-II study of patients with any of the following: clinical Stage T3 disease, prostate-specific antigen level ≥ 20 ng/mL, or Gleason score 8-10. A dose of 45 Gy (1.8 Gy/fraction) was delivered to the pelvic lymph nodes with a concomitant 22.5 Gy prostate intensity-modulated radiotherapy boost, to a total of 67.5 Gy (2.7 Gy/fraction) in 25 fractions within 5 weeks. Image guidance was performed using three gold seed fiducials. The National Cancer Institute Common Terminology Criteria for Adverse Events, version 3.0, and Radiation Therapy Oncology Group late morbidity scores were used to assess the acute and late toxicities, respectively. Biochemical failure was determined using the Phoenix definition. A total of 97 patients were treated and followed up for a median of 39 months, with 88% having a minimum of 24 months of follow-up. The maximal toxicity scores were recorded. The grade of acute gastrointestinal toxicity was Grade 0 in 4%, 1 in 59%, and 2 in 37%. The grade of acute urinary toxicity was Grade 0 in 8%, 1 in 50%, 2 in 39%, and 3 in 4%. The grade of late gastrointestinal toxicity was Grade 0 in 54%, 1 in 40%, and 2 in 7%. No Grade 3 or greater late gastrointestinal toxicities developed. The grade of late urinary toxicity was Grade 0 in 82%, 1 in 9%, 2 in 5%, 3 in 3%, and 4 in 1% (1 patient). All severe toxicities (Grade 3 or greater) had resolved at the last follow-up visit. The 4-year biochemical disease-free survival rate was 90.5%. A hypofractionated intensity-modulated radiotherapy boost delivering 67.5 Gy in 25 fractions within 5 weeks combined with pelvic nodal radiotherapy and long-term androgen deprivation therapy was well tolerated, with low rates of severe toxicity. The biochemical control rate at early follow-up has been promising. Additional follow-up is needed to determine the long-term biochemical control and prostate biopsy results.
    International journal of radiation oncology, biology, physics 01/2011; 82(2):898-905. · 4.59 Impact Factor

Publication Stats

28 Citations
417 Views
21.78 Total Impact Points

Institutions

  • 2013–2014
    • University of Manitoba
      Winnipeg, Manitoba, Canada
  • 2011–2012
    • University of Toronto
      • Department of Radiation Oncology
      Toronto, Ontario, Canada
    • Sunnybrook Health Sciences Centre
      • Department of Radiation Oncology
      Toronto, Ontario, Canada