Lawrence Frank Paszat

Dr. Lawrence Frank Paszat

Dalla Lana School of Public Health, University of Toronto, Toronto, ON M4N 3M45, Canada

Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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29 September 2011 in Implementation Science
Verified
Journal Article
Open access
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MBMelissa C Brouwers
Melissa C Brouwers
CVCarol De Vito
Carol De Vito
LBLavannya Bahirathan
Lavannya Bahirathan
ACAngela Carol
Angela Carol
JCJune C Carroll
June C Carroll
NWNadine Wathen
Nadine Wathen
Appropriate screening may reduce the mortality and morbidity of colorectal, breast, and cervical cancers. However, effective implementation strategies are warranted if the full benefits of screening are to be realized. As part of a larger agenda to create an implementation guideline, we conducted a systematic review to evaluate interventions designed to increase the rate of breast, cervical, and colorectal cancer (CRC) screening. The interventions considered were: client reminders, client incentives, mass media, small media, group education, one-on-one education, reduction in structural barriers, reduction in out-of-pocket costs, provider assessment and feedback interventions, and provider incentives. Our primary outcome, screening completion, was calculated as the overall median post-intervention absolute percentage point (PP) change in completed screening tests. Our first step was to conduct an iterative scoping review in the research area. This yielded three relevant high-quality systematic reviews. Serving as our evidentiary foundation, we conducted a formal update. Randomized controlled trials and cluster randomized controlled trials, published between 2004 and 2010, were searched in MEDLINE, EMBASE and PSYCHinfo. The update yielded 66 studies new eligible studies with 74 comparisons. The new studies ranged considerably in quality. Client reminders, small media, and provider audit and feedback appear to be effective interventions to increase the uptake of screening for three cancers. One-on-one education and reduction of structural barriers also appears effective, but their roles with CRC and cervical screening, respectively, are less established. More study is required to assess client incentives, mass media, group education, reduction of out-of-pocket costs, and provider incentive interventions. The new evidence generally aligns with the evidence and conclusions from the original systematic reviews. This review served as the evidentiary foundation for an implementation guideline. Poor reporting, lack of precision and consistency in defining operational elements, and insufficient consideration of context and differences among populations are areas for additional research.

7 February 2017 in PLOS Medicine
Verified
Journal Article
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KHKevin Ten Haaf
Kevin Ten Haaf
MTMartin C. Tammemägi
Martin C. Tammemägi
SBSusan J. Bondy
Susan J. Bondy
CACarlijn M. van der Aalst
Carlijn M. van der Aalst
SGSumei Gu
Sumei Gu
Lawrence Frank PaszatLawrence Frank Paszat
Lawrence Frank Paszat
The National Lung Screening Trial (NLST) results indicate that computed tomography (CT) lung cancer screening for current and former smokers with three annual screens can be cost-effective in a trial setting. However, the cost-effectiveness in a population-based setting with >3 screening rounds is uncertain. Therefore, the objective of this study was to estimate the cost-effectiveness of lung cancer screening in a population-based setting in Ontario, Canada, and evaluate the effects of screening eligibility criteria. This study used microsimulation modeling informed by various data sources, including the Ontario Health Insurance Plan (OHIP), Ontario Cancer Registry, smoking behavior surveys, and the NLST. Persons, born between 1940 and 1969, were examined from a third-party health care payer perspective across a lifetime horizon. Starting in 2015, 576 CT screening scenarios were examined, varying by age to start and end screening, smoking eligibility criteria, and screening interval. Among the examined outcome measures were lung cancer deaths averted, life-years gained, percentage ever screened, costs (in 2015 Canadian dollars), and overdiagnosis. The results of the base-case analysis indicated that annual screening was more cost-effective than biennial screening. Scenarios with eligibility criteria that required as few as 20 pack-years were dominated by scenarios that required higher numbers of accumulated pack-years. In general, scenarios that applied stringent smoking eligibility criteria (i.e., requiring higher levels of accumulated smoking exposure) were more cost-effective than scenarios with less stringent smoking eligibility criteria, with modest differences in life-years gained. Annual screening between ages 55–75 for persons who smoked ≥40 pack-years and who currently smoke or quit ≤10 y ago yielded an incremental cost-effectiveness ratio of $41,136 Canadian dollars ($33,825 in May 1, 2015, United States dollars) per life-year gained (compared to annual screening between ages 60–75 for persons who smoked ≥40 pack-years and who currently smoke or quit ≤10 y ago), which was considered optimal at a cost-effectiveness threshold of $50,000 Canadian dollars ($41,114 May 1, 2015, US dollars). If 50% lower or higher attributable costs were assumed, the incremental cost-effectiveness ratio of this scenario was estimated to be $38,240 ($31,444 May 1, 2015, US dollars) or $48,525 ($39,901 May 1, 2015, US dollars), respectively. If 50% lower or higher costs for CT examinations were assumed, the incremental cost-effectiveness ratio of this scenario was estimated to be $28,630 ($23,542 May 1, 2015, US dollars) or $73,507 ($60,443 May 1, 2015, US dollars), respectively. This scenario would screen 9.56% (499,261 individuals) of the total population (ever- and never-smokers) at least once, which would require 4,788,523 CT examinations, and reduce lung cancer mortality in the total population by 9.05% (preventing 13,108 lung cancer deaths), while 12.53% of screen-detected cancers would be overdiagnosed (4,282 overdiagnosed cases). Sensitivity analyses indicated that the overall results were most sensitive to variations in CT examination costs. Quality of life was not incorporated in the analyses, and assumptions for follow-up procedures were based on data from the NLST, which may not be generalizable to a population-based setting. Lung cancer screening with stringent smoking eligibility criteria can be cost-effective in a population-based setting.

24 May 2013 in BMC Public Health
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PRPaul Ritvo
Paul Ritvo
RMRonald E. Myers
Ronald E. Myers
Lawrence Frank PaszatLawrence Frank Paszat
Lawrence Frank Paszat
MSMardie Serenity
Mardie Serenity
DPDaniel F Perez
Daniel F Perez
LRLinda Rabeneck
Linda Rabeneck
Colorectal cancer screening (CRCS) is the only type of cancer screening where both genders reduce risks by similar proportions with identical procedures. It is an important context for examining gender differences in disease-prevention, as CRCS significantly reduces mortality via early detection and prevention. In efforts to increase screening adherence, there is increasing acknowledgment that obstructive attitudes prevent CRCS uptake. Precise identification of the gender differences in obstructive attitudes is necessary to improve uptake promotion. This study randomly sampled unscreened, screening - eligible individuals in Ontario, employing semi-structured interviews to elicit key differences in attitudinal obstructions towards colorectal cancer screening with the aim of deriving informative differences useful in planning promotions of screening uptake. N = 81 participants (49 females, 32 males), 50 years and above, with no prior CRCS, were contacted via random-digit telephone dialing, and consented via phone-mail contact. Altogether, N = 4,459 calls were made to yield N = 85 participants (1.9% response rate) of which N = 4 participants did not complete interviews. All subjects were eligible for free-of-charge CRCS in Ontario, and each was classified, via standard interview by CRCS screening decision-stage. Telephone-based, semi-structured interviews (SSIs) were employed to investigate gender differences in CRCS attitudes, using questions focused on 5 attitudinal domains: 1) Screening experience at the time of interview; 2) Barriers to adherence; 3) Predictors of Adherence; 4) Pain-anxiety experiences related to CRCS; 5) Gender-specific experiences re: CRCS, addressing all three modalities accessible through Ontario’s program: a) fecal occult blood testing; b) flexible sigmoidoscopy; c) colonoscopy. Interview transcript analyses indicated divergent themes related to CRCS for each gender: 1) bodily intrusion, 2) perforation anxiety, and 3) embarrassment for females and; 1) avoidant procrastination with underlying fatalism, 2) unnecessary health care and 3) uncomfortable vulnerability for males. Respondents adopted similar attitudes towards fecal occult blood testing, flexible sigmoidoscopy and colonoscopy, and were comparable in decision stage across tests. Gender differences were neither closely tied to screening stage nor modality. Women had more consistent physician relationships, were more screening-knowledgeable and better able to articulate views on screening. Men reported less consistent physician relationships, were less knowledgeable and kept decision-making processes vague and emotionally distanced (i.e. at ‘arm’s length’). Marked differences were observed in obstructive CRCS attitudes per gender. Females articulated reservations about CRCS-associated distress and males suppressed negative views while ambiguously procrastinating about the task of completing screening. Future interventions could seek to reduce CRCS-related stress (females) and address the need to overcome procrastination (males).

14 August 2016 in Canadian Journal of Gastroenterology and Hepatology
Verified
Journal Article
Open access
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JTJill Tinmouth
Jill Tinmouth
EVEmily T. Vella
Emily T. Vella
NBNancy N. Baxter
Nancy N. Baxter
CDCatherine Dubé
Catherine Dubé
MGMichael Gould
Michael Gould
Lawrence Frank PaszatLawrence Frank Paszat
Lawrence Frank Paszat
Introduction. The objectives of this systematic review were to evaluate the evidence for different CRC screening tests and to determine the most appropriate ages of initiation and cessation for CRC screening and the most appropriate screening intervals for selected CRC screening tests in people at average risk for CRC.Methods. Electronic databases were searched for studies that addressed the research objectives. Meta-analyses were conducted with clinically homogenous trials. A working group reviewed the evidence to develop conclusions.Results. Thirty RCTs and 29 observational studies were included. Flexible sigmoidoscopy (FS) prevented CRC and led to the largest reduction in CRC mortality with a smaller but significant reduction in CRC mortality with the use of guaiac fecal occult blood tests (gFOBTs). There was insufficient or low quality evidence to support the use of other screening tests, including colonoscopy, as well as changing the ages of initiation and cessation for CRC screening with gFOBTs in Ontario. Either annual or biennial screening using gFOBT reduces CRC-related mortality.Conclusion. The evidentiary base supports the use of FS or FOBT (either annual or biennial) to screen patients at average risk for CRC. This work will guide the development of the provincial CRC screening program.

29 September 2011 in Implementation Science
Verified
Journal Article
Open access
PDF file
MBMelissa C Brouwers
Melissa C Brouwers
CVCarol De Vito
Carol De Vito
LBLavannya Bahirathan
Lavannya Bahirathan
ACAngela Carol
Angela Carol
JCJune C Carroll
June C Carroll
NWNadine Wathen
Nadine Wathen
Appropriate screening may reduce the mortality and morbidity of colorectal, breast, and cervical cancers. Several high-quality systematic reviews and practice guidelines exist to inform the most effective screening options. However, effective implementation strategies are warranted if the full benefits of screening are to be realized. We developed an implementation guideline to answer the question: What interventions have been shown to increase the uptake of cancer screening by individuals, specifically for breast, cervical, and colorectal cancers? A guideline panel was established as part of Cancer Care Ontario's Program in Evidence-based Care, and a systematic review of the published literature was conducted. It yielded three foundational systematic reviews and an existing guidance document. We conducted updates of these reviews and searched the literature published between 2004 and 2010. A draft guideline was written that went through two rounds of review. Revisions were made resulting in a final set of guideline recommendations. Sixty-six new studies reflecting 74 comparisons met eligibility criteria. They were generally of poor to moderate quality. Using these and the foundational documents, the panel developed a draft guideline. The draft report was well received in the two rounds of review with mean quality scores above four (on a five-point scale) for each of the items. For most of the interventions considered, there was insufficient evidence to support or refute their effectiveness. However, client reminders, reduction of structural barriers, and provision of provider assessment and feedback were recommended interventions to increase screening for at least two of three cancer sites studied. The final guidelines also provide advice on how the recommendations can be used and future areas for research. Using established guideline development methodologies and the AGREE II as our methodological frameworks, we developed an implementation guideline to advise on interventions to increase the rate of breast, cervical and colorectal cancer screening. While advancements have been made in these areas of implementation science, more investigations are warranted.

27 March 2008 in Breast Cancer Research and Treatment
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Journal Article
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Lawrence Frank PaszatLawrence Frank Paszat
Lawrence Frank Paszat
RSRinku Sutradhar
Rinku Sutradhar
EGEva Grunfeld
Eva Grunfeld
CGCorona Gainford
Corona Gainford
VBVeronique Benk
Veronique Benk
CWCarl van Walraven
Carl van Walraven