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Objectives This dissertation had two overarching objectives: 1. To determine how stakeholders perceive women’s preferences for cervical screening modalities. 2. To understand methods to measure women’s cervical screening preferences, to inform the development and testing of a person-centered, evidence-informed approach to preference-elicitation. Methods The overarching conceptual framework was the Ottawa Decision Support Framework. The first objective was addressed by interview studies with (1) guideline developers and program managers and (2) health professionals and women considering screening. This was complemented by a systematic review of quantitative, qualitative and mixed-methods studies of women’s cervical screening preferences, using the Grading of Recommendations, Assessment, Development, and Evaluation approach to developing preference-based recommendations. This approach was also used in a systematic review of methods to elicit women’s preferences, addressing the second objective. These findings led to the development and field testing of a preference-elicitation tool using International Patient Decision Aid Standards criteria, and the development of a protocol for a population-based study of women’s preferences. iv Results Objective 1 Experts disagree about whether there is enough evidence to include alternative modalities in cervical screening programs. Women and health care professionals do not recognize that women face a choice to participate in cervical screening. A narrative synthesis of relevant literature presented challenges in aggregating preferences across diverse study objectives, designs, and contexts. Objective 2 Preference-elicitation approaches for cervical screening are heterogenous in design and rigour. I therefore developed and field tested a tool to elicit women’s preferences, which demonstrated that women found the tool helpful to identify their preferences. I then propose a study that uses multiple methods to apply the tool more broadly. Conclusions Synthesized preferences data might not be the optimal approach to incorporate preferences into cervical screening guidelines. A tool grounded in shared decision-making can help women identify their informed, values-based screening preferences.

Estimation of the sensitivity and specificity of cancer screening tests using data from population-level databases is complicated by the lack of independent confirmation of test results using a "gold standard''. The true sensitivity and specificity are unknown and errors in measurement can occur due to subjective clinical judgment, technical imperfections or interpretational differences. A further complication is clustered data (such as patients nested within examiners within screening centre), which are common in population-based screening. We propose a cancer screening model that accommodates the partially unobserved disease status, clustered data structures, general covariate effects, and the dependence between exams. The model is applied to the estimation of the diagnostic accuracy of mammography and clinical breast examination using a cohort consisting of women 50 to 69 years of age screened at the OBSP between January 1, 2002 and December 31, 2003. When offered in addition to mammography, we found CBE may benefit women using hormone therapy but not likely benefit women with dense breast tissues. The thesis also discusses two measures of interest, the length of the pre-clinical state and the false negative rate. Two estimation procedures are proposed to model the pre-clinical state duration, the false negative rate of screening exam, and the underlying incidence rate in the screened population. Both methods assume the sojourn time follows a negative exponential distribution, but we consider two different forms for the false negative rate: 1) constant with time and 2) an exponential function to compensate for the fact that lesions should become easier to detect the closer they are to become clinically evident. The proposed methods are illustrated with another cohort of women who were first screened through the OBSP between January 1, 2003, and December 31, 2004 and were followed up until December 31, 2009. / Thesis / Doctor of Philosophy (PhD)

Purpose: The objective of this study was to investigate both depression and psychological distress as determinants of breast and cervical cancer screening. Methods: Ontario female respondents to the Canadian Community Health Survey version 1.2 (2002) were assessed for both Major Depressive Disorder (World Mental Health-Composite International Diagnostic Interview for depression) and psychological distress (Kessler 6-item Distress Scale (K6)>/= 8). Respondents eligible for screening (N=4042 for cervical cancer; N=1403 for breast cancer) were linked to Ontario administrative health service data to prospectively ascertain screening outcomes. Results: Women with K6 >/= 8 had reduced breast cancer screening compliance in adjusted analyses (AOR 0.63, 95% CI 0.40-0.97). The association between K6 >/= 8 and cervical cancer screening approached significance in women over age 40 (AOR=0.65, 95%CI 0.41-1.04). Conclusion: Decreased likelihood of screening in women with clinically significant psychological distress suggests that attention to adequacy of preventive services is a potential target for intervention.

Purpose: The objective of this study was to investigate both depression and psychological distress as determinants of breast and cervical cancer screening. Methods: Ontario female respondents to the Canadian Community Health Survey version 1.2 (2002) were assessed for both Major Depressive Disorder (World Mental Health-Composite International Diagnostic Interview for depression) and psychological distress (Kessler 6-item Distress Scale (K6)>/= 8). Respondents eligible for screening (N=4042 for cervical cancer; N=1403 for breast cancer) were linked to Ontario administrative health service data to prospectively ascertain screening outcomes. Results: Women with K6 >/= 8 had reduced breast cancer screening compliance in adjusted analyses (AOR 0.63, 95% CI 0.40-0.97). The association between K6 >/= 8 and cervical cancer screening approached significance in women over age 40 (AOR=0.65, 95%CI 0.41-1.04). Conclusion: Decreased likelihood of screening in women with clinically significant psychological distress suggests that attention to adequacy of preventive services is a potential target for intervention.

Lung cancer is the number one cause of cancer related deaths in Ontario and throughout Canada. The 5-year survival rate for those diagnosed with lung cancer in 2020 was approximately 22.2%. Poor screening techniques is the main cause of low survival rates and late detection. Recent advancements in screening for lung cancer have led researchers to look at the benefits of using low-dose CT (LDCT) scanning to screen patients at high risk for lung cancer in order to detect the cancer in its earlier stages. There is strong evidence that using this new method of testing in lung cancer screening can reduce lung cancer related mortality by increasing the chance that the disease is detected in an earlier stage and in turn improving the patient’s chance at life saving treatment. Lung cancer screening requires LDCT resources and, based on the current recommendations, there is a concern that the new demand for imaging may exceed existing capacity of the imaging centers. This research evaluates impact of the Lung Cancer Screening Pilot for People at High Risk on the imaging resources and aims to answer the question: What would be the system performance for different imaging policies assuming a fixed imaging capacity? Administrative data from the Ottawa Hospital (TOH) as well as data from other research projects were used in order to develop and populate a simulation model. The policies that were assessed include: using biannual screening for patients who receive a negative baseline scan, using annual screening for patients with a negative baseline scan with all suspicious patients returning for a follow-up scan in six months, using annual screening for patients with a negative baseline scan with all suspicious patients returning for a follow-up scan in three months, using biannual screening for patients with a negative baseline scan with all suspicious patients returning for a follow-up scan in six months and using biannual screening for patients with a negative baseline scan with all suspicious patients returning for a follow-up scan in three months. These policies were assessed by looking at wait times for patients to be screened. Possible shift between lung cancer stages was also considered. The impact of this study is to look at system performances for different screening policies that could be used assuming a fixed imaging capacity. It represents a first step for further research should the data that is needed become available.

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