Under- and Overdiagnosis in BreastScreen Norway
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Sponsor
- Enrollment
- 3,915
- Locations
- 1
- Primary Endpoint
- Study 1: Prognostic and predictive histopathologic characteristics
Study Overview
Brief Summary
This PhD project will describe tumour characteristics and survival associated with of under- and overdiagnosed breast cancers, the rate of overdiagnosis in BreastScreen Norway, and whether women and family doctors are aware of, and knowledgeable about, under- and overdiagnosis in breast cancer screening.
Detailed Description
Mammographic screening among women aged 50-69 reduces breast cancer mortality but also carries some risk. This PhD project will study under- and overdiagnosis, two risks associated with mammographic screening, in BreastScreen Norway. Underdiagnosis can occur when a tumour is present but not detected as a result of screening, while overdiagnosis can occur when a woman is diagnosed with a slow growing cancer that would not become symptomatic during her lifetime.
This project will address the following topics and research questions using observational study methods.
Study 1: To determine whether tumour histopathology and survival differentially associated with potentially under- or overdiagnosed interval and screen-detected breast cancers.
- Do women with potentially underdiagnosed interval cancers have different tumour histopathology and survival than those whose interval cancers showed no signs at the prior screen?
- Do women with potentially overdiagnosed screen-detected cancer have different tumour histopathology and survival than those whose screen-detected cancer showed no signs at the prior screen?
Study 2: To estimate overdiagnosis in the screening program using individual-level data:
Study Design
- Study Type
- Observational
- Observational Model
- Other
- Time Perspective
- Retrospective
Eligibility Criteria
- Ages
- 25 Years to 75 Years (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- •Breast cancer diagnosed within BreastScreen Norway using digital mammography
- •Prior screening images available for review
- •Inclusion Criteria:
- •Women born between 1927 and 1934 (inclusive)
- •Legal resident in Norway at any time between 1996 and 2003 (inclusive)
- •Inclusion Criteria:
- •Women residing in Norway, aged 50-69 (inclusive)
- •Practising family doctors in Norway, aged 25-75 (inclusive)
- •Provide informed consent
Exclusion Criteria
- Not provided
Outcomes
Primary Outcomes
Study 1: Prognostic and predictive histopathologic characteristics
Time Frame: At time of diagnosis
- Ki67 expression (0-100%)
Study 2: Crude and adjusted rate of overdiagnosis
Time Frame: 1996 to 2016
- Crude and adjusted measures of overdiagnosis will be presented to show the amount and direction of confounding resulting from sociodemographic factors.
Study 3: Agreement between awareness and knowledge of overdiagnosis
Time Frame: One day (Measurements taken once at time of survey completion)
Agreement between awareness (yes versus no/incomplete) and knowledge (yes versus no/incomplete) of overdiagnosis
Secondary Outcomes
- Study 1: Survival(Date of diagnosis until 31 December 2017)