Breast Cancer
Conditions
Keywords
Screening, Mammography, Overdiagnosis, Womens' perspectives, Harms and benefits, False negative, Quantitative methods, Survival
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: * What was the rate of overdiagnosis for women screened in the program during 1996-2003? * How does adjusting for sociodemographic factors affect estimates of overdiagnosis? Study 3: To describe awareness and knowledge about under- and overdiagnosis and breast screening in general: * Are women aware of and knowledgeable about under- and overdiagnosis in breast screening? * Are family doctors aware of and knowledgeable about breast screening, and under- and overdiagnosis? Are they confident in their ability to relay this information to their patients? Study 1 is a quality improvement study and has approval from Personvernombudet (PVO 2016-4696). Study 2 has research ethics board (REK) approval (REK 2013/795), while REK approval will be sought for Study 3.
Interventions
OTHERUnder- or overdiagnosed cancer
Diagnosed with a cancer that was visible on prior mammograms
OTHERScreening
Invited or attended BreastScreen Norway
Sponsors
Extrastiftelsen
Norwegian Institute of Public Health
Study design
Observational model
OTHER
Time perspective
RETROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
25 Years to 75 Years
Healthy volunteers
Yes
Inclusion criteria
Study 1 Inclusion Criteria: * Breast cancer diagnosed within BreastScreen Norway using digital mammography * Prior screening images available for review Study 2 Inclusion Criteria: * Women born between 1927 and 1934 (inclusive) * Legal resident in Norway at any time between 1996 and 2003 (inclusive) Study 3 Inclusion Criteria: * Women residing in Norway, aged 50-69 (inclusive) * Practising family doctors in Norway, aged 25-75 (inclusive) * Provide informed consent
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Study 1: Prognostic and predictive histopathologic characteristics | At time of diagnosis | \- Histopathological type (Ductal carcinoma in situ, invasive carcinoma of no special type, invasive lobular carcinoma) |
| Study 2: Crude and adjusted rate of overdiagnosis | 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 | 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
| Measure | Time frame | Description |
|---|---|---|
| Study 1: Survival | Date of diagnosis until 31 December 2017 | \- Overall survival |
Other
| Measure | Time frame | Description |
|---|---|---|
| Study 3: Factors associated with awareness and knowledge of overdiagnosis | One day (Measurements taken once at time of survey completion) | Using a self-administered web-based questionnaire designed for this study, the investigators will analyse survey responses to determine whether self-reported age (categorised into 5-year age groups) is associated with awareness and knowledge of overdiagnosis. This will be done separately for women and family doctors. |
Countries
Norway
Outcome results
None listed