Under- and Overdiagnosis in BreastScreen Norway

February 11, 2022 updated by: Cancer Registry of Norway
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.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

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.

Study Type

Observational

Enrollment (Actual)

3915

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Norway
      • Oslo, Norway, 0379
        • Cancer Registry of Norway

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

25 years to 75 years (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Women aged 50-69, and practising female and male family doctors aged 25-75, residing in Norway.

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Study 1: Under- and overdiagnosed group
Non-proportional stratified sample of women diagnosed with interval or screen-detected breast cancers after participation in BreastScreen Norway. This sample will include under- or overdiagnosed cancers, as well as cancers that were not under- or overdiagnosed.
Other: Under- or overdiagnosed cancer
Diagnosed with a cancer that was visible on prior mammograms
Study 2: Rate of overdiagnosis group
Women residing in Norway, born between 1927 and 1934 (inclusive). This cohort will include women who have attended screening and who have not attended screening.
Other: Screening
Invited or attended BreastScreen Norway
Study 3: Awareness and knowledge group
Women aged 50-69, and practising family doctors aged 25-75, currently living in Norway.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Study 1: Prognostic and predictive histopathologic characteristics
Time Frame: At time of diagnosis
- Histopathological type (Ductal carcinoma in situ, invasive carcinoma of no special type, invasive lobular carcinoma)
At time of diagnosis
Study 1: Prognostic and predictive histopathologic characteristics
Time Frame: At time of diagnosis
- Maximum tumour diameter (mm)
At time of diagnosis
Study 1: Prognostic and predictive histopathologic characteristics
Time Frame: At time of diagnosis
- Tumour grade (1, 2, 3)
At time of diagnosis
Study 1: Prognostic and predictive histopathologic characteristics
Time Frame: At time of diagnosis
- Lymph node involvement (Yes/No)
At time of diagnosis
Study 1: Prognostic and predictive histopathologic characteristics
Time Frame: At time of diagnosis
- Receptor status (Positive/Negative)
At time of diagnosis
Study 1: Prognostic and predictive histopathologic characteristics
Time Frame: At time of diagnosis
- Ki67 expression (0-100%)
At time of diagnosis
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.
1996 to 2016
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
One day (Measurements taken once at time of survey completion)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Study 1: Survival
Time Frame: Date of diagnosis until 31 December 2017
- Overall survival
Date of diagnosis until 31 December 2017
Study 1: Survival
Time Frame: Date of diagnosis until 31 December 2017
- Breast cancer specific survival
Date of diagnosis until 31 December 2017

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Study 3: Factors associated with awareness and knowledge of overdiagnosis
Time Frame: 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.
One day (Measurements taken once at time of survey completion)
Study 3: Factors associated with awareness and knowledge of overdiagnosis
Time Frame: 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 formal education (none; primary school; high school; up to 4 years postsecondary; more than 4 years of postsecondary education) is associated with awareness and knowledge of overdiagnosis among women.
One day (Measurements taken once at time of survey completion)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Cancer Registry of Norway

Collaborators

Extrastiftelsen

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (ACTUAL)

July 1, 2018

Primary Completion (ACTUAL)

June 8, 2020

Study Completion (ACTUAL)

June 8, 2020

Study Registration Dates

First Submitted

November 12, 2018

First Submitted That Met QC Criteria

February 22, 2019

First Posted (ACTUAL)

February 25, 2019

Study Record Updates

Last Update Posted (ACTUAL)

March 2, 2022

Last Update Submitted That Met QC Criteria

February 11, 2022

Last Verified

January 1, 2021

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • 17/222
  • 2018/FO201362 (OTHER_GRANT: ExtraStiftelsen)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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