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Under- and Overdiagnosis in BreastScreen Norway

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ClinicalTrials.gov Identifier: NCT03852953
Recruitment Status : Active, not recruiting
First Posted : February 25, 2019
Last Update Posted : February 25, 2019
Sponsor:
Collaborator:
Extrastiftelsen
Information provided by (Responsible Party):
Cancer Registry of Norway

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.

Condition or disease Intervention/treatment
Breast Cancer Other: Under- or overdiagnosed cancer Other: 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.


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Study Type : Observational
Estimated Enrollment : 655000 participants
Observational Model: Other
Time Perspective: Retrospective
Official Title: Under- and Overdiagnosis in BreastScreen Norway
Actual Study Start Date : July 1, 2018
Estimated Primary Completion Date : June 2021
Estimated Study Completion Date : June 2021

Resource links provided by the National Library of Medicine


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.



Primary Outcome Measures :
  1. 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)

  2. Study 1: Prognostic and predictive histopathologic characteristics [ Time Frame: At time of diagnosis ]
    - Maximum tumour diameter (mm)

  3. Study 1: Prognostic and predictive histopathologic characteristics [ Time Frame: At time of diagnosis ]
    - Tumour grade (1, 2, 3)

  4. Study 1: Prognostic and predictive histopathologic characteristics [ Time Frame: At time of diagnosis ]
    - Lymph node involvement (Yes/No)

  5. Study 1: Prognostic and predictive histopathologic characteristics [ Time Frame: At time of diagnosis ]
    - Receptor status (Positive/Negative)

  6. Study 1: Prognostic and predictive histopathologic characteristics [ Time Frame: At time of diagnosis ]
    - Ki67 expression (0-100%)

  7. 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.

  8. 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 Outcome Measures :
  1. Study 1: Survival [ Time Frame: Date of diagnosis until 31 December 2017 ]
    - Overall survival

  2. Study 1: Survival [ Time Frame: Date of diagnosis until 31 December 2017 ]
    - Breast cancer specific survival


Other Outcome Measures:
  1. 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.

  2. 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.



Information from the National Library of Medicine

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Ages Eligible for Study:   25 Years to 75 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
Women aged 50-69, and practising female and male family doctors aged 25-75, residing in Norway.
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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03852953


Locations
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Norway
Cancer Registry of Norway
Oslo, Norway, 0379
Sponsors and Collaborators
Cancer Registry of Norway
Extrastiftelsen
Investigators
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Principal Investigator: Solveig Hofvind, PhD Cancer Registry of Norway

Additional Information:
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Responsible Party: Cancer Registry of Norway
ClinicalTrials.gov Identifier: NCT03852953     History of Changes
Other Study ID Numbers: 17/222
2018/FO201362 ( Other Grant/Funding Number: ExtraStiftelsen )
First Posted: February 25, 2019    Key Record Dates
Last Update Posted: February 25, 2019
Last Verified: February 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No

Keywords provided by Cancer Registry of Norway:
Screening
Mammography
Overdiagnosis
Womens' perspectives
Harms and benefits
False negative
Quantitative methods
Survival