Clinical trial NCT03852953: Under- and Overdiagnosis in BreastScreen Norway
Official title: Under- and Overdiagnosis in BreastScreen Norway
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Breast Cancer
Keywords: Screening
Mammography
Overdiagnosis
Womens' perspectives
Harms and benefits
False negative
Quantitative methods
Survival
Lead sponsor: Norwegian Institute of Public Health
Sponsor class: OTHER_GOV
Collaborators: name: Extrastiftelsen
First posted: 2019-02-25
Enrollment: 3915
Sex: ALL
Minimum age (years): 25
Maximum age (years): 75
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: OTHER
Time perspective: RETROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Women aged 50-69, and practising female and male family doctors aged 25-75, residing in 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.

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.

Eligibility 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

Primary outcomes:
measure: Study 1: Prognostic and predictive histopathologic characteristics
timeFrame: At time of diagnosis
measure: Study 1: Prognostic and predictive histopathologic characteristics
timeFrame: At time of diagnosis
measure: Study 1: Prognostic and predictive histopathologic characteristics
timeFrame: At time of diagnosis
measure: Study 1: Prognostic and predictive histopathologic characteristics
timeFrame: At time of diagnosis
measure: Study 1: Prognostic and predictive histopathologic characteristics
timeFrame: At time of diagnosis
measure: Study 1: Prognostic and predictive histopathologic characteristics
timeFrame: At time of diagnosis
measure: Study 2: Crude and adjusted rate of overdiagnosis
timeFrame: 1996 to 2016
measure: Study 3: Agreement between awareness and knowledge of overdiagnosis
timeFrame: One day (Measurements taken once at time of survey completion)
Secondary outcomes:
measure: Study 1: Survival
timeFrame: Date of diagnosis until 31 December 2017
measure: Study 1: Survival
timeFrame: Date of diagnosis until 31 December 2017
Other outcomes:
measure: Study 3: Factors associated with awareness and knowledge of overdiagnosis
timeFrame: One day (Measurements taken once at time of survey completion)
measure: Study 3: Factors associated with awareness and knowledge of overdiagnosis
timeFrame: One day (Measurements taken once at time of survey completion)
Locations:
city: Oslo
country: Norway
facility: Cancer Registry of Norway
Study officials:
affiliation: Norwegian Institute of Public Health
name: Solveig Hofvind, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Hovda T, Tsuruda K, Hoff SR, Sahlberg KK, Hofvind S. Radiological review of prior screening mammograms of screen-detected breast cancer. Eur Radiol. 2021 Apr;31(4):2568-2579. doi: 10.1007/s00330-020-07130-y. Epub 2020 Oct 1.
citation: Tsuruda KM, Hovda T, Bhargava S, Veierod MB, Hofvind S. Survival among women diagnosed with screen-detected or interval breast cancer classified as true, minimal signs, or missed through an informed radiological review. Eur Radiol. 2021 May;31(5):2677-2686. doi: 10.1007/s00330-020-07340-4. Epub 2020 Nov 12.
citation: Tsuruda KM. Overdiagnosis and 'underdiagnosis' in BreastScreen Norway [dissertation]. [Oslo, Norway]: University of Oslo; 2021. 108 p. Available at: http://urn.nb.no/URN:NBN:no-91337