The Tromsø Mammography and Breast Cancer Study

Background

How a breast appears on an x-ray image (mammogram) varies by how much fatty tissue, connective tissue, and epithelial tissue there is in the breast. Epithelial and connective breast tissues are radiodense and will appear light on a mammogram, while fatty breast tissue is radiolucent and will appear dark. A mammogram can be classified according to parenchymal patterns (the original method) and percent mammographic density (the newer method).

Mammographic density – a strong risk factor for breast cancer
Epidemiological studies have shown that mammographic parenchymal patterns and mammographic density are independent risk factors for breast cancer. Apart from age and some genetic mutations, mammographic density is regarded as one of the strongest breast cancer risk factors.

Aims

We wish to study the associations between lifestyle factors, diet, hormonal therapy, endogenous hormones, genetics, biological markers and mammographic parenchymal patterns / mammographic density.

Data collection

In 2001 the Tromsø Mammography and Breast Cancer (TMBC) study was initiated at the Institute of Community Medicine, University of Tromsø. Postmenopausal women, age 55 and over, residing in the municipality of Tromsø, Norway, and attending the population-based Norwegian Breast Cancer Screening Program (NBCSP) at the University Hospital of North Norway (UNN) were eligible for the study. During spring of 2001 and 2002, altogether 1,041 women were included in the TMBC study. After the women had undergone their NBCSP screening mammograms, they were interviewed by a nurse from the Department of Clinical Research, UNN, about reproductive and menstrual factors, previous history of cancer, smoking status, and use of HT or other medications. The participants had their height and weight measured, blood samples drawn, and each was given a questionnaire to be completed at home, and returned in a prepaid envelope.

Study group

Principal Investigator
Professor Inger Torhild Gram
Institute for Community Medicine,
UiT The Arctic University of Norway
9037 Tromsø.
Telephone:  92401177 
E-mail: inger.gram@uit.no

Professor Vessela N. Kristensen
Oslo University Hospital 
Department of Cancer Genetics
Institute for Cancer Research,
E-mail: v.n.kristensen@medisin.uio.no

Research technologist Grethe I. Grenaker Alnæs
Oslo University Hospital
Department of Cancer Genetics
Institute for Cancer Research,
E-mail: greal@rr-research.no

Systems Analyst Ilene Brill
Department of Epidemiology and International Health,
Ryals School of Public Health,
University of Alabama at Birmingham
Birmingham, AL 35294-0022, USA.
E-mail: ibrill@uab.edu

Professor Gertraud Maskarinec
University of Hawaii, Cancer Center
Honolulu, HI 96813, USA.
E-mail: gertraud@cc.hawaii.edu

Ethics

The TMBC study is approved by the Regional Committee for Medical Research Ethics and the National Data Inspection Board. All women have signed an informed consent. All data are stored and handled according to the permission given by the National Data Inspection Board.

Financial support

The Norwegian Research Council

The Norwegian Women’s Public Health Association

Pink Ribbon / The Norwegian Cancer Society

The National Cancer Institute (Grant R03CA105948)

The Northern Norway Regional Health Authority

Health and Rehabilitation

The Erna and Olav Aakre Foundation

The Rikke and Conrad Holmboes Research Fund

The Odd Fellow Medical-Scientific Research Fund

The University of Tromsø

Publications

2015
Stone J, Thompson DJ, Dos SS, I, Scott C, Tamimi RM, Lindstrom S, et al. Novel Associations between Common Breast Cancer Susceptibility Variants and Risk-Predicting Mammographic Density Measures. Cancer Res 2015 Jun 15;75(12):2457-67

PhD thesis/Doctoral thesis

2009
Anne Stuedal, Oslo. ISMN 978-82-8072-281-2. The role of selected nutritional and hormonal factors on mammographic density, a breast cancer risk factor

2007
Yngve Bremnes, Tromsø. ISBM 82-90263-05-8. Hormones, smoking and Mammographic Density in Postmenopausal Norwegian women