BMC Semniar Thursday 10 October, 12:00 in Læknagarður Vatnsmýrarvegur 16, room 343
Speaker: Laufey Tryggvadóttir, Managing Director of the Icelandic Cancer Registry, Skogarhlid 8, Reykjavik, Iceland
Title: Female hormones, menopause and breast cancer
Abstract: Endogenous progestagen and oestrogen increase proliferation in the breast and are strongly associated with breast cancer risk. Menopausal Hormone Therapy (MHT) has been used for decades and is still used by 12 million women in Western countries, although the use has declined since 2002 when the number was 35 million women. It has been known for over 20 years that MHT increases the risk of breast cancer. However, there is some controversy over the effects. There were some indications that the resulting cancers may be smaller and less agressive than other breast cancers. The magnitude of the risk has also been subject to debate and finally, the pharmaceutical industry has influenced opinions.
Prevalence of MHT use as well as the association between MHT and breast cancer have been studied at the Icelandic Cancer Registry using cohort data from the Cancer Detection Clinic. Those data were also part of a recently published worldwide meta-analysis based on individual participant data, the results of which have helped resolve the above-described controversies. In this large prospective study, over 100.000 breast cancers were diagnosed during follow-up. Relative risk (RR) of breast cancer associated with use of oestrogen-progesterone for 1-4 years was 1.60 (95% CI 1.52-1.69) and for 5-14 years the RR was 2.08 (95% CI 2.02-2.15). It was estimated that one in 50 users of oestrogen plus daily progestagen develops breast cancer as a consequence of the use.
Biography: Laufey Tryggvadóttir received a BSc degree in biology from the University of Iceland in 1983 and MSc degree in epidemiology from the University of Western Ontario, Canada, in 1986. She is a clinical professor at the Faculty of Medicine, University of Iceland, and a lecturer in epidemiology, supervisor and member of PhD- and MSc committees since 1988. Laufey has been on the steering committee of the Nordic Summer School in Cancer Epidemiology from the outset (1990). She has been on the board of directors for the Association of Nordic Cancer Registries since 1989. Current and recent collaborative projects include Survival of Nordic Cancer Patients, Nordic Obesity Surgery Cohort, life after Childhood Cancer in Scandinavia (AliCCS) and she currently leads a Nordic study on Prognostic Factors, Treatment and Breast Cancer Survival in BRCA2 Mutation Carriers (NOBRAC study).
Laufey is in charge of epidemiological research at the Icelandic Cancer Registry and has a long-standing experience in cancer epidemiology. Among subjects of interest are environmental, hormonal and genetic factors that affect cancer risk, and factors that affect survival of cancer patients. A special focus is on the epidemiology and biology of breast- and prostate cancer in BRCA2 mutation carriers.