Risk Assessment: Breast Cancer, Prediction and Screening
Progress Educational Trust
Darwin Lecture Theatre, Darwin Building, University College London, Malet Place, London WC1E 6BT
8 May 2014 6.30pm-8.30pm
A public event organised by the Progress Educational Trust (PET) at University College London, supported by the Wellcome Trust and chaired by Dr Ann Robinson, with speakers Professor Stephen Duffy, Professor Klim McPherson, Paul Serhal and Wendy Watson.
Understanding and measuring risk in medicine can be difficult, and this is certainly true of breast cancer. There are different types of risk - including absolute and relative risk, population and individual risk, lifetime risk and risk over a specific time period, and the 'chance' and 'burden' components of risk - that are easily confused in discussion of breast cancer, and that laypeople (and even experts) can find difficult to disentangle. There are also competing measures when it comes to assessing the prevention and treatment of breast cancer, such as efficacy (improvement in survival) and tolerability (side effects and quality of life).
It is said that breast cancer screening involves a risk of overdiagnosis or misdiagnosis, but more fundamentally, there are subtle ways in which early detection due to screening might change our understanding of what breast cancer actually is. Of particular relevance is the difficulty of predicting whether small invasive or in situ screen-detected tumours are liable to grow into a cancer that will result in symptoms during a patient's lifetime, whether they will grow too slowly for this to be the case, or whether they will shrink. This difficulty in predicting the fate of tumours means that traditional distinctions between 'pre-cancer' or 'pseudo-cancer' on the one hand, and cancer proper on the other hand, are blurred when screening for breast cancer. Furthermore, lead time bias (the increased duration of the patient's post-diagnosis survival due simply to the fact that they were diagnosed early, without there necessarily being any change in outcome) can make it difficult to assess the pros and cons of screening.
Risk also plays an important part in the reproductive decisions of people who know they have a genetic predisposition to breast cancer, and who wish to avoid passing this predisposition on to their children. Preimplantation genetic diagnosis for BRCA1 and BRCA2 mutations is licensed by the Human Fertilisation and Embryology Authority, and has been used in the UK to ensure that children are born without these mutations. But despite most types of inherited cancer predisposition showing autosomal dominant inheritance (meaning that on average half of a person's children will inherit the predisposition), counselling on reproduction is rarely included in guidelines on clinical management of breast cancer.
This event will see these and other aspects of breast cancer discussed in relation to risk, from contrasting perspectives, by a panel of experts. The event forms part of PET's 'Breast Cancer: Chances, Choices and Genetics' project, and will be followed by two further evening events at the same venue - 'Risk Management: Breast Cancer' on Thursday 5 June, and a concluding event on Thursday 3 July.