Fortnightly Review: Familial breast cancerBMJ 1994; 308 doi: https://doi.org/10.1136/bmj.308.6922.183 (Published 15 January 1994) Cite this as: BMJ 1994;308:183
- D G R Evans,
- I S Fentiman,
- K McPherson,
- D Asbury,
- B A J Ponder,
- A Howell
- Department of Medical Genetics, St Mary's Hospital, Manchester M13 0JH
- ICRF Clinical Oncology Unit, Guy's Hospital, London SE1 9RT
- Department of Public Health and Policy, London School of Hygiene and Tropical Medicine, London WC1E 7HT
- Department of Radiology, Nightingale Breast Screening Unit, Withington Hospital, Manchester M20 8LR
- CRC Human Cancer Genetics Research Group, Department of Pathology, University of Cambridge, Cambridge CB2 1QP
- Department of Medical Oncology, Christie Hospital, Manchester M20 9BX.
- Accepted 12 October 1993
Only about 5% of breast cancer is due to highly penetrant dominant genes
Familial breast cancer is more likely with early age at presentation, several affected relatives, bilaterality, and a history of related cancers.
There may be more than five genes causing familial breast cancer; the most important of these (BRCA1) has been located on chromosome 17, and DNA tests are possible for a few suitable families
DNA predictive tests raise several ethical issues, and adequate counselling must precede decisions whether to request testing
Family history clinics offer counselling, screening, and a focus for research into better methods of detection and prevention of breast cancer
There is now unequivocal evidence that a small proportion of breast cancer cases, perhaps 4-5%, are due to highly penetrant dominant genes.*RF 1-4* The recent publicity surrounding breast cancer in general, the national screening programme,5 and trials of prevention have heightened awareness in families where the disease has already occurred. This has led to demands for advice about risks and what to do about them. Women wish to know not only their own risks but also the risks to their daughters. The needs of these women are being met by general practitioners, surgeons, oncologists, and an increasing number of specialist cancer family history clinics. Access to such clinics is now possible in most regions. In this article we consider how best to give advice and what to do with regard to prevention and screening for women at high risk of developing cancer. The new potential for precise genetic diagnosis in some families raises important additional psychological and ethical issues.
Advances in genetics
From studies of the pattern of distribution of breast and other cancers in families it has been known for some time that inheritance is usually dominantly transmitted.6,7 To find the defective gene …