Abstract

Molecular technology holds enormous promise for screening and early detection but has so far been rather disappointing. The three NHS cancer screening programmes are based on old technologies and adoption of molecular testing has provided only modest improvements. Early diagnosis relies on symptom recognition and for the most part imaging. There is much talk of using genetic profiling to better target cancer screening, but such an approach is counter to the principles of population screening and raises important questions about data confidentiality.
There has been a huge reduction in cardiovascular disease through recognition of the risk factors of high cholesterol and blood pressure, but the advances have come from treating these risk factors rather than simply identifying high-risk individuals. There is a danger that by testing for genetic predisposition to cancer we will label millions of people as being at high risk of a particular cancer and fail to offer any intervention to the majority of people who will develop cancer. Currently individuals identified as being at high risk age 40 are less likely to develop cancer in the next 5 years that the average 70 year old!
Using examples from cervical screening and breast cancer risk prediction, I shall consider what molecular biomarkers have delivered so far. By analogy to cardiovascular disease prevention and early diagnosis, I shall consider what we should require from a new molecular biomarker for early diagnosis of cancer.