Scientists at the Wellcome Trust Sanger Institute have recently published the results from a genetic study which found that primary breast tumours do not spread until the late stages of the disease, meaning that a diagnosis before the cancer spreads, and catching the disease in time, is realistic.
Metastatic breast cancer is the term used when breast cancer cells have broken off from the primary tumour and spread to other parts of the body. It is estimated that 35,000 people in the UK have metastatic breast cancer, and once this has spread, the chances of survival are often poor. Therefore, if the cancer can be caught before it spreads there is a much better chance of surviving the disease.
There is very little understanding of the biology underpinning metastatic breast cancer, with most of the research to date having focused on primary breast cancer. There has been some controversy over whether breast cancer spreads at the early or late stages of cancer development, but the scientists in this study looked specifically at how breast cancer evolves from a primary tumour to those that have spread or metastasised. The results showed that cancer cells appeared to spread late in the disease’s development.
This is, of course, very positive news for those who are diagnosed with breast cancer in the early stages, meaning there is a greater chance of intervening before the cancer cells spread and therefore increasing the chance of survival. Dr Lucy Yates, first author from the Wellcome Trust Sanger Institute and Guys and St Thomas' NHS Trust, said: "As the cells that cause the spread of breast cancer leave relatively late, it means they are still quite similar to the cells in the primary tumour. Therefore by studying the genome of the primary breast cancer tumour, in the future we may be able to predict what cells that might have spread 'look' like, and potentially which treatments they will respond to."
The study also opens the door to predictions on which drugs will work against breast cancer that has already spread. Professor Per Eystein Lønning, joint lead author from the University of Bergen and Haukeland University Hospital in Bergen, said: "Most women who have metastatic breast cancer do not have another biopsy of the cancer, and rarely have it analysed using genetic sequencing. In this study we found that in some cases, the metastatic tumours had particular genetic changes that could be targeted with treatments. We would not have seen these mutations by sequencing the primary tumour alone. Our results suggest that it should be more routine to biopsy the metastasis and have it genetically analysed in order to open up clinical trials of treatment options for metastatic breast cancer."
The study is being extended and patients with metastatic breast cancer across Europe are now being recruited. The goal is to build a platform for identifying an appropriate clinical trial of new treatments for each patient with metastatic breast cancer.
Elise Bevan, a solicitor in the clinical negligence team at Penningtons Manches LLP, said: “We deal with many claims relating to a delay in diagnosis of breast cancer. This study reinforces the importance of getting an early diagnosis before the cancer has had a chance to spread. We hope that the results will continue to drive the need to improve methods for detecting breast cancer. The study has also proven that it is possible to understand metastatic breast cancer and in turn, this will mean that scientists can develop specific and targeted treatments in the future.”