A study published in the British Journal of Cancer further confirms the association of the BRCA2 gene mutation with prostate cancer, linking the BRCA2 gene to a more rapid progression of the disease and more aggressive form of prostate cancer. The survival rate of men who are carriers of the BRCA2 gene mutation is half that of men who do not carry the mutation.
A research team at the University of Toronto, led by Dr Steven Narod, showed that men with the BRCA2 gene mutation survived an average of four years after prostate cancer diagnosis, compared to eight years in a control group of men with a mutation in the BRCA1 gene. From a database of 2700 families with known BRCA1 or BRCA2 gene mutations, the team identified 182 prostate cancer patients with a family history of BRCA2 mutation who were considered 'known or probable carriers', and 119 patients with a family history of BRCA1 mutation. Seventy five per cent of BRCA2 carriers died within ten years of diagnosis, compared to a reported 30 per cent in non-carriers. By fifteen years post-diagnosis, 96 per cent of BRCA2 mutation carriers had died. Lesley Walker of Cancer Research UK commented: 'Although only a very small percentage of men with prostate cancer will carry a faulty BRCA2 gene, they're much more likely to die from the disease.'
The BRCA2 gene mutation was first identified in breast cancer patients and is associated with increased risk of breast and ovarian cancer in women. In men who are carriers of the mutation, the risk of developing prostate cancer is increased fivefold compared to men who are not carriers. In addition, no increased risk of prostate cancer was reported in men with a BRCA1 gene mutation. In 2007, an Icelandic research team linked the BRCA2 mutation to a more aggressive form of prostate cancer, with increased mortality in BRCA2 mutation carriers. Dr Narod's research is further evidence of this link, concluding: 'we know that carrying a faulty BRCA2 gene increases a man's risk of getting prostate cancer, and our study shows that it also affects how long he will survive a diagnosis of the disease'.
Currently in the UK, 35 000 new cases of prostate cancer and 10,000 deaths from prostate cancer are reported each year. Over the course of a lifetime, the risk of developing prostate cancer is one in 14. It is estimated that one in 500 men are carriers of the BRCA2 mutation.
Dr Narod said that his findings suggest that men with the BRCA2 mutation do not respond well to current therapies for prostate cancer. It is hoped that this information will help to develop a targeted screening strategy aimed at identifying prostate cancer at an earlier stage in men at risk of carrying the BRCA2 mutation - for example men who have a family history of breast and ovarian cancer. Further research into the genetics underlying prostate cancer aims to create targeted treatments and clinical management tailored specifically for BRCA2 carriers, to improve survival rates.