In-depth studies on families at risk show that women with hereditary mutation in BRCA1 or BRCA2 genes have an 87% chance of developing breast cancer, compared to 10% for women not carrying the mutation. Hereditary mutations at a genetic level lead to a sharp increase in the chance of developing breast cancer in young women (before the onset of menopause). Therefore, this is therefore a specific result of the hereditary susceptibility for cancer. Recent studies showed that more than half of the women with mutations in BRCA genes develop breast cancer before their 50th birthday and the average age for the diagnosis of the tumour is 41.
The risk of developing ovarian cancer in case of recurring mutations of the two genes mentioned above is between 44% and 60% compared to the 1% risk for non-carriers.
The genetic susceptibility test is very useful also for women who already developed breast cancer because, if they are carrying the BRCA gene, they have a high chance of developing a new tumour in the breast or the ovaries. For instance, studies show that BRCA1-mutation-carrying women surviving breast cancer have a 64% chance of developing the new tumour. Ovarian cancer shows similar risk percentages.
Risk of developing other types of cancer
Recent studies show that hereditary mutations of BRCA1 or BRCA2 genes increase the risk of prostate cancer in men and colon cancer in both sexes. The studies show that the likelihood of prostate cancer is 3-4 times higher compared to the general population in BRCA-mutation-carrying men, with a an 8% cumulative risk, while, according to research, the risk of colon cancer is 4-5 times higher both in women and in men, with a 6% cumulative risk.
Possible preventive therapies to reduce the risk of developing cancer
* In contralateral breast cancer.