"Should a woman have a preventive mastectomy if her lifetime breast cancer risk is 25 percent compared to the average woman’s risk of 12 percent?" The risk percentage of breast cancer by mutations of the known genes BRCA1 and BRCA2 were high enough, one would say, to make informed choices of whether to undergo mastectomy. There are now new mutations that are not as high and make choices tough for women. Read about the study.
After Angelina Julie's double mastectomy, the number of women who undergo screening has significantly risen up. She had mutations in the genes BRCA1 and BRCA2. She had a risk of 50-70% of developing breast cancer in her lifetime. To her, the choice was probably easier than for other women.
There are now more newly identified mutations that could raise the risk of breast cancer. The problem is that they are not as highly indicative as the BRCA1 and BRCA2. Women faced with percentages as 25% are in a tough choice situation regarding undergoing an elective mastectomy.
According to studies, one of those genes is PALB2 and it is associated with 35% chance of breast cancer by 70 years of age. Experts state that decisions depend on a detailed and individualized discussion of each patient and their family history.
There has been over 12 mutation genes tested over the last year. But they are low effect and probably associated with other factors like smoking.
The Boston Globe: http://www.bostonglobe.com/lifestyle/health-wellness/2014/08/17/screening-for-new-breast-cancer-genes-leaves-women-with-tough-choices/CU2GU8JC2eyjy06idePPMJ/story.html