The disease tragically took the lives of both the TV-presenter's grandmother and her mother, Fiona, who died at 66 after a 26-year-battle.
Five other female relatives have also suffered from scares, but the 44-year-old said 'I'm not mucking around or burying my head in the sand. I'm not doing this without medical advice.'
Despite her sister, Sofie, 35, undergoing a double mastectomy in 2010 - which, at the time, she likened the procedure to removing 'a potential time bomb' - Kirstie has decided to take a different preventative strategy.
The Location, Location, Location host will have; 'Annual ultrasound scans, as well as a mammogram, which is something my doctors tell me is a perfectly safe and acceptable treatment plan.'
Kirstie has also restricted her diet, cutting down drinking to once a month, to minimize risk and insisted that it would be wrong to describe this as 'a wait and see approach'.
The star, who has two sons, Bay, nine, and Oscar, seven, with husband Ben Anderson, 53, as well as two stepchildren, argued that the operation would take a big chunk of time out of her life.
Kirstie with her sister Sofie, who underwent a double mastectomy in 2010
'My understanding is that genetic breast cancer tends to affect women younger than other types of cancer - I'm already ten years older than my mother was when she got it.'
Reflecting on her mum's fight she said; 'Mum had surgery, radiotherapy and chemo again and it was another six or seven years before secondaries - metastasies - appeared and in the end she had cancer in her liver, bones, chest and brain.'
Kirstie says that for her mother it was a case of lightning striking in the same place twice.
The TV-presenter also spoke of Angelina Jolie's decision to have a mastectomy as'brave' but questioned whether being able to go straight back to work, as Angelina claimed, was a reality for most women.
'It's not something you do over a long weekend.'