If a person has a history of breast cancer they may be on certain medications or undergoing various treatment options( i.e. chemotherapy, hormonal therapies). These medications or therapies could make them more susceptible to light energies such as Lasers and IPL used for hair removal. A free consultation with full disclosure of all medications and ongoing therapies would be essential to determine the safety of light energy utilization for hair removal. Sometimes Testosterone supplementation is utilized for advanced breast cancer and at these high doses of Testosterone a person can see increased unwanted hair growth which is quite amenable to removal using light energy techniques. I would also recommend a small sample area be tried prior to large area treatments.I hope that helps you. Good luck.