There is no clinically established link between breast trauma and the greater risk of a breast cancer.
A close family history of breast cancer (mother, sister, aunt, grandmother) is what puts someone at higher risk of developing breast cancer.
Some women connects appearance of breast bruise to breast trauma, that leads to cancer.
Acctually, there is a type of breast cancer, that is very malicious, that can be initially manifested with a breast bruise (this bruise is not a result of breast trauma, just a symptom of that type of breast cancer).
Don't forget for a monthly breast self examination and clinical breast exam by a health care professional every three years, if you are over 20!
Best wishes!
Marija