The use of the space for additional information in the Common App

“You may use the space below to provide any additional information you wish to share. You may enter up to 650 words.”
I am thinking of including here how both of my parents battled cancer, and how it shaped my mentality. I know that this is not a place for another essay so I will try to keep it short.
Please tell me if you think this is suitable or not. If yes, do you have any advice on what form to write it?