Understanding

Today is a short one possibly... I am just trying to understand. Why do children die of cancer? I know this isn't a specifically new question, but it deserves an answer. A young child died last week which is horrible enough, but he is just one of many. What kind of world is this? When somebody dies as an adult, they are made up of both good and bad traits. However, a child... a child is someone who hasn't had a chance to even develop these. It is a death of pure innocence. Their life brought joy, but the death brings only pain to people who don't deserve to be hurt, and death to someone who deserves nothing but life. I know life isn't perfect, but robbing that is just wrong. I don't get it. Who is held accountable for this, somebody, or something needs to answer for all the children in the world that die. There is no justification that I can see. I don't think I will ever understand senseless death, and to be honest I hope I never do.