weebarra glad it went well, I wish you a swift recovery 
I knew the cause of my cancer as when they found the tumour they also found over a hundred polyps so knew I must have one of several genetic conditions. I'm not sure it has made any difference to me. Although I get a lot of "bowel cancer? But you're so young" so it can be helpful to say it was caused by a genetic condition, just as something to say! :)
From a scientific point of view, looking into all the possible causes is really important. It's all very well looking for better treatments and hopefully cures for cancers, but it would be even better if as many as possible could be prevented. I hate smoking, I find it disgusting, but I'd never wish that a smoker got cancer or blame them for being ill. Years ago smoking was thought to be harmless, even healthy. I'm sure there are things we do nowadays that will later be found to contribute to cancer risk, it doesn't mean anyone deserves cancer. I find the cellular stuff about how cells become cancerous and why some go on to cause cancer and others are killed straight away quite fascinating. I'm planning to do a bit of reading about it when I've finished my degree.
Some people react to any hint of a cause or contributing factor as being blame, but it isn't usually. With smoking, quite possibly, but when it comes to other cancers, I don't think anyone blames people. It's more that if causes can be identified, they can be avoided if at to all possible. For example, it would be good to know one way or another with the whole aluminium deodorant issue. If it was shown conclusively that aluminium in deodorant increased risk of cancer then there would be a rush to develop decent aluminium-free deodorants and that would reduce future risk, without people having to make the decision to have a less effective deodorant, just in case. Or if they're definitely safe then researchers can focus on other possible causes. I don't think anyone would say that people who had used deodorants were in any way to blame for their cancer.
I take the pill at the moment. If, heaven forbid, I were to get breast cancer in the future, I wouldn't accept any blame for it. I've made a conscious decision that a small risk of breast cancer in a future that I may not have is worth it for a reduction in discomfort and nerve pain now (period pains affect my new bowel design).