I hate these thoughts that are at the back of my mind

There is a screening test which checks how prone the genese of a person are to different types of cancer. I think I should do it since there is a history in my family .. But I keep postponing. Part of me feels it is a waste of money, because genese play very little role after-all as most cancer cases are not genetic actually, and I remember the doctor also telling me that some results may be "un-determined" and so many other disclaimers that I almost asked, what is the point... But I don't think this is the main reason.. The cost of the test isn't anything that I cannot afford.. But I feel I just don't have the mental strength to even think of that disease, or that I don't want to find out...

But I keep thinking, better safe than sorry.. It could actually be a good idea to do it, to take preventative or detective measures, if i need to.. and I will probably do it at some point... but I just hate to think about it anymore....