I agree cancer sucks, that being said I think your contagious cancer fear is slightly overblown. Cancer in which a transmissible clone of a cancerous cell manages to evolve into full blown cancer in another host is super rare. I think there's like 3 types of cancer identified in animals that behave like that at best.
It is and isn't overblown. We're not going to wake up one day and it spreading like the common cold, but bacteria, diseases, and the like do evolve over time. The 'contagious' cancer is shared through bodily functions, Ie saliva, sexual intercourse, etc., but it's only been found in three different types of animals so far, most recently it evolved in Tasmanian Devils, in which is two kinds of cancer that can spread exist now.
It's super rare now, and that isn't going to change overnight, but also a bit alarming, since if contagious cancer can adapt to different kinds of animals (clams are one of the three animals found to have it, and the other two including Tasmanian Devils are mammals, the other one being types of dogs), and the mere fact it can become a thing, get to that point, does mean that the possibility of a type of cancer adapting abilities to do this in humans is not out of the question. Cancer that transfers between species (or diseases in general) are extremely rare, I think more the fear is if a type of cancer that afflicts us wisens up to the point to become contagious, not that we'd catch it from Tasmanian Devils.
But like anything evolving, it takes time, and this occurrence, as said, is incredibly rare in nature. In general we need to cure cancer because, well, it's not that uncommon as is and cancer is a bitch. But, hypothetically, if cancer were to become contagious before we cure it, it'd be quite disastrous. The one found in dogs that's spread sexually is one thing, having sex or not is a controlled variable. The fearful thing is the recent one that has bloomed in Tasmanian Devils that can spread through saliva and such things.
But there's no set thing to say it will happen to humans, as to the, "if it does," part of my message, but it's scary to think about, but currently there is no threat in it to humans. I think the scary part of the news isn't that it's something that will happen to humans soon, but if forms of cancers and tumors can become contagious in other animals, then the possibility exists something like this could develop in human diseases at some point in the future. That's not to say that it will happen, but since it's something that's naturally occurred in other species, even though at this time incredibly rare, does show that it can happen.
You might as well make that game Dragon's Dogma at this point and join the hype train.
For what it's worth, Obama just pledged to pump additional cancer funding money into Cancer research the other day during the State of the Union.
Which is good, and I feel more people may take action on it too. My mother is a cancer survivor, but yes, cancer is a bitch.