Not at all.
Cancer is an extremely complicated thing from a molecular biology perspective, and thus it's the most difficult disease to treat, but the reason for its existence is a corollary of very simple evolutionary logic - complex organisms all evolved from simple ones, and the purpose of all life is self-replication.
When a group of simple organisms establish a symbiotic relationship, e.g. a small bacteria that can more efficiently generate energy (ATP) inside a larger single celled organism (the bacteria gives up some of the energy it generates to the host while the host offers protection to the bacteria), eventually natural selection fuses them into a functional group (in our textbook example the bacteria becomes the mitochondria of a single celled organism).
Now consider that human beings, as all multi-cellular life, are an ensemble of various systems of coordinated cells, tissues as we call them. And in each tissue the cells have so evolved to the group life of a tissue that they have lost their individuality. But life is an inherently selfish endeavour, all biological things seem to be selfish by design (coordination is the selfishness of a group against another group - multi-cellular organisms against other multi-celluar organisms).
So what happens when a cell in a group such as a tissue regains its individuality?
Cancer.
Cancer is, basically, a cell regaining its individuality and doing what all life does - replicating its self - at the expense of progressively decreasing functionality for the coordination of the group from which it once derived, the tissues of our bodies.
Cancer is literally the evolution of cooperation unravelling, which is - fundamentally - why it's so difficult to fight. It isn't a foreign invader like a bacteria or a virus - it's literally your own body turning against itself, some of your cells giving up the group life for the selfishness of self-replication, that thing that so far as we know - drives all life.
