"do not go gentle into that good night"

"but rage rage against the dying of the light".
What ho, the philosophical poet doth entereth!
Dylan Thomas wrote this poem, it is said, for his dying father. Makes me wonder though, should you fight against death or should you go gently? It is after all a "Good night".
Of course my wondering has at its core nasty old cancer, the thing that prompts a perhaps hastier shuffling of the mortal coil that one would have liked or chosen.
My scans are due so thoughts of mortality abound.
Another internet friend also seems to be losing the fight against cancer. Notice how one "fights" cancer but not measles, mumps or a heart attack. My question is this, is the fight worthwhile if you die in the end? It's not a question that I ask lightly or that arises from a sense of scorn at those who DO fight. When someone engages in a fight against cancer, they become awe-inspiring, people who transcend some of the shit that is part of life, their energy humour and determination leaves me breathless. I just want to know, is it worth it?