My great-grandfather was a village doctor. After a lifetime of seeing various types of illnesses of the villagers who used to get treated by him, he said that there was no cure for cancer. Yes, various therapies exist to prolong the life of cancer patients but one can be cancer-free only for a limited time as cancer always returns. He also died from stomach cancer. Despite being a doctor, he didn't seek any treatment as he knew it was futile. He just used morphine to manage his pain.
I've lost quite a few of my favourite people to cancer. They endured the harsh treatments and repulsive side-effects of all sorts of medical interventions including painful and invasive surgeries to cure their cancer. It did give them some extra time on this earth, prolonging their life of suffering as their quality of life was severely compromised. But they all finally succumbed to cancer.