>In theory Chemotherapy is a research-backed approach. In practice it is simply the best we have for those that reject proper nutrition and exercise.
Cancer is the result of DNA damage, which you can get from viruses, chemicals (of all types), sunlight, and even background radiation. Plus, I suspect, random errors in DNA transcription. That's why your body has multiple overlapping systems to detect and destroy cancerous cells.
The idea you'll never get cancer if you just eat right and exercise is a fool's hope - if you don't die of something else first you'll get cancer.
And yes, chemo isn't ideal, but it will normally stretch your life out some. It's certainly not the best we have in all cases - there are targeted drugs for some cancers now.
