A little over a year ago, my dog started developing a rapidly growing tumor on his leg. While trying to determine if we could surgically remove it, an x-ray was taken and it was determined that in addition to the external tumor, he also had osteosarcoma (bone cancer) in the same leg, which is quite rare. We soon came to find out that even though we caught it early and his chest x-rays were clear, osteosarcoma always spreads to the lungs. We saw an oncologist vet and he basically said if you do nothing, he will die within 3 months. If you just amputate he will live 4.5-5.5 months. If you amputate and start chemo, he may live about 12 months.
Since either of the two cancers is reason enough to amputate, that's what we did. Since we couldn't afford upwards of $5-10k for chemo and didn't see the point as we were definitively told there is no cure, we didn't pursue any conventional treatment. Instead we read every resource we could on natural cures. He ate a very strict diet and was taking many supplements and other things. 4 months later, we took some chest x-rays and the cancer had spread to his lungs. After a few weeks of him losing his strength, not being able to stand on his own, frequent coughing, and a general loss of will to live, we put him to sleep. That was 5 months after diagnosis. After all we did, he lived just the average.
Alternative cures can certainly perpetuate a false sense of hope. I never expected a miracle, but I certainly thought he could live beyond the average. The simple fact is that our bodies break down and we really don't have the definitive answers as to how to prolong it. Otherwise we would be able to explain how people who drink and smoke their whole lives live to be 90 and those with healthy lifestyles develop disease.