What type of cancer was it?
Here's a success story apparently. The medical establishment will come after doctors that are open to B17 treatment in the same way the main stream media is coming after Trump!
Look, Galileo.
That's not how you prove something works.
In this Covid-19 situation some idiots have been drinking bleach and claiming it works cause they either didn't get sick, or got sick but beat the disease. You could replace bleach for orange juice and nothing stops you from concluding orange juice it's effective against Covid. Of course, such conclusion would be idiotic.
You need to randomly assign the treatments, and then compare the results to the group with no treatment or placebo, and the other treatments among themselves as well. That's the only way you can control variables that will likely affect the results, because each group has the same chance of being affected by confounding variables when they're randomly assigned.
Anecdotal evidence is not used to conclude x or y medicine works because you didn't control for confounding variables.