If vitamin supplements are really to be considered serious alternatives for cancer treatment, they should prove themselves in clinical trials. Human experiments outside reproducible experimental parameters, however, are nothing more than quackery.
You quickly see what the so much advertised remedies are really about when you look at the nice flyers on which remedies for athlete's foot, hair loss, asthma and cancer are advertised right next to each other. Very serious stuff...
At WDR.de you can find the original article.