Why are there no cancer studies ?

Hi,

I have a question. In the Q&A of the cancer page I can read that studies about cancer therapies don't exist because there is no protocol to compare all the holistic remedies, used in such a cancer therapy, with a placebo. Science can not make such a placebo yet. But there are studies about CHD for instance with multi-faceted factors combined in one study (http://www.nhlbi.nih.gov/about/framingham/). So why aren't such studies done on alternative cancer therapies ? What aspects am I missing here ? Can anyone help me to find sound proof of the efficacity of alternative therapies ? The fact the someone is cured can only be used if the causality has been proven.

Thank you for your time !

Luigi