It's important to say that it claims on "two thirds" of cancer types
Different cancer types (stomach, ovary, throat, skin, and a long etc...) vary a lot in incidence (for example blood cancer happens less often than skin cancer)
So "two thirds" of different cancer types is not equal to "two thirds" of all cancer cases! - just because some types are way more common than others.
Also, some cancer types are far more complicated and destructive than others (skin=easy, pancreas=awful)
Anyways, if you live in the USA, the prostate-breast-lung-colon is the worst risk combo because of their cancer frequency and complication danger.
This full combo was, it turns out, either in the "remaining third" of non-random cancers, or in the "non-analysed" data set of this study!http://www.bbc.com/news/health-30641833