One of the cancers they mention is pancreatic cancer.

A quick Google search suggests the prevalence of pancreatic cancer in the population is 13 per 100,000.

So if you gave this test with a 0.005 false positive rate and 0.5 true positive rate to 100,000 people it would miss diagnose 500 people and only correctly detect 7 cancers.

So given you had a positive test result there would be a 1-(7/500)=98.6% chance you did _not_ have pancreatic cancer.

Doesn't seem very useful in that light...