Hi Alan,
Little clinical evidence exists that milk actually increases cancer risk:
-There is some evidence skim milk - but not whole milk - may increase prostate cancer risk.
-There is no consistent evidence relating milk to breast- or esophageal cancer risk.
-There is some evidence that milk decreases colorectal and bladder cancer risk.
-I'm not sure about other types of cancer.
-Up till now, I never read a clinical study which found milk to increase total cancer risk.
I'm not sure about the sugar thing. Here's the finding by the WCRF (october 2007): http://www.dietandcancerreport.org