The study used 15-30min of sun exposure…few of us ride that little. Even with sunscreen I think a 3-4 hour ride would still make you come out net negative in terms of risk. Cycling may improve health and wellness in many ways, but I seriously doubt that reduction of skin cancer risk is one of them.
Machka I agree with some of your concerns about transdermal absorption of sunscreen and other body lotions. If you think of the huge surface area covered, and that the skin is the largest organ, the intake could be significant. With face creams and hand lotions the area covered is much smaller, which may be why they get away with so many new fangled additives and fragrances. I think chronic body lotion users should consider using the product only on problem areas instead of all over.
However, the cancer sunscreen correlation you were alluding to I believe is the vitamin D link, not lotion toxicity. Vitamin d is hot with the anticancer folks right now and some believe the sun exposure paranoia has lead to widespread vitamin d deficiency, particularly in northern areas.