Why though? Not a loaded question genuinely curious. More smoking up north?
Exposure to Radon is the #1 cause of lung cancer on non-smoker. Canada ranks third on indoor radon concentration worldwide.
Colorectal is significantly effected by diet, physical activity and obesity.
Colorectal is an interesting case as we are already at a place where, by using current screening techniques in a well targeted manner we could essentially eliminate it.
As such, different approaches, or funding, or attitudes to screening could also lead to big disparities in incidence and ultimately survival.