One of the reasons is that health budgets in many Latinoamerican countries is low. So that preventive medicine is restricted to vaccination, but there are no other measures taken in this field. A great part of the population have restricted access to a good quality health care, so by the time a disease is diagnosed, it is far advanced. About cancer in younger populations I think that Latinoamerica has the same or fairly similar averages as the rest of the world.