The caesium finds its way into tiny pores on the surface, and the only way to remove it effectively is to grindoff the surface, a difficult procedure which can create contaminated dust.
As with the perennial struggle over the horrors of medical malpractice, the question of whether or not to screen for cancer is one of those health-care Holy Wars that will never be resolved merely shunted off into another who-pays economic grind-down because where data ought to rule, emotion will always overrule.