Which type of cancer is the most curable?

The One Prevented: The best way to cure a cancer is to identify who is at highest risk and take measures to prevent that cancer from developing. Prevention includes avoiding known carcinogens: our greatest cancer foe remains tobacco. Short of this goal, the next best strategy is to "screen" for cancer: widespread testing of at-risk populations before symptoms develop (mammograms, colonoscopy, prostate, etc).

Early stage: All cancers are curable if caught early enough to be removed or otherwise treated. The more dangerous cancers are the ones which spread early and/or are difficult to detect until it is too late.