ICD-10 Drug and Neoplasm Document Definition 2019-05-17 Allows the new/old tags to identify modifications in the addenda. Table cell (TH) definition supporting new/old tags. Collection tag for column headers sub-elements (head tags). Table cell (TD) definition supporting new/old tags. Sub-elements shared across term and mainTerm elements. Sub-class mainTerm and add the level attribute to it. The mainTerm type is the base term element. Top level element and direct child-element sequence.