Extract strings containing digit characters with StringCases

I have a large string like this:

string = {"text, 1998, TEXTDATA, text, 2007, NEXTTEXTDATA"};

Now I want to extract TEXTDATA and NEXTTEXTDATA. I tried to use StringCases and Shortestin combination with DigitCharacterlike this:

StringCases[string, Shortest[DigitCharacter .. ~~ ___ ~~ ", "]]

but this of course yields only

(* {{"1998, ", "2007, "}} *)

So either there is a way to combine DigitCharacterwith the FIRST comma (and then probably Shortestwould work) or there is a way without Shortest?