It may also be hard to prove because there were non phillies playing in the same era that died of the same cancer. Gary Carter (who did play on turk in Montreal and many games at the vet), Bobby Murcer, and DIck Howser and Dan Quisenberry come to mind. And those last two only spent 4 games in 1980 at the vet.
The other thing is.. I saw someone say about the heat of afternoon games at the vet possibly being the issue.. where the turf could reach 140 degrees. Even the hottest Sept days didnt get anywhere near that for the Eagles.
But there almost has to be more here than coincidence.. The list of Phillies now include:
Dutch
West
Vuk
Tugger
Johnny Oates
Ken Brett
The other oddity.. Its all catchers, pitchers and Vuk
Oh and then there is this from Jan: