Greg,
A TaG1 tumor is actually not too bad a prognosis - It might just be the wake-up call to stop using tobacco in any form. The way I understand it is that the carcinogens from the dip smokless tobacco are absorbed into your bloodstream through the lip, your blood is then filtered by your kidneys, which remove all the bad carcinogens and dump them into your bladder via urine. The urine sits in your bladder with all these bad carcinogens and mutates your bladder lining cells... then whalla! You get a bladder tumor.
I personally think the best thing you can do at this point is quit any form of tobacco and thank your lucky starts it wasn't an invasive tumor. I wish mine was such a mild, non-agressive grade tumor.
I think there is not a whole lot of research into how bad the smokeless tobacco is, for all I know it may have far more nasty bladder cancer causing carcinogens than cigarettes.
Of course they can never tell for sure whether your chewing caused it, but I would put a high probability that my can-a-day of Kodiak snuff tobacco habit for 20 years did.