Ben,
I think you are absolutely nuts still smoking 2 packs of cigarettes a day. I'm not going to go digging for the research, but I believe there have been several studies that show a more negative prognosis for continued tabacco users. The cancer cells are linked to carcinogens from tobacco use being filtered out of the bloodstream by your kidneys and dropped into your bladder... where they sit and mutate your bladder lining.
So, if you are willing to gamble with your bladder or life, I guess it's up to you! I was a can a day tobacco chewer for 20 years and got my wakeup call at 35YO with an agressive superficial tumor (T1G3)... I quit the day I found out I had cancer and haven't touched the stuff since (and no desire too). Luckily I have been cancer free over 2 years.
Off my high horse now - I do enjoy a few shots of whiskey every night and I don't take any Oncovite