I been taking cymbalta for 15 years can i quit cymbalta without tapering?

That is not a good idea. Discuss a taper schedule with your primary care physician or psychiatrist.

Not clear why you are taking Cymbalta, but after 15 yrs, a truly bad idea to stop "cold turkey", as the withdrawal would likely be quite nasty. Work closely with your physicians, and check first if stopping your medication is even feasible, and, if so, taper off slowly over at least 6-8 weeks, under supervision.