I don't know your age, but if you started in mid teens, the latest stats show that you are 300% more likely to die of cancer than someone that starts in their twenties. This came from good research by the way.
It's vital to beat the habit. I won't describe on this forum watching my neighbor kill himself. It was horrible, they cremated him the other day.
30 years of my mother's life was totally wrecked by smoking. It didn't kill her, but for years she wished it had. O2 bottles, nebulizers, hanging on to furniture to get across the room...it became just a way of life.
Do what 5LY says, stop, but tell them. They know that the cleaning out mechanisms will be working hard - for the first time in ages, and accept the resultant produce.