You should always trust the advice of your general practitioner. However, this seems like a one in a million case where you should NOT do as he says. Smoking leads to cancer and overall bad health. Oh, and this is coming from a smoker!
Yes. any time I hear a doctor recomend something I know to be harmful to me; then i need to ask him again to make sure I heard him correctly and if he still comfirms the reccomendation then I will surely get a second opinion.