Risk depends on your individual susceptibility, the amount you smoke on a day-to-day basis over time, and over how many years. If you don't inhale, as you shouldn't, risks are lip, throat and oral cancers. Some pipe smokers "retro-hale," which involves nasal passages. For moderate smokers, the risk is relatively low, but this depends on your susceptibility. Some people just won't be affected. My father smoked pipes or cigars from after breakfast to bedtime over decades from the age of 15, finally quitting cold turkey when he was (I think) 65. He died at 89 licensed to drive without glasses. He had little or no susceptibility to cancer from tobacco as he used it. Others have probably had trouble with much less use. I'd recommend moderate use, if you are going to smoke a pipe.