How long does it take to get oral cancer? 20 years?

Depends: I am unaware of any published studies that can quantify how long you have to chew tobacco before being diagnosed. Oral cancer from chewing tobacco is obviously a concern. The number of times you chewed tobacco and your risk of getting oral cancer may also be dependent upon the type of tobacco you chew, the location (if you keep it in the same location), as well as how long you chewed it each time.

Can put time frame: You can never put a time frame on oral cancer. I do a visual oral cancer screening on all my patients every visit 3, 6 months recall visits. I had a patient in a one visit nothing apparent 6 months later something on tongue sent to oral surgeon the to ENT , tongue respected , lasted 8 months. Was the cancer there before it showed itself probable. Now i invested in a special scope, detects early.