I sure would not think that the scare tissue (probably what it is) would turn into cancer. I am pretty sure on this.
Chronic inflammation can cause cancer, in fact it is one of the main causes. So you want to make sure that there is no inflammation in your throat. I mean it doesn't always happen this way but it is very possible. You should probably go to the doctor if you feel like there is inflammation in your throat. And what your feeling may not be a cyst. Its always good to get checked out.
Have you involved anyone from the medical field concerning this issue, I don't think it would cause cancer but as you age it could interfer with swallowing,has this cyst be removed? You do understand your eyes,ears,nose and throat are connected,I would have it checked if it is not bothering you the doctor more than likely will not bother it,OK hope this helps...