It is not always that you will experience the coming back of nasal polyps after surgery. However there are indeed chance of polyps coming back after a surgery and there is no 100% guarantee that they will vanish for ever.
This is the reason treatment for nasal polyps is required even after the surgery.
You will be prescribed some oral medicines to consume and maybe a steroid spray to prevent the re-occurrence of nasal polyps after surgery.
Some people may only see the symptoms going away temporarily after the surgery.
Some people may not see polyps for many months or perhaps years and then it may re occur after 2-3 years.
It all depends on how well your symptoms are controlled after the surgery.
Some people may respond well with a moderate strength steroid after surgery. While some others may require a stronger steroid to keep the symptoms under control.
Some people even experience worsening of the condition after surgery.
This is why the best doctors will only recommend surgery as that last resort, when nothing else works.