No, if your cyst is simple, then you can wait if your doctor feels it is ok. 5cm is just the beginning mark where they consider surgery. Some doctors do wait a bit longer. The concern is more for complex cysts. Although all cysts run a greater risk of rupture as they grow past 5cm, you body handles simple ones much better than complex ones. When a simple cyst rupture, it will release fluid that your body will reabsorb over time. A benign complex cyst like a dermoid has many things inside (like hair, teeth and nails) and it can cause infection . Of course, all malignant cysts are complex. A rupture of a malignant cyst could lead to the spread of cancer. So, the guideline of 5cm is just a starting point and each cyst has to be evluated individually.
Good luck on finding answers and the best treatment!
Shelly
It's possible that it would also depend on how big *you* are. I'm a tiny person - I weigh 90lbs - so 5cm on me takes up a lot more space than 8cm on an average person.
In any event, I'd say that symptoms vary and the impact on your day-to-day life is what they should be taking into account. What the 8cm cut off (not a number I've heard before) probably means is 'regardless of whether this was bothering you, anything over 8cms needs removing'.