The topic of this thread is interesting, although there have been no entries for a while. The paper that this thread refers to is uncertain. However, it appears to be "The Natural History of Vestibular Schwannoma" published in 2006. (
http://acusticusneurinom.dk/wp-content/uploads/2015/10/natural-history-of-vs.pdf ) In any case, it covers the same sort of material.
The paper mentioned here covers the Danish findings with 552 patients followed. Yes, the main finding is that, "Regardless of tumor localization or size, growth occurs only within the first 5 years after a diagnosis".
Of interest is that the authors state "all previous studies on VS growth have been subject to considerable referral bias and additional patient selection bias" and that in the paper's case, "The data are without patient referral bias".
For extrameatal tumors, a change of more than 2 mm was defined as growth or shrinkage. With this criteria, for extrameatal tumors, 0.9% decreased in size, 70.2% remained unchanged and 28.9% increased in diameter.
Another interesting aspect is that of those 28.9% of extrameatal tumors that did grow, 62% happened in the first year, 26% in the second, 10% in the third and 2% in the forth year following diagnosis. None grew in the fifth year onwards! The main annual growth rate was 10.32 mm in the first year, 3.83 mm in the second, 2.17 in the third and 0.92 mm in the fourth year. Of course, before diagnosis the tumor grew sufficiently to create symptoms.
It's a fascinating paper.