Article Review: Tumors grow in 31% ... or is it 13% of cases

[ANSydney]

The following table is from "Conservative Management of Vestibular Schwannoma" (2014) ( http://www.elsevier.es/en-revista-acta-otorrinolaringologica-espanola-402-articulo-conservative-management-vestibular-schwannoma-S2173573514000957 ). The table is a meta analysis showing the observed growth in 8 studies plus a study from the authors.



What is interesting is that the percent of tumors that grew in various studies is either 13 ± 1% or 31 ± 1%. Nothing in between!

So, what is it? Do 13% or 31% of tumors grow (more than 2 mm)?

[ANSydney]

The mystery may have been solved. For Suryanarayanan, "Tumour growth was defined as an increase in the maximum tumour dimension of more than 1 mm along the same axis on serial scans."

Therefore, apart from the first two entries, the prevailing number of tumors that grew > 2 mm was 13 ± 1%. There are also suggestions that both figures are correct, depending on whether your growth threshold is 1 mm or 2 mm.

In summary, it appears that the evidence is that about 13% of tumors grow more than 2 mm.

[Blw]

"In 87.7% of patients there was no evidence of tumour growth."

[ANSydney]

Yes, the article referenced and the last entry in the table has only 12.3% of tumors demonstrate growth beyond 2 mm.

I came across a more recent article, that was published in October 2016. It's entitled "Size as a Risk Factor for Growing Conservatively Managed Vestibular Schwannomas". It observed 555 tumors and observed that 11.9% of "Tumors that had shown more than 1-mm increase in diameter".

So, it appears that in the 1990's it was thought that about 31% of tumors grew more than 2 mm, then in the first decade of the 2000's that about 13% of tumors grew more than 2 mm and now it's down to about 11.9% that grow more than 1 mm. The trend is certainly towards reporting fewer tumors that grow. Why?

Has tumor growth pattern changed over the decades or has measurement techniques become more accurate. In the past, perhaps only using films, it would have been more difficult to take measurements. If in doubt, it would have been prudent to err on the side of caution. Now that measurements can be made using a computer, perhaps more accurate growth details can be reported.

[Blw]

Better imaging. Better measurement. Better management so that the best time to measure is known.