Author Topic: New study regarding AN growth  (Read 151 times)


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New study regarding AN growth
« on: August 20, 2019, 10:54:33 am »
Hot off the presses,

J Neurosurg. 2019 Aug 2:1-7. doi: 10.3171/2019.5.JNS1923. [Epub ahead of print]
Volumetric growth rates of untreated vestibular schwannomas.
Schnurman Z1, Nakamura A1, McQuinn MW1, Golfinos JG1, Roland JT2, Kondziolka D1.

There remains a large discrepancy among surgeons in expectations of vestibular schwannoma (VS) growth. The anticipated growth rate of a VS and its potential clinical impact are important factors when deciding whether to observe the lesion over time or to intervene. Previous studies of VS natural growth remain limited, mostly confined to linear measurements, often without high-resolution, thin-sequence imaging. The present study comprehensively assessed natural tumor growth rates using volumetric measurements.
Between 2012 and 2018, 212 treatment-naïve patients diagnosed with a unilateral VS were evaluated. A total of 699 MR images were assessed, with a range of 2-11 MR images per patient. All MR images preceded any intervention, with patients subsequently being observed through completion of data analysis (36%) or treated with stereotactic radiosurgery (32%) or microsurgical resection (32%). To determine precise tumor volumes, the tumor area was outlined on every slice, and the products of the area and slice thickness were summed (99% of scans were ≤ 1-mm slice thickness). A multilevel model with random effects was used to assess the mean volume change over time. Each tumor was categorized as one of the following: growing (volume increase by more than 20% per year), fast growing (volume increase by more than 100% per year), stable (volume change between 20% decrease and 20% increase per year), and shrinking (volume decrease by more than 20% per year).
The mean VS volumetric growth rate was 33.5% per year (95% CI 26.9%-40.5%, p < 0.001). When assessing the frequencies of individual tumor annual growth rates, 66% demonstrated growth (30% fast growing), 33% were stable, and 1% exhibited shrinking over an average interval of 25 months. Larger tumors were associated with increased absolute growth, but there was no relationship between tumor size and proportional growth rate. There was also no relationship between patient age and tumor growth rate.
This study comprehensively assessed VS volumetric growth rates using high-resolution images and was conducted in a large and diverse patient sample. The majority of the tumors exhibited growth, with about one-third growing at a rate of 100% per year. These findings may contribute to a consensus understanding of tumor behavior and inform clinical decisions regarding whether to intervene or observe.


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Re: New study regarding AN growth
« Reply #1 on: August 20, 2019, 05:10:42 pm »
Thanks for that very recent article. The findings surprise me as they are not consistent with other studies. Hopefully this study initiates debate among the profession. And I bet it will.

The study findings may be academic since what really matters is, is it still growing in your case. Waiting for 2 followup MRIs 6 months apart may prevent surgery in some cases since "33% were stable". If it growing rapidly and threatening to exceed 2 cm diameter, you probably want to act.

My examination of studies on what percentage of vestibular schwannoma tumors grow is at . My summary of the papers is that about 13% of tumors grow more than 2 mm.