ESTRO 2024 - Abstract Book

S915

Clinical - CNS

ESTRO 2024

Results:

Overall, 118 patients were considered eligible for the purpose of the volumetric analysis. After a mean time of follow-up of 86.5 months (median 84, range 60 – 120 months) the median reduction in tumor volume was -26%. Baseline volumes were similar in each group (p = 0.092), and final volumes were significantly larger in tumors that progressed (p < 0.001) using a ΔV of 20% as a cutoff for progression. The 20% ΔV became significantly different starting from 10 months after f-RS, with continued diversion up to 36 months. The optimal number of clusters was found to be 4, identifiable as the groups progression disease (PD), stable disease (SD), partial response (PR), and complete response (CR). The following cut- off values of ΔV% suitable for separating the aforementioned clusters were determined: about +20% between PD and SD, -20% between SD and PR, and -42% between PR and CR. Furthermore, as an exploratory analysis, we found that all patients that had at least +20% ΔV at any follow -up were the only ones that showed an increased tumor volume at last visit with respect to baseline, meaning that such cut off was well-calibrated and temporally robust.

Conclusion:

Our results suggest quantitative volumetric assessment of tumor response to f-RS may help clinicians to better understand early response profiles and provide a valuable tool for patient management following f-RS for meningiomas.

Keywords: meningioma, radiosurgery, outcome

References:

[1] R.M. Starke, B.J. Williams, C. Hiles, J.H. Nguyen, M.Y. Elsharkawy, J.P. Sheehan. Gamma knife surgery for skull base meningiomas: clinical article. J. Neurosurg., 116 (3) (2012), pp. 588-

[2] Hartigan, J. A., Wong, M. A. (1979) Algorithm AS 136: A K-Means Clustering Algorithm. Journal of the Royal Statistical Society. Series C: Applied Statistics, 28(1), 100 – 108. https://doi.org/10.2307/2346830

[3] Tibshirani, R., Walther, G., Hastie, T. (2001) Estimating the Number of Clusters in a Data Set Via the Gap Statistic. Journal of the Royal Statistical Society. Series B: Statistical Methodology, 63(2), 411 – 423. https://doi.org/10.1111/1467-9868.00293

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Digital Poster

Long-term outcomes of paediatric and adult craniopharyngioma treated with multimodality approach.

Anjali V Ramdulari 1 , Aswin Ravi 1 , Anindya Dutta 1 , Vaishali Suri 2 , Manoj Phalak 3 , Haresh K Parambath 1 , Subhash Gupta 1