Abstract
Objective: a considerable subgroup of meningiomas (MN) exhibit indolent and insidious growth. Strategies to detect earlier treatment responses based on tumour biology rather than on size can be useful. We aimed to characterize therapy-induced changes in the apparent diffusion coefficient (ADC) of MN treated with proton-therapy (PT), determining whether the pre- and early post-treatment ADC values may predict tumour response. Methods: Forty-four subjects with MN treated with PT were retrospectively enrolled. All patients underwent conventional magnetic resonance imaging (MRI) including diffusion-weighted imaging (DWI) at baseline and each 3 months for a follow-up period up to 36 months after the beginning of PT. Mean relative ADC (rADCm) values of 46 MN were measured at each exam. The volume variation percentage (VV) for each MN was calculated. The Wilcoxon test was used to assess the differences in rADCm values between pre-treatment and post-treatment exams. Patients were grouped in terms of VV (threshold −20%). A p < 0.05 was considered statistically significant for all the tests. Results: A significant progressive increase of rADCm values was detected at each time point when compared to baseline rADCm (p < 0.05). Subjects that showed higher pre-treatment rADCm values had no significant volume changes or showed volume increase, while subjects that showed a VV < −20% had significantly lower pre-treatment rADCm values. Higher and earlier rADCm increases (3 months) are related to greater volume reduction. Conclusion: In MN treated with PT, pre-treatment rADCm values and longitudinal rADCm changes may predict treatment response.
Highlights
Meningiomas (MN) are extra-axial tumours arising from the inner layer of the dura
From the overall patient samples that were screened (n = 67), not all of them had a diffusion-weighted imaging (DWI) sequence acquired at the 1-month pre-treatment exam (14) and/or magnetic resonance imaging (MRI) acquired in our institute (n = 7)
Our study revealed the utility of DWI in the detection of early tumour response and its ability to predict treatment outcome in MN patients treated with PT since MN structural changes induced by PT can be detected and quantified in vivo with DWI through apparent diffusion coefficient (ADC) maps
Summary
Meningiomas (MN) are extra-axial tumours arising from the inner layer of the dura. They are the most common adult intracranial tumour, and most of them are benign [1]. In the case of partial excision, difficult surgical accessibility, recurrence, and higher-grade MN (WHO II and III), other kinds of treatments can be considered These include photon-based fractionated radiotherapy, intensity-modulated radiotherapy, volumetric modulated arc therapy, and stereotactic radiotherapy [2,3]. Protons deliver a lower entry dose, depositing the majority of their energy at the end of their path, yielding a typical narrow dose energy peak called the “Bragg peak” [5] This steep fall-off allows for the delivery of high doses and spares of healthy tissue beyond the tumour, reducing acute and late side effects. A considerable subgroup of MN exhibit indolent and insidious growth In these cases, other strategies to detect earlier treatment responses and to refine treatment decisions based on tumour biology rather than only on size can be useful [7]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
