Impact of androgen deprivation therapy on apparent diffusion coefficient and T2w MRI for histogram and texture analysis with respect to focal radiotherapy of prostate cancer

Abstract

Purpose Accurate prostate cancer (PCa) detection is essential for planning focal external beam radiotherapy (EBRT). While biparametric MRI (bpMRI) including T2-weighted (T2w) and diffusion-weighted images (DWI) is an accurate tool to localize PCa, its value is less clear in the case of additional androgen deprivation therapy (ADT). The aim of this study was to investigate the value of a textural feature (TF) approach on bpMRI analysis in prostate cancer patients with and without neoadjuvant ADT with respect to future dose-painting applications. Methods 28 PCa patients (54–80 years) with ( n = 14) and without ( n = 14) ADT who underwent bpMRI with T2w and DWI were analyzed retrospectively. Lesions, central gland (CG), and peripheral zone (PZ) were delineated by an experienced urogenital radiologist based on localized pre-therapeutic histopathology. Histogram parameters and 20 Haralick TF were calculated. Regional differences (i. e., tumor vs. PZ, tumor vs. CG) were analyzed for all imaging parameters. Receiver-operating characteristic (ROC) analysis was performed to measure diagnostic performance to distinguish PCa from benign prostate tissue and to identify the features with best discriminative power in both patient groups. Results The obtained sensitivities were equivalent or superior when utilizing the TF in the no-ADT group, while specificity was higher for the histogram parameters. However, in the ADT group, TF outperformed the conventional histogram parameters in both specificity and sensitivity. Rule-in and rule-out criteria for ADT patients could exclusively be defined with the aid of TF. Conclusions The TF approach has the potential for quantitative image-assisted boost volume delineation in PCa patients even if they are undergoing neoadjuvant ADT. Electronic supplementary material The online version of this article (10.1007/s00066-018-1402-3) contains supplementary material, which is available to authorized users.

Impact of neoadjuvant androgen deprivation therapy on magnetic resonance imaging features in prostate cancer before radiotherapy

“…ADT affects the tumour and results in decreased prostate cancer conspicuity on MRI [1] , [2] , [3] , [12] , [13] . This challenges the use of MRI, after neoadjuvant hormonal therapy, for RT target delineation.…”

“…There is a growing interest in the use of advanced imaging for dose prescription and planning [14] . For MRI, image texture analysis has been suggested as a supporting tool to separate tumour from normal tissue [15] , even in cases with low contrast between tumour and surrounding tissue [13] . Texture features for prostate cancer [16] , [17] , [18] , [19] can be derived using grey-level co-occurrence matrices (GLCM) with the aim to separate or classify different tissue types.…”

4D perfusion CT of prostate cancer for image-guided radiotherapy planning: A proof of concept study

“…In addition to lesion detection and lesion segmentation, quantitative and other advanced imaging methods have been explored for response assessment [2,30,31]. Although, at present, most studies concerning lesion characterization for both segmentation and response assessment focus on mpMRI, DCE-CT might also be of value in the response assessment and serve as an imaging biomarker for these patients.…”

“…Radiotherapy encompassing external beam intensity-modulated radiation therapy (IMRT) and brachytherapy represent established treatment options for patients with localized prostate cancer (PCa). In the current daily clinical routine, it is still recommended to include the whole prostate in the clinical target volume for radiotherapy [1,2]. As local recurrences mainly occur at the site of the primary tumor lesion [3], ongoing efforts are being made to establish a boost focused on the tumor tissue, with a current standard dose for the remaining prostate [4].…”

MR-Guided Radiotherapy for Prostate Cancer

“…This is achievable on 1.5 T MR-linacs with diffusion scanning capabilities but, at present, 0.35T machines do not provide sufficient resolution to visualize DILs. Therefore rigid propagation is one option for this technique on a 0.35T MR-linac but alternative techniques to improve primary tumor visibility may be required; these have been employed in the diagnostic MR setting ( 63 ) but not as of yet in the therapeutic field. The feasibility of DIL visualization is also decreased with concomitant androgen deprivation therapy ( 62 ).…”