Keven Ayse, Gürbüz Ahmet Faruk, Özgül İsmail, Özen Anıl, Arslan Ahmet Gökhan, Çubuk Süleyman Metin
Department of Radiology, Akdeniz University, School of Medicine, Antalya, Turkey.
Department of General Surgery, Akdeniz University, School of Medicine, Antalya, Turkey.
Abdom Radiol (NY). 2025 Aug 14. doi: 10.1007/s00261-025-05161-x.
Microsatellite instability (MSI) status in rectal cancer has significant implications for treatment selection, particularly regarding immunotherapy eligibility. This study aimed to evaluate the preoperative magnetic resonance imaging (MRI) features, specifically regional lymph node morphology, in predicting MSI status in rectal cancer patients.
This retrospective, single-center observational study analyzed 80 patients with histopathologically confirmed rectal cancer who underwent preoperative MRI and MSI/mismatch repair protein expression analysis between August 2021 and January 2025. Two experienced radiologists independently assessed radiological features through consensus reading. Evaluated parameters included tumor localization, T-stage, growth pattern, volume, apparent diffusion coefficient values, T2 signal characteristics, and lymph node features encompassing necrosis presence, contour characteristics, location, and short-axis diameter. Statistical analysis employed univariate and multivariate logistic regression to identify independent predictors of MSI status.
Among 80 patients, 23 (28.8%) were MSI-positive and 57 (71.2%) were MSI-negative. Multivariate analysis identified three independent predictors of MSI positivity: lymph node necrosis on T1-weighted contrast-enhanced MRI (OR: 7.86, 95% CI: 1.68-36.79, p = 0.010), intermediate-risk tumor T-stage (T3b) (OR: 6.19, 95% CI: 1.43-26.68, p = 0.015), and polypoid growth pattern (OR: 6.14, 95% CI: 1.06-35.54, p = 0.043). Lymph node necrosis demonstrated significantly higher prevalence in MSI-positive patients compared to MSI-negative patients (26.1% vs. 7.0%, p = 0.029).
Lymph node necrosis on T1-weighted contrast-enhanced MRI, intermediate-risk T-stage (T3b), and polypoid growth pattern serve as valuable radiological biomarkers for predicting MSI status in rectal cancer. These imaging features enable preoperative patient stratification, facilitating personalized treatment planning and appropriate selection of candidates for immunotherapy.
直肠癌中的微卫星不稳定性（MSI）状态对治疗选择具有重要意义，尤其是在免疫治疗适用性方面。本研究旨在评估术前磁共振成像（MRI）特征，特别是区域淋巴结形态，以预测直肠癌患者的MSI状态。
这项回顾性、单中心观察性研究分析了80例经组织病理学确诊的直肠癌患者，这些患者在2021年8月至2025年1月期间接受了术前MRI检查以及MSI/错配修复蛋白表达分析。两名经验丰富的放射科医生通过一致性阅读独立评估放射学特征。评估参数包括肿瘤定位、T分期、生长模式、体积、表观扩散系数值、T2信号特征以及淋巴结特征，包括有无坏死、轮廓特征、位置和短轴直径。采用单因素和多因素逻辑回归进行统计分析，以确定MSI状态的独立预测因素。
80例患者中，23例（28.8%）为MSI阳性，57例（71.2%）为MSI阴性。多因素分析确定了MSI阳性的三个独立预测因素：T1加权对比增强MRI上的淋巴结坏死（OR：7.86，95%CI：1.68 - 36.79，p = 0.010）、中危肿瘤T分期（T3b）（OR：6.19，95%CI：1.43 - 26.68，p = 0.015）和息肉样生长模式（OR：6.14，95%CI：1.06 - 35.54，p = 0.043）。与MSI阴性患者相比，MSI阳性患者中淋巴结坏死的发生率显著更高（26.1%对7.0%，p = 0.029）。
T1加权对比增强MRI上的淋巴结坏死、中危T分期（T3b）和息肉样生长模式是预测直肠癌MSI状态的有价值的放射学生物标志物。这些影像学特征能够实现术前患者分层，有助于个性化治疗规划以及免疫治疗候选者的恰当选择。
