早发性直肠癌（EORC）具有独特的疾病过程，与晚发性直肠癌（LORC）相比具有不同的临床病理特征。然而，关于 EORC 患者复发风险的研究有限。我们的目标是开发一个预测模型来准确预测EORC复发风险。 回顾性入组2012年11月至2018年11月来自三个医疗机构接受根治性手术并进行T2加权成像和弥散加权成像磁共振成像（MRI）的直肠癌患者比较了 EORC 和 LORC 之间的临床病理特征的差异。根据临床病理学变量和 EORC 治疗前 MRI 的五种放射组学特征，构建了五种无病生存预测模型。使用训练集中计算的固定截止值将 EORC 患者分为术后复发的高风险组和低风险组。通过一致性指数（C-index）和受试者工作特征曲线评估模型性能。共有264名EORC患者（中位年龄，43岁，163名男性）和778名LORC患者（中位年龄，62岁，520名男性）入组。治疗前癌胚抗原阳性[风险比 (HR) = 2.84，P = 0.006]、病理阳性淋巴结状态（pN 阳性）[HR = 2.86，P = 0.011] 和基于 MRI 的放射组学评分 [HR = 2.72，P < 0.001 ] 是 EORC 患者无病生存的独立危险因素。通过整合 EORC 的临床病理特征和基于 MRI 的放射组学特征构建的 EORC-ClinPathRadiom 模型在训练、内部和外部测试集中的 C 指数分别为 0.82、0.82 和 0.81。该模型有效地将 EORC 患者分为高复发风险和低复发风险（训练集、内部测试集和外部测试集的 HR 分别为 8.96、6.81 和 7.46）。EORC-ClinPathRadiom 模型可以有效预测和分层风险EORC 患者术后复发。版权所有 © 2024 作者。由爱思唯尔有限公司出版。保留所有权利。

Early-onset rectal cancer (EORC) is characterized by a unique disease process with different clinicopathological features compared with late-onset rectal cancer (LORC). Research on the risk of recurrence in EORC patients, however, is limited. We aim to develop a predictive model to accurately predict EORC recurrence risk.Rectal cancer patients who underwent radical surgery and T2-weighted imaging and diffusion-weighted imaging magnetic resonance imaging (MRI) were retrospectively enrolled from three medical institutions from November 2012 to November 2018. Differences in clinicopathological characteristics between EORC and LORC were compared. Five prediction models for disease-free survival were constructed based on clinicopathological variables and five radiomic features from pretreatment MRI of the EORC. A fixed cut-off value calculated in the training set was used to stratify EORC patients into high-risk and low-risk groups of post-operative recurrence. Model performance was evaluated by concordance index (C-index) and receiver operating characteristic curve.A total of 264 EORC patients (median age, 43 years, 163 males) and 778 LORC patients (median age, 62 years, 520 males) were enrolled. Pretreatment positive carcinoembryonic antigen [hazard ratio (HR) = 2.84, P = 0.006], pathological positive lymph node status (pN positive) [HR = 2.86, P = 0.011] and MRI-based radiomics score [HR = 2.72, P < 0.001] are independent risk factors for disease-free survival in EORC patients. The EORC-ClinPathRadiom model, constructed by integrating the clinicopathological characteristics and MRI-based radiomics features of EORC, showed C-index of 0.82, 0.82, and 0.81 in the training, internal, and external test sets, respectively. This model effectively stratified EORC patients into high risk and low risk of recurrence (HRs for the training, internal, and external test sets were 8.96, 6.81, and 7.46, respectively).The EORC-ClinPathRadiom model can effectively predict and stratify the risk of post-operative recurrence in EORC patients.Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.