直肠系膜筋膜状态及演变在行新辅助放化疗局部晚期直肠癌患者中的预后价值:一项回顾性研究OA

Background and purpose:Mesorectal fascia(MRF)involvement identified on MRI is a key imaging surrogate of high-risk disease in patients with locally advanced rectal cancer(LARC).However,its prognostic significance in the era of modern neoadjuvant chemoradiotherapy(nCRT)remains controversial.This study aimed to evaluate the prognostic impact of baseline MRF positivity and its dynamic"conversion"pattern on clinical outcomes and survival.Methods:This study retrospectively reviewed 1 159 consecutive LARC patients treated with nCRT followed by curative resection at the Department of Colorectal Surgery,Fudan University Shanghai Cancer Center between 2018 and 2024.Patients were categorized according to baseline MRF status(positive vs negative),and 1∶2 propensity score matching(PSM)was used to balance clinicopathological characteristics.Disease-free survival(DFS)and overall survival(OS)were analyzed using the Kaplan-Meier method and Cox regression models.Multivariable analyses were further performed within the MRF-positive subgroup to identify independent prognostic determinants.This study was approved by the Ethics Committee of the Cancer Hospital affiliated with Fudan University(1807188-10-2001B)and acquired informed consent.Results:Among the 1 159 included patients,270(23.3%)had MRF-positive disease.Before propensity score matching(PSM),the 5-year DFS rate of MRF-positive patients in the cohort was 73.2%,and the OS rate was 78.9%,both significantly lower than the 86.7%and 90.5%in the MRF-negative group(P<0.001).After 1:2 PSM matching,the 5-year DFS rate in the MRF-positive group was 70.4%,and the OS rate was 76.5%,still significantly lower than the 84.1%and 88.7%in the MRF-negative group(P=0.002,P=0.004).Within the MRF-positive subgroup,multivariable analysis identified mrT4 stage,mrN2 stage,and Miles/Hartmann procedures as independent adverse prognostic factors.Notably,radiologic"conversion"from positive to negative MRF was not independently associated with improved survival.Among patients with MRF-positive findings on preoperative MRI,only 7.2%had pathologically confirmed circumferential resection margin(CRM)involvement,indicating limited specificity of MRI for MRF assessment.Conclusions:MRI-defined MRF positivity remains a robust independent predictor of poor prognosis in LARC,even after PSM adjustment.However,radiologic MRF"conversion"does not independently predict survival outcomes,and most MRI-suspected MRF-positive cases ultimately achieve negative pathological margins.These findings highlight both the prognostic value and inherent limitations of MRI,emphasizing the need for integrated radiologic-pathologic evaluation when tailoring individualized treatment strategies for rectal cancer.