Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.
Department of Radiation Oncology, Korea Institute of Radiological & Medical Sciences, Seoul, Korea.
Cancer Res Treat. 2019 Jul;51(3):1188-1197. doi: 10.4143/crt.2018.434. Epub 2018 Dec 20.
The purpose of this study was to evaluate treatment response to neoadjuvant chemoradiotherapy (CRT) with regard to mucin status in pathology and pretreatment magnetic resonance imaging (MRI) in locally advanced rectal cancer.
Between 2003 and 2011, 306 patients with locally advanced rectal cancer received neoadjuvant CRT followed by surgery, and mucinous adenocarcinoma (MAC) was found in 27 (8.8%). All MAC patients had MRI before and after CRT and mucin proportion at MRI was measured. Therapeutic response was assessed by pathology after total mesorectal excision. To determine the optimal cut-off for mucin proportion in predicting good CRT response (near total or total regression) and negative circumferential resection margin (CRM), the receiver-operating characteristic analysis was performed.
After neoadjuvant CRT, overall downstaging occurred in 44.4% of MAC and 72.4% of non-MAC (p=0.001), and positive CRM (≤1 mm) was observed more frequently in MAC (p<0.001). The optimal threshold for treatment response was 30% for mucin proportion, and there are nine with low mucin proportion (<30%) and 18 with high mucin proportion (≥30%) in pretreatment MRI. Negative CRM and tumor downstaging occurred more common in patients with mucin <30%, although statistically insignificant (p=0.071 and p=0.072, respectively). Regarding oncologic outcomes, lower mucin proportion in pretreatment MRI was associated with better disease-free and overall survival in MAC group (p=0.092 and 0.056, respectively), but the difference did not reach statistical significance.
Poor treatment outcome with neoadjuvant CRT was observed in patients with MAC, especially those with high mucin proportion at pretreatment MRI.
本研究旨在评估局部晚期直肠癌患者新辅助放化疗（CRT）后病理黏液状态和术前磁共振成像（MRI）对治疗反应的影响。
2003 年至 2011 年间，306 例局部晚期直肠癌患者接受新辅助 CRT 治疗，随后接受手术治疗，其中 27 例（8.8%）为黏液性腺癌（MAC）。所有 MAC 患者均在 CRT 前后进行 MRI 检查，并测量 MRI 上的黏液比例。采用全直肠系膜切除术评估治疗反应。通过接受者操作特征分析，确定 MRI 上黏液比例的最佳截断值，以预测良好的 CRT 反应（近乎完全或完全消退）和阴性环周切缘（CRM）。
新辅助 CRT 后，MAC 的总降期率为 44.4%，非-MAC 的总降期率为 72.4%（p=0.001），MAC 中阳性 CRM（≤1mm）更为常见（p<0.001）。黏液比例的最佳截断值为 30%，MRI 检查中术前黏液比例<30%的患者有 9 例，黏液比例≥30%的患者有 18 例。在黏液比例<30%的患者中，CRM 阴性和肿瘤降期更为常见，但差异无统计学意义（分别为 p=0.071 和 p=0.072）。在 MAC 组中，MRI 检查中术前黏液比例较低与无病生存和总生存更好相关（p=0.092 和 0.056），但差异无统计学意义。
MAC 患者新辅助 CRT 治疗效果较差，尤其是术前 MRI 上黏液比例较高的患者。
