Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, Republic of Korea.
Department of Clinical Epidemiology and Biostatistics, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, Republic of Korea.
Br J Cancer. 2014 Jul 15;111(2):249-54. doi: 10.1038/bjc.2014.256. Epub 2014 Jun 26.
Pelvic lymph node (LN) status after preoperative chemoradiotherapy (CRT) is an important indicator of oncologic outcome in patients with locally advanced rectal cancer. The purpose of this study was to develop a nomogram to predict LN status after preoperative CRT in locally advanced rectal cancer patients.
The nomogram was developed in a training cohort (n=891) using logistic regression analyses and validated in a validation cohort (n=258) from a prospectively registered tumour registry at Asan Medical Center. The model was internally and externally validated for discrimination and calibration using bootstrap resampling. Model performance was evaluated by the concordance index (c-index) and calibration curve.
Pretreatment ypT stage, patient age, preCRT tumour differentiation, cN stage, lymphovascular invasion, and perineural invasion were reliable predictors of LN metastasis after preoperative CRT. The nomogram developed using these parameters had c-indices of 0.81 (training) and 0.77 (validation). The calibration plot suggested good agreement between actual and nomogram-predicted LN status after preoperative CRT.
This nomogram improves prediction of LN status after preoperative CRT in patients with locally advanced rectal cancer. It will be useful for counselling patients as well as for the design and stratification of patients in clinical trials.
术前放化疗（CRT）后盆腔淋巴结（LN）状态是局部进展期直肠癌患者肿瘤学结局的重要指标。本研究旨在建立一个预测局部进展期直肠癌患者术前 CRT 后 LN 状态的列线图。
利用 logistic 回归分析在训练队列（n=891）中建立列线图，并在从 Asan 医疗中心前瞻性注册的肿瘤登记处获得的验证队列（n=258）中进行验证。使用 bootstrap 重采样对内、外部进行区分度和校准验证。通过一致性指数（c-index）和校准曲线评估模型性能。
术前 ypT 分期、患者年龄、术前 CRT 肿瘤分化、cN 分期、淋巴血管侵犯和神经周围侵犯是术前 CRT 后 LN 转移的可靠预测因素。使用这些参数建立的列线图的 c-index 分别为 0.81（训练）和 0.77（验证）。校准图表明，术前 CRT 后实际和列线图预测的 LN 状态之间存在良好的一致性。
该列线图提高了对局部进展期直肠癌患者术前 CRT 后 LN 状态的预测能力。它将有助于为患者提供咨询，以及为临床试验的设计和患者分层提供帮助。
