Supplementary Material for: Are Incidental Minute Pulmonary Nodules Ultimately Determined to Be Metastatic Nodules in Esophageal Cancer Patients?

<b><i>Purpose:</i></b> Esophageal cancer patients may simultaneously have resectable esophageal cancer and undiagnosable incidental minute solid pulmonary nodules. While the latter is rarely metastatic, only a few studies have reported on the outcomes of such nodules after surgery. In this retrospective study, we assessed the incidence of such nodules, the probability that they are ultimately metastatic nodules, and the prognosis of patients after esophagectomy according to the metastatic status of the nodules. <b><i>Methods:</i></b> Data of 398 patients who underwent esophagectomy for resectable esophageal cancer between January 2012 and December 2016 were collected. We reviewed computed tomography (CT) images from the first visit and searched for incidental minute pulmonary nodules &lt;10 mm in size. We followed the outcomes of these nodules and compared the characteristics of metastatic and nonmetastatic nodules. We also assessed the prognosis of patients whose minute pulmonary nodules were metastatic. <b><i>Results:</i></b> Among the patients who underwent esophagectomy, 149 (37.4%) had one or more minute pulmonary nodules, with a total of 285 nodules. Thirteen (4.6%) of these nodules in 12 (8.1%) patients were ultimately diagnosed as being metastatic. Thirteen (8.7%) patients experienced recurrence at a different location from where the nodules were originally identified. Characteristics of the metastatic nodules were not unique in terms of size, SUVmax, or location in the lungs. Two-year and 5-year overall survival rates of patients whose nodules were metastatic were 64.2 and 32.1%, respectively. <b><i>Conclusion:</i></b> The rate of minute pulmonary nodules which were ultimately metastatic was 4.6%. Our findings suggest that esophagectomy followed by the identification of minute pulmonary nodules is an acceptable strategy even if the nodules cannot be diagnosed as being metastatic on the first visit CT due to their small size.

<b><i>Purpose:</i></b> 食管癌患者可能同时罹患可切除性食管癌（resectable esophageal cancer）与未明确诊断的偶然发现的微小实性肺结节。尽管此类结节极少发生转移，但目前仅有少数研究报道了术后此类结节的转归情况。本回顾性研究旨在评估此类结节的发生率、最终确诊为转移性结节的概率，并根据结节的转移状态分析食管切除术（esophagectomy）后患者的预后。<b><i>Methods:</i></b> 收集2012年1月至2016年12月期间因可切除性食管癌接受食管切除术的398例患者的临床资料。回顾患者首次就诊时的计算机断层扫描（computed tomography, CT）影像，搜寻直径＜10mm的偶然发现的肺小结节。对这些结节的转归进行随访，并对比转移性与非转移性结节的临床特征。同时评估伴转移性微小肺结节患者的预后情况。<b><i>Results:</i></b> 在接受食管切除术的患者中，149例（37.4%）存在1个或多个微小肺结节，共计285个结节。其中12例（8.1%）患者的13个（4.6%）结节最终被确诊为转移性结节。8.7%的患者在结节原发部位以外的区域出现肿瘤复发。转移性结节的大小、最大标准摄取值（SUVmax）以及肺部受累位置均无特异性表现。伴转移性结节患者的2年、5年总生存率分别为64.2%与32.1%。<b><i>Conclusion:</i></b> 最终确诊为转移性的微小肺结节占比为4.6%。本研究结果提示，即便首次就诊CT因结节体积过小无法确诊为转移性，先行食管切除术并后续明确微小肺结节性质的诊疗策略仍具备临床可行性。