The longest diameter of tumor as a parameter of endoscopic resection in early gastric cancer: In comparison with tumor area

Background and aimTumor burden is important to predict clinical behaviors of cancer such as lymph node metastasis (LNM). Tumor size has been used as a parameter of tumor burden such as indication of endoscopic resection in early gastric cancer (EGC) to predict LNM. Thus, we aimed to investigate whether tumor area can be more helpful to predict clinical behaviors than longest diameter of tumor in EGC.Patients and methods3,059 patients who underwent gastrectomy for EGC were reviewed retrospectively. Tumor area was calculated by multiplying long and short diameter of the tumor in surgical specimen. Longest diameter means maximal longitudinal diameter of tumor in specimen. Clinicopathologic features were compared between longest diameter and area using area under receiver operating characteristic (AUROC) curves.ResultsLongest diameter and area of tumor showed a strong correlation (correlation coefficient 0.859, p2 of tumor area. There was no significant difference between longest diameter and area for prediction of LNM (AUC 0.850 vs. 0.848, respectively). In differentiated-type EGC and undifferentiated-type EGC, there was no significant difference between longest diameter and area for prediction of LNM. Among mucosal or submucosal cancer prediction value of LNM between longest diameter and area was not significantly different.ConclusionTumor area may not be more helpful to predict LNM than longest diameter in EGC. Therefore, the longest diameter of tumor may be sufficient as an indicator of tumor burden in EGC.

研究背景与目的：肿瘤负荷是预测癌症临床行为（如淋巴结转移（LNM））的重要指标。既往临床常以肿瘤大小作为肿瘤负荷的评估参数，例如早期胃癌（EGC）内镜切除的适应证判定，用于预测淋巴结转移。本研究旨在探讨在早期胃癌中，肿瘤面积是否较肿瘤最长径更有助于预测癌症临床行为。

患者与方法：本研究回顾性分析了3059例因早期胃癌接受胃切除术的患者资料。通过手术标本中肿瘤的长径与短径相乘计算肿瘤面积，最长径指标本中肿瘤的最大纵向直径。采用受试者工作特征曲线下面积（AUROC）比较肿瘤最长径与面积的临床病理预测效能。

结果：肿瘤最长径与肿瘤面积呈强相关性（相关系数0.859，P<0.001）。肿瘤面积的对数转换值与最长径的相关性弱于原始肿瘤面积与最长径的相关性（相关系数0.771，P<0.001）。在预测淋巴结转移方面，肿瘤最长径与面积的预测效能无显著差异（AUROC分别为0.850与0.848）。在分化型早期胃癌及未分化型早期胃癌亚组中，二者预测淋巴结转移的效能均无显著差异。在黏膜癌或黏膜下癌亚组中，肿瘤最长径与面积预测淋巴结转移的价值亦无显著差异。

结论：在早期胃癌中，肿瘤面积并不优于肿瘤最长径用于预测淋巴结转移。因此，肿瘤最长径可作为早期胃癌肿瘤负荷的评估指标。