Although the prognostic significance of grade in endometrial cancer is well known, grade 2 cases have not been evaluated separately in most of the previous studies. In this study, we aim to investigate whether the oncologic outcomes of grade 2 endometrioid endometrial carcinomas trend towards grade 1 or 3 tumors. Patients’ records and pathological reports were reviewed retrospectively and eligible patients with endometrioid endometrial carcinoma were determined and distributed into 3 groups according to their 1988 International Federation of Gynecology and Obstetrics (FIGO) grade. Groups’ characteristics and oncologic outcomes were compared. Differences between grades were tested with z-test and adjusted by Bonferroni method. Kaplan–Meier method was performed for the survival analysis. In total, 776 patients of endometrioid endometrial carcinoma were included in this study. Mean follow-up time was 52 ± 14 months. Patients’ mean age was 56.3 ± 10.8 years. Even though grade 2 endometrioid endometrial carcinomas were different from both grade 1 and 3 in terms of the pathological features, survival analyses demonstrated that their oncologic outcomes trended towards grade 1. The grade was determined as an independent prognostic factor for overall survival (OS). The interobserver reproducibility will be improved among pathologists by combining FIGO grade 1 and 2 endometrioid endometrial carcinomas, while prognosis prediction is not likely to be affected.

尽管等级对子宫内膜癌的预后意义是众所周知的，但是在先前的大多数研究中，尚未单独评估2级病例。在这项研究中，我们旨在调查2级子宫内膜样子宫内膜癌的肿瘤学结果是否趋向1级或3级肿瘤。回顾性地回顾患者的病历和病理报告，根据其1988年国际妇产科联合会的等级，确定合格的子宫内膜样子宫内膜癌患者并将其分为3组。比较各组的特征和肿瘤学结局。等级之间的差异通过z检验进行了测试，并通过Bonferroni方法进行了调整。用Kaplan–Meier方法进行生存分析。总共，这项研究包括776例子宫内膜样子宫内膜癌患者。平均随访时间为52±14个月。患者的平均年龄为56.3±10.8岁。尽管2级子宫内膜样子宫内膜癌在病理特征方面与1级和3级不同，但生存分析表明其肿瘤学结果趋于1级。该级别被确定为总体生存（OS）的独立预后因素。通过结合FIGO 1级和2级子宫内膜样子宫内膜癌，病理学家之间的观察者间可重复性将得到改善，而预后预测则可能不会受到影响。尽管2级子宫内膜样子宫内膜癌在病理特征方面与1级和3级不同，但生存分析表明其肿瘤学结果趋于1级。该级别被确定为总体生存（OS）的独立预后因素。通过结合FIGO 1级和2级子宫内膜样子宫内膜癌，病理学家之间的观察者间可重复性将得到改善，而预后预测则可能不会受到影响。尽管2级子宫内膜样子宫内膜癌在病理特征方面与1级和3级不同，但生存分析表明其肿瘤学结果趋于1级。该级别被确定为总体生存（OS）的独立预后因素。通过结合FIGO 1级和2级子宫内膜样子宫内膜癌，病理学家之间的观察者间可重复性将得到改善，而预后预测则可能不会受到影响。