Sociodemographic disparities in stage-specific incidences of endometrial cancer: a registry-based study in West Sweden, 1995–2016

<b>Background:</b> For a few types of cancer, lower socioeconomic status (SES) is associated with higher incidence, and for even more cancer types it is associated with having a less favorable tumor stage at diagnosis. For endometrial cancer (EC), however, there is no clear evidence of such associations with SES. There is a need for analysis of sociodemographic disparities in EC incidences according to stage at diagnosis, which may provide support for trying to improve early detection of EC. <b>Material and methods:</b> Stage-specific incidences of endometrioid and non-endometrioid endometrial carcinomas [EECs (∼90% of all EC cases) and NECs (∼10%)] were analyzed for the population of the Western Swedish Healthcare Region, taking into account year (1995–2016), age, educational level (low, intermediate and high), and immigrant status (Swedish-born, foreign-born). All EC cases were identified and data were obtained from population-based registries. <b>Results:</b> Stage distribution of diagnosed EECs differed significantly according to the educational level of patients who were aged between 50 and 74 years at diagnosis, but not in the case of younger or older patients. An analysis based on 3113 EEC cases aged 50–74 years at diagnosis revealed marked disparities in the stage-II to stage-IV EEC incidences but not in the stage-I EEC incidence. Compared to women with a high level of education, the incidence rate ratios of stage-I, stage-II and stage-III and -IV EEC in women with a low level of education were 1.00 (95% CI: 0.90–1.12), 1.65 (1.13–2.42), and 1.82 (1.33–2.49), respectively. For NEC, we found no such association. <b>Conclusions:</b> Elevated incidences of stage-II to stage-IV EEC in 50- to 74-year-old women with a low level of education suggest that there should be targeted health service trials aimed at improving awareness of EC. Well-targeted EC awareness programs might lead to considerable health benefits.

<b>背景：</b> 针对少数癌症类型，较低的社会经济地位（socioeconomic status, SES）与更高的发病风险相关；而在更多癌症类型中，低社会经济地位则与诊断时肿瘤分期更晚密切相关。但就子宫内膜癌（endometrial cancer, EC）而言，目前尚无明确证据表明其与社会经济地位存在此类关联。因此有必要依据诊断时的肿瘤分期，分析子宫内膜癌发病中的社会人口学差异，这或可为改善子宫内膜癌的早期筛查提供依据。
<b>材料与方法：</b> 本研究针对瑞典西部医疗区的人群，分析了子宫内膜样子宫内膜癌（endometrioid endometrial carcinomas, EECs，约占所有子宫内膜癌病例的90%）与非子宫内膜样子宫内膜癌（non-endometrioid endometrial carcinomas, NECs，约占10%）的分期特异性发病情况。研究纳入1995年至2016年的相关数据，综合考虑了研究时段、患者年龄、受教育水平（低、中、高三个等级）以及移民身份（瑞典出生、外国出生）等变量。所有子宫内膜癌病例均经确认，数据来源于人群登记库。
<b>结果：</b> 对于诊断时年龄处于50~74岁的患者，确诊的子宫内膜样子宫内膜癌的分期分布随患者受教育水平呈现显著差异，但年轻或老年患者中未观察到此差异。针对3113例诊断时年龄为50~74岁的子宫内膜样子宫内膜癌病例开展的分析显示，Ⅱ期至Ⅳ期子宫内膜样子宫内膜癌的发病情况存在显著差异，但Ⅰ期子宫内膜样子宫内膜癌的发病情况无此差异。与受教育水平较高的女性相比，受教育水平较低的女性的Ⅰ期、Ⅱ期以及Ⅲ~Ⅳ期子宫内膜样子宫内膜癌的发病比（incidence rate ratios）分别为1.00（95% CI：0.90~1.12）、1.65（1.13~2.42）以及1.82（1.33~2.49）。针对非子宫内膜样子宫内膜癌，未发现此类关联。
<b>结论：</b> 50至74岁受教育水平较低的女性中，Ⅱ期至Ⅳ期子宫内膜样子宫内膜癌的发病风险升高，这提示应开展旨在提升子宫内膜癌认知的针对性医疗服务试点。针对性的子宫内膜癌认知宣教项目或可带来显著的健康收益。