Isolated tumor cells versus micrometastasis in the regional lymph node in T1 endometrial cancer: A comparative study (344)

Abstract

<b>Objectives:</b> To compare the patient, tumor, and treatment characteristics of women with T1 endometrial cancer in whom regional lymph node evaluation identified isolated tumor cells (ITCs) or micrometastasis. <b>Methods:</b> This is a retrospective cohort study querying the National Cancer Institute's Surveillance, Epidemiology, and End Results Program. The study population included surgically staged women with T1 endometrial cancer. Exposure allocation was regional lymph node status (ITCs vs micrometastasis). Main outcome measures were demographic and tumor characteristics assessed with multivariable binary logistic regression. Secondary outcome was adjuvant therapy type per the exposure allocation, assessed with propensity score inverse probability of treatment weighting. <b>Results:</b> A total of 111 cases with ITCs were compared to 141 cases with micrometastasis. In a multivariable analysis, T1b disease (62.4% vs 51.4%, adjusted-odds ratio: 2.23, 95% CI: 1.24-4.00) and poor differentiation (31.2% vs 13.5%, adjusted-odds ratio: 3.47, 95% CI: 1.62-7.41) were independently associated with micrometastasis versus ITCs. In a propensity score weighted model, women in the micrometastasis group were more likely to receive a combination of chemotherapy and external beam radiotherapy (47.7% vs 24.0%) or chemotherapy without radiotherapy (21.3% vs 7.0%). In contrast, women in the ITCs group were more likely to receive external beam radiotherapy without chemotherapy (20.2% vs 3.9%) (<i>p</i><0.001). <b>Conclusions:</b> Endometrial cancer with micrometastasis in regional lymph nodes has distinct tumor characteristics compared to ITCs. Discrete adjuvant therapy patterns based on the type of regional lymph node suggest that care providers are taking this information (micrometastasis vs ITCs) into account for a tailored treatment approach.