Objectives: To assess associations between treatment and recurrence-free survival (RFS) among patients with isolated tumor cells (ITCs) in sentinel lymph nodes (SLN) and otherwise stage I/II endometrioid endometrial cancer (EC).
Methods: A multi-institutional retrospective study of patients with SLN ITCs (<200 cells and < 0.2 mm) was performed. Only patients with otherwise stage I/II EC, endometrioid histology, and no evidence of micro-or macrometastases were included. Univariate and multivariable Cox proportional hazard models were used to evaluate associations between treatment, tumor characteristics, and RFS.
Results: 175 patients were included. Median follow up time was 31 months. 39% stage IB and 12% stage II disease. 76 (43%) received no adjuvant therapy or vaginal brachytherapy only (NAT/VBT), 21 (12%) had external beam radiation (EBRT), and 78 (45%) received chemotherapy +/- radiation. Patients who received chemotherapy more often had tumors with deep myoinvasion, lymphovascular space invasion (LVSI), and higher grade. Nine (5.1%) patients recurred; 5 distant, 3 retroperitoneal, and 1 vaginal. Extra-vaginal recurrences were similar in patients with or without chemotherapy (5.2% vs 3.8%, p = 0.68). After controlling for stage, LVSI and grade, chemotherapy and EBRT were not associated with RFS (HR = 0.63, 95%CI 0.11-3.52, and HR = 0.90, 95%CI 0.22-3.61, respectively). Type of lymph node dissection and ITC detection method were not associated with RFS.
Conclusions: Risk of retroperitoneal and/or distant recurrence is low (4.6%) for patients with stage I/II endometrioid EC and ITCs in SLNs regardless of treatment. Our preliminary data suggests that adjuvant therapy may not be significantly associated with RFS. However, longer follow-up time and a larger sample size are needed before definitive recommendations regarding adjuvant therapy for patients with EC and only ITCs in SLN can be made.
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