The aim of this study was to characterize treatment patterns and oncologic outcomes in patients with low-volume lymph node metastasis (isolated tumor cells [ITCs] and micrometastasis [MM]) discovered during sentinel lymph node (SLN) mapping for endometrial carcinoma.

We identified endometrial cancer cases treated surgically from September 2005 to April 2013 in which SLN mapping was performed. MM was defined as tumor within a lymph node measuring >0.2 mm but <2.0 mm, and ITCs were those measuring ≤0.2 mm.

Overall, 844 patients, with a median age of 61 years (range 30-90), met the inclusion criteria. Histology was as follows: endometrioid, 724 (85.8 %) patients; serous, 104 (12.3 %) patients; and clear cell, 16 (1.9 %) patients. The median number of lymph nodes resected was six (range 0-60), and the median number of SLNs was two (range 0-15). Overall, 753 (89.2 %) patients were node-negative, 23 (2.7 %) had ITCs only, 21 (2.5 %) had MM only, and 47 (5.6 %) had macrometastasis. Adjuvant chemotherapy was administered to 106 (14 %) of 753 node-negative patients, 19 (83 %) of 23 patients with ITCs, 17 (81 %) of 21 patients with MM, and 42 (89 %) of 47 with macrometastasis. Median follow-up was 26 months (range 0-108). Three-year recurrence-free survival was as follows: node-negative patients, 90 % (±1.5); ITCs only, 86 % (±9.4); MM only, 86 % (±9.7); and macrometastasis, 71 % (±7.2) [p < 0.001].

Patients with ITCs and MM frequently received adjuvant chemotherapy and had improved oncologic outcomes in comparison to those with macrometastasis to the lymph nodes. Further prospective study is needed to determine optimal post-resection management in patients with ITCs or MM alone.