UC Davis

OBJECTIVE: To assess the rates and distribution of first recurrence in patients with FIGO stage IIIC1 endometrial cancer (EC) who did not undergo paraaortic dissection at surgical staging. METHODS: We retrospectively selected all (n = 207) stage IIIC1 patients treated at a single institution from 5/1993-1/2017. Sites of first recurrence were identified, disease-free (DFS) and overall survival (OS) calculated, multivariate logistic regression performed to identify factors associated with recurrence. RESULTS: Three-year DFS and OS were 66.5% and 85.7%, respectively. The most common histology was endometroid (64.2%). Three-year DFS was 81% (SE±3.8%) endometrioid vs. 39.5% (SE±6.6%) non-endometrioid (P < 0.001). Three-year OS was 96.9% (SE±1.8%) endometrioid vs. 65.6% (SE±6.7%) non-endometrioid (P < 0.001). Sixty-two (30.1%) patients recurred. Patterns of recurrence were: 14 (8.3%) multiple sites, 17 (8.2%) abdominal, 14 (6.8%) extra-abdominal, 17 (8.3%) isolated nodal (8 of these (3.9%) paraaortic). Patients with isolated tumor cells (ITCs) in lymph nodes only had 12/71 (17%) recurrence rate vs. 50/135 (37%) for patients with micro-/macrometastasis. On univariate analysis, grade (HR 4.67 95%CI 1.5-14.5, P = 0.008), histology (HR 4.9 95%CI 2.6-9.3, P < 0.001), myometrial invasion (HR 1.9 95%CI 1.04-3.5, P = 0.04), pelvic washing (HR 2.2 95%CI 1.1-4.5, P = 0.03), tumor volume in pelvic LNs (ITC vs. micro-/macrometastasis; HR 0.3 95%CI 0.2-0.7, P = 0.003) were associated with recurrence. On multivariate analysis, only histology was associated with recurrence (HR 7.88 95%CI 3.43-18.13, P < 0.001). CONCLUSIONS: Isolated paraaortic recurrence in stage IIIC1 EC is uncommon. Micro-/macrometastasis were associated with twice the recurrence rate compared to ITC. These data will help clinicians counsel patients with stage IIIC1 EC regarding paraaortic assessment.