Results
A total of 256 patient postoperatively diagnosed with IR and HIR endometrioid type EC were included to study. The study population included 141 (55 %) and 115 (45 %) patients identified as IR and HIR EC, respectively. Among IR EC patients, 94 (66.6%) had underwent pelvic and para-aortic lymphadenectomy (PPLND), 14 (9.9%) had pelvic lymphadenectomy (PLND) and lymphadenectomy was not performed in remaining 33 (23.4%) cases. In HIR EC patients, 73 (63.5%) had underwent PPLND, 11 (9.5%) had underwent PLND, and 31 (27%) patients had no lymphadenectomy. The mean number of pelvic lymph nodes removed in LND group was 25.7±11.8. Among IR EC patients with LND, 36.7% (n=32) patients had ≤ 20 pelvic lymph nodes, and the remaining had more than 20 pelvic lymph nodes. While these figures were 38.1 % (n=32) and 61.9 % (n=52), respectively in HIR EC patients with LND (p=0.19). Figure 1 shows the flow of patients through the study design.
The demographics and clinicopathologic characteristics of the whole cohort are shown in Table 1. Mean (range) patients’ age was 61.1±9.7 (range, 27-86) years and the mean BMI was 29.1±7.9 kg/m2. The comorbidities was detected in 122 (47.6%) patients. Tumors larger than 3 cm were seen in 30.4% (n=78) of all patients. Eighty-two patients (32%) had <50% MI and the remaining 174 (68%) had ≥ 50 % MI. One hundred thirty-seven patients (53.5%) had grade 1, 63 (24.6%) had grade 2, and 56 (21.9%) had grade 3 endometrioid EC. Presence of LVSI was identified in 63 (25%) patients. For the 195 IR and HIR EC patients who had undergone LND, the rate of lymph node involvement was 10.3% (n=20). Adjuvant treatment was not received in 103 patients (40.2%). Remaining 153 (59.8%) patients recieved adjuvant treatment including radiotherapy (50.5%, n=129), chemoradiotherapy (6.2%, n=16), and chemotherapy (3.1%, n=8). Four (1.6%), 3 (1.2%), and 10 (3.9%) patients experienced local, pelvic and distant recurrences, respectively (Table 1).
Comparisons between EC patients with LND and no LND groups are summarized in Table 2. Patients with LND were significantly younger with a mean age of 60.3±9.8 years compared to the patients with no LND group with a mean age of 63.4±10.8 years (p < 0.05). The BMI was significantly lower in LND group. The rate of comorbidities in patients with EC was significantly lower in the LND group (p < 0.05). There were no notable differences between other comparisons including tumor size (p=0.73), EC risk group (p=0.13), FIGO stages (p=0.21) and grade (p=0.68), LVSI (p=0.43) and adjuvant treatments (p=0.22) among both groups. During the median follow-up of 41 months (range, 12–222), 12 (6.2 %) patients with LND, and 5 (7.8 %) patients without LND had disease recurrence (p=0.77).
Survival analysis showed a 5-year OS of 86.7% in the LND group, and 84.2% in the no LND group (log-rank test=0.39), Kaplan-Meier analysis revealed a similar 5-year DFS in the LND group compared to the no LND group (81.5% vs. 82.9%, respectively; log-rank test=0.13). LND did not improve OS and DFS in IR and HIR EC patients (p=0.92, p=0.80) (Figure 2). Moreover, LND did not improve OS and DFS in either the IR and HIR group of patients, separately (p= 0.87, p=0.84; p=0.95, p=0.63).
Table 3 showed the cox proportional-hazards models of OS and DFS among IR and HIR EC. Patients were categorized according to pelvic lymph node counts into three groups as no lymph node group, lymph nodes ≤20 and lymph nodes > 20. The lymph node count was not associated with OS and DFS for all subsets of patients with EC grouped by recurrence risks.