Results
92 patients with endometrial cancer underwent total hysterectomy, bilateral salpingoophorectomy and lymphatic mapping between September 2016 and February 2020. The surgeries were all performed at our institution by two Gynecologic Oncology surgeons. Demographic and clinicopathologic characteristics of the study population are summarized in Table 1. The median age of the patients was 62 years old (range 28-83), and the median BMI was 30.85 kg/m2 (range 19.9-53.4). Surgical approach was at the discretion of the provider. 70 out of the 92 cases evaluated were performed with robotic assistance (76%), while 22 cases were completed laparoscopically (24%).
The distribution of histologic types was as follows: endometrioid (73%), followed by UPSC (15.0%), MMMT (5.0%) and CC (4%). Stage I disease was confirmed in the majority of patients; 69 stage IA (71%), 12 stage IB (14%). A total of 8 patients were found to have stage III disease, of which 6 were stage III based on node positivity: 2 IIIA, 2 IIIC1, 4 IIIC2. Of the stage III patients, 2 patients had endometrioid histology and 6 had UPSC.
One unilateral sentinel lymph node was detected in 88 (95.4%) patients. The overall rate of bilateral SLND was 75.3%. Overtime bilateral SLN detection rate improved from 70.5% (2017) to 80% (2020) (Figure 1). Twenty patients underwent PPALND (16 for high-grade histology, 3 for failed mapping, and 1 secondary to a clinically suspicion lymph node). Per the algorithm, intraoperative evaluation of the uterine specimen was performed for 12 patients with failed SLN mapping and findings were consistent with low-risk for lymph node metastasis and therefore PPALND was not performed.
SLN mapping rates were analyzed among five subgroups based on additional patient specific and pathologic factors: depth of invasion (DOI), presence of lymphovascular space invasion (LVSI), uterine leiomyoma, uterine adenomyosis, and BMI. None of these factors were significantly associated with rate of successful bilateral SLN mapping (DOI p = 0.1; LVSI p = 0.22; uterine leiomyoma p = 1.0; adenomyosis p = 0.29; BMI p = 0.91.).
Three patients were found to have positive nodes other than the surgically identified SLN. All three had serous histology. Two of the patients underwent planned PPALND for known high-risk histology. The third patient had a suspicious enlarged lymph node on preoperative imaging, which was found to be positive for disease at time of surgery. Of note, the pre-operative diagnosis for this patient was endometrioid adenocarcinoma and the UPSC component was diagnosed on final pathology.
In a comparison to the selected meta-analysis [5], both bilateral (75.3% vs. 61%; p = 0.0001) and unilateral (95.4% vs. 78%; p = 0.0111) SLN mapping rates were significantly higher in our cohort.