Methods
After institutional board review approval, all patients with clinical stage I endometrial cancer who underwent either robot-assisted or laparoscopic total hysterectomy from our institution were retrospectively selected from 2016-2020. Clinical stage I endometrial cancer was determined by preoperative physical exam and imaging. The decisions to perform surgery robotically verses laparoscopically was based on surgeon preference. Patients with endometrioid, uterine papillary serous (UPSC), malignant mixed mesodermal tumor (MMMT), and clear cell (CC) histologic subtypes were included.
Indocyanine green was reconstituted per the manufacturer’s directions and injected into the cervix bilaterally at 3 and 9 o’clock both superficially (submucosally) and deep (1 cm into the stroma). Sentinel nodes were identified using near-infrared technology. Patients with suboptimal lymph node mapping or nodes suspicious for metastasis during surgical evaluation underwent a side specific pelvic lymph node dissection (LND). Paraaortic LND was performed at the discretion of the surgeon. In addition to SLNB, complete pelvic and paraaortic lymph node dissection (PPALND) was performed for patients with the following high-risk histologic subtypes: UPSC, CC and MMMT. SLNs were then evaluated by gynecologic pathologists using ultra-staging protocols including serial sectioning and cytokeratin staining. The medical record was queried for clinical or radiographic evidence of recurrence; median follow up was 22 months for this cohort.
The primary objective was to evaluate the accuracy and sensitivity of SLN mapping at our university affiliated community-based institution. In addition, rates of SLN detection were evaluated over 3 years to chart potential improvements over time as correlating to surgeon experience. Descriptive statistics, such as frequency distribution, mean, median, interquartile range, minimum and maximum were calculated for relevant variables. To compare successful mapping rates at our institution to those in the literature a one sample test of proportion was performed. Chi square and Fisher’s Exact test were performed to determine whether successful mapping rates among patients was related to patient specific factors such as BMI as well as pathologic factors such as the presence of uterine leiomyoma, adenomyosis, lymphovascular space invasion and tumor depth of invasion (<50% vs. > 50%).