Strict Adherence to Algorithm Required

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A prospective cohort study found sentinel lymph node biopsy had a 96% sensitivity rate and a 99% negative predictive value for detecting nodal metastasis among patients with clinical stage I low-grade and high-grade endometrial cancer.1 “Our study suggests that [sentinel lymph node biopsy] has comparable, if not improved, diagnostic accuracy and prognostic ability compared with lymphadenectomy in patients with high-grade endometrial cancer and should be considered for the surgical staging of apparent clinical stage I endometrial cancer with no evidence of extrauterine disease on imaging or intraoperative survey,” the investigators stated.

“If [sentinel lymph node biopsy] is to be adopted,” they advised, “surgeons must strictly follow a [sentinel lymph node biopsy] algorithm that incorporates both side-specific pelvic lymphadenectomy and para-aortic lymphadenectomy for nonmapped hemipelves in patients with high-grade endometrial cancer. Sentinel lymph nodes may not map when infiltrated with tumor or when lymphatic drainage is altered, and this may be particularly common in patients with high-grade endometrial cancer at increased risk of nodal metastasis. Of 27 patients with node-positive disease, 2 patients (7.5%) with unilateral mapping in our study would have been missed without a side-specific lymphadenectomy that included para-aortic lymphadenectomy.”

Document Proficiency

“We are always worried when it doesn’t map on one side,” corresponding author of the study Sarah E. Ferguson, MD, of the University of Toronto, told The ASCO Post. “It could be just the technique—injected too quickly, too deeply. But it could be there is lymphatic blockage due to tumor emboli or some other factor.” That is why the investigators stress the importance of following the sentinel lymph node algorithm. “If it does not map, you do a lymph node dissection,” Dr. Ferguson stated.

“We also propose that initial adoption of [sentinel lymph node biopsy] occur alongside continued performance of pelvic lymphadenectomy and para-aortic lymphadenectomy so that centers can document proficiency,” the investigators stated. “Our surgeons participated in a validation study of cervical [sentinel lymph node biopsy] before initiating the SENTOR study for endometrial [sentinel lymph node biopsy]; we accordingly achieved a bilateral detection rate of 78%. Comparable prospective studies with surgeons for whom [sentinel lymph node biopsy] was a novel technique have reported bilateral detection rates of 52% to 58%.”

Dr. Ferguson reiterated: “For centers, or even individual surgeons, combining sentinel lymph node biopsy with full nodal dissection and assessing your own sensitivity and false-negative rate are important. We most definitely did this as part of a quality program before we initiated the study.” 

DISCLOSURE: Dr. Ferguson reported no conflicts of interest.


1. Cusimano MC, Vicus D, Pulman K, et al: Assessment of sentinel lymph node biopsy vs lymphadenectomy for intermediate- and high-grade endometrial cancer staging. JAMA Surg. November 11, 2020 (early release online).

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