In a Canadian prospective cohort study (SENTOR) reported in JAMA Surgery, Cusimano et al found that sentinel lymph node biopsy showed “acceptable diagnostic accuracy” compared with lymphadenectomy in detecting nodal metastatic disease in patients with intermediate- and high-grade endometrial cancers.
Study Details
The study included 156 women consecutively enrolled between July 2015 and June 2019 who had clinical stage I grade 2 endometrioid or high-grade endometrial cancer. Patients were scheduled to undergo laparoscopic or robotic hysterectomy with intent to complete staging at three cancer centers in Toronto. All patients underwent a standard algorithm for sentinel lymph node biopsy using indocyanine green, followed by lymphadenectomy as the reference standard. Patients with grade 2 endometrioid endometrial cancer underwent pelvic lymphadenectomy alone; patients with high-grade endometrial cancer were to undergo both pelvic lymphadenectomy and para-aortic lymphadenectomy. In total, 126 women (81%) had high-grade endometrial cancer and 30 (19.2%) had grade 2 endometrioid endometrial cancer.
“In this prospective cohort study, sentinel lymph node biopsy had acceptable diagnostic accuracy for patients with high-grade endometrial cancer at increased risk of nodal metastases and improved the detection of node-positive cases compared with lymphadenectomy. The findings suggest that sentinel lymph node biopsy is a viable option for the surgical staging of endometrial cancer.”— Cusimano et al
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Key Findings
All patients underwent sentinel lymph node biopsy and pelvic lymphadenectomy; 101 (80%) of those with high-grade endometrial cancer also underwent para-aortic lymphadenectomy.
Sentinel lymph node detection rates were 97.4% per patient, 87.5% per hemipelvis, and 77.6% bilaterally.
Among 27 patients with node-positive disease, 26 were correctly identified by the sentinel lymph node biopsy algorithm, yielding a sensitivity rate of 96.3%, a false-negative rate of 3.7% (1 of 27), and a negative predictive value of 99.2% (129 of 130). Misclassification on sentinel lymph node biopsy occurred in only one patient (0.6%).
Maria C. Cusimano, MD
Of the 26 patients with node-positive disease identified by sentinel lymph node biopsy, 24 were diagnosed based on sentinel lymph nodes from mapped hemipelves and 2 (with high-grade endometrial cancer and a single positive pelvic or para-aortic lymph node) were diagnosed based on side-specific pelvic lymphadenectomy or para-aortic lymphadenectomy specimens from nonmapped hemipelves.
Seven (26%) of the 27 patients with node-positive disease were identified via a single metastatic sentinel lymph node mapped outside traditional pelvic lymphadenectomy boundaries (n = 2) or required immunohistochemistry for diagnosis (n = 5).
The investigators noted, “The study suggests that sentinel lymph node biopsy may improve the detection of nodal metastases in ways not captured by traditional calculations of diagnostic accuracy. Fourteen patients with node-positive disease (52%) had metastatic disease in sentinel lymph nodes only, and 7 cases (26%) were found outside lymphadenectomy boundaries or required immunohistochemistry for diagnosis. These patients would not have been identified by pelvic lymphadenectomy or para-aortic lymphadenectomy alone.”
They concluded: “In this prospective cohort study, sentinel lymph node biopsy had acceptable diagnostic accuracy for patients with high-grade endometrial cancer at increased risk of nodal metastases and improved the detection of node-positive cases compared with lymphadenectomy. The findings suggest that sentinel lymph node biopsy is a viable option for the surgical staging of endometrial cancer.”
Sarah E. Ferguson, MD, of the Division of Gynecologic Oncology, University Health Network/Sinai Health Systems, and the Department of Obstetrics and Gynaecology, University of Toronto, is the corresponding author for the JAMA Surgery article.
Disclosure: The study was supported by the Princess Margaret Cancer Foundation of Princess Margaret Cancer Centre and the McArthur Research Fund of the Department of Obstetrics and Gynecology at the University of Toronto. For full disclosures of the study authors, visit jamanetwork.com.
