In a retrospective study of 378 patients who had hysterectomies for EIN, those with a preoperative endometrial stripe of 20 mm or greater were two times more likely to have endometrial cancer on final pathology, and those with an endometrial thickness of 15 mm or greater were 1.8 times more likely to have cancer.
“This data suggests that increasing endometrial thickness may be a useful preoperative marker to identify who’s at higher risk of concurrent endometrial cancer. It could also be considered a criterion for selectively using a sentinel lymph node algorithm in patients with a preoperative diagnosis of EIN. However, prospective studies are warranted to further establish this association,” said Devon Abt, MD, of Beth Israel Deaconess Medical Center in Boston.
She presented the data at the Society of Gynecologic Oncology’s Virtual Annual Meeting on Women’s Cancer (Abstract 11103).
Risk of overtreatment
There are no clear consensus guidelines on lymph node assessment for patients with EIN, Dr. Abt noted. She pointed out that roughly 40% of patients with EIN are diagnosed with endometrial cancer. However, it’s usually low-stage, low-grade disease, and only about 10% of patients will have high-risk features that warrant lymph node evaluation.
“Typically, we identify patients with concurrent endometrial cancer based on intraoperative pathology, or frozen section,” Dr. Abt explained. “We then apply the Mayo criteria, which stratifies patients as high or low risk for lymph node metastasis based on pathologic criteria. ... This information helps guide our intraoperative decisions to perform, or not perform, pelvic and para-aortic lymphadenectomy.”
Dr. Abt noted, however, that “lymphadenectomy is not benign” and increases surgical time as well as the risk of complications.
Taking these factors into account, some centers have implemented routine sentinel lymph node algorithms for staging endometrial cancers, Dr. Abt said.
What she and her colleagues wanted to determine is if there is value in this practice. Should sentinel lymph node mapping and biopsy be offered routinely to all patients with a preoperative diagnosis of EIN?
Study details
Dr. Abt and colleagues conducted a retrospective, single-center study of 378 patients with EIN. Ultimately, 27% (n = 103) of the patients were diagnosed with endometrial cancer – 95% with stage 1a disease and 5% with stage 1b.
Increasing age, White race, and hypertension were significantly associated with the presence of endometrial cancer. Body mass index, parity, hormone therapy exposure, and baseline CA 125 were not.
The median preoperative endometrial thickness was 14 mm among patients with endometrial cancer and 11 mm in patients without cancer (P = .002).
Overall, 31% of the cancer cases were considered high risk for nodal metastases by Mayo criteria, but an endometrial stripe of 15 mm or higher increased the chance of being considered high risk.
The risk of cancer was 47% among patients with an endometrial stripe of at least 20 mm versus 21% among patients with a measurement below 15 mm.
Only 10 patients underwent lymph node evaluation, 5 with sentinel lymph node dissection and 5 with lymphadenectomy. Six of the 10 patients had endometrial cancer on final pathology, but none had positive lymph nodes.
“Given the low-grade and early-stage disease in this cohort, adherence to a routine sentinel lymph node algorithm in all patients with EIN would result in overtreatment,” Dr. Abt said.
Discussant Nicole Fleming, MD, of the University of Texas MD Anderson Cancer Center, Houston, said she would advocate for more selective use of sentinel lymph node biopsies in EIN as well.
Dr. Fleming said, in general, lymph node biopsy may be reasonable in settings where frozen sections are unreliable and the patient seems to be at high risk of invasive cancer. However, at academic centers with dedicated gynecologic pathologists, given the low risk of invasive cancer and the fact that lymph nodes “are probably not going to provide you a lot of useful therapeutic decision-making tools,” potentially eliminating sentinel lymph node biopsy might make sense, Dr. Fleming said.
Dr. Fleming disclosed relationships with Tesaro, Bristol-Myers Squibb, Pfizer, and GlaxoSmithKline. Dr. Abt reported having no relevant disclosures and did not report any study funding.