In a study of women with high-grade endometrial cancer, researchers at The University of Texas MD Anderson Cancer Center found sentinel lymph node mapping accurately identified all women with node-positive, high-risk endometrial cancer, when prospectively compared to a complete pelvic and para-aortic lymphadenectomy, the current standard of care. Pamela Soliman, MD, Associate Professor of Gynecologic Oncology and Reproductive Medicine at MD Anderson, presented the findings at the Society of Gynecologic Oncology Annual Meeting on Women’s Cancer (Abstract 5026).
The study offers promise the less-invasive procedure may one day serve as a staging tool for the most common gynecologic malignancy—as it does now for other cancers—with fewer associated risks and complications to patients.
According to the American Cancer Society, 54,870 women will be diagnosed with endometrial cancer in 2015, and 10,170 will die from the disease. It is the most common gynecologic cancer, said Dr. Soliman, and with its strong association with obesity, there has been an increase both in overall incidence and in the number of younger women diagnosed with disease.
For women with endometrial cancer, the current standard of care for initial evaluation usually involves a hysterectomy and complete lymphadenectomy. However, in addition to obesity, other risk factors associated with the disease include diabetes and hypertension. These comorbidities inherently can make surgery more difficult, and put women at higher risk for complications such as lymphedema and swelling, explained Dr. Soliman.
Sentinel lymph node mapping involves the use of dyes and/or radioactive substances to identify the first lymph nodes in which the cancer is most likely to spread. Hypothetically, cancer should appear in the sentinel node first, before other nodes and places in the body, said Dr. Soliman.
As the technique has been proven and accepted for the staging of diseases such as breast and vulva cancers and melanoma, other institutions have looked at the technique in endometrial cancer. This is the first validation study where patients received both the mapping and the complete lymphadenectomy.
“It was important for us to understand if we performed only the sentinel lymph node mapping, would there be patients that wouldn’t be identified with appropriate disease, as well as to understand the false-negatives rate of the technique,” she explained. “If we could still identify patients with positive nodes yet not have to do a full lymphadenectomy, we could potentially decrease the morbidity of the procedure, and still appropriately determine postoperative therapy.”
For the single-institution prospective study, MD Anderson is currently enrolling 100 patients with high-risk, grade 3 endometrial cancer.
At the meeting, Dr. Soliman reported on 73 enrolled patients, 60 of whom were evaluable. The median age of the women was 61.1 years, and the median body mass index was 30.1. Patients were considered evaluable if sentinel lymph node mapping was attempted and a full lymphadenectomy was performed.
To date, when comparing the mapping results to final surgical pathology, the researchers found that each patient with positive lymph nodes was also found to have a positive sentinel lymph node—meaning no false-negatives were found. In the evaluable women, researchers identified at least one positive sentinel lymph node, and bilateral sentinel lymph nodes in 92.3% (56) and 60.7% (37) of the patients, respectively. These findings are consistent with other research to date, showing the feasibility of the procedure.
For each patient with a node positive for metastatic disease, at least one sentinel lymph node was also positive for metastatic disease, for both a specificity and sensitivity of 100%.
With further study, the findings could impact standard of care for women with both high- and low-risk disease, said Dr. Soliman.
“This study serves as a proof of principle and based on our early results, finds an acceptable false-negative rate,” she explained. “Potentially, if we continue to see such promising results, and can identify patients with positive nodes by sentinel lymph node mapping only, it could change practice for the overall management of the endometrial cancer general population, much like we have for other diseases.”
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