Mapping Endometrial Cancer Metastases With Dye Preferable to Lymphadenectomy

Until recently, the most common way to stage endometrial cancer was through surgical staging. Lymphadenectomy required removing large amounts of tissue to find impacted nodes. While this surgery is effective in helping determine staging, it has drawbacks, including scar tissue build-up and lymphedema. To address this issue, The Lancet Oncology recently published the results of the FIRES trial, considered to be the largest, most conclusive study on the accuracy of this technology on endometrial cancer.¹

The researchers had found sentinel lymph node mapping to be a better and safer option over lymphadenectomy for most women. When performing sentinel lymph node mapping, surgeons inject a small amount of dye into the uterus and monitor which nodes absorb the dye. This allows the surgeons to remove only the nearby sentinel nodes, rather than large amounts of tissue.

"With fewer lymph nodes removed, there is less damage to the patient's tissue and therefore less trauma to the patient," principal investigator Emma Rossi, MD, assistant professor of obstetrics and gynecology at the University of North Carolina School of Medicine in Chapel Hill, said in a news release.² "The concept is that reviewing a smaller number of more specific lymph nodes is a lower-volume, higher-quality procedure. Our study showed that this procedure is just as accurate as lymphadenectomy."

The multicenter, prospective cohort study included 340 women who underwent sentinel lymph node mapping with complete pelvic lymphadenectomy, and 196 (58%) also underwent and para-aortic lymphadenectomy. The findings showed that 293 patients (86%) had successful mapping of at least one sentinel lymph node; 41 patients (12%) had positive nodes, 36 of whom had at least one mapped sentinel lymph node. The researchers identified nodal metastases in the sentinel lymph nodes of 35 (97%) of these 36 patients.

"Stage 3 endometrial cancer typically requires treatment with chemotherapy and radiation. As sentinel lymph nodes are involved in less than 5% of grade 1 and grade 2 endometrial cancer, patients whose sentinel nodes present no sign of metastases can avoid this treatment," said Rossi.

The procedure is not without the risk of adverse events. Four patients experienced postoperative neurological disorders and four more patients experienced postoperative respiratory distress or failure (4 patients). Twenty-two patients had serious adverse events, with one related to the study intervention: a ureteral injury incurred during sentinel lymph node dissection.

The researchers concluded that “sentinel lymph nodes identified with indocyanine green have a high degree of diagnostic accuracy in detecting endometrial cancer metastases and can safely replace lymphadenectomy in the staging of endometrial cancer.” While the sentinel lymph node biopsy may not identify metastases in 3% of patients with node-positive disease, the procedure does have the potential to expose fewer patients to the morbidity of a complete lymphadenectomy.

References:

1. Rossi EC, Kowalski LD, Scalici J, et al. A comparison of sentinel lymph node biopsy to lymphadenectomy for endometrial cancer staging (FIRES trial): a multicentre, prospective, cohort study. Lancet Oncol. 2017 Jan 31. pii: S1470-2045(17)30068-2.
2. UNC School of Medicine. UNC researcher finds safer, less-invasive method of staging endometrial cancer. 2017 Feb 20.