Sentinel lymph node mapping showed high diagnostic accuracy in endometrial cancer

TAMPA – Sentinel lymph nodes identified using robotic fluorescence imaging show a high degree of diagnostic accuracy in women with endometrial cancer, according to interim findings from a prospective, multicenter cohort study.

Of 106 patients with clinical stage I disease who have undergone complete surgical staging thus far in the FIRES (Fluorescence Imaging for Robotic Endometrial Cancer Sentinel Node Mapping) trial, 96 had successful sentinel lymph node (SLN) mapping, and 11 of those had positive lymph nodes, or stage 3c disease. The SLN mapping identified metastatic disease in all 11 cases, resulting in a sensitivity of 100% and a negative predictive value of 100%, Dr. Emma C. Rossi of Indiana University, Indianapolis, reported at the annual meeting of the Society of Gynecologic Oncology.

Ten patients had no SLNs identified after injection of indocyanine green (ICG) dye, and 2 of those had stage 3c disease on complete lymphadenectomy, Dr. Rossi said.

Of the patients with stage 3c disease, all had at least one known risk factor for metastases to the nodes or recurrence, she noted.

The patients had a mean age of 61 years and a mean body mass index of about 35 kg/mm². They received cervical injection of 1 mg ICG to a 1-cm depth of the cervix at 3 and 9 o’clock. To achieve this dose, a 0.5-mg/mL concentration of ICG was created and delivered at both sites.This concentration is substantially lower than that advertised for the on-label approved use of ICG (vascular injection for perfusion imaging), Dr. Rossi said.

After cervical injection, surgical access was obtained and the robot was stopped. Near infrared imaging was activated and SLN mapping performed. All patients also underwent pelvic lymphadenectomy, and 70% underwent para-aortic lymphadenectomy as well.

All lymph nodes were evaluated using hematoxylin and eosin staining, and SLNs were ultrastaged with immunohistochemistry for cytokeratin.

Most patients (87%) had endometrioid cell type with stage 1 disease, and 85% of patients had confirmed stage1 disease on final pathology.

The mean number of sentinel nodes removed was 3.8, and the mean number of total nodes removed was 22.9.

"Those were seen bilaterally in 69% of the patient population," Dr. Rossi said.

A para-aortic sentinel lymph node was described in 30% of patients, but the majority of these were downstream from the pelvic sentinel lymph node, with only two isolated para-aortic sentinel lymph nodes found.

"Interestingly, in both of these patients, there was metastatic disease in the para-aortic SLN and no disease in the pelvic nonsentinel lymph nodes," she noted.

Sentinel nodes have been thought to have potential for improving upon the accuracy of metastatic disease detection. Part of the theory is that sentinel nodes are more likely than nonsentinel nodes to contain metastatic disease, and in fact, 7 of 13 node-positive patients in the FIRES trial had metastatic disease only in the sentinel nodes, with negative nonsentinel nodes – a finding that supports this theory, Dr. Rossi said.

"Part of the reason for this ... is the concept that we apply ultrastaging techniques to the sentinel nodes," she said, noting that the 7 of 13 patients with node-positive disease had that disease detected with ultrastaging alone, and that a significant number of those patients had isolated tumor cells. The clinical significance of isolated tumor cells is unknown.

"In conclusion, the identification of nodal metastases in endometrial cancer with robotic-assisted near infrared imaging appears to have a high degree of sensitivity and negative predictive value, with no false-negative sentinel nodes detected to date in the FIRES trial," she said.

She noted, however, that the sample size is currently inadequate for making any conclusions about the comparative accuracy of sentinel nodes detected using lymphadenectomy specimens.

"It’s also really important to reiterate that lymphatic metastases can be found in patients who fail to map sentinel lymph nodes, so the absence of finding a sentinel node after injection of dye does not exclude a patient from the possibility of metastatic disease," she said.

The FIRES trial, which is sponsored by Indiana University, is ongoing and is currently recruiting at seven U.S. centers.

Dr. Rossi reported having no relevant financial disclosures.

TAMPA – Sentinel lymph nodes identified using robotic fluorescence imaging show a high degree of diagnostic accuracy in women with endometrial cancer, according to interim findings from a prospective, multicenter cohort study.

Of 106 patients with clinical stage I disease who have undergone complete surgical staging thus far in the FIRES (Fluorescence Imaging for Robotic Endometrial Cancer Sentinel Node Mapping) trial, 96 had successful sentinel lymph node (SLN) mapping, and 11 of those had positive lymph nodes, or stage 3c disease. The SLN mapping identified metastatic disease in all 11 cases, resulting in a sensitivity of 100% and a negative predictive value of 100%, Dr. Emma C. Rossi of Indiana University, Indianapolis, reported at the annual meeting of the Society of Gynecologic Oncology.

Ten patients had no SLNs identified after injection of indocyanine green (ICG) dye, and 2 of those had stage 3c disease on complete lymphadenectomy, Dr. Rossi said.

Of the patients with stage 3c disease, all had at least one known risk factor for metastases to the nodes or recurrence, she noted.

The patients had a mean age of 61 years and a mean body mass index of about 35 kg/mm². They received cervical injection of 1 mg ICG to a 1-cm depth of the cervix at 3 and 9 o’clock. To achieve this dose, a 0.5-mg/mL concentration of ICG was created and delivered at both sites.This concentration is substantially lower than that advertised for the on-label approved use of ICG (vascular injection for perfusion imaging), Dr. Rossi said.

After cervical injection, surgical access was obtained and the robot was stopped. Near infrared imaging was activated and SLN mapping performed. All patients also underwent pelvic lymphadenectomy, and 70% underwent para-aortic lymphadenectomy as well.

All lymph nodes were evaluated using hematoxylin and eosin staining, and SLNs were ultrastaged with immunohistochemistry for cytokeratin.

Most patients (87%) had endometrioid cell type with stage 1 disease, and 85% of patients had confirmed stage1 disease on final pathology.

The mean number of sentinel nodes removed was 3.8, and the mean number of total nodes removed was 22.9.

"Those were seen bilaterally in 69% of the patient population," Dr. Rossi said.

A para-aortic sentinel lymph node was described in 30% of patients, but the majority of these were downstream from the pelvic sentinel lymph node, with only two isolated para-aortic sentinel lymph nodes found.

"Interestingly, in both of these patients, there was metastatic disease in the para-aortic SLN and no disease in the pelvic nonsentinel lymph nodes," she noted.

Sentinel nodes have been thought to have potential for improving upon the accuracy of metastatic disease detection. Part of the theory is that sentinel nodes are more likely than nonsentinel nodes to contain metastatic disease, and in fact, 7 of 13 node-positive patients in the FIRES trial had metastatic disease only in the sentinel nodes, with negative nonsentinel nodes – a finding that supports this theory, Dr. Rossi said.

"Part of the reason for this ... is the concept that we apply ultrastaging techniques to the sentinel nodes," she said, noting that the 7 of 13 patients with node-positive disease had that disease detected with ultrastaging alone, and that a significant number of those patients had isolated tumor cells. The clinical significance of isolated tumor cells is unknown.

"In conclusion, the identification of nodal metastases in endometrial cancer with robotic-assisted near infrared imaging appears to have a high degree of sensitivity and negative predictive value, with no false-negative sentinel nodes detected to date in the FIRES trial," she said.

She noted, however, that the sample size is currently inadequate for making any conclusions about the comparative accuracy of sentinel nodes detected using lymphadenectomy specimens.

"It’s also really important to reiterate that lymphatic metastases can be found in patients who fail to map sentinel lymph nodes, so the absence of finding a sentinel node after injection of dye does not exclude a patient from the possibility of metastatic disease," she said.

The FIRES trial, which is sponsored by Indiana University, is ongoing and is currently recruiting at seven U.S. centers.

Dr. Rossi reported having no relevant financial disclosures.

TAMPA – Sentinel lymph nodes identified using robotic fluorescence imaging show a high degree of diagnostic accuracy in women with endometrial cancer, according to interim findings from a prospective, multicenter cohort study.

Of 106 patients with clinical stage I disease who have undergone complete surgical staging thus far in the FIRES (Fluorescence Imaging for Robotic Endometrial Cancer Sentinel Node Mapping) trial, 96 had successful sentinel lymph node (SLN) mapping, and 11 of those had positive lymph nodes, or stage 3c disease. The SLN mapping identified metastatic disease in all 11 cases, resulting in a sensitivity of 100% and a negative predictive value of 100%, Dr. Emma C. Rossi of Indiana University, Indianapolis, reported at the annual meeting of the Society of Gynecologic Oncology.

Ten patients had no SLNs identified after injection of indocyanine green (ICG) dye, and 2 of those had stage 3c disease on complete lymphadenectomy, Dr. Rossi said.

Of the patients with stage 3c disease, all had at least one known risk factor for metastases to the nodes or recurrence, she noted.

The patients had a mean age of 61 years and a mean body mass index of about 35 kg/mm². They received cervical injection of 1 mg ICG to a 1-cm depth of the cervix at 3 and 9 o’clock. To achieve this dose, a 0.5-mg/mL concentration of ICG was created and delivered at both sites.This concentration is substantially lower than that advertised for the on-label approved use of ICG (vascular injection for perfusion imaging), Dr. Rossi said.

After cervical injection, surgical access was obtained and the robot was stopped. Near infrared imaging was activated and SLN mapping performed. All patients also underwent pelvic lymphadenectomy, and 70% underwent para-aortic lymphadenectomy as well.

All lymph nodes were evaluated using hematoxylin and eosin staining, and SLNs were ultrastaged with immunohistochemistry for cytokeratin.

Most patients (87%) had endometrioid cell type with stage 1 disease, and 85% of patients had confirmed stage1 disease on final pathology.

The mean number of sentinel nodes removed was 3.8, and the mean number of total nodes removed was 22.9.

"Those were seen bilaterally in 69% of the patient population," Dr. Rossi said.

A para-aortic sentinel lymph node was described in 30% of patients, but the majority of these were downstream from the pelvic sentinel lymph node, with only two isolated para-aortic sentinel lymph nodes found.

"Interestingly, in both of these patients, there was metastatic disease in the para-aortic SLN and no disease in the pelvic nonsentinel lymph nodes," she noted.

Sentinel nodes have been thought to have potential for improving upon the accuracy of metastatic disease detection. Part of the theory is that sentinel nodes are more likely than nonsentinel nodes to contain metastatic disease, and in fact, 7 of 13 node-positive patients in the FIRES trial had metastatic disease only in the sentinel nodes, with negative nonsentinel nodes – a finding that supports this theory, Dr. Rossi said.

"Part of the reason for this ... is the concept that we apply ultrastaging techniques to the sentinel nodes," she said, noting that the 7 of 13 patients with node-positive disease had that disease detected with ultrastaging alone, and that a significant number of those patients had isolated tumor cells. The clinical significance of isolated tumor cells is unknown.

"In conclusion, the identification of nodal metastases in endometrial cancer with robotic-assisted near infrared imaging appears to have a high degree of sensitivity and negative predictive value, with no false-negative sentinel nodes detected to date in the FIRES trial," she said.

She noted, however, that the sample size is currently inadequate for making any conclusions about the comparative accuracy of sentinel nodes detected using lymphadenectomy specimens.

"It’s also really important to reiterate that lymphatic metastases can be found in patients who fail to map sentinel lymph nodes, so the absence of finding a sentinel node after injection of dye does not exclude a patient from the possibility of metastatic disease," she said.

The FIRES trial, which is sponsored by Indiana University, is ongoing and is currently recruiting at seven U.S. centers.

Dr. Rossi reported having no relevant financial disclosures.