MELBOURNE – Staging endometrial cancer using sentinel lymph node mapping reduces side effects for patients, and enables selection of lymph nodes for pathology that are more likely to have disease in them, an investigator reported at the biennial meeting of the International Gynecologic Cancer Society.
The procedure results in fewer lymph nodes being removed – usually two to three on each side, and no more than ten – which meant less side effects such as lymphedema, and potentially avoided the need for pelvic lymphadenectomy said Dr. Nadeem Abu-Rustum, chief of the gynecology service at Memorial Sloan Kettering Cancer Center, New York.
“One, you are removing fewer lymph nodes so there’s less radicality in surgery and less side effects; two, it makes the operating time faster, and three, you give the pathologist fewer lymph nodes but they can work on them in more depth to try to find low-volume metastases,” Dr. Abu-Rustum said in an interview.
“It’s a win-win situation for the patient.”
Dr. Abu-Rustum and colleagues at Memorial Sloan-Kettering have developed a sentinel lymph node mapping algorithm for stage I cervical or endometrial cancers.
“It is applicable for any women who has endometrial cancer where the surgeon feels that the cancer is contained, and you need staging information,” he said.
However he stressed it was not applicable in patients with obvious metastases or with abnormal lymph nodes.
“This is for normal-appearing lymph nodes, clinical stage I, and the algorithm checklist really protects you because it will exclude those patients [with abnormal lymph nodes].”
While there was ongoing debate about where to inject the dye to best identify the sentinel node, Dr. Abu-Rustum told the conference that he and his colleagues believed injecting into the cervix at the three o’clock and nine o’clock positions was the most reasonable option.
He also commented on the different dyes used, saying that while methylene blue or lymphazurin had been the traditional choice – with or without technetium-99 – the near-infrared fluorescing indocyanine green and use of a laser significantly improved accuracy of the procedure.
“Now you’re able to increase the chance of finding the lymph node from 80% to almost 100%, and finding it on the right and the left was 60%, now it’s 80%,” he said.
In another presentation, a speaker reported an overall sentinel lymph node detection rate of 92%, and a 74% rate of bilateral detection, using a combination of methylene blue, technetium-99, and indocyanine green, in 100 patients who underwent sentinel lymph node mapping for endometrial cancer.
Among the 10 patients in the prospective study who had metastatic disease, 9 had a positive sentinel lymph node. The sentinel node was found to be the only positive node in 66% of these patients, suggesting that this was the most clinically relevant node. There was one case of a false negative for a sentinel lymph node, reported Dr. Jeffrey How, obstetrics and gynecology resident at the McGill University Health Centre, Montreal.
The addition of indocyanine green increased the precision of in vivo detection of sentinel lymph nodes, aiding detection of the highest-yield lymph nodes for pathology, he said.
No conflicts of interest were declared.