ORLANDO, FL—Sentinel lymph node (SLN) mapping, which revolutionized surgical staging of breast cancer and melanoma, can also help minimize surgery and preserve quality of life in patients with gastric cancer, according to Japanese researchers.
They said data from their prospective multicenter study, reported here at the Gastrointestinal Cancers Symposium, validated SLN mapping as a method of avoiding unnecessary prophylactic regional lymph node dissection for cancer metastasis in cases with negative sentinel nodes.
A total of 397 patients with T1N0M0 or T2N0M0 previously untreated single tumors with diameters smaller than 4 cm were accrued at 12 comprehensive cancer center hospitals. Surgeons used a dual tracer approach with technetium-99m colloid and isosulfan blue dye, the same as in breast or melanoma surgery.
The detection rate of “hot” and/or blue nodes was 97.5% (387 of 397), and 53 of 57 cases with lymph node metastases showed positive lymph nodes.
The sensitivity to detect metastasis based on SLN status was therefore 93%, said first author Yuko Kitagawa, MD, PhD, Professor and Chair of the Department of Surgery at Keio University of School of Medicine, Tokyo, who presented the data here. A mean of 5.6 sentinel nodes were identified.
“Minimized gastrectomy with individualized selective and modified lymphadenectomy for early gastric cancer with negative sentinel nodes should become feasible and clinically useful as a less invasive surgical procedure,” Dr. Kitagawa said.
In an interview after his oral presentation, Dr. Kitagawa said it is feasible for pathologists to check five lymph nodes during surgery and that, of course, if even one sentinel lymph node is positive by H&E staining, a D2 resection would be done.
He called SLN mapping a “safety net” in surgery for gastric cancer. “In breast cancer they usually pick up just one or two [sentinel] nodes, and if metastases do not exist, they can totally avoid dissection. If there is recurrent breast cancer you can do a re-resection or radiation.
“But for gastric cancer, any lymph node recurrence is fatal for patients.”
To avoid recurrence, a small basin with a margin of 3 to 5 cm adjacent to the sentinel is resected, he said. “Usually micrometastases can be removed by this kind of a minimal lymph node dissection. This is what I think of as a kind of safety net.”
Dissecting the basin is not the problem with gastric cancer, Dr. Kitagawa said.
“The problem is how to preserve the size or function of the stomach, and that's quite different from the staging breast surgery.”
Mapping Value Less in US, Though
Discussing Dr. Kitagawa's presentation, the Chair of the Symposium's Program Committee, Christopher G. Willett, MD, Professor and Chair of the Department of Radiation Oncology at Duke University Medical Center, noted that Japanese surgeons see much more T1 and T2 disease than surgeons in the United States.
“With sentinel node mapping they might use a less aggressive surgery because they wouldn't have to do all that lymph node removal with a formal gastrectomy for sentinel-negative, early disease.
“But I don't know how applicable that approach is in the US, since we see practically all T3 and more advanced disease,” Dr. Willet said. “Node mapping isn't going to change the management of T3 disease.”
Regarding the fact that SLN mapping is used much more often in Japan than in the US, the Chair of the Symposium News Planning Committee, Robert P. Sticca, MD, Chairman and Director of Surgical Oncology at the University of North Dakota, said, “The incidence of gastric cancer in Japan is so much higher that I tell my residents that, in Japan, if you burp twice you get an endoscopy. [In Japan,] they're very, very sensitive to it and they screen a lot more frequently than we do in this country.”
US oncologists are not likely to see a patient with gastric cancer until the patient is symptomatic and at a much later stage. “Sentinel lymph node mapping might have a place in surgery for early gastric cancers, but in later stage gastric cancers most surgeons would do full lymph node dissections.”
Science & Multidisciplinary
The Gastrointestinal Cancers Symposium, with the subtitle “Science and Multidisciplinary Management of GI Malignancies,” was co-sponsored by the American Society of Clinical Oncology, the American Gastroenterological Association Institute, the American Society for Radiation Oncology, and the Society of Surgical Oncology.