SEATTLEIntraoperative colon-oscopy with lesion tattooing and lymphatic mapping during laparoscopic colectomy can improve accuracy in identifying a small primary colorectal neoplastic lesion and its lymphatic drainage, according to a study presented at the President’s Plenary Session of the 67th Annual Scientific Meeting of the American College of Gastroenterology (ACG abstract 4).
The technique assisted in guiding resection and improved staging of patients with colorectal cancer, said lead author Nicholas Karyotakis, MD, an attending physician at Cedars-Sinai Medical Center, and chief scientific officer of Gastrointestinal Biosciences, Los Angeles.
"The 5-year survival for colorectal cancer has not improved all that much over the last 15 years," Dr. Karyotakis said. "The problem is that 30% of colorectal cancers at stage II tend to recur. Is that because of false-negative nodal status? We believe that direct examination of the lymph nodes of the surgical specimen may improve detection."
The main obstacle to lymph node examination is that every surgical specimen usually has 15 to 20 or more nodes that need to be meticulously dissected and examined. Dr. Karyotakis and his colleagues hope to improve upon this procedure by using lymphatic mapping to identify the sentinel nodes for closer examination.
The sentinel node is the first regional node in the lymphatic drainage pathway from the primary neoplasm, and the tumor status of the sentinel node reflects the tumor status of the nodal basin. "Sentinel lymph node mapping has been used for many years in melanoma and breast cancer, and we’re trying to use this technology in the gastrointestinal tract," Dr. Karyotakis said.
The researchers looked at 22 patients (median age, 65 years) who had small, early-stage colorectal neoplasms. The distribution of lesions by location was as follows: rectum, 2 patients (9%); left colon, 6 patients (28%); and right colon, 14 patients (63%). The median size of the lesions was 2.2 cm (range, 0.3 to 5 cm). The primary lesion was a dysplastic polyp in 4 patients (18%), stage T1 in 11 patients (50%), stage T2 in 4 patients (18%), and stage T3 in 3 patients (14%).
The study subjects all underwent intraoperative colonoscopy, with tumor site identification done laparoscopically, and efferent lymph channels tracked to the sentinel nodes using blue dye. The sentinel nodes were marked and sent to pathology along with the surgical specimen. Colonoscopy and lymphatic mapping added only about 15 minutes to the total operative time.