Utility of the sentinel node concept for detection of lateral pelvic lymph node metastasis in lower rectal cancer

Abstract

BackgroundThere are two lymphatic flows in lower rectal cancer; one along the inferior mesenteric artery and another towards the internal iliac artery. The benefit of dissection of lateral pelvic (LP) lymph nodes (LPLN) remains controversial. This study aimed to clarify the possibility of detecting the sentinel node (SN) of the LP region (LPSN) and examine metastasis, including micrometastasis, using a radio isotope (RI) method.MethodsIn total, 62 patients with clinical (c)T1-T4 rectal cancer were enrolled in this study (11, 16 and 35 patients had tumor located in the upper, middle and lower rectal third, respectively). LPSNs were detected using a radio-isotope method in which 99 m technetium-tin colloid was endoscopically injected into the submucosa in patients with cT1, and into the muscularis propria in patients with cT2, cT3 and cT4. All patients underwent curative resection with lymphadenectomy. LPSN metastases were diagnosed by HE staining, immunohistochemical staining using AE1/AE3 as a primary antibody and by RT-PCR using CEA as a marker.ResultsOf the lower rectal (c)T2–4 tumors, 38.4% had lateral pelvic lymphatic flow that was significantly greater than that of cT1 tumors in the upper and middle thirds of the rectum (p = 0.0074). HE and immunohistochemical staining did not detect LPSN metastases but RT-PCR detected micrometastasis of three SNs. The remaining half of LPSNs were immunohistochemically re-examined; in all three cases, isolated tumor cells were detected.ConclusionThe SN concept may be useful for detecting lateral pelvic lymphatic flow and LPSN metastases, including micrometastasis in lower rectal cancer.

Fascial Organisation and Lymphatic Systems Around the Pelvic Floor: A Literature Review

“…Moreover, studies on the lymphatic flow of the lateral ligament were mainly based on the macroscopic anatomy and on speculations from the clinical metastatic features (1,31). Yanagita et al suggested the existence of lymph node metastatic pathways between the pararectal and lateral regions, using the isotope method (37). However, this study did not indicate whether the pathway involved the lateral ligament or whether it involved the lateral ligament and other pathways.…”

“…These routes were the lateral and mesorectal drainage routes (49). Recently, Yanagita et al reported the utility of the radioisotope method by the submucosal injection of 99mTc to detect metastatic LPLNs in low rectal cancer cases (37). Thus, radioisotope methods have been used to examine lateral lymphatic drainage from the lower rectum.…”

Near-Infrared Imaging Using Indocyanine Green for Laparoscopic Lateral Pelvic Lymph Node Dissection for Clinical Stage II/III Middle-Lower Rectal Cancer: A Propensity Score-Matched Cohort Study

“…11,13,14 However, laparoscopic LPLND is one of the most complicated surgical procedures from the viewpoint of anatomical complexity of the lateral region in the pelvis and autonomic nerve preservation. [15][16][17] Thus far, details on the lymphatic flow in the lateral region of the pelvis have not been completely clear and the quality of LPLND has been a problem for colorectal surgeons. As a result, the recurrence of lateral lesions of the pelvis after LPLND has been experienced.…”

Prediction of lateral lymph node metastasis using OSNA method for mesorectal lymph nodes in low rectal cancer: A prospective study by the Kanagawa Yokohama Colorectal Cancer Study Group (KYCC1801)

“…Recently, this concept has been applied to gastrointestinal cancer 26 . Yanagita et al 27 reported that after preoperative local radioisotope injection in 62 patients with rectal cancer, the SLN could be identified in the LatLN in 12 patients. Noura et al 28 reported that preoperative local indocyanine green dye injection in 25 patients with lower rectal cancer resulted in the identification of the SLN in 23 patients.…”