Sentinel Lymph Node Detection by Blue Dye Versus Indocyanine Green Fluorescence Imaging in Colon Cancer

Abstract

Abstract. Background In patients with colorectal cancer (CRC), the accurate establishment of the pathological status of tumor-draining mesenteric lymph nodes (LN) is of central importance for therapeutic management. In patients with stage III disease with demonstrated LN metastases, adjuvant systemic chemotherapy is indicated, reducing the risk of recurrence and improving long-term overall survival (1). The accuracy of mesenteric nodal staging depends primarily on the number of resected LN, and the seventh American Joint Committee on Cancer (AJCC) edition recommends harvesting and analysis of at least 12 to 14 LN for correct staging (2). Despite this, 20-30% of patients with no LN metastases demonstrated at pathology (pN0), and therefore classified as stage II, still develop recurrent disease (3). These recurrences could potentially be associated with unrecognized locoregional nodal metastases, which could lead to understaging and undertreatment.The sentinel lymph node (SLN) is defined as the first LN draining the primary tumor. In melanoma and breast cancer, it has been shown that pathological status of the SLN is indicative of the risk of nodal metastases, thus providing an indication for lymphadenectomy when SLN pathological examination is positive and for avoiding mutilating surgery when it is negative (4, 5). The concept, and potential utility, of the SLN is different in CRC since mesenteric lymphadenectomy is systematically performed during surgery for the primary tumor. In patients with CRC, the particular contribution of SLN examination could be to focus the pathological analysis specifically on draining LNs in order to improve the sensitivity for cancer cell detection by the use of advanced methods, such as serial sectioning, immunohistochemistry (IHC), and molecular analyses such as reverse transcriptase polymerase chain reaction (RT-PCR) to increase pathological staging (6).Accordingly, a recent meta-analysis concluded that the use of SLN examination allowed for nodal up-staging of patients with CRC, providing a potential benefit (7). However, the technique of SLN analysis is still not widely used in patients with CRC. This could be related to the variability of the sensitivity of techniques for SLN detection which ranges from 33% to 100%, to the risk of missed metastases, and also to uncertainty related to the clinical significance and prognostic value of nodal micrometastases in CRC (7-9).Recently, fluorescence imaging (FI) using indocyanine green (ICG) has emerged as a new technique for SLN detection in various tumors (10)(11)(12). Only few studies have 4853

Ex vivo detection of tumoral lymph nodes of colorectal origin with fluorescence imaging after intraoperative intravenous injection of indocyanine green

“…More recently, we have reported the results of a study using ex vivo ICG-FI for SLN detection in colorectal cancer and compared it with the standard blue dye technique. Although the sensitivity was higher for the ICG-FI technique in obese patient, the sensitivity of both techniques was low, 57% for ICG and 43% for the blue dye technique [15]. In this study, using ICG-FI after IV injection, the concept is completely different as the pathway used to visualize LNs is the systemic route.…”

Sensitivity and specificity of indocyanine green near‐infrared fluorescence imaging in detection of metastatic lymph nodes in colorectal cancer: Systematic review and meta‐analysis

“…The ability of ICG NIR flouresence to detect metastatic LNs was compared with patent blue dye in one study. Liberale et al examined both techniques in 20 patients with colon cancer and reported that both techniques had the same detection rates (95%), yet with higher sensitivity in favor to ICG (57 vs 43%), especially in patients with BMI above 25 kg/m 2 . The overall correlation between the two techniques was greater than 80%.…”

Ex vivo indocyanine green fluorescence imaging for the detection of lymph node involvement in advanced‐stage ovarian cancer

“…Near‐infrared fluorescence imaging (NIR‐FI)‐guided surgery using indocyanine green (ICG), a non‐specific fluorophore, has been used as a new tool for sentinel lymph node (SLN) detection in various gynecological (breast, endometrium, cervix, ovary), digestive (colon, stomach), skin, and lung cancers . More recently, it has been reported that ex vivo ICG‐FI is able to detect metastatic LNs of colorectal and head and neck cancer origin .…”