Role of methylene blue in detecting the sentinel lymph node in colorectal cancer: In vivo vs. ex vivo technique

Abstract

The identification of sentinel lymph nodes is a valuable oncological method, which aims at mapping lymphatic drainage and has the advantage of correctly staging the disease and assessing prognosis. Lymph node invasion is an important prognostic feature. In colorectal cancer, lymphadenectomy is not influenced by the positive or negative status of the sentinel lymph node. The identification of lymph nodes with possible invasion by staining the primary tumor with methylene blue can lead to improved staging and management. In other words, the consequent administration of neoadjuvant therapy (chemotherapy) to the appropriate patients may result in lower recurrence rates. Thus, the aim of the present study was to use methylene blue to identify the sentinel node/nodes in colorectal cancer and to determine whether the dye-capturing nodes were invaded by the tumor. This is a non-randomized prospective study, in which 26 patients with colon cancer with surgical indication were enrolled. Two types of methods were utilized: in vivo (16 patients) and ex vivo (10 patients). The identification rate was 75% for the in vivo technique and 60% for the ex vivo technique, resulting in a 69.26% overall identification rate. Of 18 patients with sentinel lymph nodes identified using dye, routine histological examination detected metastases in 6 (33.33%) of these patients. In conclusion, further research should be conducted into how the clinical application of sentinel node detection can be employed in colorectal cancer.

Lymphatic Mapping in Colon Cancer Depending on Injection Time and Tracing Agent: A Systematic Review and Meta-Analysis of Prospective Designed Studies

“…All individual patient data (IPD) available from the included studies were further analyzed according to factors influencing the effectiveness of LN mapping and aberrant LN detection. Data on tumor characteristics, the timing, and the tracer application site from ten studies could be extracted and included in this analysis [ 12 , 16 , 17 , 28 , 29 , 31 , 32 , 159 , 174 , 190 ]. Studies neither searching nor resecting aberrant LNs or not reporting the mapped LN yield did not contribute to the respective analysis.…”

“…All searches were conducted on 20 July 2021; the original search string can be found in the Supplementary Data (Data S1) . A second search using the same search strategies was conducted on 13 February 2023, which led to five newly published studies [ 28 , 29 , 30 , 31 , 32 ]. Reviews [ 8 , 9 , 10 , 11 , 12 , 33 , 34 ] concerning similar research topics were manually searched for possible missed publications.…”

“…The pooled estimate of the proportion of traced LNs is 14.3%. CI—confidence interval; ES—effect size; ICG—indocyanine green [ 12 , 16 , 19 , 25 , 26 , 28 , 32 , 35 , 157 , 158 , 159 , 162 , 163 , 165 , 168 , 169 , 170 , 171 , 174 , 175 , 176 , 178 , 179 , 180 , 181 , 182 , 183 , 187 , 188 , 190 , 192 , 193 , 194 , 195 , 197 ].…”

Application of indocyanine green lymphography combined with methylene blue staining in lymphaticovenular anastomosis of lower limb vessels: A prospective study

“…MB is a generic tracer and is frequently employed in sentinel lymph node biopsy during radical surgery for malignant tumors. 9,39–41 However, there is scarce evidence for the clinical value of MB staining in intraoperative localization during LVA. The advantages of MB in this study are as follows: (1) It is a conventional lymph node tracer, has a solid affinity for the lymphatic system, is easily absorbed by organisms, has a quick tissue uptake, and is safe, thereby avoiding severe adverse reactions and amplifying the effect on the body; (2) the surgical incision was washed intraoperatively with heparin saline 20 s after the second instance of MB staining; all the lymph vessels except the blue-stained ones were washed clean to avoid staining the surrounding fibrous tissue and maintain a clear field of vision during the operation; (3) as MB retains the blue color in the lymphatic vessels for a prolonged time, the operation could be carried out 30 min after the first MB injection, without any significant impact on the anastomosed lymphatic vessels.…”

Simultaneous, Multi-Channel, Near-Infrared Fluorescence Visualization of Mesenteric Lymph Nodes Using Indocyanine Green and Methylene Blue: A Demonstration in a Porcine Model

“…Due to its renal clearance, NIRF imaging with MB has mostly been used in colorectal cancer surgery for intraoperative visualization of the urinary tract [ 41 , 42 , 43 ]. Moreover, there have been several studies using MB to detect sentinel lymph nodes in colorectal cancer [ 44 ] and for postoperative lymph node harvesting [ 45 , 46 ]. Its use is limited in a few optical imaging devices since most NIRF imaging systems are designed for imaging with ICG and dyes with smiliar optical properties.…”