Carbon dye staining of sentinel lymph nodes facilitates microstaging of colon cancer patients

Sentinel lymph node biopsy with carbon dye in endometrial cancer: a single center, prospective cohort study

BACKGROUND

Many agents have been used for the detection of sentinel lymph nodes in endometrial cancer. Carbon dye, which has a strong staining ability and high contrast due to its dark black color, identifies the lymph nodes efficiently. Our aim was to evaluate the safety and efficacy of carbon dye for the detection of sentinel lymph nodes in endometrial cancer.

METHODS

We conducted a single-center, prospective, cohort study in 89 patients with early-stage endometrial cancer between September 2021 and August 2022. The procedure was performed under laparoscopy.

RESULTS

The sensitivity and negative predictive value of the sentinel lymph node biopsy (SLNB) with carbon dye injection were 83.3% and 98.8%, respectively. Mapping identified at least one sentinel lymph node in 84 patients (94.4%) on one pelvic side and at least one sentinel lymph node in 73 patients (82.0%) on each pelvic side out of 89 patients. In addition, no carbon dye-associated allergic reaction was detected.

CONCLUSION

Carbon dye is a non-allergenic, inexpensive, and effective agent for SLNB with a satisfying sensitivity and a negative predictive value. In addition, both unilateral and bilateral detection rates were sufficient. Accordingly, carbon dye may be a promising tracer and a considerable option, particularly for low-income countries.

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

An optimized lymph node yield leads to better survival in colon cancer, but extended lymphadenectomy is not associated with survival benefits. Lymphatic mapping shows several colon cancers feature aberrant drainage pathways inducing local recurrence when not resected. Currently, different protocols exist for lymphatic mapping procedures. This meta-analysis assessed which protocol has the best capacity to detect tumor-draining and possibly metastatic lymph nodes. A systematic review was conducted according to PRISMA guidelines, including prospective trials with in vivo tracer application. The risk of bias was evaluated using the QUADAS-2 tool. Traced lymph nodes, total resected lymph nodes, and aberrant drainage detection rate were analyzed. Fifty-eight studies met the inclusion criteria, of which 42 searched for aberrant drainage. While a preoperative tracer injection significantly increased the traced lymph node rates compared to intraoperative tracing (30.1% (15.4, 47.3) vs. 14.1% (11.9, 16.5), p = 0.03), no effect was shown for the tracer used (p = 0.740) or the application sites comparing submucosal and subserosal injection (22.9% (14.1, 33.1) vs. 14.3% (12.1, 16.8), p = 0.07). Preoperative tracer injection resulted in a significantly higher rate of detected aberrant lymph nodes compared to intraoperative injection (26.3% [95% CI 11.5, 44.0] vs. 2.5% [95% CI 0.8, 4.7], p < 0.001). Analyzing 112 individual patient datasets from eight studies revealed a significant impact on aberrant drainage detection for injection timing, favoring preoperative over intraoperative injection (OR 0.050 [95% CI 0.010-0.176], p < 0.001) while indocyanine green presented itself as the superior tracer (OR 0.127 [95% CI 0.018-0.528], p = 0.012). Optimized lymphatic mapping techniques result in significantly higher detection of aberrant lymphatic drainage patterns and thus enable a personalized approach to reducing local recurrence.

The Value of Sentinel Lymph Node Mapping for the Staging of Node-Negative Colon Cancer: Propensity Score and Mediation Analyses

Objectives

Mediation analysis to assess the protective impact of sentinel lymph node (SLN) mapping on prognosis and survival of patients with colon cancer through a more precise evaluation of the lymph node (LN) status.

Background

Up to 20% of patients with node-negative colon cancer develop disease recurrence. Conventional histopathological LN examination may be limited in describing the real metastatic burden of LN.

Methods

Data of 312 patients with stage I & II colon cancer was collected prospectively. Patients were either staged using intraoperative SLN mapping with multilevel sectioning and immunohistochemical staining of the SLN or conventional techniques. The value of the SLN mapping for the detection of truly node-negative patients was assessed using Cox regression and mediation analysis.

Results

SLN mapping was performed in 143 patients. Disease recurrence was observed in 13 (9.1%) patients staged with SLN mapping and in 27 (16%) staged conventionally. Five-year overall survival (OS) rate was 82.7% (95% confidence interval [CI], 76.5-89.4%) with SLN mapping compared with 65.8% (95% CI, 58.8-73.7%). Five-year cancer-specific survival (CSS) was 95.1% (95% CI, 91.3-99.0%) with SLN mapping compared with 92.5% (95% CI, 88.0-97.2%). Node-negative staging with SLN mapping was associated with significantly better OS (hazard ratio [HR], 0.64; 95% CI, 0.56-0.72; P < 0.001) and CSS (HR, 0.49; 95% CI, 0.39-0.61; P < 0.001) in multivariate analysis. Mediation analysis confirmed a direct protective effect of SLN mapping on OS (HR, 0.78; 95% CI, 0.52-0.96; P < 0.01) and disease-free survival (DFS) (HR, 0.75; 95% CI, 0.48-0.89; P < 0.01).

Conclusions

Staging performed by SLN mapping with multilevel sectioning provides more accurate results than conventional staging. The observed clinically relevant and statistically significant benefit in OS and DFS is explained by a more accurate detection of positive LN by SLN mapping.

Sentinel Lymph Node Mapping with Isosulfan Blue or Indocyanine Green in Colon Cancer Shows Comparable Results and Identifies Patients with Decreased Survival: A Prospective Single-Center Trial

BACKGROUND

Sentinel lymph node (SLN) mapping was reported to improve lymph node staging in colon cancer. This study compares isosulfan blue (IB) with indocyanine green (ICG)-based SLN-mapping and assesses the prognostic value of isolated tumor cells (ITC) and micro-metastases in upstaged patients.

METHODS

A total of 220 stage I-III colon cancer patients were included in this prospective single-center study. In 170 patients, SLN-mapping was performed in vivo with IB and in 50 patients ex vivo with ICG. Three levels of each SLN were stained with H&E. If negative for tumor infiltration, immunostaining for cytokeratin (AE1/3; cytokeratin-19) was performed.

RESULTS

SLN detection rate for IB and ICG was 100 and 98%, respectively. Accuracy and sensitivity was 88 and 75% for IB, 82 and 64% for ICG, respectively (p = 0.244). Overall, 149 (68%) patients were node negative. In these patients, ITC and micro-metastases were detected in 26% (31/129) with IB and 17% (5/29) with ICG (p = 0.469). Patients with ITC and micro-metastases did show decreased overall survival (hazard ratio = 1.96, p = 0.09) compared to node negative disease.

CONCLUSIONS

This study demonstrates a high diagnostic accuracy for both the IB and the ICG SLN-mapping. SLN-mapping upstaged a quarter of patients with node negative colon cancer, and the detected ITC and micro-metastases were an independent negative prognostic marker in multivariate analysis.

Comparative Analysis of Tumor Cell Dissemination to the Sentinel Lymph Nodes and to the Bone Marrow in Patients With Nonmetastasized Colon Cancer: A Prospective Multicenter Study

Importance

Small nodal tumor infiltrates (SNTI; isolated tumor cells and micrometastases) in sentinel lymph nodes and bone marrow micrometastases (BMM) were independently described as prognostic factors in patients with colon cancer.

Objective

To examine the association between the occurrence of SNTI and BMM as well as their prognostic relevance.

Design, Setting, and Participants

This prospective study was conducted at 3 university-affiliated institutions in Switzerland between May 2000 and December 2006. Statistical analyses were performed in October 2016. A total of 122 patients with stage I to III colon cancer were included. Follow-up time exceeded 6 years, with no patients lost to follow-up.

Interventions

Bone marrow aspiration from the iliac crests and in vivo sentinel lymph node mapping were performed during open standard oncological resection. Bone marrow aspirates were stained with the pancytokeratin marker A45-B/B3. All sentinel lymph nodes underwent multilevel sectioning and were stained with hematoxylin-eosin and the pancytokeratin marker AE1/AE3.

Main Outcomes and Measures

Association of SNTI in sentinel lymph nodes and BMM in patients with stage I to III colon cancer and the prognostic effect on disease-free survival (DFS) and overall survival (OS).

Results

Of the 122 patients, 63 (51.6%) were female, with a mean (SD) age of 71.2 (11.7) years. Small nodal tumor infiltrates and BMM were found in a total of 21 patients (17.2%) and 46 patients (37.7%), respectively. The occurrence of BMM was not associated with the presence of SNTI by standard correlation (κ, -0.07; 95% CI, -0.29 to 0.14; P = .49) nor by univariate logistic regression analysis (odds ratio, 0.64; 95% CI, 0.22-1.67; P = .37) or multivariate logistic regression analysis (odds ratio, 1.09; 95% CI, 0.34-3.28; P = .88). The presence of SNTI was an independent negative prognostic factor for DFS (hazard ratio [HR], 2.93; 95% CI, 1.24-6.93; P = .02) and OS (HR, 4.04; 95% CI, 1.56-10.45; P = .005), as was BMM (HR, 2.07; 95% CI, 1.06-4.06; P = .04; and HR, 2.68; 95% CI, 1.26-5.70; P = .01; respectively). The combined detection of BMM and SNTI demonstrated the poorest DFS (HR, 6.73; 95% CI, 2.29-19.76; P = .006) and OS (HR, 5.96; 95% CI, 1.66-21.49; P = .03).

Conclusions and Relevance

This study demonstrates no association between the occurrence of SNTI and BMM in patients with stage I to III colon cancer. However, both SNTI and BMM are independent negative prognostic factors regarding DFS and OS, and the occurrence of both is associated with significantly worse prognosis compared with either one of them.

Trial Registration

clinicaltrials.gov Identifier: NCT00826579.

Endoscopic tattooing of early colon carcinoma enhances detection of lymph nodes most prone to harbor tumor burden

Background

Colorectal cancer (CRC) screening programs result in the detection of early-stage asymptomatic carcinomas suitable to be surgically cured. Lymph nodes (LN) from early CRC are usually small and may be difficult to collect. Still, at least 12 LNs should be analyzed from colectomies, to ensure a reliable pN0 stage. Presurgical endoscopic tattooing improves LN procurement. In addition, molecular detection of occult LN tumor burden in histologically pN0 CRC patients is associated with a decreased survival rate. We aimed to study the impact of presurgical endoscopic tattooing on the molecular detection of LN tumor burden in early colon neoplasms.

Methods

A prospective cohort study from a CRC screening-based population was performed at a tertiary academic hospital. LNs from colectomies with and without preoperative endoscopic tattooing were assessed by two methods, hematoxylin and eosin (HE), and RT-LAMP, to detect tumor cytokeratin 19 (CK19) mRNA. We compared the amount of tumor burden and LN yields from tattooed and non-tattooed specimens.

Results

HE and RT-LAMP analyses of 936 LNs were performed from 71 colectomies containing early carcinomas and endoscopically unresectable adenomas (8 pT0, 17 pTis, 27 pT1, 19 pT2); 47 out of 71 (66.2 %) were tattooed. Molecular positivity correlated with the presence of tattoo in LN [p < 0.001; OR 3.1 (95 % CI 1.7–5.5)]. A significantly higher number of LNs were obtained in tattooed specimens (median 17 LN vs. 14.5 LN; p = 0.019).

Conclusions

Endoscopic tattooing enables the analysis of those LNs most prone to harbor tumor cells and improves the number of LN harvested.

Electronic supplementary material

The online version of this article (doi:10.1007/s00464-016-5026-3) contains supplementary material, which is available to authorized users.

Intranodal Mapping Using Carbon Dye Results in More Accurate Lymph Node Staging in Colon Cancer Patients

INTRODUCTION

Small nodal tumor infiltrates (SNTI)-defined as isolated tumor cells and micrometastases-are associated with worse disease-free and overall survival in stage I and II colon cancer patients. Their detection, however, remains challenging. The objective of the present study was to evaluate whether there is a correlation between the location of SNTI and phagocytosed carbon dye particles in sentinel lymph nodes (SLN) of colon cancer patients.

MATERIALS AND METHODS

Isosulfan blue and carbon dye were injected intraoperatively near the tumor to mark the SLN. Serial sections of SLN were stained with hematoxylin-eosin and immunohistochemistry. Intranodal distribution of phagocytosed carbon particles was compared to the presence of SNTI.

RESULTS

Of a cohort of 159 patients, 24 patients had SNTI in their lymph nodes (LN). SNTI were found in a total of 116 LN of which 66 were SLN and 50 were non-SLN. In 59, these 116 LN with SNTI phagocytosed carbon dye were found (50.9 %). Phagocytosed carbon dye was identified significantly more often in SLN (49 of 66 SNTI positive SLN) compared to 10 of 50 SNTI positive non-SLN (p < 0.001). In 52 out of 59 LN (88.1 %), phagocytosed carbon dye was in close proximity to SNTI.

CONCLUSIONS

In the majority of patients, SNTI are located in the same SLN compartment as phagocytosed carbon dye particles. Our investigation provides evidence that the use of carbon dye facilitates SNTI detection and improves LN staging in colon cancer. Therefore, the concept of intranodal mapping-which has been previously described for melanoma-can be extended to colon cancer patients.

Blue dye injection does not induce dissemination of epithelial cells during SLN procedure in colon cancer patients

INTRODUCTION

The sentinel lymph node (SLN) procedure for colon cancer patients has been increasingly performed over the past decade and has shown advantages regarding lymph node staging. However, there are concerns that the manipulation of the colon, particularly the blue dye injection, results in isolated tumor cell dissemination to lymph nodes. Therefore, the objective of the present study was to evaluate whether the blue dye injection during the SLN procedure for colon cancer induces epithelial cell dissemination to the regional lymph nodes using a fake SLN procedure as a model.

METHODS

One hundred seventy-four colon cancer patients underwent open oncologic colon resection and SLN procedure according to a standardized protocol. For the fake SLN procedure, blue dye was injected ex vivo, into the subserosa of a nontumor-bearing segment of the resected colon in 37 unselected patients. Three levels of each SLN were stained with H&E and with the pancytokeratin marker AE1/AE3 and were analyzed for the presence of cytokeratin positive cells.

RESULTS

Identification of fake SLN was successful in 32 of the 37 patients (86 %). Seventy fake SLN were histologically confirmed. The median number of fake SLN was 2 per patient (range 1-8). None of the fake SLN showed any disseminated epithelial cells.

CONCLUSIONS

The present prospective study provides compelling evidence that blue dye injection during sentinel lymph node procedure for colon cancer does not induce epithelial cell dissemination to the sentinel lymph nodes. Therefore, isolated tumor cells in sentinel lymph nodes result from a true metastatic process.

Ex vivo sentinel node mapping in colon cancer combining blue dye staining and fluorescence imaging

BACKGROUND

The sentinel lymph node procedure has been proposed to improve nodal staging in colon cancer patients. The aim of this study was to assess the added value of near-infrared (NIR) fluorescence imaging to conventional blue dye staining for ex vivo sentinel lymph node mapping.

MATERIALS AND METHODS

We included 22 consecutive patients undergoing surgery for colon cancer. After tumor resection, we submucosally injected a premixed cocktail of the near-infrared lymphatic tracer HSA800 and blue dye around the tumor for detection of sentinel lymph nodes. We used the Mini-FLARE imaging system for fluorescence imaging.

RESULTS

In 95% of patients, we identified at least one sentinel lymph node. Overall, a total of 77 sentinel lymph nodes were identified, 77 of which were fluorescent (100%) and 70 of which were blue (91%). Sentinel lymph nodes that were located deeper in the mesenteric fat could easily be located by NIR fluorescence. In four of five patients with lymph node metastases, tumor cells were present in at least one of the sentinel lymph nodes.

CONCLUSIONS

This study shows the successful use and added value of the NIR fluorescence tracer HSA800 to conventional blue dye for the ex vivo sentinel lymph node procedure in colon cancer.

Carbon coated superparamagnetic iron oxide nanoparticles for sentinel lymph nodes mapping

Intra-operative lymphatic mapping and sentinel lymph-adenectomy (LM/SL) maps the lymphatic path from the primary tumor to the regional nodes and permits selective excision of the first sentinel lymph nodes. It is a well established technique to detect occult regional node metastases for melanoma patients and breast cancer patients. In continuing attempts to improve accuracy, most surgeons now combine a dye (such as carbon particles) and radiopharmaceuticals when performing LM/SL. We developed a proto-type of carbon coated superparamagnetic iron oxide nanoparticles (SPIO@C) for sentinel lymph nodes mapping. Compared with combining carbon particles and radiopharmaceuticals for performing LM/SL, there are a number of advantages with our approach: I. SPIO is an MRI contrast agent, thus pre-operative MRI may be used for LM/SL instead of gamma camera. There is no radiation associated with MRI, and MRI offers good tissue contrast and detailed cross-sectional images. II. There will be only needed one injection of SPIO@C nanoparticles, instead of administrating two successive injections of radiopharmaceuticals and carbon particles. III. During the operation, an intra-operative MRI scanner can be used, or more conveniently by a simple magnetometer.

Sentinel lymph node procedure leads to upstaging of patients with resectable colon cancer: results of the Swiss prospective, multicenter study sentinel lymph node procedure in colon cancer

BACKGROUND

The value of the sentinel lymph node (SLN) procedure in colon cancer patients remains a matter of debate. The objective of this prospective, multicenter trial was 3-fold: to determine the identification rate and accuracy of the SLN procedure in patients with resectable colon cancer; to evaluate the learning curve of the SLN procedure; and to assess the extent of upstaging due to the SLN procedure.

METHODS

One hundred seventy-four consecutive colon cancer patients were enrolled onto this prospective trial. They underwent an intraoperative SLN procedure with isosulfan blue 1% injected peritumorally followed by open standard colon resection with oncologic lymphadenectomy. Three levels of each SLN were stained with hematoxylin and eosin (H&E) and immunostained with the pancytokeratin marker AE1/AE3 if H&E was negative.

RESULTS

SLN identification rate and accuracy were 89.1% and 83.9%, respectively. SLN were significantly more likely to contain tumor infiltrates than non-SLN (P < 0.001). Both SLN identification rate (P = 0.021) and the sensitivity of the procedure (P = 0.043) significantly improved with experience. The use of immunohistochemistry in SLN resulted in an upstaging of 15.4% (16 of 104) stage I and II patients considered node-negative in initial H&E analysis.

CONCLUSIONS

The SLN procedure for colon cancer has good identification and accuracy rates, which further improve with increasing experience. Most importantly, the SLN procedure results in upstaging of >15% of node-negative patients. The potential advantage of performing the SLN procedure appears to be particularly important in these patients because they may potentially benefit from adjuvant therapy.

A new concept for the role of ex vivo sentinel lymph nodes in node-negative colorectal cancer

BACKGROUND

We recently introduced ex vivo, intra-arterial methylene blue injection as a simple method to improve the lymph node (LN) harvest in gastrointestinal cancer. We now combined it with a novel ex vivo sentinel lymph node (evSLN) mapping technique.

METHODS

evSLN mapping was performed by subserosal (n = 20) or submucosal (n = 30) India ink injection. Subsequently, methylene blue was injected intra-arterially to enhance visibility of all LNs to improve the overall LN harvest. Manual LN dissection was carried out after fixing overnight. evSLNs nodes were identified by detecting carbon particles during histological examination. In primary node-negative cases, all detected LNs were step sectioned and immunohistochemically stained for pan-cytokeratin.

RESULTS

India ink injection was easy to perform. Methylene blue injection failed in 1 case. The mean lymph node harvest was 42 ± 18 LNs, and the SLN detection rate was 78%. The sensitivity for detecting metastases was 75%. The mean SLN number was 3 ± 1. LN metastases were found in 20 of 47 malignant cases (43%). Skip metastases occurred in 4 cases. Of these cases, 3 showed involvement of at least 1 entire LN. True upstaging (N0 → N1mi) was found in 1 of 23 cases (4%) within a SLN after advanced evaluation.

CONCLUSIONS

Combination of methylene blue technique and ex vivo sentinel mapping is feasible, easy to perform, and cost effective. It guarantees an optimal LN harvest and has the potential to heighten the sensitivity of metastasis detection.