Validation of lymphatic mapping in colorectal cancer: in vivo, ex vivo, and laparoscopic techniques

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.

Upstaging nodal status in colorectal cancer using ex vivo fluorescence sentinel lymph node mapping: preliminary results

BACKGROUND

Sentinel lymph node (SLN) mapping using near-infrared fluorescence (NIRF) imaging is a recent technique to improve nodal staging in several tumors. The presence of colorectal cancer (CRC) micro-metastases has recently been defined as N1 disease and no longer as N1mi, determining the need for adjuvant chemotherapy. In CRC, the reported rate of SLN micro-metastases detected by ultrastaging techniques is as high as 30%. The aim of this prospective study is to report the preliminary results of the sensitivity analysis of NIRF imaging for ex vivo SLN mapping and the research of micro-metastases in CRC, in patients with node-negative disease (NND).

MATERIAL AND METHODS

On the specimen of 22 CRC patients, 1 mL of ICG (5 mg/mL) was injected submucosally around the tumor to identify SLNs. NND SLNs were further investigated with ultrastaging techniques.

RESULTS

Three-hundred and sixty-three lymph nodes were retrieved (59 SLNs; mean per case: 2.7). The detection, sensitivity and false-negative rate were 100%, 100% and 0% respectively. Ultrastaging investigations showed no micro-metastases in the NND SLNs.

CONCLUSIONS

The ex vivo SLN fluorescence-based detection in CRC was confirmed to be easy to perform and reliable. In this preliminary results report of an ongoing study, the SLN assay was congruent with the nodal status, as confirmed by histological investigations.

Sentinel Lymph Node Mapping in the Management of Colorectal Cancer: Preliminary Report

Aim and background

The problem of understaging the lymph node status in colorectal cancer because of missed micrometastases led authors to investigate the role of sentinel node (SN) mapping also in colorectal malignancies. The aim of this study was to evaluate the feasibility of the technique and to correlate the results with some characteristics of the primary tumor.

Methods

Sentinel lymph node mapping was performed in 23 patients who underwent a standard lymphadenectomy for colorectal cancer. The vital dye Patent Blue had been injected into the peritumoral subserosa in vivo in 17 cases and ex vivo in seven, including one case where the in vivo method did not allow to identify the sentinel node. The nodes that took up the dye were removed and analyzed with standard hematoxylin-eosin staining in serial sections. Immunohistochemistry (AE1-AE3 cytokeratin markers) was performed in hematoxylin-eosin-negative nodes. SN status was related to the status of the other lymph nodes in the surgical specimen analyzed with the standard technique and to the following characteristics of the primary tumor: stage, grade and diameter.

Results

The in vivo technique allowed to identify the SN in 16/17 cases (94.1%), the ex vivo technique in 7/7. A total of 336 lymph nodes dissected from the surgical specimens was analyzed, with an average of 14.6 nodes per patient (range, 7-35). Of these nodes 58 were SNs, with an average of 2.5 nodes per patient (range, 1-8). In the 19 cases where the SN was tumor negative, the non-SNs were also negative (specificity: 100%), whereas in the four cases where the non-SNs were positive, in two cases the SN was positive and in two cases of pT3 rectal carcinoma the SN was negative (sensitivity: 50%). Immunohistochemistry did not modify the negative results of the standard hematoxylin-eosin evaluation.

Conclusions

The method used to identify the SN using vital dye proved to be easy to use both in vivo and ex vivo and allowed to identify the SN in all cases. The preliminary results indicate that there is a risk of false negative findings and therefore further studies are required to improve the sensitivity and the specificity of the technique and to evaluate the role of SN mapping in colorectal cancer management.

Ex vivo sentinel lymph node mapping in colorectal cancer using a magnetic nanoparticle tracer to improve staging accuracy: a pilot study

AIM

Nodal status is the most important prognostic factor in colorectal cancer (CRC). Small occult metastases may remain undetected on conventional histopathological examination, potentially resulting in undertreatment. Ex vivo sentinel lymph node mapping (SLNM) can be used to improve the accuracy of nodal staging, but the currently used tracers suffer from drawbacks, which hamper implementation of the technique in routine clinical practice. Magnetic tracers are the optimal size for sentinel lymph node (SLN) retention and allow objective quantitative selection of SLNs; they therefore have great potential for SLNM in CRC. The study evaluates the feasibility of ex vivo magnetic SLNM and compares the performance of this technique with blue dye SLNM.

METHOD

Twenty-eight ex vivo SLNM procedures were performed in 27 histological node-negative patients with CRC using a magnetic tracer and blue dye. A magnetometer was used to select magnetic SLNs after formalin fixation of the CRC specimen. Both magnetic and blue SLNs were subjected to serial sectioning and immunohistochemical staining to reveal occult metastases.

RESULTS

At least one SLN was successfully identified in 27/28 (96%) and 25/28 (89%) of the cases with the magnetic technique and blue dye. Isolated tumour cells were detected in 10 patients. This was predicted with 100% sensitivity and accuracy using the magnetic technique, and with 91% sensitivity and 96% accuracy using the blue dye technique.

CONCLUSION

This study demonstrates that ex vivo magnetic SLNM is a feasible technique for use in routine clinical practice, improving nodal staging accuracy of CRC patients.

Sentinel lymph node biopsy as a prognostic factor in non-metastatic colon cancer: a prospective study

PURPOSE

Around a third of node-negative patients with colon cancer experience a recurrence after surgery, suggesting poor staging. Sentinel lymph node techniques combined with immunochemistry could improve colon cancer staging. We prospectively assessed the effect of Sentinel node mapping on staging and survival in patients with non-metastatic colon cancer.

METHODS

An observational and prospective study was designed. 105 patients with colon cancer were selected. Patients were classified according to node involvement as: N1, with node invasion detected by the conventional techniques; up-staged, with node invasion detected only by sentinel node mapping; and N0, with negative lymph node involvement by both techniques. Five-year survival and disease-free survival rates were analysed. Multivariate regression analyses were performed to identify prognostic factors for disease-free and overall survival.

RESULTS

Sentinel node mapping was successfully applied in 78 patients: 33 % were N1; 24.5 % were up-staged (18 patients with isolated tumour cells and 1 patient with micrometastases); and 42.5 % were N0. N1 patients had the poorest overall 5-year survival (65.4 %) and 5-year disease-free survival (69.2 %) rates compared with the other two groups. No significant 5-year survival differences were observed between N0 patients (87.9 %) and up-staged patients (84.2 %).

CONCLUSIONS

Patients up-staged after sentinel node mapping do not have a poorer prognosis than patients without node involvement. Detection of isolated cancer cells was not a poor prognosis factor in these patients.

Sentinel lymph node biopsy and nodal ultrastaging in colorectal cancer

The tumor status of the regional lymph nodes is the most important prognostic indicator in colorectal cancer (CRC), as it is in other solid tumors. Sentinel lymph node biopsy (SLNB), which has profoundly impacted the treatment of melanoma and breast cancer, has been applied in CRC in an attempt to improve nodal staging accuracy. The challenge lies in identifying patients who have tumor-negative nodes but are at high risk of regional or distant failure and therefore may benefit from adjuvant chemotherapy. Because standard pathological analysis of lymph nodes may incorrectly stage colon cancer, multiple studies have investigated nodal ultrastaging based on identification and immunohistochemical and/or molecular assessment of the sentinel node. This review focuses on the technique of SNLB, its feasibility and validity, and the controversies that remain regarding the clinical significance of nodal ultrastaging in CRC.

Management of nodal disease from colon cancer in the laparoscopic era

PURPOSE

In colon cancer (CC), nodal involvement is the main prognostic factor following potentially curative (R0) resection. The purpose of this study was to examine data from the literature to provide an up-to-date analysis of the management of nodal disease with special reference to laparoscopic treatment.

METHODS

MEDLINE and EMBASE databases were searched for potentially eligible studies published in English up to July 15, 2014.

RESULTS

In CC, nodal involvement is a frequent event and represents the main risk of cancer recurrence. Node negative patients recur in 10-30 % of cases most likely due to underdiagnosed or undertreated nodal disease. Extended colonic resections (complete mesocolic excision with central vascular ligation; D3 lymphadenectomy) provides a survival benefit and better local control. Sentinel lymph node mapping in addition to standard surgical resection represents an option for improving staging of clinical node negative patients. Both extended resection and sentinel lymph node mapping are feasible in a laparoscopic setting.

CONCLUSIONS

Both extended colonic resection and sentinel lymph node mapping should play a role in the laparoscopic treatment of CC with the purpose of improving control and staging of nodal disease.

In vivo lymph node mapping and pattern of metastasis spread in locally advanced mid/low rectal cancer after neoadjuvant chemoradiotherapy

PURPOSE

The lymph node status is one of the strongest prognostic determinants in rectal cancers. After chemoradiotherapy (CRT), lymph nodes are difficult to detect. This study aims to evaluate the feasibility of lymph node mapping in the mesorectum after CRT to analyze the pattern of metastasis spread and to assess the reliability of blue dye injection in sentinel lymph node detection.

METHOD

Ten patients with cN+ mid/low RCs after CRT were prospectively enrolled. The protocol scheduled intraoperative blue dye injection, surgery, and specimen examination with fat clearance technique. The mesorectum was divided into three equal "levels" (upper, middle, and lower); each level was divided into three equal "sectors" (right anterolateral, posterior, and left anterolateral). Lymph nodes were defined "small" if ≤5 mm.

RESULTS

Two hundred seventy-six lymph nodes were retrieved in ten patients; 76.5 % were small lymph nodes. Six patients were pN+ (33 metastatic lymph nodes, 76 % small); small lymph node analysis upstaged one patient from N0 to N1 and four patients from N1 to N2. Metastasis distribution across sectors was continuous, without "skip sectors." The blue dye detected the sentinel lymph node in all patients; in half of the cases, it was out of the tumor sector. Blue dye identified 69.7 % of metastatic lymph nodes; its sensitivity decreased together with the metastatic deposit size (84 % macrometastases, 28.6 % micrometastases, 0 % occult tumor cells; p = 0.004).

CONCLUSION

The fat clearance technique should be the standard pathological examination in patients with RCs after CRT; N staging was improved by small lymph node identification. Lymph node metastases have a continuous spread through mesorectal sectors. Blue dye injection is effective in sentinel lymph node detection.

[Sentinel lymph node biopsy technique in colon cancer. Experience in 125 cases]

INTRODUCTION

The level of lymph node involvement is the most important factor in staging colorectal cancer without metastasis. Sentinel lymph node mapping identifies the node(s) that most accurately reflect the lymph node status of patients, and intensive techniques that improve staging can be focused on these nodes. The aim of this study was to assess the efficacy of ex vivo sentinel lymph node mapping in the staging of colon cancer.

MATERIALS AND METHODS

A prospective study was conducted on 125 patients from the Alava-Txagorritxu University Hospital Health Region (Alava), who were diagnosed prior to surgery with colon cancer without distant metastasis from September 2009 to December 2011. Ex vivo sentinel lymph node mapping with methylene blue was use in these patients to study the sentinel nodes with multiple slices using immunohistochemical techniques and haematoxylin-eosin staining. A comparative study was also performed based on a control group of 170 patients staged with conventional techniques, and involving a single slice and haematoxylin-eosin staining.

RESULTS

The sentinel lymph node identification rate was 98%, with 5.6% false negatives. Upstaging occurred in 14.2% of cases compared to the group studied using conventional techniques (P=.006).

CONCLUSIONS

Ex vivo sentinel lymph node mapping with methylene blue accurately reflects the lymph node status of patients with colon cancer. This approach upstages patients classified as stages i and ii by conventional techniques to stage iii, indicating chemotherapy that may improve their prognosis.

What is the optimal means of staging colon cancer?

Although staging for colon cancer has become more complex over time, it is not clear that this complexity has improved prognostic assessment. Even with revisions in the 7th edition of the AJCC staging system, a clear rank order of prognosis from substage to substage has not been established. Improved staging models will need to be developed, and attempts at further identifying those high-risk patients within each stage may be clinically useful. Through improved quality measures with lymph node yield, advances in colon cancer staging accuracy have been made over the last decade. Determining how to incorporate ultrastaging and molecular techniques will be the challenge for future staging models.

Distribution of lymph node metastases is an independent predictor of survival for sigmoid colon and rectal cancer

OBJECTIVE

This study evaluated the prognostic significance of the distribution of lymph node metastases (LND) in patients with colorectal cancer.

BACKGROUND

The impact of the LND on survival in colorectal cancer is unknown.

METHODS

A total of 1205 consecutive patients who underwent potentially curative surgery for sigmoid colon or rectal cancer with high ligation of the inferior mesenteric artery (IMA) from January 1997 to February 2008 were assigned to 4 groups based on LND: LND0, no lymph node metastases-615 patients (51.0%); LND1, metastases in the pericolic nodes-324 patients (26.9%); LND2, metastases in the intermediate nodes-172 patients (14.3%); and LND3, node metastases at the origin of the IMA-94 patients (7.8%).

RESULTS

The 5-year overall survival rates of patients with LND0, LND1, LND2, and LND3 were 83%, 63%, 52%, and 28%, respectively (P < 0.001). The 5-year disease-free survival rates of patients with LND0, LND1, LND2, and LND3 were 83%, 54%, 43%, and 21%, respectively (P < 0.001). On multivariate analysis, LND was an independent prognostic factor for both overall survival and disease-free survival. However, the 5-year local recurrence-free survival rate was not inversely related to the LND. On a subset analysis that compared stage III disease with stage IV disease, the 5-year overall survival and disease-free survival rates were 45% and 31% for the patients with stage IV disease compared with 40% and 32% for the patients with stage III, LND3 disease, respectively (P = 0.761 and 0.704). For the patients with pN1 tumors, the overall survival and disease-free survival did not differ significantly according to the LND (P = 0.471 and 0.347, respectively). However, for patients with pN2 tumors, the overall survival and disease-free survival curves among the LND groups significantly differed (P < 0.001 and <0.001, respectively).

CONCLUSION

LND is an independent predictor of survival for colorectal cancer patients, but it does not predict local recurrence. The N categorization including LND may enhance the prognostic value of the TNM staging system for patients with node-positive sigmoid colon or rectal cancer.

Factors predicting oncologic outcomes in patients with fewer than 12 lymph nodes retrieved after curative resection for colon cancer

PURPOSE

The aim of this study was to determine which clinicopathological factors influenced the long-term survival after potentially curative resection of patients with colon cancer having fewer than 12 retrieved lymph nodes.

METHODS

Prospective data were collected from 179 patients who had fewer than 12 resected lymph nodes after curative resection for stages I-III colon cancer. The oncological outcomes and the risk factors for recurrence were analyzed, focusing on lymph node ratio (LNR).

RESULTS

The median number of harvested lymph nodes was 7 (range, 1-11). The LNR was associated significantly with T category and lymphovascular invasion. Multivariate analysis revealed that tumor diameter (P = 0.006), perineural invasion (P = 0.043), LNR (P = 0.002), and preoperative carcinoembryonic antigen (CEA) level (P = 0.013) were the independent predictors for 5-year disease-free survival; T category (P = 0.032), postoperative chemotherapy (P = 0.001), LNR (P = 0.007), and preoperative CEA level (P = 0.023) were the independent predictors for 5-year overall survival.

CONCLUSIONS

The LNR and preoperative CEA level may be reliable predictors of recurrence and survival after curative surgery in patients with colon cancer who have less than 12 lymph nodes examined.

The Feasibility of an Ex-vivo Sentinel Lymph Mapping Using Preoperative Radioisotope Injection in Cases of Extraperitoneal Rectal Cancer

PURPOSE

The purpose of this research was to evaluate the feasibility of sentinel lymph node (SLN) mapping involving transanal injection with an ex-vivo mapping in patients with rectal cancer.

METHODS

Between April 2007 and December 2009, 20 consecutive patients with T1-3, N0-1 clinical stage rectal cancer preoperatively underwent a SLN procedure using submucosal (99m)Tc-phytate injection. All the patients underwent a total mesorectal excision. After the standard surgical resection, all specimens were identified on lymphoscintigraphy, and bench work was done to pick up the sentinel node basin. All the lymph nodes (non-SLNs and SLNs) were examined using conventional hematoxylin and eosin staining and immunohistochemistry with anti-cytokeratin antibodies.

RESULTS

SLNs were identified from 19 of 20 patients with rectal cancer. The total number of sentinel nodes retrieved from the surgical specimens was 29, and the mean number per patient was 1.6 (range, 0 to 4). In three patients, the SLN was the only positive lymph node. There was one false-negative case with a sensitivity of 88.8% and two upstaged cases (20.0%). The SLN samples from rectal cancer are mainly localized in the pararectal region, but aberrant nodes receive direct drainage from the rectal cancer. On planar lymphoscintigraphy, 15.7% of all patients had aberrant lymphatic drainage to the sigmoid mesenteric or sigmoid lymph node station.

CONCLUSION

In conclusion, the intraoperative transanal injection for ex-vivo SLN navigation is a safe, feasible surgical modality in patients with rectal cancer. Large studies are warranted to determine the clinical significance of the SLN concept and micrometastasis in rectal cancer.

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.

Intratumoral as well as peritumoral lymphatic vessel invasion correlates with lymph node metastasis and unfavourable outcome in colorectal cancer

The aim of this study was to assess the intratumoral and peritumoral distribution of lymphatic vessel density (LVD) and lymphatic vessel invasion (LVI) in colorectal cancer and their relationships with patients' clinicopathological characteristics and survival. Paraffin sections of 81 primary colorectal cancers were examined by immunohistochemical staining using monoclonal antibody D2-40. Peritumoral LVD was significantly higher than intratumoral LVD (P = 0.000). Both intratumoral LVD and peritumoral LVD were correlated with the presence of LVI (P = 0.006 and P = 0.003, respectively). LVI, intratumoral LVI and peritumoral LVI were identified, respectively in 38, 28 and 32% of the samples investigated. Both intratumoral LVI and peritumoral LVI were correlated with lymph node metastasis (P = 0.030 and P = 0.014, respectively). Lymph node metastasis, the presence of intratumoral LVI and peritumoral LVI were adversely associated with the 5-year overall survival in a univariate analysis (P = 0.001, P = 0.011 and P = 0.017, respectively). Multivariate analysis using Cox proportional hazard model showed that neither intratumoral LVI nor peritumoral LVI was an independent prognostic factor of overall survival. The results of this study demonstrated that intratumoral as well as peritumoral LVI was associated with lymph node metastasis and adverse outcome in colorectal cancer.

The accuracy of sentinel node mapping according to T stage in patients with gastric cancer

BACKGROUND

Sentinel lymph node (SLN) mapping has been recently introduced to the field of gastric cancer. To the best of our knowledge, no study has dealt with the accuracy of SLN mapping according to the T stage of the primary tumor. The aim of the present study was to evaluate SLN status according to the T stage of the primary tumors.

METHODS

Eighty patients with gastric cancer underwent SLN mapping with patent blue dye during gastric resection.

RESULTS

Forty-seven patients underwent distal subtotal gastrectomy; 17 patients, proximal gastrectomy; 14, total gastrectomy; and 2, gastric stump resection. SLNs were stained in 61/80 patients (76.3%). The number of stained SLNs varied from 1 to 16 (mean, 3.3). Patients undergoing proximal gastrectomy had a mean of 3 stained SLNs, whereas patients undergoing distal subtotal gastrectomy had a mean of 2.8 stained SLNs. In 55/61 patients (90.2%) with stained SLNs a positive correlation was found between the presence of metastases and stained or non-stained SLNs. Ten out of 11 patients (90.9%) with T1 tumors (mean, 3.27 SLNs per patient) and 15/17 patients with T2 tumors (88.2%; mean, 3 SLNs per patient) had stained SLNs as compared to only 33/48 (68.8%) of patients with T3 tumors (mean, 3.3 SLNs per patient). The positive predictive value of the SLN mapping was 100%, the negative predictive value was 76.9%, and sensitivity was 85.4%.

CONCLUSION

While in T1 and T2 tumors sentinel node mapping may be of assistance in the decision-making process regarding the extent of lymphadenectomy (sensitivity, 100%; negative predictive value, 90%-100%), SLN mapping in patients with T3 tumors will be misleading in a third of the patients and should not be attempted.

Diagnosing occult tumour cells and their predictive value in sentinel nodes of histologically negative patients with colorectal cancer

PURPOSE

Most studies on the sentinel node (SN) procedure in patients with colorectal cancer include immunohistochemical analysis of the SN only. To evaluate the real diagnostic accuracy of the SN procedure with immunohistochemical analysis, the presence of occult tumour cells in all histologically negative lymph nodes was compared to the presence of these cells in SNs. Also the reproducibility of diagnosing occult tumour cells (OTC) and the sensitivity of three different antibodies was assessed.

METHODS

Between November 2006 en July 2007, an ex vivo SN procedure was performed in 58 histologically N0 patients with colorectal cancer. All lymph nodes (n = 908, mean 15.7) were step-sectioned and immunohistochemistry was performed using two antibodies against cytokeratins (Cam5.2, and CK 20) and one antibody against BerEp-4.

RESULTS

OTC were identified in 19 of 58 patients, with micrometastases (0.2-2 mm) in 7 and isolated tumour cells (ITC)(<0.2 mm) in 12 patients. The overall agreement in diagnosing OTC between two independent pathologists was 86%. An SN was identified in 53 of 58 patients. All micrometastases were found in SNs. In two patients with negative SNs, ITC's were demonstrated in non-SNs (sensitivity 88%, and overall accuracy 96%).

CONCLUSION

Additional immunohistochemical analysis of histologically negative lymph nodes demonstrates occult tumour cells in 33% of the patients resulting in an upstaging rate of 12%. Occult tumour cells are predominantly found in the SN, therefore SN mapping has the potential to refine the staging system for patients with colorectal cancer.

Comparison of ex vivo and in vivo injection of blue dye in sentinel lymph node mapping for colorectal cancer

BACKGROUND

The technique of sentinel lymph node (SLN) mapping in patients with colorectal cancer varies between reports, and the optimal method has not been established. The purpose of this study was to determine the optimal injection technique for SLN mapping.

METHODS

Sixty-nine consecutive patients who underwent curative surgery for colorectal cancer were enrolled. The SLNs was identified intraoperatively by subserosal blue dye injection (in vivo) or by submucosal injection after standard colectomy (ex vivo). If negative by conventional hematoxylin and eosin staining analysis, all lymph nodes, SLNs and non-SLNs, were subjected to further analysis by multi-level section and immunohistochemical examination.

RESULTS

The in vivo and ex vivo injected groups were similar in demographic character, tumor size, and histological grade. The mean number of SLNs identified was 2.3 in the in vivo group and 2.6 in the ex vivo group (p = 0.192). The detection rate of SLNs by blue dye injection was somewhat higher in the ex vivo group than in the in vivo group: 90.6 vs. 81.1% (p = 0.219). The false-negative rate was 23.5% for the in vivo group and 13.3% for the ex vivo group (p = 0.392). The upstaging rate, which was 18.5% overall, was similar in both groups (p = 0.538).

CONCLUSIONS

These findings suggest that ex vivo blue dye injection is an effective alternative to in vivo injection for identifying SLNs in patients with colorectal cancer. Because of its simplicity and applicability in routine clinical settings, further investigation of the ex vivo mapping technique is warranted.

Factors affecting false-negative rates on ex vivo sentinel lymph node mapping in colorectal cancer

PURPOSE

Despite the increasing use of sentinel lymph node (SLN) mapping after colorectal cancer resection, reported node identification and false-negative rates vary considerably. The main aim of this prospective study was to quantify the false-negative rates on SLN mapping after resection and to evaluate factors influencing them.

METHODS

Sixty-nine patients with biopsy-proven cancer of the colon and rectum underwent SLN mapping according to a protocol involving the ex vivo submucosal and peritumoral injection of 2-4 ml of Patent Blue V dye. All lymph nodes visualized were marked as SLN and totally embedded, then two 4 microm sections were cut for hematoxylin and eosin staining, and cytokeratin (AE1/AE3) immunostaining. A standard examination of the whole specimen and of the regional non-sentinel lymph nodes was also performed.

RESULTS

SLNs were identified in 97.3% of the evaluable cases. A mean of 5.0 SLNs were removed per patient (SD+/-4.2). Nine false negatives were identified. Rectal cancer, tumor size>60mm, number of metastatic non-sentinel lymph nodes, and mucinous tumors were associated with false-negative SLNs. At multivariate analysis, a rectal location and mucinous differentiation were independently associated with false-negative SLNs.

CONCLUSIONS

Ex vivo SLN mapping after colorectal cancer surgery is technically feasible with a high identification rate. Tumor size and stage, rectal involvement and a mucinous histology seem to interfere with the reliability of SLN staging. It is mandatory to standardize the procedure and selection criteria in order to deal with the question of the reliability of SLN mapping in colorectal cancer.

Metastatic lymph node ratio as an independent prognostic variable in colorectal cancer: study of 113 patients

BACKGROUND

In patients with colorectal cancer, involvement of the lymph nodes is one of the most important prognostic factors. The aim of this study was to determine the independent prognostic value of the lymph node ratio (LNR), that is the relationship between the involved and examined lymph nodes, in patients with colorectal cancer.

METHODS

Included in the study were 113 patients with colorectal adenocarcinoma. The patients were divided into three groups according to the proportion of involved lymph nodes: LNR-0, when there was no lymph node involvement; LNR-1, when there was involvement of up to 20% of the examined lymph nodes, and LNR-2, when there was involvement of 21% or more of the examined nodes. The relationship between lymph node ratio, the number of lymph nodes removed, and the number of lymph nodes involved by cancer was determined. The 5-year survival was evaluated using the Kaplan-Meier test.

RESULTS

There was a significant difference in 5-year overall between patients in the different LNR groups (p=0.009). Patients in the LNR-0 group had a 5-year overall survival greater than 80%, while those in the LNR-1 and LNR-2 groups had 5-year overall survival rates less than 60% and 40%, respectively. Multivariate analysis demonstrated that the LNR is an independent prognostic variable in 5-year overall survival (p=0.009).

CONCLUSION

The results showed that the LNR can be considered an independent prognostic variable in overall survival of patients with colorectal cancer.

Sentinel node biopsy for the individualization of surgical strategy for cure of early-stage colon cancer

INTRODUCTION

The requirement for nodal analysis currently confounds the oncological propriety of focused purely endoscopic resection for early-stage colon cancer and complicates the evolution of innovative alternatives such as natural orifice transluminal endoscopic surgery (NOTES) and its hybrids. Adjunctive sentinel node biopsy (SNB) deserves consideration as a means of addressing this shortfall.

METHODS

Data from two prospectively maintained databases established for multicentric studies of SNB in colon cancer that employed similar methodologies were pooled to establish technique potency selectively in T1/T2 disease (both overall and under optimized conditions) and to project potential clinical impact.

RESULTS

Of 891 patients with T1-4, M0 intraperitoneal colon cancer, 225 had T1/T2 disease. Sentinel nodes were either not found or were falsely negative in 18 patients with T1/T2 cancers (8%) as compared with 17% (112/646) in those with T3/T4 disease (P = 0.001). Negative predictive value (NPV) in the former exceeded 95%, while sensitivity [including immunohistochemistry (IHC)] was 81%. In the 193 patients with T1/T2 disease recruited from those centers contributing >22 patients, sensitivity was 89% and NPV 97%. Thus, in this cohort, SNB could have correctly prompted localized resection (obviating en bloc mesenteric dissection) in 75% (144) of patients, including 59 with T1 lesions potentially amenable to intraluminal resection alone as their definitive treatment. Forty-four patients (23.4%) would still have conventional resection, leaving three patients (1.6% overall) understaged (11% false-negative rate).

CONCLUSION

These findings support the further investigation of SNB as oncological augment for localized resective techniques. Specific prospective study should pursue this goal.

Lymph node evaluation in early-stage colon cancer

Accurate nodal staging is of crucial importance in patients with nonmetastatic colon cancer, because it affects patient prognosis and delivery of adjuvant chemotherapy. In this article, we review the role of 2 controversial aspects of lymph node staging in colon cancer: the number of lymph nodes evaluated and sentinel lymph node (SLN) biopsy. Although it is clear that the number of lymph nodes assessed correlates with patient survival, the underlying mechanisms are far more uncertain, and thus, more research is warranted to determine whether interventions to increase nodal assessment will lead to improved patient outcomes. Sentinel lymph node biopsy does not appear to have the same advantages in the treatment of patients with colon cancer as in the treatment of patients with breast cancer or melanoma. Also, it might not improve colon cancer staging above standard pathology, and should be restricted to use in research settings.

Could lymphatic mapping and sentinel node biopsy provide oncological providence for local resectional techniques for colon cancer? A review of the literature

BACKGROUND

Endoscopic resectional techniques for colon cancer are undermined by their inability to determine lymph node status. This limits their application to only those lesions at the most minimal risk of lymphatic dissemination whereas their technical capacity could allow intraluminal or even transluminal address of larger lesions. Sentinel node biopsy may theoretically address this breach although the variability of its reported results for this disease is worrisome.

METHODS

Medline, EMBASE and Cochrane databases were interrogated back to 1999 to identify all publications concerning lymphatic mapping for colon cancer with reference cross-checking for completeness. All reports were examined from the perspective of in vivo technique accuracy selectively in early stage disease (i.e. lesions potentially within the technical capacity of endoscopic resection).

RESULTS

Fifty-two studies detailing the experiences of 3390 patients were identified. Considerable variation in patient characteristics as well as in surgical and histological quality assurances were however evident among the studies identified. In addition, considerable contamination of the studies by inclusion of rectal cancer without subgroup separation was frequent. Indeed such is the heterogeneity of the publications to date, formal meta-analysis to pool patient cohorts in order to definitively ascertain technique accuracy in those with T1 and/or T2 cancer is not possible. Although lymphatic mapping in early stage neoplasia alone has rarely been specifically studied, those studies that included examination of false negative rates identified high T3/4 patient proportions and larger tumor size as being important confounders. Under selected circumstances however the technique seems to perform sufficiently reliably to allow it prompt consideration of its use to tailor operative extent.

CONCLUSION

The specific question of whether sentinel node biopsy can augment the oncological propriety for endoscopic resective techniques (including Natural Orifice Transluminal Endoscopic Surgery [NOTES]) cannot be definitively answered at present. Study heterogeneity may account for the variability evident in the results from different centers. Enhanced capacity (perhaps to the level necessary to consider selective avoidance of en bloc mesenteric resection) by its confinement to only early stage disease is plausible although not proven. Specific study of the technique in early stage tumors is clearly essential before proffering this approach.

Technique of sentinel lymph node biopsy and lymphatic mapping during laparoscopic colon resection for cancer

Background:

The utility of lymph node mapping to improve staging in colon cancer is still under evaluation. Laparoscopic colectomy for colon cancer has been validated in multi-centric trials. This study assessed the feasibility and technical aspects of lymph node mapping in laparoscopic colectomy for colon cancer.

Methods:

A total of 42 patients with histologically proven colon cancer were studied from January 2006 to September 2007. Exclusion criteria were: advanced disease (clinical stage III), rectal cancer, previous colon resection and contraindication to laparoscopy. Lymph-nodal status was assessed preoperatively by computed tomography (CT) scan and intra-operatively with the aid of laparoscopic ultrasound. Before resection, 2–3 ml of Patent Blue V dye was injected sub-serosally around the tumour. Coloured lymph nodes were marked as sentinel (SN) with metal clips or suture and laparoscopic colectomy with lymphadenectomy completed as normal. In case of failure of the intra-operative procedure, an ex vivo SN biopsy was performed on the colectomy specimen after resection.

Results:

A total number of 904 lymph nodes were examined, with a median number of 22 lymph nodes harvested per patient. The SN detection rate was 100%, an ex vivo lymph node mapping was necessary in four patients. Eleven (26.2%) patients had lymph-nodal metastases and in five (45.5%) of these patients, SN was the only positive lymph node. There were two (18.2%) false-negative SN. In three cases (7.1%) with aberrant lymphatic drainage, lymphadenectomy was extended. The accuracy of SN mapping was 95.2% and negative predictive value was 93.9%.

Conclusions:

Laparoscopic lymphatic mapping and SN removal is feasible in laparoscopic colectomy for colon cancer. The ex vivo technique is useful as a salvage technique in case of failure of the intra-operative procedure. Prospective studies are justified to determine the real accuracy and false-negative rate of the technique.

Is sentinel lymph node mapping in colorectal cancer a future prognostic factor? A meta-analysis

The diagnostic value of sentinel lymph node mapping (SLNM) in patients with colorectal cancer (CRC) is controversial. Prognostic factors for CRC must be detected to improve its treatment. A PubMed query (key words: colorectal cancer, sentinel node) provided 182 studies on the sentinel lymph node (SLN) for CRC, the abstracts of which were reviewed. Altogether, 48 studies dealing with the diagnostic value of SLNM were selected from PubMed, and 6 other studies were retrieved from reviews. We compared the diagnostic value of SLNM with that of conventional histopathologic examination. We used the diagnostic accuracy odds ratio (DAOR) method. Because of significant heterogeneity, we chose the random effect model (Der Simonian and Laird). Statistics were performed on 33 studies, including 1794 patients (1201 colon and 332 rectum cancers). The mean SLNM failure rate was 10%. The global sensitivity and specificity of the SLNM were, respectively, 70% and 81%. The pooled DAOR was 10.7 (95% confidence interval 7.0-16.5). That means that a patient whose SLN is invaded has 10.7 times more risk to be node-positive than an SLN-negative patient. Lymphatic mapping appears to be readily applicable to CRC. One of the main reasons for the heterogeneity is the performance of the SLNM by Saha et al., whose data had better sensitivity (90%) than those in other studies. The SLNM technique should be better standardized in future studies. Understanding the cause of false-negative SLNs (9%) is a major issue to resolve before routinely using this technique in CRC management. The prognostic implication of micrometastases found in SLNs requires further evaluation.

Sentinel lymph nodes of colorectal carcinoma: reappraisal of 123 cases

AIMS

Results concerning the usefulness of the sentinel lymph node (SLN) in colorectal carcinoma have been discordant. The SLN technique may be used to guide surgical resection (lymph mapping), restrict the lymph node analysis solely to the SLN (accuracy) and upgrade tumor staging when micrometastases are specifically detected in the SLN.

METHODS

The blue dye injection technique was used. Serial sections of the SLNs were analyzed after hematoxylin-eosin (HES) staining.

RESULTS

The SLN technique was tested in 123 patients, successfully in 112/118 (feasibility 95%) (five intraoperative exclusions). On average, twenty lymph nodes (range: 5-74) and two SLNs (range: 1-5) were identified. Lymph mapping was used in 11% of patients to guide surgical resection; the SLN was negative in 14 of 36 N+ patients (39% false-negatives); HES staining enabled detection of micrometastases in 8 of 84 initially N0 patients (10% secondary upgrading to N+).

CONCLUSION

Limiting node analysis to the SLN cannot replace a complete pathology examination of all resected lymph nodes. Careful examination of serial sections of the SLN can however affect therapeutic decision making since staging may be upgraded in up to 10% of initially N0 patients.

Prospective randomized study comparing sentinel lymph node evaluation with standard pathologic evaluation for the staging of colon carcinoma: results from the United States Military Cancer Institute Clinical Trials Group Study GI-01

BACKGROUND

The principal role of sentinel lymph node (SLN) sampling and ultrastaging in colon cancer is enhanced staging accuracy. The utility of this technique for patients with colon cancer remains controversial.

PURPOSE

This multicenter randomized trial was conducted to determine if focused assessment of the SLN with step sectioning and immunohistochemistry (IHC) enhances the ability to stage the regional nodal basin over conventional histopathology in patients with resectable colon cancer.

PATIENTS AND METHODS

Between August 2002 and April 2006 we randomly assigned 161 patients with stage I-III colon cancer to standard histopathologic evaluation or SLN mapping (ex vivo, subserosal, peritumoral, 1% isosulfan blue dye) and ultrastaging with pan-cytokeratin IHC in conjunction with standard histopathology. SLN-positive disease was defined as individual tumor cells or cell aggregates identified by hematoxylin and eosin (H&E) and/or IHC. Primary end point was the rate of nodal upstaging.

RESULTS

Significant nodal upstaging was identified with SLN ultrastaging (Control vs. SLN: 38.7% vs. 57.3%, P = 0.019). When SLNs with cell aggregates < or =0.2 mm in size were excluded, no statistically significant difference in node-positive rate was apparent between the control and SLN arms (38.7% vs. 39.0%, P = 0.97). However, a 10.7% (6/56) nodal upstaging was identified by evaluation of H&E stained step sections of SLNs among study arm patients who would have otherwise been staged node-negative (N0) by conventional pathologic assessment alone.

CONCLUSION

SLN mapping, step sectioning, and immunohistochemistry (IHC) identifies small volume nodal disease and improves staging in patients with resectable colon cancer. A prospective trial is ongoing to determine the clinical significance of colon cancer micrometastasis in sentinel lymph nodes.

Sentinel lymph node mapping in colon cancer: current status

BACKGROUND

The primary role of sentinel lymph node (SLN) mapping in colon cancer is to increase the accuracy of nodal staging by identifying those lymph nodes with the greatest potential for harbouring metastatic disease. Ultrastaging techniques aim to identify the otherwise undetected metastases. Until now, no consensus exists as to the most optimal procedure in patients with colon cancer.

METHODS

A systematic literature search on the value of different SLN mapping techniques in patients with colon cancer was performed using the electronic search engine PubMed. Prospective studies published before 1 December 2005 were included and further articles were selected by cross-referencing. The results of different techniques using either blue dye or radiocolloid, were investigated.

RESULTS

The literature search yielded 17 relevant articles. SLN mapping using blue dye was described in 15 studies. Two studies reported the results of SLN mapping using a combination of blue dye and radiocolloid. The reported results on identification rate varied between 71 and 100%. Accuracy rates were between 78 and 100%, sensitivity rates between 25 and 100% and true upstaging rates between 0 and 26%. The results were not affected by the addition of radiocolloid to blue dye.

CONCLUSIONS

Sentinel lymph node mapping in patients with colon cancer remains an experimental procedure with varying results. Further evaluation may lead to a standardized technique that offers the potential for significant upstaging of stage II patients. This may have important implications as to tailor adjuvant chemotherapeutic regimens in these patients.

Current status of sentinel lymph node navigation surgery in breast and gastrointestinal tract

Sentinel lymph node biopsy (SLNB) has been developed as a new diagnostic and therapeutic modality in melanoma and breast cancer surgery. The purpose of the SLNB include preventing the operative morbidity and improving the pathologic stage by focusing on fewer lymph nodes using immunocytochemic and molecular technology has almost achieved in breast cancer surgery. The prognostic meaning of immunocytochemically detected micrometastases is also evaluating in the SLN and bone marrow aspirates of women with early-stage breast cancer. SLNB using available techniques have suggested that the lymphatic drainage of the gastrointestinal tract is much more complicated than other sites, skip metastasis being rather frequent because of an aberrant lymphatic drainage outside of the basin exist. At the moment, the available data does not justify reduced extent of lymphadenectomy, but provides strong evidence for an improvement in tumor staging on the basis of SLNB. Two large scale prospective multi-center trials concerning feasibility of gamma-probe and dye detection for gastric cancer are ongoing in Japan. Recent studies have shown favorable results for identification of SLN in esophageal cancer. CT lymphography with endoscopic mucosal injection of iopamidol was applicable for SLN navigation of superficial esophageal cancer. The aim of surgical treatment is complete resection of the tumor-infiltrated organ including the regional lymph nodes. Accurate detection of SLN can achieve a selection of a more sophisticated tailor made approach. The patient can make a individualized choice from a broader spectrum of therapeutic options including endoscopic, laparoscopic or laparoscopy-assisted surgery, modified radical surgery, and typical radical surgery with lymph node dissection. Ultrastaging by detecting micrometastasis at the molecular level and the choice of an adequate treatment improve the postoperative quality of life and survival. However these issues require further investigation.

Predictors of Distant Metastasis and Mortality in Patients with Stage II Colorectal Cancer

The aim of our study was to determine clinical factors that predicted distant metastasis and mortality in patients with stage II colorectal cancer (CRC). A retrospective review of all patients admitted to the Dallas Veteran's Affairs Medical Center from 1998 to 2002 with stage II CRC was performed. Factors associated with distant metastasis and mortality were assessed by univariate analysis. Independent predictors of mortality and distant metastasis were assessed by multivariate analysis. Fifty-five patients with stage II CRC were identified (96% men, age 65 ± 1.2 years old). Univariate analysis demonstrated that patients with distant metastasis (n = 13) had a history of alcohol intake (54% vs 20%; P = 0.029), less history of angiotensin-converting enzyme inhibitor use for the management of hypertension (31% vs 67%; P = 0.029), greater incidence of a rectal location for cancer (54% vs 12%; P = 0.004), an abdominoperineal resection (APR) for surgical management of their cancers (23% vs 0%; P = 0.011), and less negative lymph nodes examined during surgical resection (9 ± 2.2 vs 15 ± 1.2, P = 0.022). Follow-up of at least 3 years revealed 14 mortalities. Survivors had a less preoperative serum carcinoembryonic antigen level (5.9 ± 0.9 vs 19.1 ± 8.6; P = 0.031), an average less tumor depth involvement (T stage: 3.0 ± 0.03 vs 3.2 ± 0.11; P = 0.065), more negative lymph nodes examined at the time of surgical resection (14.0 ± 1.3 vs 10.0 ± 1.7; P = 0.058), less incidence of rectal cancer (21% vs 43%; P = 0.060), and none had undergone an APR (0% vs. 21%; P = 0.010). Multivariate analysis revealed that alcohol intake ( P = 0.014; odds ration [OR] = 5.3), patients undergoing an APR ( P = 0.011; OR = 25), and less frequency of angiotensin-converting enzyme inhibitor use ( P = 0.007; OR = 4.5) independently predicted distant metastasis, whereas preoperative carcinoembryonic antigen ( P = 0.038; OR = 2.8) and patients undergoing an APR ( P = 0.019; OR = 25) independently predicted mortality.

Laparoscopic lymphatic mapping and sentinel lymph node detection in colon cancer: technical aspects and preliminary results

BACKGROUND

The utility of lymph node mapping to improve staging in colon cancer is under evaluation. Laparoscopic colectomy for colon cancer has been validated in multicentric trials. This study assessed the feasibility of lymph node mapping in laparoscopic colectomy for colon cancer.

METHODS

From March 2004 to December 2005, 22 patients were studied. Before resection, 2 to 3 ml of Patent Blue V dye was injected subserosally around the tumor. Colored lymph nodes were marked as sentinel nodes (SNs) with metal clips, and laparoscopic colectomy with lymphadenectomy was completed as normal. In SNs, multiple 4-microm slices at 50-microm intervals were stained with hematoxylin and eosin and examined. Anticytokeratin antibody immunostaining was applied in doubtful cases. Other lymph nodes were examined with multiple slices at 100- to 500-microm intervals by standard methods.

RESULTS

The SN detection rate was 100%, although ex vivo lymph node mapping was necessary for an obese patient. Five patients (22.7%) were SN positive. There was one false-negative SN (16.7%). In two cases (9.1%) with aberrant lymphatic drainage, lymphadenectomy was extended. The SN reflected the status of the regional lymph nodes in 21 patients (95.4%). Accuracy was 95.4%, and negative predictive value was 94.1%.

CONCLUSIONS

Laparoscopic lymphatic mapping and SN removal is feasible in laparoscopic colectomy for colon cancer. Although the false-negative rate was high (16.7%), the overall results are promising and justify prospective studies to determine the real accuracy and false-negative rate for the technique.

Detection of micrometastases and skip metastases with ex vivo sentinel node mapping in carcinoma of the colon and rectum

BACKGROUND

The debate over sentinel lymph node mapping (SLNM) and focused pathologic examination to detect micrometastases in patients with colorectal cancer (CRC) continues. We present in this paper our experience with SLNM for CRCs to improve staging. In addition, we have detailed the mapping procedure on an anatomical basis to define skip metastasis.

MATERIALS AND METHODS

Forty-seven patients underwent ex vivo SLNM. Immediately after resection, 1 ml of patent blue VF was injected submucosally around the tumor. Lymph nodes harvested from the first 15 patients were mapped in a standard fashion as the blue-stained nodes (SLNs), and the others (non-SLNs) were dissected away. In the remaining 32 patients, the lymph nodes were also mapped separately in relation to their anatomic location and described as epicolic-paracolic, intermediate, and principal. The blue-stained nodes (SLNs) and non-SLNs, negative by hematoxylin and eosin stain, were further stained with cytokeratin immunohistochemical analysis and carcinoembryonic antigen.

RESULTS

A total of 873 histologically confirmed LNs were examined with a mean of 18.6+/-8.1 nodes per patient. In 46 of 47 patients (97.8%), SLNs were identified. Immunohistochemical staining revealed micrometastases in the lymph nodes of four patients, which were negative by conventional methods. Anatomical skip metastases were noted in 4 of 32 patients studied (12.5%).

CONCLUSION

Ex vivo SLNM in CRCs is a feasible technique with a high SLN identification rate. Results of anatomical mapping of lymph nodes correlates with the limited literature, suggesting that occult skip metastases can occur in the apical lymph node group and may occur outside the resected area.

A preliminary study of the draining lymph node basin in advanced lower rectal cancer using a radioactive tracer

PURPOSE

This study was designed to examine the draining lymph node basin at highest risk of metastasis in lower rectal cancer using 99 mTc-tin colloid.

METHODS

In 43 patients, the area with highest hot nodes density was defined as the draining lymph node basin using a gamma probe. Metastatic states of all removed lymph nodes were examined histologically.

RESULTS

A total of 203 hot nodes were identified in 39 patients (91 percent) with a mean of 5.2 nodes. The number of removed lymph nodes was 808 nodes: 670 nodes in the mesorectum, and 138 nodes in the pelvis. In 21 patients, the metastatic states of 119 nodes were investigated histologically. From the distribution of the identified hot nodes, the draining lymph node basins were classified into two patterns: lateral type (n = 17), and mesorectal type (n = 22). Only 20 (17 percent) of 119 positive nodes were identified as hot node. Tumor cells that occupied the lymph node diffusely or massively probably interfered with the exact diagnosis of metastasis. Lymph node metastasis in the pelvis was observed in 5 patients (13 percent). One false negative was of the mesorectal type with diffuse metastases in the para-aortic lymph nodes. The remaining four patients were of the lateral type and all positive lymph nodes, including positive nonhot nodes, were located within the draining lymph node basin. Consequently, in 20 (95.2 percent) of 21 patients with lymph node metastasis, all positive lymph nodes were located within the draining lymph node basin of the tumor.

CONCLUSIONS

Two types of the draining lymph node basin of advanced lower rectal cancer were identified using this method. The concordance between lymph node metastases and the draining lymph node basin is good.

RT-PCR and immunohistochemical evaluation of sentinel lymph nodes after in vivo mapping with Patent Blue V in colon cancer patients

OBJECTIVE

Lymph node status is the most important predictive factor in the treatment of colorectal cancer. As sentinel lymph node (SLN) biopsy might upstage stage II colon cancer, it could have therapeutic consequences in the future. We investigated the feasibility of in vivo SLN detection with Patent Blue V dye and evaluated nodal microstaging and ultrastaging using cytokeratin immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR).

MATERIAL AND METHODS

In 30 consecutive patients operated on for colon cancer, subserosal injection with Patent Blue dye was used for SLN detection in four different hospitals under the supervision of one regional coordinator. In searching for occult micrometastases, each SLN was examined at three levels. In tumor-negative SLNs at routine hematoxylin-eosin (H&E) examination (pN0) we performed CK8/CK18 immunohistochemistry (IHC) and RT-PCR for carcinoembryonic antigen (CEA).

RESULTS

The procedure was successful in 29 out of 30 patients (97%). The SLN was negative in 18 patients detected by H&E and IHC. In 16 patients the non-SLN was also negative, leading to a negative predictive value of 89% and an accuracy of 93%. Upstaging occurred in 10 patients (33%) - 7 by IHC and 3 by RT-PCR. Aberrant lymphatic drainage was seen in 3 patients (10%).

CONCLUSIONS

The SLN concept in colon carcinoma using Patent Blue V is feasible and accurate. It leads to upstaging of nodal status in 33% of patients when IHC and PCR techniques are combined. Therefore, the clinical value of SLN should be the subject of further studies.

A multicenter trial of sentinel lymph node mapping in colorectal cancer: prognostic implications for nodal staging and recurrence

BACKGROUND

Sentinel lymph node (SLN) mapping (M) for staging in colorectal cancer (CRCa) remains controversial and needs to be validated. This study analyzes results of SLNM at a multi-institutional level for CRCa.

METHODS

Group A patients underwent SLNM with 1 to 3 mL of 1% lymphazurin. First 1 to 4 blue lymph nodes were designated as SLNs and had focused analysis. Group B had standard resection and nodal staging. Patients with a minimum of 2 years of follow-up were analyzed for recurrence.

RESULTS

Overall nodal metastasis were 50% for 500 group A patients versus 35% for 368 group B patients. In SLNM patients success, accuracy, sensitivity, and negative predictability values were 98%, 96%, 90%, and 93%, respectively. With a 2-year minimum follow-up, 153 group A patients had 7% recurrences compared with 25% in 162 group B patients.

CONCLUSION

SLNM is highly feasible and accurate for staging CRCa with higher detection of nodal metastasis and lower recurrences.

Sentinel node mapping in colon carcinoma: in-vivo versus ex-vivo approach

AIM

The aim of this study was to determine if ex-vivo and in-vivo technique of lymphatic mapping for colorectal cancer (CCR) result in similar sentinel lymph node (SLN) identification and accuracy rates.

METHODS

Thirty consecutive patients with 32 CCR underwent in vivo SLN mapping. After completion of the colectomy, we remapped the SLN in the operative specimens from patients who had undergone successful in vivo lymphatic mapping.

RESULTS

At least one SLN was identified by in vivo approach in 32 tumours. 1.5 SLNs (1-3) and 1.8 SLNs (1-4) (p=0.24) were identified by the in vivo and the ex vivo technique, respectively. All SLNs identified by the in vivo technique were also identified by the ex vivo technique. In six cases one and in two cases two additional SLNs were identified with the ex vivo technique. Twelve percent of tumours were upstaged.

CONCLUSION

Ex vivo SLN mapping is as accurate as the in vivo technique in defining SLN and does have the ability to upstage some patients with CCR. The ex vivo technique could be used either as a primary lymphatic mapping procedure or secondarily for failed in vivo attempts at lymphatic mapping.

Is there any role for sentinel node mapping in colorectal cancer staging? Personal experience and review of the literature

BACKGROUND

We explored the role of lymphatic mapping and sentinel lymphadenectomy (originally described for melanoma and breast cancer) in colon cancer. Pathologic techniques can successfully identify micrometastatic disease in lymph nodes, but they are not suitable for clinical routine use. We evaluated the role of sentinel node (SN) mapping in refining the staging of colorectal cancer.

METHODS

A total of 56 open colorectal resections were performed, and Patent Blue V dye was injected under the serosa surrounding the tumor immediately after opening the abdomen. SNs were analysed by immunohistochemistry to find micrometastatic disease. A literature search for the role of SNs in colorectal cancer was also performed.

RESULTS

We identified the SN in 100% of patients, with a mean of 2.02 SNs/patient (range 1-5). After immunohistochemical staining, we could upstage 21 out of 56 patients (37.5%), and we observed 10.7% false negative SNs (6/56 patients). Fewer than half of the articles described false negative rates of <15%, and most articles showed an upstaging rate of >5% of patients. These differences are probably the result of different sensitivities of the methods used in identifying the lymph node micrometastases.

CONCLUSIONS

SN mapping is an easy and cost-effective technique that holds promise and warrants further investigations.

Clinical significance of ex vivo detection of sentinel lymph node in gastric cancer

AIM: To investigate the feasibility of ex vivo sentinel lymph node (SLN) mapping and its clinical significance in improving the staging of gastric cancer.

METHODS: Nineteen patients received curative resection of primary gastric cancer with extended lymph node dissection were included in this study. Gastric specimens were submucosally or subserosally injected with 10 g/L Patent Blue. The blue-stained SLNs were excised for routine pathological examination (hematoxylin and eosin staining). The SLNs, which were negative after HE staining, were further examined by cytokeratin immunohistochemistry.

RESULTS: The SLNs were identified in 89.5%(17/19) cases, with a mean number of 1.4 (1-3) for each case. After HE staining, the accuracy of the SLNs in diagnosis of the regional lymph node metastasis was 70.5% (12/17), and the false-negative rate was 38.4%. However, one case (25%) was upstaged by cytokeratin immunohistochemistry. Thus, the diagnostic accuracy increased to 88.2% and the false-negative rate decreased to 14.2%.

CONCLUSION: Ex vivo SLN mapping in gastric cancer is technically feasible and may upstage some of the gastric cancer.