Sentinel lymph node mapping for adenocarcinoma of the colon does not improve staging accuracy

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.

Chronologic trends of cancer-related lymph node research in PubMed: informetrics analysis

Purpose

Given the long history of investigation into cancer and its relevance to the lymph node (LN), it would be meaningful to plot the trends of research on cancer-related LN.

Methods

Queries such as “cancer,” “lymph node,” and “cancer and lymph node” were submitted to PubMed to collect articles on cancer and LN published between 1945 and 2017. The collected articles were then extracted by an automatic web crawler and examined through informetrics and linguistic analysis.

Results

The number of articles related to cancer was 2,795,476 and 127,897 articles (4.6%) were found to be relevant to LN. With regard to cancer types, breast cancer was the most studied (37%), followed by gastric cancer (17%). With regard to the subjects in which the surgeon is interested, LN metastasis (57%) was found to be the topic most discussed, followed by LN dissection (22%) and sentinel LN (17%). Publications on LN metastasis gradually increased over time from 1988 to 2017 although those on sentinel LN and LN dissection have stagnated since the early 2000s.

Conclusion

Although research on cancer was abundant, only a small portion was dedicated to investigating its relevance to LN. Western countries had led the research on cancer-related LN, but Asian countries began to participate as major players, expanding their contributions. While LN metastasis, one of the major cancer-related LN topics, showed a steady increase, those involved in oncologic surgery such as LN dissection and sentinel LN did not.

Sentinel Lymph Node Detection in Colorectal Cancer - First Experience

BACKGROUND:

Colorectal cancer (CRC) is the second commonest cancer in women, the third in men, being the fourth commonest cause of cancer death. The most important factor for prognosis and staging in CRC patients is the status of the regional lymph nodes (LN).

AIM:

To implement the method for sentinel lymph node (SLN) detection in CRC patients using radiocolloid, and test its detection rate, sensitivity, accuracy, negative predictive value and the possibility for upstaging.

MATERIAL AND METHODS:

The study included 40 CRC patients, age 63 ± 14 years, without LNs detected on CT or MRI. SLN detection was performed after endoscopically peri- and intratumoral injection of 99mTc-SENTISCINT. All patients underwent resection with systemic lymphadenectomy, and the SLNs were detected ex vivo. Pathohistology was performed to all resected LNs.

RESULTS:

The identification rate was 95%, the accuracy of the procedure was 92.1%, the negative predictive value was 86.95%, the sensitivity was 83.3%, and the upstage was 22.5%.

CONCLUSION:

Identification of SLNs in CRC patients with this method is possible and the detection rate, negative predictive value, accuracy and sensitivity are reliable. We expect to contribute in the upstaging of stage II CRC patients and the selection of appropriate oncology treatment protocols.

Ultrastaging of colon cancer by sentinel node biopsy using fluorescence navigation with indocyanine green

PURPOSE

Lymph node status is the most important prognostic factor in colon cancer, but the role of sentinel lymph node biopsy (SLNB) as a tool for identification of micrometastatic disease and extraanatomical lymph nodes for adjuvant strategies and a tailored approach still remains unclear. Indocyanine green (ICG) fluorescence detection is a new method for SLNB allowing real-time lymphography and lymph node detection. This study was designed to evaluate the feasibility of fluorescence-guided sentinel lymph node detection in colon carcinoma.

METHODS

Twenty six patients with colon adenocarcinoma were prospectively included in this study. Intraoperatively, a peritumorous injection with a mean of 2.0 ml ICG was performed, followed by lymphatic mapping and SLNB. Clinical feasibility, detection rate, and sensitivity of the method were analyzed.

RESULTS

No adverse reactions occurred due to the injection of ICG. Overall, ICG fluorescence imaging identified 1.7 sentinel lymph node (SLN) in average in 25 out of 26 patients (detection rate, 96%). Metastatic involvement of the SLN was found in nine out of 11 nodal positive patients by conventional histopathology. The sensitivity of the method was 82% for colon carcinoma, respectively.

CONCLUSION

ICG fluorescence imaging is a new, feasible method for SLNB of colon carcinoma and enables ultrastaging with improved accuracy but with limited validity due to the small number of cases. One advantage of this technique is real-time visualization of lymphatic vessels and SLNB without radiation exposure. Further, larger series are necessary to analyze the role of fluorescence-guided SLNB for colon cancer.

Ex vivo sentinel lymph node mapping in laparoscopic resection of colon cancer

AIM

The study examined the feasibility and potential benefit of ex vivo sentinel lymph node (SLN) mapping, including multilevel sectioning (MLS) and immunohistochemistry (IHC) in colon cancer patients undergoing laparoscopic colectomy. The secondary goals were (i) to identify patient and tumour characteristics that might influence the success of the SLN technique, (ii) to investigate the extent of lymphadenectomy required to encompass tumour-positive nonsentinel lymph nodes (NSLN) and (iii) to ascertain the association of SLN status with oncological outcomes.

METHOD

SLN mapping was performed after specimen extraction using 1% Isosulfan blue. The SLNs were analysed with H&E staining after MLS, and if negative, IHC was performed. NSLNs were grouped by distance either greater than or less than 4 cm from the tumour.

RESULTS

Seventy-one patients completed the study between 2003 and 2007. Using H&E with MLS, the accuracy of SLN mapping was 76%, sensitivity was 52% and the false-negative rate was 48%. Excluding patients with clinically positive lymph nodes resulted in a significant improvement in accuracy to 81% and decreased the false-negative rate to 30%. Furthermore, as the only positive NSLN > 4 cm from the tumour was grossly positive, SLN mapping with a 4-cm mesenteric cuff would have given 100% sensitivity in patients without macroscopically involved nodes.

CONCLUSIONS

SLN mapping may be of value in selected patients. It may be possible to accurately stage patients with a 4-cm cuff of mesentery, although further validation of this proposal is required.

Clinical value of sentinel node mapping in carcinoma of the colon

AIM

Sentinel lymph node mapping has been used in colon cancer to improve prognosis. This study aimed to determine the accuracy of in vivo SLNM in patients with colon carcinoma undergoing surgery with curative intent.

METHOD

Thirty-one patients operated for colon carcinoma underwent in vivo sentinel lymph node mapping using patent blue dye. Each sentinel lymph node (SLN) was marked intraoperatively, and histological examination was performed after en bloc resection. If no metastasis was found, step sectioning with immunohistochemistry was performed.

RESULTS

The SLN was successfully identified in 28 (90%) of 31 patients. The false-negative rate to identify stage III disease was 66% (eight of 12), the negative predictive value was 46% (19 of 27) and the accuracy was 14% (four of 28). One patient negative on routine histopathology had micrometastasis on step sectioning of the SLN.

CONCLUSION

Sentinel lymph node mapping in colon carcinoma cannot accurately predict nodal status.

Lymph road mapping obtained via blue sentinel node detection to avoid middle colic artery resection for highly selected colon cancer cases: proof of a concept?

BACKGROUND

In theory, perioperative detection of lymph nodes with the injection of isosulfan blue dye should provide lymph road mapping (LRM) able to direct the resection. However, there is no supporting evidence for this theory in cases of colon cancer. We reanalysed all operative reports using the sentinel lymph node technique with blue dye injection.

MATERIALS AND METHODS

The retrospective study included 140 patients who underwent the sentinel lymph node (SLN) procedure between February 2001 and November 2007, including 70 cases in which the in vivo technique was used. In 8 cases (11%), LRM was used by the surgeon to determine the extent of resection.

RESULTS

In 5 cases, including limited or extended resection, the final pathological stage was II at the end of the follow-up period, and the patients had no recurrent disease. However, findings for 3 cases of stage III cancer were more relevant to the aims of this study. In these 3 patients, one with cancer (T3N1(3/22)) located at the hepatic flexure, and 2 with cancers (T3N2(7/41) and T2N2 (4/15)) at the splenic flexure, the middle colic artery was conserved as a result of LRM information. Of these 3 patients, 1 was alive without disease at 6-year follow-up and 2 at 5-year follow-up.

CONCLUSION

LRM obtained via blue sentinel node detection makes it possible to avoid middle colic artery resection for selected colon cancer cases. LRM seems particularly suitable in cases of colonic flexure location or prior colon surgery.

Ex vivo sentinel lymph node mapping in patients undergoing proctectomy for rectal cancer

PURPOSE

Controversy exists over the utility of sentinel lymph node mapping in the treatment of rectal cancer. The purpose of this study was to evaluate the use of ex vivo sentinel lymph node mapping in the setting of proctectomy for rectal cancer, with and without multilevel sectioning and immunohistochemistry.

METHODS

A prospective phase 2 clinical study of subjects undergoing proctectomy for rectal cancer from 2003 to 2008 was conducted. Sentinel lymph node mapping was performed with ex vivo injection of isosulfan blue. Sentinel lymph nodes were examined by hematoxylin and eosin evaluation, and when the results were negative, they were examined by multilevel sectioning and immunohistochemistry.

RESULTS

The study population consisted of 58 subjects; 88% received neoadjuvant therapy. Tumors were downstaged in 25 (49%) subjects receiving neoadjuvant therapy, 24% were clinical complete responders, and 20% were pathologic complete responders. The mean total lymph node harvest was 12.1 nodes per patient. Twenty-five subjects had positive nodal disease on final pathology. The sentinel lymph node detection rate was 85%, with a mean sentinel lymph node harvest of 2.2 nodes per subject. Fifteen (26%) subjects had sentinel lymph node nodal metastasis on routine hematoxylin and eosin examination. Neither multilevel sectioning nor immunohistochemistry evaluation improved detection of sentinel lymph node positivity. The accuracy of sentinel lymph node mapping was 71%, the sensitivity was 53%, the negative predictive value was 79%, and the false negative rate was 47%. Seven subjects were determined to have nodal disease only in the sentinel lymph node.

CONCLUSION

Ex vivo sentinel lymph node mapping is feasible after proctectomy for rectal cancer but did not improve staging. Neither multilevel sectioning nor immunohistochemistry improved the sensitivity of sentinel lymph node mapping.

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.

Intraoperative methylene blue sentinel lymph node mapping in colorectal cancer

BACKGROUND

Isosulfan blue is not available for clinical use in Malaysia. This study describes the use of methylene blue as an alternative to isosulfan blue in colorectal sentinel node mapping.

METHODS

Methylene blue dye was injected around colonic and rectal tumours and the first blue-stained nodes were suture tagged and harvested after standard colorectal resection. Standard histopathological examination was then carried out to detect nodal metastasis. All negative sentinel lymph nodes (SLN) were subjected to 10 further step sectioning and immunoperoxidase staining for cytokeratin 20 to detect tumour deposits.

RESULTS

Thirty-one patients were enrolled from August 2005 to July 2006. Twenty-five attempts at identifying the SLN were successful (80.7%). Of the 18 (58.1%) who had nodal metastases (stage III), 3 had negative SLN but positive other lymph nodes (false-negative rate of 21.4%). In one (4%), the SLN was the exclusive site of metastasis.

CONCLUSION

Methylene blue can be used as an alternative sentinel node marker for rectal cancer (above the peritoneal reflection) and colonic cancer.

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.

Sentinel node mapping does not improve staging of lymph node metastasis in colonic cancer

PURPOSE

This study was designed to evaluate the reliability of the sentinel node concept in colonic cancer.

METHODS

Patent blue was used as tracer. The four blue nodes closest to the tumor were defined as the sentinel node(s) by the pathologist. All nodes were examined by routine microscopy (hematoxylin-eosin staining). If no metastases were detected, all lymph nodes were examined immunohistochemically with antibody to cytokeratin.

RESULTS

Two hundred colon specimens were examined. Sentinel node(s) were identified in 93 percent. Sixty contained metastases in hematoxylin-eosin sections. In 32 these were found in sentinel nodes (sensitivity 53 percent). Twenty-eight patients had metastases in nonsentinel nodes only, giving a false-negative rate of 47 percent. Immunostaining revealed 39 (30 percent) micrometastases or submicrometastases in 131 TNM Stages I and II patients, and in 17 of these patients metastases were found in nonsentinel nodes only (false-negative rate 44 percent).

CONCLUSIONS

Sentinel lymph node mapping shows low sensitivity for detection of ordinary metastases, micrometastases, and submicrometastases. If only the sentinel nodes had been examined, approximately half of the metastases would have been lost after routine staining, as well as half of the micrometastases and submicrometastases when immunohistochemical examination was added.

What’s wrong with sentinel node mapping in colon cancer?

Despite near-universal embrace of the concept and clinical relevance of lymphatic mapping for sentinel node identification and analysis for cancers of the breast and integument, the same technique has struggled to a find a role in gastrointestinal cancers in general and, perhaps, in colon cancer in particular. Despite many studies demonstrating its feasibility in malignancies of the large bowel, concern is continually aroused by the variable and often unacceptably low sensitivity rates. Additionally, many confess uncertainty as to what benefit it could ever confer to patients even if it were proven sufficiently accurate given that standard surgical resection incorporates mesenteric resection anyway. However, the huge impact sentinel node mapping has had on clinical practice in certain cancers means that each of these aspects merit careful reconsideration, from very first principles.

Sentinel lymph node biopsy for gastrointestinal cancers

Sentinel lymph node biopsy (SLNB) in gastrointestinal-(GI)-tract cancer is not yet of clinical relevance. Nevertheless, the results in the upper GI-tract promise to be helpful to individualize the indication for surgical therapy. SLNB in colon cancer still fails to show high validity to predict the nodal status, but may be helpful to clarify the prognostic role of micrometastases/isolated tumor cells. In anal cancer SLNB is able to guide the indication for groin irradiation.

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.

The impact of the largest metastasis size on nodal tumor burden in colorectal carcinomas: implications for the sentinel lymph node theory in cancers of the large intestine

BACKGROUND AND OBJECTIVES

Successful sentinel lymph node (SLN) biopsy has been reported in colorectal cancer (CRC), but its results are still controversial. The SLN theory suggests that there is an orderly spread from the primary tumor to the SLNs first, and from the SLNs to further nodes later. This study examines the influence of nodal metastasis size on further nodal involvement.

METHODS

CRC resection specimens with nodal metastasis have been evaluated for the maximum nodal metastasis size for a period of 5 years. All lymph nodes (LNs) were submitted to standard histological examination.

RESULTS

Two hundred thirty-five CRC specimens with a single invasive tumor were assessed. The mean numbers of LNs examined and involved were 18 and 4, respectively. The largest metastasis size ranged from 0.14 to 22.1 mm. There was a significant correlation between this parameter and the number or the ratio of LNs involved (Spearman's Rho: 0.517, and 0.382, respectively; P < 0.0001). A cluster analysis identified three relatively distinct groups of low, intermediate, and extensive nodal involvement.

CONCLUSIONS

The correlation of the largest metastasis size with the number and the ratio of involved nodes may be an indirect proof of the sequential spread from first echelon LNs to further nodes. However, the data suggest a more complex process: with increasing metastasis size, the number of involved nodes and its variability increase more than might be expected. This suggests a recruitment or cascade process, which becomes more unpredictable as nodal tumor burden increases.

Sentinel lymph node biopsy in colon cancer: a prospective multicenter trial

INTRODUCTION

The clinical impact of sentinel lymph node biopsy (SLNB) in colon cancer is still controversial. The purpose of this prospective multicenter trial was to evaluate its clinical value to predict the nodal status and identify factors that influence these results.

METHODS

Colon cancer patients without prior colorectal surgery or irradiation were eligible. The sentinel lymph node (SLN) was identified intraoperatively by subserosal blue dye injection around the tumor. The SLN underwent step sections and immunohistochemistry (IHC), if classified free of metastases after routine hematoxylin and eosin examination.

RESULTS

At least one SLN (median, n = 2) was identified in 268 of 315 enrolled patients (detection rate, 85%). Center experience, lymphovascular invasion, body mass index (BMI), and learning curve were positively associated with the detection rate. The false-negative rate to identify pN+ patients by SLNB was 46% (38 of 82). BMI showed a significant association to the false-negative rate (P < 0.0001), the number of tumor-involved lymph nodes was inversely associated. If only slim patients (BMI < or =24) were investigated in experienced centers (>22 patients enrolled), the sensitivity increased to 88% (14 of 16). Moreover, 21% (30 of 141) of the patients, classified as pN0 by routine histopathology, revealed micrometastases or isolated tumor cells (MM/ITC) in the SLN.

CONCLUSIONS

The contribution of SLNB to conventional nodal staging of colon cancer patients is still unspecified. Technical problems have to be resolved before a definite conclusion can be drawn in this regard. However, SLNB identifies about one fourth of stage II patients to reveal MM/ITC in lymph nodes. Further studies must clarify the clinical impact of these findings in terms of prognosis and the indication of adjuvant therapy.

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.

The sentinel node procedure in colon carcinoma: a multi-centre study in The Netherlands

BACKGROUND

Lymph node status is the most important predictive factor in colorectal carcinoma. Recurrences occur in 20% of the patients without lymph node metastases. The sentinel lymph node (SLN) biopsy is a tool to facilitate identification of micrometastatic disease and aberrant lymphatic drainage. We studied the feasibility of in vivo SLN detection in a multi-centre setting and evaluated nodal micro-staging using immunohistochemistry (IHC).

MATERIALS AND METHODS

Sub-serosal injection with Patent Blue dye was used in the SLN procedure in 69 patients operated for localized colon cancer in six Dutch hospitals. Each SLN was examined with routine haematoxylin-eosin staining. In tumour-negative SLNs, we performed CK7/8 or 18 IHC.

RESULTS

The procedure was successful in 67 of 69 patients (97%). The SLN was negative in 43 patients. In three cases, it was false negative, resulting in a negative predictive value of 93% and an accuracy of 96%. In 24 of 27 patients with lymph node metastases in a successful SLN procedure, the SLN was positive (sensitivity 89%). In 15 patients, the SLN was the only positive node (21%). In nine patients, we only found micrometastases or isolated tumour cells, resulting in 18% upstaging. Aberrant lymphatic drainage was seen in three patients (4%).

CONCLUSION

The SLN procedure in localized colon carcinoma is reliable in a multi-centre setting. It is helpful to identify patients who would be classified as stage II with conventional staging (18%) and who might benefit from adjuvant treatment.

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.

Use of Sentinel Node Mapping for Cancer of the Colon: ‘To Map or Not to Map’

Sentinel lymph node (SLN) mapping has become a cornerstone of oncologic surgery because it is a proven method for identifying nodal disease in melanoma and breast cancer. In addition, it can ameliorate the surgical morbidity secondary to lymphadenectomy. However, experience with SLN mapping for carcinoma of the colon and other visceral malignancies is limited. This study represents an update to our initial pilot experience with SLN mapping for carcinoma of the colon. Consenting patients over the age of 18 diagnosed with adenocarcinoma of the colon were included in this study. At the time of operation, 1 to 2 mL of isosulfan blue was injected with a 25-gauge needle into the subserosa at 4 sites around the edge of the palpable tumor. The SLN was identified visually and excised followed by a standard lymphadenectomy and surgical resection. SLNs were evaluated by standard hematoxylin and eosin (H&E) evaluation as well as immunohistochemical (IHC) techniques for carcinoembryonic antigen and cytokeratin if the H&E was negative. Sixty-nine patients underwent SLN mapping. A SLN was identified in 93 per cent (64 of 69) of patients. Nodal metastases were identified in 38 per cent (26 of 69) of patients overall. In 5 patients, the only positive node identified was the SLN, 2 of which were positive by IHC criteria alone. Therefore, 3 per cent (2 of 69) of patients were upstaged by SLN mapping. This technique was 100 per cent specific while being 46 per cent sensitive. Fourteen patients had false-negative SLNs. Metastasis to regional lymph nodes remains the key prognostic factor for colon cancer. SLN mapping is feasible for colon cancer and can identify a subset of patients who could benefit from adjuvant chemotherapy. Although SLN mapping did not alter the surgical management of colon cancer, it does make possible a more focused and cost-effective pathologic evaluation of nodal disease. We do not suggest routine utilization of SLN mapping for colon cancer, but we believe that the data supports proceeding with a national trial.

Analysis of micrometastatic disease in sentinel lymph nodes from resectable colon cancer: results of Cancer and Leukemia Group B Trial 80001

PURPOSE

To determine whether sentinel lymph node (LN) sampling (SLNS) could reduce the number of nodes required to characterize micrometastatic disease (MMD) in patients with potentially curable colon cancer.

PATIENTS AND METHODS

Cancer and Leukemia Group B 80001 was a study to determine whether SLNS could identify a subset of LNs that predicted the status of the nodal basin for resectable colon cancer and, therefore, could be extensively evaluated for the presence of micrometastases. Patients enrolled onto this study underwent SLNS after injection of 1% isosulfan blue, and both sentinel nodes (SNs) and non-SNs obtained during primary tumor resection were sectioned at multiple levels and stained using anti-carcinoembryonic antigen and anticytokeratin antibodies.

RESULTS

Using standard histopathology, SNs failed to predict the presence of nodal disease in 13 (54%) of 24 node-positive patients. Immunostains were performed for patients whose LNs were negative by standard histopathology. Depending on the immunohistochemical criteria used to assign LN positivity, SN examination resulted in either an unacceptably high false-positive rate (20%) or a low sensitivity for detection of MMD (40%).

CONCLUSION

By examining both SNs and non-SNs, this multi-institutional study showed that SNs did not accurately predict the presence of either conventionally defined nodal metastases or MMD. As a result, SLNS is not a useful technique for the study of MMD in patients with colon cancer.

Detection of lymph node micrometastases and isolated tumor cells in sentinel and nonsentinel lymph nodes of colon cancer patients

About 20% to 30% of colon cancer patients classified as node negative by routine hematoxylin-eosin (H&E) staining are found to have micrometastases (MM) or isolated tumor cells (ITC) in sentinel lymph nodes (SLNs) if analyzed by step sections and immunohistochemistry (IHC). Whether SLNs are in this respect representative for all lymph nodes was addressed in this study. SLNs were identified using the intraoperative blue dye detection technique. If all lymph nodes (SLNs and non-SLNs) of a patient were negative by routine H&E staining, they were step-sectioned and analyzed by IHC using pancytokeratin antibodies. We identified at least one SLN in 47 of the 55 patients (85%) and examined a median of 26 lymph nodes per patient (range 10-59). By routine H&E staining, 14 of the 47 patients showed lymph node metastases (30%); the remaining 33 were classified as node-negative. In this group (33 patients), 1011 lymph nodes were analyzed by step sections and IHC: 14 of 70 SLNs. (20%) but only 37 of 941 non-SLNs (4%) had MM/ITC (p < 0.001). Furthermore, 13 of the 33 H&E-negative patients were found to have MM/ITC (39%). In 11 of the 13 patients, MM/ITC were identified in both SLNs and non-SLNs in 1 patient in the SLN only, and in 1 patient in a non-SLN only (sensitivity for the identification of MM/ITC: 92%; negative predictive value: 95%). The SLN biopsy is a valid tool to detect, as well as exclude, the presence of MM/ITC in colon cancer patients. Our results may be of prognostic relevance and influence patient stratification for adjuvant therapy trials.

Sentinel node biopsy and head and neck tumors—Where do we stand today?

BACKGROUND

Sentinel lymph node sampling may be studied profitably in series of patients with 1 tumor type, such as breast carcinoma, in 1 anatomic locale. The present work analyzes the efficacy of sentinel node sampling in a pathologically diverse group of lesions from an anatomically diverse region such as the head and neck; however, there are risks conflating the findings in different tumors with radically different behaviors, in the process producing muddled data. This report reviews the head and neck experience with sentinel sampling and concludes that certain tumor types that have a known propensity for aggressive behavior are the best candidates for trials employing sentinel node sampling; candidates include many cutaneous melanomas of the head and neck, oropharyngeal squamous carcinomas, and selected thyroid carcinomas. Despite the growing popularity of sentinel node sampling in a variety of regions of the body, however, at this juncture this technique remains an investigational procedure, pending demonstration of a tangible improvement in patient outcome through its use. It is recommended that studies of the efficacy of this technique strive, whenever possible, to segregate results of different tumor types in different head and neck locales from one another so as to produce more focused findings for discrete types of malignancies, and not group together tumor types that may in reality exhibit different biological behaviors.