Intraoperative sentinel lymph node mapping in patients with colon cancer

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.

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.

Intraoperative Radiochromoguided Mapping of Sentinel Lymph Node in Colon Cancer

Aims and Background

The aim of our study was to assess the feasiblility of sentinel lymph node (SLN) detection in colon cancer using a radiochromoguided technique. The regional lymph node status is crucial for colorectal cancer staging and the stage of disease at the time of diagnosis is the main factor influencing therapeutic decision-making and patient survival.

Methods and Study Design

Between April and June 2001 eight patients with colon cancer were studied by radiochromoguided sentinel lymph node mapping. At the time of surgery 2 ml of patent blue dye was injected around the tumor, followed after 10 minutes by 2 ml of 99mTc-labeled albumin. After 30 minutes the SLN was identified by a gamma probe. Surgery was completed by standard resection. The SLN was processed for permanent hematoxylin and eosin staining and for immunohistochemical examination with anti-CEA and anti-cytokeratin antibodies.

Results

SLNs were identified in six patients; two were negative for metastasis by hematoxylin-eosin and immunohistochemical examination, two were positive for metastasis by both methods, and two were negative for metastasis by hematoxylin-eosin but positive by immunohistochemical examination. There were no false negative SLNs and no complications occurred.

Conclusion

The actual utility of SLN detection for prognostic purposes is still unknown, but intraoperative radiochromoguided SLN mapping is technically feasible in colon cancer, although it is associated with more technical difficulties than in breast cancer and malignant melanoma.

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

This review aimed to determine the overall sensitivity and specificity of indocyanine green (ICG) near-infrared (NIR) fluorescence in sentinel lymph node (SLN) detection in Colorectal cancer (CRC). A systematic search in electronic databases was conducted. Twelve studies including 248 patients were reviewed. The median sensitivity, specificity, and accuracy rates were 73.7, 100, and 75.7. The pooled sensitivity and specificity rates were 71% and 84.6%. In conclusion, ICG-NIR fluorescence is a promising technique for detecting SLNs 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.

Prognostic biomarkers in colorectal cancer: where do we stand?

Colorectal cancer remains a major cause of cancer-related death worldwide. One way to reduce its staggering mortality rate and socio-economic burden is to predict outcome based on the aggressiveness of the tumor biology in order to treat patients accordingly to their risk profile. As such, it comes as no surprise that prognostic biomarker discovery is a hot topic in colorectal cancer research. The last two decades have literally produced tons of new data and an avalanche of potential clinically applicable biomarkers. This review explores and summarizes data concerning the prognostic strength and clinical utility of current and future tissue biomarkers in the diagnosis and treatment of colorectal cancer.

In vivo identification of sentinel lymph nodes using MRI and size-controlled and monodispersed magnetite nanoparticles

PURPOSE

To develop a sentinel lymph node (SN) identification method using accurately synthesized magnetic nanoparticles (MNPs), as an enhanced specific SN tracer in combination with magnetic resonance imaging (MRI) in intact rodent and SN metastasis models.

MATERIALS AND METHODS

Three sizes of MNPs were originally synthesized. We developed an experimental rat SN model, with brachial lymph nodes (Br) as the SN and the axillary lymph node (Ax) as the second lymph node, and injection of MNPs via the front paw. SN detectability was evaluated in vivo using T1 -weighted MR images after injection of the synthesized MNPs, and the amount of iron in the Br and in the Ax was assessed using inductively coupled plasma optical emission spectrometry.

RESULTS

The highest ratios of the amount of iron in the Br versus the Ax were 3.1 and 3.3, using 20-nm MNPs after 2- and 24-hour injections. The appropriate dose and particle diameter for MRI detection was optimized, and the SN was optimally distinguished in the normal and metastatic rat models using MRI after a 0.4 mg/kg 20-nm MNP injection.

CONCLUSION

We developed and optimized a useful SN identification method using MRI in rodent models.

Sentinel lymph node in colorectal cancer — 5 years follow up

To assess the impact of micrometastases in sentinel and non-sentinel lymph nodes on long-term survival rates of patients treated for colorectal cancer (CRC). Data of 57 patients diagnosed with CRC and treated in the Department of Surgical Oncology in Gdansk in the years 2002–2006 were retrospectively analyzed. Clinico-histopathological data were analyzed using chi-square tests. The effect on long-time survival rates was analyzed using Kaplan-Meier survival probability estimates. Identification of the SLN was performed using the blue dye staining method. All regional lymph nodes were subject to standard histopathological examination. Additionally in 32(56.14%) patients whose nodes were found negative for metastases on standard staining further immunohistochemical analyses were performed. In the analyzed group SLNB was performed in 42(73.7%) patients with colon cancer and in 15(26.3%) with rectal cancer. Identification of the SLN was possible in 45(78.9%) patients. The sensitivity of SLNB was 33%. False negatives were found in 66%. SLNB is a feasible method in CRC patients. We presume that lack of micrometastases in the SLN and non-SLN cannot be regarded as a prognostic factor.

Suggestion of optimal patient characteristics for sentinel lymph node mapping in colorectal adenocarcinoma

CONTEXT

In a previously published study, the variables lower rectal tumor site, preoperative chemoradiotherapy and large tumors were considered as independent risk factors for the inability of sentinel lymph node identification in patients with colorectal adenocarcinoma.

OBJECTIVES

To determine if these variables could interfere in the precision and upstaging benefit of sentinel lymph node mapping in colorectal cancer.

METHODS

A database composed of 52 patients submitted to lymphatic mapping using technetium-99m-phytate and patent blue was reviewed. Only patients with tumors smaller than 5.0 cm, not submitted to preoperative chemoradiotherapy and without lower rectal cancer were included.

RESULTS

With these parameters, 11 patients remained to be studied. The sentinel lymph node identification rate was 100%, with a sensitivity of 100%, negative predictive value of 100%, no false negatives and accuracy of 100%. Sentinel lymph nodes were the only metastatic nodes in 36.4% of the patients, micrometastases (<0.2 cm or only identified by immunohistochemistry) provided an upstaging rate of 27.1% and metastases an upstaging rate of 9.1%.

CONCLUSION

The parameters proposed in this study for selection of colorectal adenocarcinoma patients to be submitted to sentinel lymph node mapping identified optimal accuracy and good upstaging results. As the number of included patients was low, these results could serve as guidance for proper patient selection in further prospective lymph node mapping studies in colorectal cancer patients.

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.

Upstaging benefits and accuracy of sentinel lymph node mapping in colorectal adenocarcinoma nodal staging

BACKGROUND AND OBJECTIVES

Sentinel lymph node (SLN) mapping is an additional method for improving colorectal cancer nodal staging. The purpose of the study was to define the method's accuracy in nodal staging, its upstaging benefits and to identify the predictive factors for its failure.

METHODS

Lymphatic mapping was performed using technetium-99m-phytate and patent blue in 52 consecutive colorectal adenocarcinoma patients. Enhanced pathological examination was carried out on SLNs with hematoxylin-eosin step-sectioning and immunochemistry.

RESULTS

The patients studied had an average tumor size of 6.5 cm; 85% had T3/T4 tumors; and rectal tumors represented 57.7% of the group. Overall SLN mapping accuracy was 79.5%, with sensitivity of 65.2% and 34.8% false negatives. Upstaging with SLN mapping was 23.1%. Colon tumors had an SLN identification rate of 90.9% and rectal tumors had 63.3% (P = 0.023). Multivariate statistical analysis identified lower rectal tumor (P = 0.009), neoadjuvant treatment (P = 0.029) and tumor size (P = 0.036) as independent risk factors for the inability to detect SLNs.

CONCLUSIONS

Upstaging benefits of SLN mapping should be considered in colon and mid- and upper rectal tumors. The method should be avoided in patients with lower rectal tumors, large tumors and having had neoadjuvant therapy.

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.

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.

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.

Technical limitations of lymph node mapping in pancreatic cancer

AIM

The high incidence of lymphatic and peri-neural invasion in pancreatic cancer results in poor loco-regional control. Radical pancreatico-duodenectomy may achieve better loco-regional control, but is accompanied by increasing morbidity. Our hypothesis was that if intra-operative mapping of pathological lymph nodes (LN) is technically feasible in pancreatic cancer, it would allow for selective radical resection.

METHODS

In an ethically approved and statistically powered feasibility study of 72 (stopped after 20% enrollment) patients with suspected pancreatic cancer undergoing resection, we injected methylene blue dye peri- and intra-tumorally and studied its progress to identify putative 'sentinel lymph node(s)'. The Kausch-Whipple procedure (or total pancreatectomy, if required) was carried out in addition to radical LN dissection, which was evaluated histopathologically according to the Japanese criteria.

RESULTS

Over 18 months, 14/16 patients prospectively recruited underwent lymph node mapping and a mean of 20 (range 11-37) LNs per patient were harvested. Methylene blue dye injection identified blue LN(s) in 4/14 patients, none of which were positive for malignant deposits, whilst 10/14 patients had LN metastases. The commonest stations for LN metastasis were 17A or B (9/10), 8A (2/10) and 6 (3/10). The median survival for the 13 patients with cancer was 22.3 months (IQR: 10.4-30 months).

CONCLUSION

Sentinel lymph node mapping is not technically feasible in pancreatic cancer.

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.

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.

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.

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.

Effects of 5-fluorouracil adjuvant treatment of colon cancer

Since the late 1980s and early 1990s, 5-fluorouracil-based chemotherapy has been the standard adjuvant treatment for Stage III colon cancer. After the initial introduction of 5-fluorouracil in standard treatment protocols, several changes have been made based on results of randomized studies on various treatment regimens, including new cytotoxic agents. In Stage II patients, the role of adjuvant chemotherapy is debatable. However, there might be a role for adjuvant treatment in certain high-risk patients. Following a search of the Medline database, the results of randomized studies on 5-fluorouracil-based adjuvant therapy are reviewed, and future therapeutic options are discussed.

Quality control issues in the management of colon cancer patients

Quality assurance in colon cancer demands a multidisciplinary effort involving general practitioners, surgeons, radiologists, gastroenterologists, medical oncologists, and pathologists, among others. Maximal improvements in survival will result when colon cancer screening, diagnosis, staging, treatment and surveillance are optimized. We seek to identify those issues most relevant to the quality of care we provide our colon cancer patients.

Lymphatic mapping and sentinel node analysis in colon cancer

Accurate staging of colon cancer is prognostically and therapeutically important. By identifying those patients who would most benefit from adjuvant chemotherapy, accurate staging should decrease recurrence rates and improve overall survival. Lymphatic mapping and sentinel node analysis allow for a focused review of the lymph nodes, which are most likely to harbor a metastasis and may make ultrastaging techniques, such as immunohistochemistry and reverse-transcriptase polymerase chain reaction, more practical. The prognostic significance of micrometastatic disease detected via ultrastaging techniques remains controversial.

Sentinel lymph node mapping of the colon and stomach using lymphoseek in a pig model

BACKGROUND

Lymphoseek is a radiopharmaceutical designed for sentinel lymph node (SLN) mapping. The purpose of this study was to compare Lymphoseek colon and gastric pharmacokinetics with filtered [(99m)Tc]sulfur colloid (fTcSC).

METHODS

Eight anesthetized pigs received an endoscopic injection of Lymphoseek or fTcSC in the stomach and colon. Scintigraphy was obtained of both administration sites at 15-minute intervals up to 3 hours after injection, after which all SLNs were identified by a handheld gamma probe through a laparotomy incision. Isosulfan blue was administered at the injection site 5 minutes before SLN mapping. The percentage of injected dose (%ID) was measured for all harvested nodes, and the clearance half-life (T(c)) was calculated for all injection sites.

RESULTS

The mean Lymphoseek clearance for colon (T(c), 2.56 +/- 1.04 hours) and gastric (T(c), 3.83 +/- 1.18 hours) injection sites was statistically faster (P =.030) compared with fTcSC (colon T(c), 14.98 +/- 3.41 hours; stomach T(c), 14.52 +/- 4.08 hours). After 3 hours, Lymphoseek exhibited a mean SLN %ID of 1.32% +/- 1.71% in the colon and 2.04% +/- 2.12% in the stomach; this was not statistically different from fTcSC (colon,.63% +/-.39%; stomach, 2.35% +/- 2.90%). SLN uptake of Lymphoseek was significantly different from second-echelon node %ID for the colon (P =.011) and gastric (P =.029) injection sites. All SLNs exceeded 10 times background, and there was no discordance between isosulfan blue and Lymphoseek or fTcSC.

CONCLUSIONS

Three hours after colon stomach administration, Lymphoseek demonstrated rapid injection site clearance, detectable SLN uptake, and low second-echelon node uptake.

Adjuvant therapy for stage II colon cancer: an elephant in the living room?

At present, standard adjuvant treatment for patients with stage III colon cancer after surgical resection is represented by 6 months of chemotherapy based on 5-fluorouracil/leucovorin regimens. Even elderly patients enjoy the benefit of chemotherapy in terms of superior overall survival with no detrimental effects on quality of life. More questionable is the role of adjuvant chemotherapy for stage II colon cancer patients, the standard of care for whom is surgical resection alone. Although a majority of patients will be cured with resection, a significant minority will ultimately relapse, suggesting the need to identify patients who may benefit from adjuvant therapy. Putative prognostic markers for stage II patients, as well as the state-of-the-art of the adjuvant treatment in this setting, are reviewed in this paper.

Lymphatic staging in colorectal cancer: pathologic, molecular, and sentinel node techniques

PURPOSE

Accurate staging in colorectal cancer is important to predict prognosis and identify patients who could benefit from adjuvant therapy. Patients with lymphatic metastasis, Stage III/Dukes C, are generally treated with adjuvant chemotherapy. Still, patients without lymphatic metastasis do have relapse as high as 27 percent in five years in Dukes B2. It is hypothesized that these patients have occult (micro)metastasis in their lymph nodes. If these (micro)metastasis can be identified, these patients might benefit from adjuvant therapy. We reviewed the literature on procedures to improve lymph node staging.

METHODS

An extensive literature search was performed in PubMed (www.pubmed.com). Using the reference lists, more articles were found.

RESULTS

We found 30 articles about sentinel node in colorectal cancer describing original series. Some groups reported several studies including the same patients. We reported their largest studies. For all other techniques, we only included key articles.

CONCLUSIONS

Many techniques to improve staging have been described. The finding of occult (micro)metastasis is of prognostic significance in most studies. The sentinel node technique has been recently described for use in colorectal cancer. Although it seems clear that this technique has prognostic potential, it is not yet been shown in a follow-up study. Furthermore, the finding of occult (micro)metastasis in any technique used has not been shown to be clinically significant. Whether to treat patients with adjuvant therapy if occult (micro)metastasis are found needs to be proven in future studies.

Identification of sentinel nodes in patients with colon cancer

AIMS

Lymphatic mapping and sentinel node biopsy entails better staging in malignant melanoma and breast cancer and we used this technique in patients with colon cancer to possibly improve detection of lymphatic spread.

METHODS

Thirty patients with invasive adenocarcinomas were investigated. The tumour status in identified sentinel node(s) was compared with the status in all other harvested regional nodes for each patient. Patients were followed at regular visits for more than 30 months.

RESULTS

Sentinel nodes were identified in all cases, either per-operatively (28 cases) or at dissection of the formalin-fixed specimen (2 cases). The sentinel nodes were diagnostic for the entire lymphatic field in 28 patients and the false negative rate was 2/12. In four cases, the sentinel nodes were the only metastatic nodes. After at minimum 30 months, three patients had died of colon cancer metastases.

CONCLUSION

This method improved the identification of patients with lymph-node metastases, especially those with only few metastatic nodes. Patients dying from metastatic disease had lymph-node metastases at diagnosis.

Sentinel lymph node mapping in colon cancer

BACKGROUND

By systematically reviewing the literature on sentinel lymph node mapping of colon cancers, this study aimed to evaluate this technique as it applies to colon cancers.

METHODS

Human studies on lymphatic mapping for colon cancers were reviewed. Multiple publications of the same studies, abstracts, and case reports were excluded. Current Contents, MEDLINE, EMBASE, and Cochrane Library databases were investigated.

RESULTS

Lymphatic mapping appears to be readily applicable to colon cancers, identifying lymph nodes most likely to harbor metastases. Identification of sentinel lymph nodes varied from 58% to 100% and carried a false-negative rate of approximately 10% in larger studies, but potentially rose 4% to 25% among patients representing a range from node-negative to node-positive (micrometastases) conditions. The prognostic implication of these micrometastases requires further evaluation. Lymphatic mapping in 6% to 29% of cases identified aberrant lymphatic drainage that altered the extent of the lymphadenectomy.

CONCLUSIONS

Further follow-up evaluation to assess the prognostic significance of micrometastases for colon cancers is required before the staging benefits of sentinel node mapping can have therapeutic implications. Lymphatic mapping offers the possibility of improving staging by identifying patients with early disseminated disease who should be considered for adjuvant treatment or included in trials of adjuvant treatment to speed up the breakthrough of more effective adjuvant regimens. Large studies are needed to determine whether the sentinel node concept is as valid for colon cancers as studies so far have shown it is for malignant melanoma and breast cancer.

Adverse events associated with the intraoperative injection of isosulfan blue

STUDY OBJECTIVE

To describe the adverse events associated with the intraoperative injection of isosulfan blue in a large group of patients having a wide range of surgical procedures, and to identify risk factors for these events.

DESIGN

Retrospective chart review.

SETTING

University-affiliated institution specializing in malignancies

PATIENTS

1835 patients representing a total of 1852 surgical procedures.

MEASUREMENTS

Incidence, type, severity, onset time, duration, management, and the presence of potential risk factors for adverse events. Events were considered "major" if potentially life-threatening hypotension occurred.

MAIN RESULTS

Adverse events occurred in 28 procedures (1.5%) and 14 of these adverse events (0.75%) were classified as major. The types of events were: skin reactions in 21 patients, hypotension in 14 patients, edema in 1 patients, and unspecified in 1 patient. The time of onset for adverse events was 42.2 +/- 53.9 minutes (median, 17.5; range, 1 to 180 min) after isosulfan blue injection, and was significantly longer for minor reactions compared with major events (p = 0.015). The longest adverse event lasted at least 21 hours. Treatment was successful with usual antiallergy/antianaphylaxis medications. Ten patients received diphenhydramine alone, and four patients received intravenous epinephrine infusions. Factors associated with a significantly increased incidence of adverse events were isosulfan blue injection in the vulvar area (p = 0.000038), and the chronic preoperative use of angiotensin-converting enzyme inhibitors or angiotensin receptor-blocking agents (p = 0.043). Trends toward an increased risk of an adverse event were noted with isosulfan blue injection in the breast area (p = 0.19), and having more than one surgical procedure with isosulfan blue (p = 0.14).

CONCLUSIONS

Although the most frequent adverse event associated with injection of isosulfan blue was a skin reaction, potentially life-threatening hypotension occurred in 0.75% of all procedures. Anesthesiologists must be aware of the variable onset time and potentially prolonged duration of the adverse events. They should recognize the need for extra vigilance in patients with potential risk factors, and have the usual antiallergy/antianaphylaxis medications available for administration if necessary.

Current status of sentinel lymph node biopsy in solid malignancies

Lymphatic mapping and sentinel lymph node biopsy were first reported in 1977 by Cabanas for penile cancer. Since that time, the technique has become rapidly assimilated into clinical practice. The sentinel node concept has been validated in cutaneous melanoma and breast cancer. However, follow-up data of patients from randomised trials is needed to establish the clinical significance of sentinel lymph node biopsy before accepting the procedure as a standard of care. This technique has the potential to be utilised in all solid tumours like colon, gastric, oesophageal, lung, gynaecologic, and head and neck cancer. This paper reviews the current status of sentinel lymph node biopsy in solid tumours.

Identification of sentinel lymph nodes in colon cancer depends on the amount of dye injected relative to tumor size

Recent studies have shown that the sentinel lymph node (SLN) procedure might improve staging in colon cancer. However, low SLN identification and high false negative rates have also been reported. In a two-institution study, the SLN procedure with isosulfan blue 1% was performed according to a standardized protocol in 31 patients with open resections for colon cancer. Data were collected prospectively. The database was analyzed retrospectively to determine factors contributing to a low identification rate. The SLN identification rate was 87% and the false negative rate was 50%. Successful SLN identification was significantly associated with application of higher volumes of dye relative to the tumor diameter ( p = 0.04) and more frequent tumor localization in the sigmoid colon ( p = 0.04) as compared to missing SLN identification. The tumor diameter was not significantly different in the two groups. Sentinel lymph node identification in colon cancer depends on the amount of dye injected relative to the tumor size. Application of only 1 ml of dye-the amount generally recommended in the literature-is not sufficient in large tumors.

Colorectal carcinoma nodal staging. Frequency and nature of cytokeratin-positive cells in sentinel and nonsentinel lymph nodes

CONTEXT

Nodal staging accuracy is important for prognosis and selection of patients for chemotherapy. Sentinel lymph node (SLN) mapping improves staging accuracy in breast cancer and melanoma and is being investigated for colorectal carcinoma.

OBJECTIVE

To assess pathologic aspects of SLN staging for colon cancer.

DESIGN

Sentinel lymph nodes were identified with a dual surgeon-pathologist technique in 51 colorectal carcinomas and 12 adenomas. The frequency of cytokeratin (CK)-positive cells in mesenteric lymph nodes, both SLN and non-SLN, was determined along with their immunohistochemical characteristics.

RESULTS

The median number of SLNs was 3; the median number of total nodes was 14. The CK-positive cell clusters were detected in the SLNs of 10 (29%) of 34 SLN-negative patients. Adjusted per patient, SLNs were significantly more likely to contain CK-positive cells than non-SLNs (P <.001). Cell clusters, cytologic atypia, and/or coexpression of tumor and epithelial markers p53 and E-cadherin were supportive of carcinoma cells. Single CK-positive cells only, however, could not be definitively characterized as isolated tumor cells; these cells generally lacked malignant cytologic features and coexpression of tumor and epithelial markers and in 2 cases represented mesothelial cells with calretinin immunoreactivity. Colorectal adenomas were associated with a rare SLN CK-positive cell in 1 (8%) of 12 cases.

CONCLUSIONS

Sentinel lymph node staging with CK-immunohistochemical analysis for colorectal carcinomas is highly sensitive for detection of nodal tumor cells. Cohesive cell clusters can be reliably reported as isolated tumor cells. Single CK-positive cells should be interpreted with caution, because they may occasionally represent benign epithelial or mesothelial cells.

Sentinel lymph node mapping in colorectal cancer

BACKGROUND

Ultrastaging, by serial sectioning combined with immunohistochemical techniques, improves detection of lymph node micrometastases. Sentinel lymph node mapping and retrieval provides a representative node(s) to facilitate ultrastaging. The impact on staging of carcinoma of the colon and rectum in all series emphasizes the importance of this technique in cancer management. Now the challenge is to determine the biological relevance and prognostic implications.

METHODS

The electronic literature (1966 to present) on sentinel node mapping in carcinoma of the colon and rectum was reviewed. Further references were obtained by cross-referencing from key articles.

RESULTS

Lymphatic mapping appears to be readily applicable to colorectal cancer and identifies those lymph nodes most likely to harbour metastases. Sentinel node mapping carries a false-negative rate of approximately 10 per cent in larger studies, but will also potentially upstage a proportion of patients from node negative to node positive following the detection of micrometastases. The prognostic implication of these micrometastases requires further evaluation.

CONCLUSION

Further follow-up to assess the prognostic significance of micrometastases in colorectal cancer is required before the staging benefits of sentinel node mapping can have therapeutic implications.

A new agent, blue and radioactive, for sentinel node detection

BACKGROUND

Although with some disadvantages, combining radiotracer and isosulfan blue facilitates the detection of sentinel lymph nodes. This study was designed to evaluate the use of (99m)Tc-labeled phthalocyanine tetrasulfonate ((99m)Tc-PCTS) as a single agent for simultaneous blue staining and radiotracer localization of the sentinel lymph node.

METHODS

Twelve rabbits were injected into the dermis and subcutaneously in the distal hind limb with 1 mL of blue (99m)Tc-PCTS (.5 mCi). The popliteal and inguinal fossae were explored between 15 minutes and 24 hours after injection for blue and/or radioactive tissue. Popliteal and inguinal fossae and other lymph nodes and organs were harvested for determination of the concentration of radioactivity and for histology.

RESULTS

Within minutes of (99m)Tc-PCTS injection, the lymphatic channels were easily identified by the blue color. At 10 minutes, the radioactive count over the popliteal fossa was significantly higher than over other areas. At exploration, a blue and radioactive popliteal node was identified in all animals; inguinal nodes were neither blue nor radioactive. At death, the radioactivity in the popliteal node was 1000 times higher than in other nodes or organs. Although fainter, the blue color in the popliteal node was still visible at 6 weeks. Histological sections of popliteal node identified the dye in the cytoplasmic compartment of the cells.

CONCLUSIONS

Technetium-99m PCTS is a single agent that identifies sentinel lymph nodes by color and radioactivity and is retained for an extended period of time without migrating to other tissues.

Accuracy of determining nodal negativity in colorectal cancer on the basis of the number of nodes retrieved on resection

BACKGROUND

Correct determination of nodal status is pivotal to accurate staging and predicting survival.

METHODS

This is a secondary analysis of INT0089, an intergroup trial of adjuvant chemotherapy for high-risk stage II and III colon cancer. A subset of patients was studied who underwent right or left hemicolectomy and from whom at least 10 lymph nodes were examined. A mathematical model was created to estimate the probability of a true negative result on the basis of the number of nodes examined. The number of nodes needed to predict nodal negativity with 85%, 50%, and 25% probability on the basis of tumor stage was calculated.

RESULTS

In this analysis, 1585 patients were studied. The average number of nodes removed at surgery was comparable between treatment groups at 18.5 (median of 16 in all groups). With this model, when 18 nodes are removed at resection, there is a <25% probability of true node negativity in T1/T2 tumors, whereas <10 nodes need to be examined in T3 and T4 tumors to achieve the same probability.

CONCLUSIONS

Tumor stage and the number of nodes retrieved at resection influence the accuracy of determining nodal status in colon cancer. Most patients are understaged. Underestimating nodal stage may influence decisions regarding adjuvant therapy, as well as overall prognosis.

Validation of sentinel node mapping in patients with colon cancer

BACKGROUND

Sentinel lymph node (SLN) mapping techniques have been validated in breast cancer and melanoma. This study summarizes our experience with SLN mapping for colon cancer.

METHODS

Fifty-five patients with colon cancer underwent intraoperative SLN mapping. One mL of 1% isosulfan blue was injected subserosally around the tumor. The first nodes highlighted with blue were identified as the SLNs. SLNs underwent multiple sectioning and immunohistochemical staining for cytokeratin. The overall learning curve was calculated.

RESULTS

Lymphatic mapping adequately identified at least 1 SLN in 45 patients (82%). SLNs adequately predicted regional status in 44 of 45 (98%) cases. In 9 of 45 cases (20%), the SLNs were the only sites of metastases. Among the 14 cases that were SLN positive, 6 of 55 patients (11%) were positive only by immunohistochemistry. Of the 31 cases with negative SLNs, 1 case had a 3.5-mm pericolonic tumor-replaced non-SLN (3% false-negative rate). The overall learning curve stabilized after five cases.

CONCLUSIONS

Intraoperative SLN mapping is a feasible technique, with a quick learning curve, and had a reasonable SLN identification rate. Negative SLNs accurately predict the status of non-SLNs 97% of the time. Eleven percent of patients were upstaged by demonstration of micrometastases and may benefit from adjuvant chemotherapy.

Lymphatic mapping in solid neoplasms: state of the art

BACKGROUND

Lymphatic mapping and sentinel lymph node biopsy is an established technique for the staging and treatment of melanoma. The success of lymphatic mapping in this realm has broadened its application to other solid neoplasms. This update reviews the status of sentinel lymph node biopsy in its most widely cited applications.

METHODS

Seminal manuscripts on lymphatic mapping in melanoma, breast, colon, vulvar, cervical, lung, gastric, and head and neck cancers are reviewed.

RESULTS

Studies suggest that the application of lymphatic mapping as a staging tool in breast cancer and melanoma is justified when applied by trained surgeons. Additional validation is necessary before sentinel node biopsy is advocated in gynecologic, colon, lung, and head and neck cancer.

CONCLUSIONS

As in breast cancer and melanoma, validation of the sentinel node concept in other solid tumors must occur in institutions other than those in which the technique is being developed before it is generally applied to other neoplasms.