The feasibility and reliability of sentinel node mapping in colorectal cancer

Ex vivo sentinel lymph node investigation in colorectal cancer

Introduction In Brazil, about 26,000 cases of colorectal cancer are diagnosed per year. Pa- tients considered at the early stage of disease (without lymph node) evolve with tumor relapse or recurrence in up to a quarter of cases, probably due to understaging.

Objective Research on ex vivo sentinel lymph node in patients with colorectal adenocarcinoma.

Materials and methods We studied 37 patients who underwent curative surgical resection. The marker used to identify lymph nodes was patent blue dye injected into the peritu- moral submucosa of the open surgical specimen immediately after its removal from the abdominal cavity.

Results  Ex vivo identification of sentinel lymph node with marker occurred in 13 (35.1%) patients. The sensitivity was 40% and 60% false negative. The detailed histological examina- tion of sentinel lymph nodes with multilevel section and immunohistochemistry showed metastasis in one (4.3%) individual, considered ultra-staging.

Conclusion The ex vivo identification of sentinel lymph node had questionable benefits, and worse results when include patients with rectal cancer. Restaging of one patient was possible after multilevel section and immunohistochemistry of the sentinel lymph node, but more research is needed to evaluate the role of micrometastases in patients with colorectal cancer.

Evaluation of lymph flow patterns in splenic flexural colon cancers using laparoscopic real-time indocyanine green fluorescence imaging

PURPOSE

The treatment of splenic flexural colon cancer is not standardized because the lymphatic drainage is variable. The aim of this study is to evaluate the lymph flow at the splenic flexure.

METHODS

From July 2013 to January 2016, consecutive patients of the splenic flexural colon cancer with a preoperative diagnosis of N0 who underwent laparoscopic surgery were enrolled. Primary outcome is frequency of the direction of lymph flow from splenic flexure. We injected indocyanine green (2.5 mg) into the submucosal layer around the tumor and observed lymph flow using the laparoscopic near-infrared camera system in 30 min after injection.

RESULTS

Thirty-one patients were enrolled in this study. The lymph flow was visualized in 31 patients (100 %) without any complications. No case exhibited lymph flow in both the left colic artery (LCA) and left branch of the middle colic artery (lt-MCA) areas. There were 19 cases (61.3 %) with lymph flow directed to the area of the root of the inferior mesenteric vein (IMV), regardless of the presence of the left accessory aberrant colic artery. Lymph node metastases were observed in six cases (19.4 %), and all of the involved lymph nodes existed in lymph flow areas determined by real-time indocyanine green fluorescence imaging.

CONCLUSIONS

The findings of the lymph flow pattern of splenic flexure suggest that lymph node dissection at the root of the IMV area is important, and it may be not necessary to ligate both the lt-MCA and LCA, at least in cases without widespread lymph node metastases.

Immunohistochemical Study of Sentinel Lymph Node in Colon Cancer

Identification of sentinel lymph node (SLN) in colon cancer is very important in order to increase the accuracy of lymph node staging. The number of examined lymph nodes represents a significant predictor of survival. This study aims to show the importance of SLN histological and immunohistochemical examination in adjuvant oncological treatment. The study includes 23 patients with colon cancer (44% women and 56% men) who came in our clinic for surgical intervention. In all cases, the SLN was identified and prepared for histological examination. In 13 of the cases, micrometastases were found onhaematoxylin-eosin (HE) staining, there were 5 cases with positive immunohistochemistry using antibodies anti-p53, anti-VEGF-C, anti-CD34, and 5 cases with SLN negative both for HE and immunohistochemistry. Altogether we had a detection rate of 92%, an accuracy of 78,2%, a sensitivity of 90%, a false negative rate of 10% and a negative predictive value of 71,4%, good values according to the literature. Four (17,3%) patients had micrometastases exclusively in the sentinel lymph node, after performing additional histological examination, using multilevel section and immunohistochemistry. After assessing the SNL on our patients, we concluded that it is a reproducible practice for lymph node analysis.

Determinants of recurrence after intended curative resection for colorectal cancer

Despite intended curative resection, colorectal cancer will recur in ∼45% of the patients. Results of meta-analyses conclude that frequent follow-up does not lead to early detection of recurrence, but improves overall survival. The present literature shows that several factors play important roles in development of recurrence. It is well established that emergency surgery is a major determinant of recurrence. Moreover, anastomotic leakages, postoperative bacterial infections, and blood transfusions increase the recurrence rates although the exact mechanisms still remain obscure. From pathology studies it has been shown that tumors behave differently depending on their location and recur more often when micrometastases are present in lymph nodes and around vessels and nerves. K-ras mutations, microsatellite instability, and mismatch repair genes have also been shown to be important in relation with recurrences, and tumors appear to have different mutations depending on their location. Patients with stage II or III disease are often treated with adjuvant chemotherapy despite the fact that the treatments are far from efficient among all patients, who are at risk of recurrence. Studies are now being presented identifying subgroups, in which the therapy is inefficient. Unfortunately, only few of these facts are implemented in the present follow-up programs. Therefore, further research is urgently needed to verify which of the well-known parameters as well as new parameters that must be added to the current follow-up programs to identify patients at risk of recurrence.

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.

Clinical translation of ex vivo sentinel lymph node mapping for colorectal cancer using invisible near-infrared fluorescence light

Background

Sentinel lymph node (SLN) mapping in colorectal cancer may have prognostic and therapeutic significance; however, currently available techniques are not optimal. We hypothesized that the combination of invisible near-infrared (NIR) fluorescent light and ex vivo injection could solve remaining problems of SLN mapping in colorectal cancer.

Methods

The FLARE imaging system was used for real-time identification of SLNs after injection of the NIR lymphatic tracer HSA800 in the colon and rectum of (n = 4) pigs. A total of 32 SLN mappings were performed in vivo and ex vivo after oncologic resection using an identical injection technique. Guided by these results, SLN mappings were performed in ex vivo tissue specimens of 24 consecutive colorectal cancer patients undergoing resection.

Results

Lymph flow could be followed in real-time from the injection site to the SLN using NIR fluorescence. In pigs, the SLN was identified in 32 of 32 (100%) of SLN mappings under both in vivo and ex vivo conditions. Clinically, SLNs were identified in all patients (n = 24) using the ex vivo strategy within 5 min after injection of fluorescent tracer. Also, 9 patients showed lymph node involvement (N1 disease). In 1 patient, a 3-mm mesenteric metastasis was found adjacent to a tumor-negative SLN.

Conclusions

The current pilot study shows proof of principle that ex vivo NIR fluorescence-guided SLN mapping can provide high-sensitivity, rapid, and accurate identification of SLNs in colon and rectum. This creates an experimental platform to test optimized, non-FDA-approved NIR fluorescent lymphatic tracers in a clinical setting.

Quantitative RT-PCR detection of tumor cells in sentinel lymph nodes isolated from colon cancer patients with an ex vivo approach

OBJECTIVE

To investigate quantitative RT-PCR-based detection of tumor cells in lymph nodes (LNs) isolated from colon cancer patients by ex vivo sentinel lymph node (SLN) mapping.

SUMMARY BACKGROUND DATA

Although lymph node status is among the strongest prognostic factors in colon cancer patients, 20% to 30% of node negative patients experience disease recurrence. These patients may have LN metastases that are not detected by routine examination.

METHODS

Ex vivo SLN mapping was applied to 131 prospectively recruited patients undergoing curative surgery for primary colon cancer. The SLNs were analyzed for the presence of tumor cells by routine histology and real-time RT-PCR quantitation of cytokeratin 20 (CK20) and mucin 2(MUC2) mRNA.

RESULTS

SLNs were identified in 125 (95%) of the 131 patients included.Routine histologic analysis of SLNs and other regional lymph nodes revealed LN metastases in 42 patients (N+), of which 29 (69%) had metastases detected in 1 or more SLNs (sensitivity, 69%; false negative rate, 31%).When analyzing the SLNs by quantitative RT-PCR, the sensitivity, compared with routine LN examination, was 37/42 (88%) for both the CK20 and the MUC2 mRNA markers. In addition, 46% and 27% of the patients' node negative by routine LN examination (N0) were positive for the CK20 and MUC2 mRNA markers, respectively, possibly reflecting the presence of occult tumor cells in their SLNs.

CONCLUSIONS

Quantitative RT-PCR analysis of SLNs identified N+ patients with high sensitivity and revealed a subgroup of N0 patients with potential occult LN disease.

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.

Lymphoscintigraphic localization of sentinel node in early colorectal cancer: results of a monocentric study

BACKGROUND AND OBJECTIVES

Evaluation of the feasibility of the sentinel node technique in early colorectal neoplasms and its overall accuracy in predicting nodal metastases.

METHODS

Thirty-five patients with colon or rectal lesions or degenerate polyps not radically excised by endoscopy were included. Lymphatic mapping was performed with 99mTc labeled albumin colloid injected submucosally by an endoscopic route the afternoon before the surgical procedure. The day of the intervention, 2.5% patent blue V dye (S.A.L.F: Italy) was injected circumferentially around the tumor. A hand held gamma detecting probe (Scintiprobe m100, Pol-Hi-Tech, Italy) was employed to detect "hot" nodes, in vivo and ex vivo. All sentinel nodes were embedded separately for haematoxylin and eosin staining. No IHC or PCR techniques were employed.

RESULTS

Sentinel lymph nodes (SLN) were successfully identified in 35 out of 35 patients. Concordance between SLN and nodal status was observed in 32 out of 35 cases (91.4%); four patients (11.4%) were upstaged. Three skip nodal metastases were observed (false-negative rate: 8.5%).

CONCLUSIONS

The sentinel node technique with blue dye and radiotracer seems valuable in early colorectal cancers detected by screening programs: a good organization and a learning curve are needed, as further multicentric studies.

Detection of metastatic disease with sentinel lymph node dissection in colorectal carcinoma patients

BACKGROUND

In curative colorectal cancer surgery, radical lymph node dissection is essential for staging and decision-making for adjuvant treatment.

PURPOSE

The aims of the study were to analyse to what extent sentinel lymph node dissection (SLND) in colorectal cancer could upstage N0 patients and how lymphatic mapping could demonstrate micrometastatic disease.

PATIENTS AND METHODS

In a prospective study, patients were selected by CT scanning, avoiding bulky disease and distant metastasis. When standard staining (HE) was negative, micrometastases were searched for by immunohistochemistry (cytokeratin 11, CEA and Ca19-9 antibodies). Micrometastatic lymph nodes were classified N+(i).

RESULTS

Detection of sentinel lymph nodes was successful in 48 out of 52 colorectal cancer patients. Among the 44 M0 patients, 22 were N0 (i-) and 22 were N+ (13 with standard HE procedure, three were N+ (macrometastasis) with the SN as the only positive node and six patients had 1-4 micrometastatic SN (N+(i)). An overall potential upstaging of 9/44 could be considered after SLND. With a mean follow-up of 48 months survival, analysis showed that disease-specific survival of the group of six N+(i) patients was intermediate between the group of 22 N0 (i-) patients and the group of 16 N+ patients.

CONCLUSION

SLND may improve the detection of metastasis in conventionally bivalved nodes. Further studies could assess if micrometastatic disease detected in SN could be integrated into the risk factors for stage II patients in order to consider adjuvant chemotherapy.

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.

Importance of sentinel lymph nodes in colorectal cancer: a pilot study

Accurate identification of lymph nodes involved in metastases is vitally important for predicting survival, and it facilitates decision making with regard to adjuvant therapy. The study described here, which was undertaken to evaluate the role of sentinel lymph node mapping in refining the staging of colorectal cancer, was performed prospectively in 19 patients with colorectal cancer who underwent surgery from January to July 2005. Sentinel lymph node sampling was performed during each operation with isosulfan blue dye. Additional immunohistochemical staining was performed only if the sentinel nodes were negative for metastasis. In 18 of 19 patients, at least 1 sentinel node was identified. In 5 of 18 patients, sentinel nodes were positive for metastasis, and in 3 of 5, the sentinel node was the only node containing metastasis that was detected by immunohistochemical staining. In 3 patients, metastases in nonsentinel lymph nodes were detected by hematoxylin and eosin staining; these were determined to be false-negative results. Upstaging associated with sentinel lymph node mapping may reveal disease that might otherwise remain undetected by conventional methods. Patients who are upstaged may benefit from adjuvant therapies that have been shown to improve survival.

Ex vivo sentinel lymph node "mapping" in colorectal cancer

BACKGROUND

The purpose of this study was to evaluate the feasibility and reliability of ex vivo sentinel lymph node mapping in patients with colorectal cancer.

METHODS

In the period January-June 2006, 44 consecutive patients underwent curative surgery for colorectal cancer. In patients with colon and rectal cancer, 0.5-2 ml of Patent Blue Dye was injected submucosally. The injection sites where then gently massaged for 5 min.

RESULTS

In 96% of the patients with colon cancer and 94% of the patients with rectal cancer, at least one sentinel lymph node was found. There were no patients with a false negative sentinel node. The sensitivity was 100% with a negative predictive value of 100%. In 19% of the patients with colon cancer and 18% of the patients with rectal cancer the sentinel node was the exclusive site of lymph node metastases. After additional sectioning and staining, 7 of the 23 patients (30%) with a Dukes B colorectal cancer were upstaged.

CONCLUSION

The technique of ex vivo sentinel lymph node mapping is technically feasible with high sensitivity, high negative predictive value and a high rate of upstaging. The next step is to investigate, if detection of micro-metastases is associated with decreased survival and/or increased local recurrence rates.

Recommendations for the reporting of surgically resected specimens of colorectal carcinoma

The reporting of colorectal cancer is facilitated by the provision of a checklist giving the features required for good patient care. However, the practicalities of applying such a checklist may not be straightforward. Familiar examples include finding the prescribed number of lymph nodes, distinguishing mesenteric tumor deposits from replaced lymph nodes, and deciding if a cluster of malignant cells in a lymph node sinus counts as metastasis. Checklists have traditionally focused on prognostic factors and, particularly, tumor stage. It is becoming increasingly clear that additional factors, whether morphological or molecular, will be needed for future clinical management. It is also evident that prognosis is strongly influenced by the surgical technique used, most notably by the introduction of total mesorectal excision in the case of rectal cancer. Adjuvant therapy is playing an increasingly important role in the management of colorectal cancer, and it is inevitable that morphological and molecular markers will be used to predict responses to the expanding range of therapeutic modalities. Neoadjuvant or preoperative radiotherapy is being offered to patients with advanced rectal cancer and can greatly modify the pathologic findings in operative specimens. For all the preceding reasons, the work of diagnostic pathologists has become increasingly complex and demanding. The 6th edition of the TNM classification fails to meet many of the challenges posed by the realities of modern cancer management. In fact, by changing the rules for staging without strong justification and introducing diagnostic criteria that are unhelpful and lack a good evidence base, there is a real danger that the community of pathologists will fail to engage with reporting recommendations in a standardized manner and that the quality of reporting will decline.

Prognostic value of additional pathological variables for long-term survival after curative resection of rectal cancer

AIM: To evaluate the prognostic value of some pathological variables in rectal cancer survival.

METHODS: 247 patients who underwent curative resection of rectal cancer were included in the study. The influence on survival of five pathological variables (histopathological tumor type, histopathological tumor grade differentiation, blood vessel invasion, perineural invasion and lymphatic invasion) was assessed using statistical analyses.

RESULTS: Overall 5-year survival was 71.2%. Univariate analysis of all tested variables showed an effect on survival but only the effect of lymphatic invasion was statistically significant. At stages three and four it had a negative effect on survival (P = 0.0212). Lymphatic invasion also significantly affected cancer related survival in multivariate analysis at stages three and four. At lower stages (stage 0, stage 1 and stage 2) multivariate analysis showed a negative effect of perineural invasion on cancer related survival.

CONCLUSION: Patients with lymphatic and perineural invasion have a higher risk for rectal cancer related death after curative resection. Examination of these variables should be an important step in detecting patients with a poorer prognosis.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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