The role of sentinel lymph node mapping in staging of colon and rectal cancer

PURPOSE: Nodal metastasis is the best predictor of survival for patients with colon cancer. Statistical models based on random distribution of positive lymph nodes suggest that to correctly classify nodal status with 95 percent confidence, 20 nodes are needed for T1 lesions, 17 nodes for T2, and 15 nodes for T3. The mean number of nodes identified in American patients is 8, suggesting that they might not be accurately staged. Patients in our tumor registry staged as "node-negative" had a short survival when they had < or =10 lymph nodes evaluated when compared with patients with >10 lymph nodes evaluated (p < 0.01). We hypothesized that the use of sentinel lymph node may assist in the staging of colon cancer. METHODS: Thirty-eight consecutive patients with colon lesions were prospectively enrolled into this trial between February 1998 and November 1999. Thirty-one patients met criteria for analysis. During surgery, Lymphazurin blue dye was injected subserosally into the area around the tumor. Routine nodal evaluation, with extra cuts of all sentinel nodes, was undertaken. RESULTS: At least one sentinel lymph node was found in 18 of 31 patients (58 percent). Sensitivity of 67 percent, specificity and positive predictive value of 100 percent, and negative predictive value of 94 percent were found when sentinel lymph nodes were identified. In 2 of these 18 patients, the sentinel lymph node was the only positive lymph node found. CONCLUSIONS: Application of the sentinel lymph node technique to colon cancer may make it easier to identify lymph nodes most likely to contain metastatic disease, potentially "down-staging" more patients. This may have implications in postoperative care.     

胃癌术中前哨淋巴结的定位检测研究

目的 探讨胃癌术中前哨淋巴结(SLN)定位检测的可行性及意义.方法 在106例胃癌手术中,将亚甲蓝注射至肿瘤周围1 cm的胃壁上,循蓝染的淋巴管找寻第一个蓝染淋巴结,即SLN.结果 106例胃癌患者获得SLN 者103例 (97.17%).根据SLN预测胃周淋巴结转移的准确率、敏感性、假阴性率、特异性在Ⅰ、Ⅱ期胃癌分别为94.74%(36/38)、90%(18/20)、10% (2/20)、100% (18/18),Ⅲ、Ⅳ期胃癌分别为68.33%(41/60)、67.24%(39/58)、32.76% (19/58)、100% (2/2). 结论 使用亚甲蓝染色术中定位胃癌SLN是可行的.在Ⅰ、Ⅱ期胃癌中SLN能准确预测淋巴结转移的情况.     

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.     

Should sentinel lymph node mapping be performed for colorectal cancer?

BACKGROUND/AIMS: Correct determination of lymphatic nodal statement is essential to stage correctly and to predict survival. As it is vital to make an assessment about the adjacent lymph node(s), this study was designed to compose a sensitive detection on the sentinel lymph nodes (SLN) indicating tumoral lymphatic basin using advanced pathologic examination. MATERIALS AND METHODS: From June 2002 to June 2003, this prospective study was performed in 41 patients undergoing standard resection for colorectal cancer. In this study we employed the ex-vivo SLN mapping technique. RESULTS: At least one SLN in 37 of 41 patients was identified (90.2%). The lymph nodes (LN) from those patients were studied by hematoxylin and eosin dye (H&E) and multisectioning. Twenty of 37 patients with trace of the metastasis were found. The remaining 17 patients without any metastatic LN by H&E underwent clarification of micrometastases (MM) using immunohistochemical (IHC) staining technique. Two patients (11.7%) had MM in the SLN(s). Upstaging was evaluated in those two. The sensitivity of SLNs was obtained as 90%. Two patients with no metastatic SLN had metastasis in the non-sentinel LNs. CONCLUSIONS: In the LNs from the basin of tumor, MM exposed by IHC staining was still not obvious to indicate poor prognosis. The need for treatment adjustment in those patients is clear since the upstaging was evident.     

中老年人胃癌前哨淋巴结术中定位的临床研究

目的　探讨胃癌前哨淋巴结 (SLN)术中定位和检测应用的可行性及其预测胃癌淋巴转移的准确性。方法　应用 1 %亚甲蓝染色剂 ,对 2 8例 (T1、T2期 )胃癌病人进行术中SLN定位 ,切除蓝染淋巴结〔平均每例病人 (2 6± 1 7)个〕 ,随后对患者均行胃癌扩大根治术。SLNs和非前哨淋巴结 (nSLNs)均行苏木精 伊红 (HE)染色。结果　 2 8例中有 2 7例 (96 4% )成功检出SLN ,1 0例患者有淋巴结转移 ,其中 6例存在SLN及n SLN转移 ,3例存在SLN转移 ,1例只有n SLN转移。由SLN状态预测胃周淋巴结转移情况的敏感性为 90 % (9/ 1 0 ) ,特异性为 1 0 0 % (1 7/ 1 7) ,准确率为 96 3 % (2 6/ 2 7)。T1组 (1 2例 )与T2组 (1 6例 )敏感性分别为 1 0 0 %和 88%。结论　应用亚甲蓝染色剂对胃癌SLN定位检测成功率高 ,SLN状态 ,尤其是T1期胃癌 ,能够准确预测胃癌患者的淋巴结转移状况。     

Single skip metastasis in sentinel lymph node: In an early gastric cancer

Lymph node status is considered a key prognostic and predictive factor in patients with gastric cancer(GC).Although there is a practical approach to the intraoperative detection of sentinel lymph nodes(SLNs),such a procedure is not included in the European surgical protocol.In this report,we present a practical approach to SLN mapping in a representative case with early gastric cancer(EGC).A 74-year-old female was hospitalized with an endoscopically observed,superficially ulcerated tumor located in the antral region.Subtotal gastrectomy with D2 lymphadenectomy and SLN mapping was performed by injecting methylene blue dye into the peritumoral submucosal layer.An incidentally detected blue-stained lymph node located along the middle colic artery was also removed.This was detected 40 min after injection of the methylene blue.Histopathologic examination showed a p T1b-staged well-differentiated HER-2-negative adenocarcinoma.All of the 41 LNs located at the first,third,and fifth station of the regional LN compartments were found to be free of tumor cells.The only lymph node with metastasis was located along the middle colicartery and was considered a non-regional lymph node.This incidentally identified skip metastasis indicated stage Ⅳ GC.A classic chemotherapy regimen was given,and no recurrences were observed six months after surgery.In this representative case,low-cost SLN mapping,with a longer intraoperative waiting time,totally changed the stage of the tumor in a patient with EGC.     

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

Purpose

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

Method

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

Results

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

Conclusion

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

Sentinel node staging in colon carcinoma: value of sentinel lymph node biopsy with radiocolloid and blue staining

BACKGROUND: Nodal staging accuracy is important in the prognosis and selection of patients for chemotherapy. This prospective study aims to assess the feasibility and accuracy of the sentinel lymph node procedure (SNP) using radiocolloid and blue dye in colon carcinoma. METHODS: In 56 patients, lymphatic mapping was accomplished by means of intraoperatively injecting patent blue and nanocoll subserosally around the tumour. Sentinel nodes (SNs) were harvested ex-vivo. Nodes were stained with H&E. If lymph nodes were interpreted as negative for metastatic tumour, serial sectioning and immunohistochemical staining were performed. RESULTS: At least one SN was detected in 49 of 53 patients (92.5%). Three patients were excluded because of preoperatively detected metastases. Overall, 121 SN were harvested with a mean of 2.2 SN/patients. Eighteen patients had tumour positive nodes. In four patients, pathological nodes were palpable during operation and were excluded. The SN was histologically negative in 2 of 14 patients with positive nodes (false-negative rate 14.3%). In 5 of 14 patients with positive nodes, the SN was the exclusive site of regional nodal metastasis. Four patients were upstaged by immunohistochemical staining (28.6%). The negative predictive value was 93.9% and the overall accuracy 95.6%. Scintigraphy was done in 17 patients. In three patients the SN was detected only by this modality. DISCUSSION: The SN biopsy with the combined technique proved a feasible technique with a steep learning curve. It can change the initial staging from stage II to stage III colon carcinoma. Scintigraphy can improve the success rate of the technique.     

Anal melanoma in the era of sentinel lymph node mapping: a diagnostic and therapeutic challenge

Abstract Melanoma of the anal canal is a rare malignancy that often has an atypical presentation. Locoregional metastases, which are often present at the initial presentation, may occur in both groin and pelvic lymph nodes, but the utility of lymph node dissection remains unknown. We explored the possibility of applying the technique of sentinel lymph node (SLN) mapping to anal melanoma. SLN mapping was performed in 2 patients with anal melanoma. Radioactive tracer and blue dye were injected around the lesions. The SLN was identified pre-operatively by lymphoscintigraphy, and at surgery with a hand-held gamma detector and by visualization of the dye. The SLN was identified in both patients, only in the groin in one and only in the presacral region in the other. One patient had a wide local excision of the anal lesion with house flap anoplasty, while the other had abdominoperineal resection with total mesorectal excision. There were no SLN metastases in either patient. The technique of SLN mapping and biopsy is easily adapted to surgery for malignant melanoma of the anus. SLN mapping and biopsy could aid in planning surgical strategy, but definitive conclusions may only be reached after more experience has been acquired.This work was presented at the 12th Congress of the European Society of Surgical Oncology (ESSO 2004), Budapest, Hungary, 31 March—3 April 2004.