Effectiveness of paraaortic lymph node dissection for advanced gastric cancer

BACKGROUND/AIMS: To evaluate the effectiveness of paraaortic lymph node dissection (D4) for gastric cancer from the viewpoint of long-term results. METHODOLOGY: Among 879 patients who underwent gastrectomy for advanced gastric cancer, 130 patients who underwent D4 lymphadenectomy were evaluated in relation to clinicopathological findings and long-term results. RESULTS: The frequency of histological paraaortic lymph node metastasis (n4) was 23.1% (30/130). The cumulative 5-year survival rate of 30 n4 patients with D4 lymphadenectomy was 16.7%, which was higher than that (4.2%) of n4 patients without D4 (sampling of paraaortic lymph nodes). Among n4 patients with D4 lymphadenectomy, the cumulative survival rate in 8 patients with 1-2 paraaortic lymph nodes involved (5-year survival rate: 50%) was significantly higher than that in 21 patients with 3 or more paraaortic lymph nodes involved (5-year survival rate: 4.6%). According to the intra-operative macroscopic extent of lymph node metastasis, the cumulative survival rate of patients who were judged as N2 was higher than that of patients judged as N4. CONCLUSIONS: Paraaortic lymph node dissection for advanced gastric cancer was effective, especially when it was done prophylactically and when the number of paraaortic lymph node metastases were 2 or less.     

Indications of limited surgery for gastric cancer with submucosal invasion--analysis of 715 cases with special reference to site of the tumor and level 2 lymph nodes

BACKGROUND/AIMS: There is controversy as to whether limited or extended lymph node dissection should be performed for gastric cancer with submucosal invasion. METHODOLOGY: To clarify the indications of limited surgery for gastric cancer invading the submucosa, we retrospectively examined the incidence of lymph node metastases with regard to the location of the tumor and distant lymph node station in 715 patients who underwent curative gastrectomy with D2 lymphadenectomy for gastric cancer with submucosal invasion. We classified the level 2 lymph nodes into four groups as follows: group 1 was defined as perigastric lymph nodes far from the primary tumors, group 2 as nodes around the left gastric and the common hepatic arteries, group 3 as nodes around the celiac axis, and group 4 as nodes along the splenic artery. RESULTS: The occurrence of the metastases to level 1 nodes was 14.5% (104 of 715) and that to level 2 nodes was 4.5% (32 of 715). Among the latter, metastases to group 1 lymph nodes were detected in 6 only in the lower third (2.1%) and that to group 2 in 5 in the upper third (6.2%), 9 in the middle third (2.6%), and 12 in the lower third of the stomach (4.1%). Metastases to groups 3 and 4 were only recognized in 2 in the middle third of the stomach (0.3%). Tumors less than 8 mm did not metastasize to lymph nodes and those less than 12 mm did not metastasize to distant ones. CONCLUSIONS: These results suggested that in gastric cancer invading the submucosa, it would be sufficient to dissect group 2 lymph nodes for tumors located at the upper third or the middle third of the stomach, and for tumors located in the lower third of the stomach nodes of groups 1 and 2 should be dissected. For tumors less than 8 mm in the diameter partial resection alone could do and for those less than 12 mm D1 dissection is recommended.     

Micrometastases in the cervical lymph nodes in esophageal squamous cell carcinoma

Few studies have investigated the presence of lymph node micrometastases (MM) in the cervical region of patients with esophageal squamous cell cancer. The present study examines the presence of cervical MM and attempts to determine a way to predict the occurrence and site of such micrometastases. A total of 2203 cervical lymph nodes and 118 mediastinal recurrent nerve nodes obtained from 86 patients with esophageal carcinoma were examined immunohistochemically using cytokeratins. Cervical lymph nodes and mediastinal recurrent nerve nodes metastases were detected histologically in 33 and 41 of the 86 patients respectively. Cervical lymph node and mediastinal recurrent nerve node MM were immunohistochemically detected in 16 (18.6%) and 6 (7.0%) patients respectively. Of these 16 patients with cervical MM, seven were found to have lymph node metastases in different cervical regions, whereas cervical MM only were detected in nine patients. Among the former group of patients, five were diagnosed by ultrasound examination as having cervical lymph node metastases. Mediastinal recurrent nerve node metastases and MM correlated with the presence of cervical MM in all but one patient. Cervical lymph node metastasis, including micrometastasis, can be predicted by preoperative ultrasonography and the routine histologic examination of mediastinal recurrent nerve nodes.     

Prognostic Significance of Lateral Lymph Node Micrometastases in Lower Rectal Cancer

PURPOSE: The aims of this study were to determine the rate of lymph node micrometastases and to evaluate their prognostic value in lateral lymph nodes in lower rectal cancer at or below the peritoneal reflection. METHODS: A retrospective analysis was made of 892 lymph nodes from 66 consecutive patients who had undergone radical resection with lateral lymph node dissection. These lymph nodes were examined immunohistochemically with an antibody against cytokeratins 7 and 8, CAM5.2. RESULTS: Routine hematoxylin-eosin staining revealed 9 patients with positive lateral lymph nodes that were stained consistently with CAM5.2. Among 57 patients in whom lateral lymph node metastases were not detected by hematoxylin-eosin staining, cytokeratin staining was positive in 19 nodes (2.7 percent) from 11 patients (19.3 percent). These 11 patients with micrometastases in lateral nodes showed a significantly high recurrence rate (P = 0.048) and worse overall survival (P = 0.01) than the 46 patients without lateral node metastases. The recurrence rate and overall survival of patients with micrometastases did not differ significantly from those of patients with positive lateral nodes with hematoxylin-eosin staining. Local recurrence developed in 6 of 66 patients, but neither the presence nor the absence of micrometastases in lateral nodes influenced the local recurrence rate. CONCLUSION: The presence of nodal micrometastases leads to a poor prognosis. The survival of patients with micrometastases was not different from that of patients with overt metastases. Therefore, patients with cytokeratin-positive cells in lateral lymph nodes should be regarded as having overt metastases.     

Effects of extended lymphadenectomy and postoperative chemotherapy on node-negative gastric cancer

AIM:To investigate the effects of extended lymphadenectomy and postoperative chemotherapy on gastric cancer without lymph node metastasis.METHODS:Clinical data of 311 node-negative gastric cancer patients who underwent potentially curative gastrectomy with more than 15 lymph nodes resected,from January 2002 to December 2006,were analyzed retrospectively.Patients with pT4 stage or distant metastasis were excluded.We analyzed the relationship between the D2 lymphadenectomy and the 5-year survival rate among different subgroups stratified by clinical features,such as age,tumor size,tumor location and depth of invasion.At the same time,the relationship between postoperative chemotherapy and the5-year survival rate among different subgroups were also analyzed.RESULTS:The overall 5-year survival rate of the entire cohort was 63.7%.The 5-year survival rate was poor in those patients who were:(1)more than 65 years old;(2)with tumor size larger than 4 cm;(3)with tumor located in the upper portion of the stomach;and(4)with pT3 tumor.The survival rate was improved significantly by extended lymphadenectomy only in patients with pT3 tumor(P=0.019),but not in other subgroups.Moreover,there was no significant difference in survival rate between patients with and without postoperative chemotherapy among all of the subgroups(P>0.05).CONCLUSION:For gastric cancer patients without lymph node metastasis,extended lymphadenectomy could improve the survival rate of those who have pT3-stage tumor.However,there was no evidence of a survival benefit from postoperative chemotherapy alone.     

Gastric cancer surgery in cirrhotic patients： Result of gastrectomy with D2 lymph node dissection

AIM: To explore the feasibility of performing gastrectomy with D2 lymphadenectomy in gastric cancer patients with liver cirrhosis. METHODS: A total of 7 178 patients were admitted with a diagnosis of liver cirrhosis from January 1993 to December 2003. We reviewed the records of 142 patients who were diagnosed with liver cirrhosis and gastric adenocarcinoma during the same period. Gastrectomy with D2 lymph node dissection for carcinoma of the stomach was performed in 94 patients with histologically proven hepatic cirrhosis. RESULTS: All but 12 patients were classified as Child's class A. Only 35 patients (37.2%) were diagnosed with cirrhosis before operation. Seventy-three patients underwent a subtotal gastrectomy (77.7%) and 21 patients (22.3%) underwent a total gastrectomy, each with D2 or more lymph node dissection. Two patients (3.8%) who had prophylactic intra-operative drain placement, died of postoperative complications from hepatorenal failure with intractable ascites. Thirty-seven patients (39.4%) experienced postoperative complications. The extent of gastric resection did not influence the morbidity whereas serum aspartate aminotransferase level (P=0.011) and transfusion did (P=0.008). The most common postoperative complication was ascites (13.9%) followed by wound infection (10.6%). CONCLUSION: We concluded that the presence of compensated cirrhosis, i.e. Child class A, is not a contraindication against gastrectomy with D2 or more lymph node dissection, when curative resection for gastric cancer is possible. Hepatic reserve and meticulous hemostasis are the likely determinants of operative prognosis.     

Risk factors for lymph node metastasis and evaluation of reasonable surgery for early gastric cancer

AIM: To give the evidence for rationalizing surgical therapy for early gastric cancer with different lymph node status. METHODS: A series of 322 early gastric cancer patients who underwent gastrectomy with more than 15 lymph nodes retrieved were reviewed in this study. The rate of lymph node metastasis was calculated. Univariate and multivariate analyses were performed to evaluate the independent factors for predicting lymph node metastasis. RESULTS: No metastasis was detected in No.5, 6 lymph nodes (LN) during proximal gastric cancer total gastrectomy, and in No.10, 11p, 11d during for combined resection of spleen and splenic artery and in No.15 LN during combined resection of transverse colon mesentery. No.11p, 12a, 14v LN were proved negative for metastasis. The global metastastic rate was 14.6% for LN, 5.9% for mucosa, and 22.4% for submucosa carcinoma, respectively. The metastasis in group Ⅱ?was almost limited in No.7, 8a LN. Multivariate analysis identified that the depth of invasion, histological type and lymphatic invasion were independent risk factors for LN metastasis. No metastasis from distal cancer (≤ 1.0 cm in diameter) was detected in group Ⅱ?LN. The metastasis rate increased significantly when the diameter exceeded 3.0 cm. All tumors (≤ 1.0 cm in diameter) with LN metastasis and mucosa invasion showed a depressed macroscopic type, and all protruded carcinomas were > 3.0 cm in diameter. CONCLUSION: Segmental/subtotal gastrectomy plus D1/D1 No.7 should be performed for carcinoma (≤ 1.0 cm in diameter, protruded type and mucosa invasion).Subtotal gastrectomy plus D2 or D1 No.7, 8a, 9 is the most rational operation, whereas No.11p, 12a, 14v lymphadenectomy should not be recommended routinely for poorly differentiated and depressed type of submucosa carcinoma (> 3.0 cm in diameter). Total gastrectomy should not be performed in proximal, so does combined resection or D2 /D3 lymphadenectomy.     

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.     

胃癌中胸苷磷酸化酶和基质金属蛋白酶2的表达及意义

目的探讨胃癌中胸苷磷酸化酶（TP）和基质金属蛋白酶2（MMP-2）表达的意义及其与肿瘤浸润转移的关系。方法免疫组化SP法检测69例不同胃黏膜组织（正常胃黏膜组10例、慢性胃炎组10例、胃癌组39例、胃癌转移的淋巴结组10例）中TP和MMP-2的表达情况。结果胃癌组织及淋巴结胃癌转移灶中TP与MMP-2的表达较正常组及慢性胃炎组显著增高（P〈0．05）。TP与MMP-2表达与胃癌患者的性别、年龄及肿瘤的分化程度无关。肿瘤≥5cm组及T3-4组TP阳性率湿著高于〈5cm组及T1-2组,有远处转移的胃癌组TP阳性率高于无远处转移组,差具有显著性（P〈0．05）;临床Ⅰ-Ⅱ期和Ⅲ-Ⅳ期之间TP阳性率的差异也具有显著性（P〈0．001）。MMP-2在T1-2组与T3-4组的阳性率分别为60．87％和93．75％,有显著性差异（P〈0．05）。在有淋巴结转移的胃癌组MMP-2阳性率显著高于无淋巴结转移组（P〈0．05）;临床Ⅰ-Ⅱ期阳性表达59．09％,Ⅲ-Ⅳ期阳性表达为94．12％,两组有显著性差异（P〈0．05）。而MMP-2表达却与肿瘤大小及远处转移无关。TP表达阳性的胃癌中MMP-2阳性率88．00％高于TP阴性组的50．00％。结论胃癌中TP与MMP-2表达增高与肿瘤进展的病理临床参数有关;TP的表达与MMP-2的表达有关,提示TP在影响肿瘤进展的过程中可能通过MMP-2促进肿瘤浸润转移。     

Prophylactic lymph node dissection for early gastric cancer invading submucosa

BACKGROUND/AIMS: Prophylactic lymph node dissection for gastric cancer patients was considered to prolong survival time and D2 lymph node dissection was a standard treatment for early gastric cancer invading submucosa without lymph node metastasis. We investigated the possibility of minimizing the extent of prophylactic lymph node dissection for early gastric cancer invading submucosa if there was no evidence of lymph node metastasis. METHODOLOGY: We analyzed data on 404 patients with early gastric cancer invading the submucosa who underwent gastrectomy from 1979 to 1998 in the National Kyushu Medical Center, Fukuoka, Japan. The postoperative survival rate of patients with standard D2 dissection was compared with cases of those with limited D2 dissection which was defined as confined as D2 dissection dissections No.7 (lymph nodes were those along the left gastric artery), No.8 (lymph nodes along the anterosuperior common hepatic artery) and No.9 (lymph nodes along the celiac artery). RESULTS: Of the 404 patients, 52 and 17 had lymph node metastasis in group 1 and group 2 nodes, respectively. Of 17 patients with lymph node metastasis in group 2, 14 (82.4%) had metastasis confined to No.7, 8 and 9 of group 2 nodes. The 5-year survival rate of patients with submucosal cancer without lymph node metastasis was 94.4% after limited D2 dissection and 97.3% after standard D2 dissection, respectively. CONCLUSIONS: The appropriate prophylactic lymph node dissection for early gastric cancer invading the submucosa without lymph node metastasis was considered to be minimized to limited D2 dissection.     

Does extended lymphadenectomy influence prognosis of gastric carcinoma after curative resection?

BACKGROUND/AIMS: It is unclear whether gastric cancer prognosis is improved by extended lymph node dissection more than by lymph node dissection limited to the contiguous N1 perigastric lymph nodes. METHODOLOGY: Four hundred and thirty-eight patients treated by curative gastrectomy were evaluated. Outcomes of D1/D1.5 lymphadenectomy, limited lymph node dissection and of D2/D2.5 lymphadenectomy, extended lymph node dissection and histopathological prognostic factors as in the 1993 TNM staging classification supplement were analyzed. RESULTS: Estimated overall 5-year survival was 54.9%. Five-year survival was 58.4% in the limited lymph node dissection group and 54% in the extended lymph node dissection (P n.s.). Stage I 5-year survival was 59% after D2.5 lymph node dissection, 58% after D1.5 and 50% after D2 dissection (P n.s.). Stage II 5-year survival was 86% in D2.5 group and 56% in D1.5 group (P = 0.041). Stage IIIa survival was 61% in the D2.5 group and 22% in the D1.5 group (P = 0.001). Stage IIIb 5-year survival was 42% after D2.5 resection and 0% in D1.5 group (P = 0.001). In the pT3 group 5-year survival was 72% after D2.5 dissection and 33% after D2 dissection (P = 0.001). In the positive N1 lymph nodes group 5-year survival was better after extended lymph node dissection than after limited lymph node dissection. In pN2a patients 5-year survival was 57% after D2.5 resection and 0% after D2 resection (P < 0.001). In pN2b and pN2c patients extended lymph node dissection did not statistically improve survival. CONCLUSIONS: Even if no statistical differences were found in overall survival, prognosis was improved by extended lymph node dissection in stage II and III, particularly in T2 and T3 subgroups and in N1 and N2a subgroups. When large numbers of positive nodes were found, improved survival was dependent upon resection of extragastric nodes distal to the uppermost echelon of positive nodes.     

The value of D1 lymphadenectomy as prognostic marker in gastric cancer.

BACKGROUND/AIMS: To assess if the study on the involvement of perigastric lymph nodes, the only ones resected in D1 lymphadenectomy, is a valid prognostic marker in patients undergoing curative resection for gastric cancer. METHODOLOGY: A retrospective study was performed in 101 patients with gastric cancer, 34 women and 67 men, with a mean age of 61 years, undergoing curative resection by gastrectomy and D1 lymphadenectomy. Tumor size, the depth of tumoral invasion of the wall, nodal involvement and 5-year survival were assessed. RESULTS: Both tumor size and the depth of tumoral invasion of the wall were significantly related to metastatic involvement of perigastric lymph nodes. Similarly, tumoral involvement of the first-level lymph nodes was significantly associated with survival. CONCLUSIONS: D1 lymphadenectomy can provide adequate prognostic information in patients with gastric cancer undergoing curative resection.     

癌胚抗原在结直肠癌淋巴结微转移检测中的应用

目的 探讨Ⅰ和Ⅱ期结直肠癌术后病理因素及淋巴结微转移对术后5年无瘤生存率的影响.方法 Ⅰ和Ⅱ期结直肠癌患者共126例,均行结直肠癌根治术.每例结直肠癌患者的淋巴结数平均为16枚(10～28枚),用癌胚抗原(CEA)指标对所有淋巴结进行免疫组化染色.统计分析临床病理因素及微转移对术后5年无瘤生存率的影响.结果 术后平均随访64.11(64～106)个月.淋巴管侵犯和肿瘤侵袭深度与淋巴结的CEA表达呈正相关,而其他临床病理因素与淋巴结CEA表达无明显相关性.10项临床病理因素对5年无瘤生存率的影响差异均无统计学意义(P＞0.05).淋巴结CEA表达阴性、孤立肿瘤细胞巢和微转移患者的5年无瘤生存率分别为75.4%、68.2%和46.2%.孤立肿瘤细胞巢患者与CEA阴性患者5年无瘤生存率比较差异无统计学意义(P=0.245).微转移患者与CEA阴性患者比较,前者5年无瘤生存率明显较低(P=0.003).结论 对于Ⅰ和Ⅱ期结直肠癌,若淋巴结中检测到微转移,其预后较差,术后复发率较高,应予以积极的术后辅助化学治疗.     

Analysis of micrometastatic disease in histologically negative lymph nodes of patients with adenocarcinoma of the distal esophagus or gastric cardia

SUMMARY. Lymphatic dissemination is the most important prognostic factor in patients with esophageal carcinoma. However, the clinical significance of lymph node micrometastases is still debated due to contradictory results. The aim of the present study was to identify the incidence of potentially relevant micrometastatic disease in patients with histologically node‐negative esophageal adenocarcinoma and to analyze the sensitivity and specificity of three different immunohistochemical assays. From a consecutive series of 79 patients who underwent a transthoracic resection with extended 2‐field lymphadenectomy, all 20 patients with pN0 esophageal adenocarcinoma were included in this study. A total of 578 lymph nodes were examined for the presence of micrometastases by immunohistochemical analysis with the antibodies Ber‐EP4, AE1/AE3 and CAM 5.2. Lymph node micrometastases were detected in five of the 20 patients (25%). They were identified in 16 of the 578 lymph nodes examined (2.8%) and most frequently detected with the Ber‐EP4 and AE1/AE3 antibody (sensitivity 95% and 79% respectively). In 114 of the 559 negative lymph nodes (20.4%), positive single cells were found that did not demonstrate malignant characteristics. These false‐positive cells were more frequently found with the AE1/AE3 staining (specificity of the Ber‐Ep4 and AE1/AE3 antibody 94% and 84% respectively). The presence of nodal micrometastases was associated with the development of locoregional recurrences (P=0.01), distant metastases (P=0.01), and a reduced overall survival (log rank test, P=0.009). For the detection of clinically relevant micrometastatic disease in patients operated upon for adenocarcinoma of the distal esophagus or gastric cardia, Ber‐EP4 is the antibody of first choice because of its high sensitivity and specificity. Immunohistochemically detected micrometastases in histologically negative lymph nodes have potential prognostic significance and are associated with a high incidence of both locoregional and systemic recurrence. Therefore, this technique has the potential to refine the staging system for esophageal cancer and to help identify patients who will not be cured by surgery alone.     

Perigastric lymph node status can be a simple prognostic parameter in patients with gastric cancer

BACKGROUND/AIMS: The number of metastatic lymph nodes has been a significant prognostic factor after curative resection of gastric cancer and adopted as a new UICC classification of nodal stages in gastric cancer. The extent of lymphadenectomy is another significant factor but has been fiercely debated. Regardless of the type of lymphadenectomy, perigastric lymph node dissection is always carried out. In this study, we examined whether the number of metastatic perigastric nodes can be a prognostic indicator of gastric cancer. METHODOLOGY: For the purpose of evaluating perigastric lymph node status, a retrospective study was carried out with 760 patients who underwent curative gastric resection from June 1994 to November 1998. RESULTS: The 4-year cumulative survival rate was 64% and the survival rate decreased significantly when the number of positive perigastric nodes exceeded 3. Comparing with the patients having 0-2 positive perigastric nodes, patients whose metastatic perigastric lymph nodes exceeded 3 or more exhibited deeper tumor invasion, larger tumor size and older age. Multivariate analysis identified the number of positive perigastric nodes, together with depth of tumor invasion, as the strongest independent prognostic factors for survival. CONCLUSIONS: We suggest that the number of metastatic perigastric nodes can be used as a simple prognostic parameter in patients with gastric cancer and that intensive follow-up and adjuvant chemotherapy should be recommended for the patients with more than 3 metastatic perigastric nodes.     

Dissection of No. 13 lymph node in radical gastrectomy for gastric carcinoma

AIM： To evaluate the feasibility and safety of No. 13 lymphadenectomy in radical gastrectomy for gastric carcinoma. METHODS： Medical records of the patients undergone No. 13 lymph node dissection during D2 gastrectomy for gastric carcinoma, were reviewed from March 2003 to May 2007. RESULTS： One hundred and fifty-eight patients underwent No. 13 lymph node dissection for D2 gastric carcinoma, of them, 4 （2.53%） were found to have metastasis in No. 13 lymph node. Metastasis to No. 12 lymph node was detected in 6 patients and 4 of them had positive No. 13 lymph node. The operative morbidity except for wound infection was 15.19% （24/158）, and hospital death rate was 1.27% （2/158）. No obstructive jaundice caused by No. 13 lymph node metastasis after No. 13 lymph node dissection in radical gastrectomy for gastric carcinoma was detected during the follow-up study to end of January 2007. CONCLUSION： Dissection of No. 13 lymph node in D2 gastrectomy for gastric carcinoma is safe with a low morbidity and mortality rate. Further study is needed to explore its long-term effect.     

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.