Immunohistochemically demonstrated lymph node micrometastasis and prognosis in patients with gallbladder carcinoma

OBJECTIVE: To investigate whether immunohistochemically demonstrated lymph node micrometastasis has a survival impact in patients with advanced gallbladder carcinoma (pT2-4 tumors). SUMMARY BACKGROUND DATA: The clinical significance of immunohistochemically detected lymph node micrometastasis recently has been evaluated in various tumors. However, few reports have addressed this issue with regard to gallbladder carcinoma. METHODS: A total of 1476 lymph nodes from 67 patients with gallbladder carcinoma (pN0, n = 40; pN1, n = 27) who underwent curative resection were immunostained with monoclonal antibody against cytokeratins 8 and 18. The results were correlated with clinical and pathologic features and with patient survival. RESULTS: Lymph node micrometastases were detected immunohistochemically in 23 (34.3%) of the 67 patients and in 37 (2.5%) of the 1476 nodes examined. Of the 37 nodal micrometastases, 21 (56.8%) were single-cell events, and the remaining 16 were clusters. Five micrometastases were detected in the paraaortic nodes. Clinicopathologic features showed no significant associations with the presence of lymph node micrometastases. Survival was worse in the 27 patients with pN1 disease than in the 40 with pN0 disease (5-year survival; 22.2% vs. 52.6%, P = 0.0038). Similarly, survival was worse in the 23 patients with micrometastasis than in the 44 without micrometastasis (5-year survival; 17.4% vs. 52.7%, P = 0.0027). Twenty-eight patients without any lymph node involvement had the best prognosis, whereas survival for the 11 patients with both types of metastasis was dismal. The grade of micrometastasis (single-cell or cluster) had no effect on survival. The Cox proportional hazard model identified perineural invasion, lymph node micrometastasis, and microscopic venous invasion as significant independent prognostic factors. CONCLUSIONS: Lymph node micrometastasis has a significant survival impact in patients with pN0 or pN1 gallbladder carcinoma who underwent macroscopically curative resection. Extensive lymph node sectioning with keratin immunostaining is recommended for accurate prognostic evaluation for patients with gallbladder carcinoma.     

Lymph node micrometastasis and prognosis in patients with oesophageal squamous cell carcinoma

BACKGROUND: The purpose of this study was to investigate whether the presence of lymph node micrometastasis in pathological lymph node-negative (pN0) oesophageal squamous cell carcinoma had prognostic value. METHODS: Some 1840 lymph nodes were obtained from 50 patients with pN0 oesophageal squamous cell carcinoma who underwent curative resection of the primary tumour with systematic lymphadenectomy. These lymph nodes were examined immunohistochemically with anticytokeratin antibody (AE1/AE3). Lymph node micrometastases newly detected by immunohistochemistry were classified as micrometastasis. Additionally, lymph node micrometastases were classified into three stages: stage 1, one individual AE1/AE3-positive cell; stage 2, multiple individual positive cells; stage 3, one or multiple positive clusters. RESULTS: Micrometastases were detected in 20 patients (40 per cent). A higher stage of micrometastasis was associated with greater pathological tumour (pT) size (P = 0.023). Recurrent tumours developed in nine patients. However, the frequency of recurrence was similar in patients with, or without, micrometastasis (five of 20 and four of 30 patients respectively; P = 0.25). Twenty-three of 30 patients without micrometastasis survived, whereas 15 of 20 patients with micrometastasis were still alive (5-year overall survival 75 and 78 percent respectively, P = 0.91). Twenty-six of 30 patients without micrometastasis had no recurrence, whereas 15 of 20 patients with micrometastasis had no recurrence (5-year relapse-free survival 86 and 73 per cent respectively, P = 0.37). There was no significant difference in prognosis with respect to the stages of micrometastasis. Multivariate analysis also showed that micrometastasis was not an independent prognostic factor (P = 0.73). CONCLUSION: Immunohistochemical detection of lymph node micrometastasis may be an indicator of lymphatic dissemination of tumour cells. However, the presence of micrometastasis had no impact on the prognosis of node-negative patients with oesophageal squamous cell carcinoma.     

Prognostic effect of lymph node micrometastasis in patients with histologically node-negative gastric cancer

Background There is no consensus as to the impact of lymph node micrometastasis on survival of patients with gastric cancer. The aim of this study was to clarify the prognostic significance of lymph node micrometastasis in patients with histologically node-negative gastric cancer Methods Lymph nodes (n=2039) from 64 patients with histologically node-negative gastric cancer (T2, T3) were evaluated for micrometastasis. Three serial 5-μm sections of the resected lymph nodes were prepared for immunohistochemical staining with the anti-cytokeratin antibody CAM 5.2. Results Micrometastasis was found in 73 of 2039 nodes (4%) and 20 of 64 patients (32%). The 5-year survival rate was significantly lower for patients with lymph node micrometastasis than for those without lymph node micrometastasis (66% vs. 95%,P<.01). The 5-year survival rate was significantly lower when there were four or more positive micrometastatic nodes (94% vs. 29%,P <.01) and when there were extragastric micrometastatic nodes (89% vs. 53%,P<.01). Conclusions Lymph node micrometastasis was associated with poor outcome in patients with histologically node-negative gastric cancer. The number and the level of lymph node micrometastases are useful prognostic markers for deciding treatment strategies for additional therapy and follow-up.     

Impact of Lymph Node Micrometastasis in Patients with Pancreatic Head Cancer

Purpose The purpose of this study was to investigate the clinical significance of nodal micrometastasis in patients who underwent a curative operation for pancreatic cancer. Experimental Design Fifty-eight patients underwent a macroscopically curative resection with extended lymph node dissection for pancreatic cancer. The total number of resected lymph nodes was 1,058, and 944 histologically negative lymph nodes were subjected to immunohistochemical staining to detect occult micrometastases. Results Nodal micrometastases were detected immunohistochemically in 147 out of 944 resected histologically negative lymph nodes (15.6%). Forty-four of all 58 patients (75.9%) and 13 of the 23 histologically node-negative patients (56.5%) had nodal micrometastases. Nodal micrometastases existed in the N1 lymph node area most frequently, followed by the N2 and N3 lymph node areas. The distribution was similar to that of histologically metastatic lymph nodes. Ten out of 16 patients (62.5%) with histological N1, and 5 out of 16 patients (31.3%) with histological N2 had nodal micrometastases beyond the histological lymph node status. Three and 5-year survival rates of pN0 patients without lymph node nodal micrometastases were both 60.0%, while those with nodal micrometastases were 19.2% and 0%, respectively. There was statistically significant difference between the both groups (P = 0.041). Conclusions Nodal micrometastasis in pancreatic cancer existed in wider and more distant areas than histological lymph node status, and it was an unfavorable predictive factor, even in N0 patients.     

Lymph node micrometastases in early gastric cancer and their impact on prognosis

Abstract While the presence of lymph node metastases in early gastric cancer (EGC) is the most significant prognostic factor, the relevance of lymph node micrometastases remains uncertain. The authors studied 5400 lymph nodes dissected from 300 patients treated surgically for EGC between 1976 and 1999, all of whom were histologically pN0. Micrometastases were defined as single or small clusters of neoplastic cells identifiable only by immunohistochemical methods. Lymph node micrometastases were observed in 30 of the 300 patients (10%). No significant correlation was observed between micrometastases and other clinicopathological characteristics. Analysis of overall survival showed no significant difference between positive or negative micrometastasis groups. The results of our study show that the presence of lymph node micrometastases in EGC does not influence patient prognosis. Electronic Publication     

Clinical significance of lymph node micrometastasis in gallbladder carcinoma

BACKGROUND: This retrospective study was intended to define the clinical significance of lymph node micrometastasis in gallbladder carcinoma. METHODS: A total of 1136 regional lymph nodes taken from 63 consecutive patients undergoing radical resection were examined histologically. Micrometastasis was defined as a metastasis missed on routine histologic examination with hematoxylin-and-eosin but detected by immunohistochemical examination with an antibody against cytokeratins 8 and 18. RESULTS: None of 9 patients (0%) with pT1 disease and 19 of 54 patients (35%) with pT2-4 disease had nodal micrometastases. Univariate analysis identified nodal micrometastasis, type of radical resection, M classification, pT classification, perineural invasion, pTNM stage, timing of radical resection, lymphatic vessel invasion, and pN classification as significant variables. Multivariate analysis revealed that nodal micrometastasis (P =.0003) and type of radical resection (P=.0044) were independent prognostic factors. Nodal micrometastasis affected survival adversely, despite the absence (P=.0002) or presence (P <.0001) of overt nodal metastasis. Nodal micrometastasis correlated significantly with invasive characteristics: lymphatic vessel invasion, perineural invasion, and distant metastasis. CONCLUSIONS: Lymph node micrometastasis is the strongest independent predictor of worse survival regardless of the overt nodal status and may indicate aggressive tumor biology among patients undergoing curative resection for gallbladder carcinoma.     

Outcome of Histologically Node-negative Esophageal Squamous Cell Carcinoma

The outcome of node-negative esophageal carcinoma and the prognostic significance of lymph node micrometastasis remain unknown. The aim of this retrospective study was to clarify these two points. A series of 98 patients who underwent curative operation for histologically node-negative (pN0 in TNM classification) esophageal carcinoma were enrolled in the study. We reviewed the cause of death of these patients. The survival curves were calculated and compared after stratifications according to clinicopathologic parameters. Lymph node micrometastasis in the patients with recurrences was examined using immunohistochemical staining of cytokeratin. Their ages ranged from 45 to 83 years (mean 64.3 years). There were 83 men and 15 women. Altogether, 54 patients were still alive, and 44 had died. A total of 9 patients died from recurrence of their esophageal carcinoma, 33 died from other causes (pneumonia 11, extraesophageal carcinoma 7, and so on), and 2 died from unknown causes. Eight patients had locoregional recurrences, and two patients had distant recurrences. The overall survival rate for the 98 patients was 58.2%. The survival for patients with pT2 or pT3 tumors was significantly worse than for those with pTis or pT1 tumors (p = 0.02, log-rank test). Other clinicopathologic factors did not affect the prognosis. Immunohistochemical study found no lymph node micrometastasis in 365 lymph nodes resected from the patients with recurrences. Only the depth of tumor invasion affected the outcome of patients with node-negative esophageal carcinoma. Altogether, 75% of patients died of other causes without recurrence, with the two main causes of death being pulmonary complications and extraesophageal carcinoma in these patients. Lymph node micrometastasis was not associated with recurrence in this series.     

Lymph Node Micrometastases in Patients With Early Gastric Cancer: Experience With 139 Patients

Background:Although lymph node metastases in patients with early gastric cancer (EGC) is an important prognostic factor, the prognostic relevance of lymph node micrometastases is still uncertain.Methods:The authors studied 1488 lymph nodes, which were histologically confirmed as pN0, dissected from 139 patients who were treated for EGC between 1976–1994. Micrometastases were defined as a single or small cluster of neoplastic cells identifiable only by immunohistochemical methods.Results:Lymph node micrometastases was observed in 24 of the 139 patients (17%). No significant correlation was observed between micrometastases and other clinicopathological characteristics. Analysis of overall survival showed no significant difference between the micrometastases positive and negative groups.Conclusion:The results of our study show that the presence of lymph node micrometastases in EGC does not have an influence on patient prognosis.     

Outcome of histologically node-negative esophageal squamous cell carcinoma

The outcome of node-negative esophageal carcinoma and the prognostic significance of lymph node micrometastasis remain unknown. The aim of this retrospective study was to clarify these two points. A series of 98 patients who underwent curative operation for histologically node-negative (pN0 in TNM classification) esophageal carcinoma were enrolled in the study. We reviewed the cause of death of these patients. The survival curves were calculated and compared after stratifications according to clinicopathologic parameters. Lymph node micrometastasis in the patients with recurrences was examined using immunohistochemical staining of cytokeratin. Their ages ranged from 45 to 83 years (mean 64.3 years). There were 83 men and 15 women. Altogether, 54 patients were still alive, and 44 had died. A total of 9 patients died from recurrence of their esophageal carcinoma, 33 died from other causes (pneumonia 11, extraesophageal carcinoma 7, and so on), and 2 died from unknown causes. Eight patients had locoregional recurrences, and two patients had distant recurrences. The overall survival rate for the 98 patients was 58.2%. The survival for patients with pT2 or pT3 tumors was significantly worse than for those with pTis or pT1 tumors (p = 0.02, log-rank test). Other clinicopathologic factors did not affect the prognosis. Immunohistochemical study found no lymph node micrometastasis in 365 lymph nodes resected from the patients with recurrences. Only the depth of tumor invasion affected the outcome of patients with node-negative esophageal carcinoma. Altogether, 75% of patients died of other causes without recurrence, with the two main causes of death being pulmonary complications and extraesophageal carcinoma in these patients. Lymph node micrometastasis was not associated with recurrence in this series.     

Clinical impact of micrometastasis of the lymph node in gastric cancer

Micrometastasis in regional lymph nodes has been observed immunohistochemically, but the biological and clinical roles of minute nodal invasion of carcinoma in gastric cancer remain unclear. We used the anti-cytokeratin (AE1/AE3) antibody to immunohistochemically detect nodal micrometastatic lesions that could not be identified by routine pathological examination. A total of 4203 lymph nodes were examined in 180 gastric cancer patients. Lymph node metastasis was found in 36 of the 180 patients by routine pathological evaluation. Immunohistochemically micrometastasis was detected in the lymph nodes of 19 node-negative patients. Micrometastasis was not detected in any of the mucosal gastric cancer patients who underwent lymph node dissection. Gastric cancer patients with more than six metastatic lymph nodes all had nodal micrometastasis. Patients with micrometastasis had a significantly poorer survival rate than those without micrometastasis (P < 0.05). Based on the present results the presence of lymph node micrometastasis may provide a more accurate indication for surgical outcome in gastric cancer patients at the same clinical stage.     

Lymph node metastasis from hilar cholangiocarcinoma: audit of 110 patients who underwent regional and paraaortic node dissection

OBJECTIVE: To assess the status of the regional and paraaortic lymph nodes in hilar cholangiocarcinoma and to clarify the efficacy of systematic extended lymphadenectomy. SUMMARY BACKGROUND DATA: There have been no studies in which regional and paraaortic lymphadenectomies for hilar cholangiocarcinoma have been routinely performed. Therefore, the metastasis rates to the regional and paraaortic nodes, the mode of lymphatic spread, and the effect of extended lymph node dissection on survival remain unknown. METHODS: This study involved 110 patients who underwent surgical resection for hilar cholangiocarcinoma with lymph node dissection including both the regional and paraaortic nodes. A total of 2,652 nodes retrieved from the surgical specimens were examined microscopically. RESULTS: Of the 110 patients, 52 (47.3%) had no involved nodes, 39 (35.5%) had regional lymph node metastases, and 19 (17.3%) had regional and paraaortic node metastases. The incidence of positive nodes was significantly higher in the patients with pT3 disease than in those with pT2 disease. The pericholedochal nodes were most commonly involved (42.7%), followed by the periportal nodes (30.9%), the common hepatic nodes (27.3%), and the posterior pancreaticoduodenal nodes (14.5%). The celiac and superior mesenteric nodes were rarely involved. The 3-year and 5-year survival rates were 55.4% and 30.5% for the 52 patients without involved nodes, 31.8% and 14.7% for the 39 patients with regional node metastases, and 12.3% and 12.3% for the 19 patients with paraaortic node metastases, respectively. Of the 19 patients with positive paraaortic nodes, 7 had no macroscopic evidence of paraaortic disease on intraoperative inspection. The survival in this group was significantly better than in the remaining 12 patients. CONCLUSION: The paraaortic nodes and the regional nodes are frequently involved in advanced hilar cholangiocarcinoma. Whether extended lymph node dissection provides a survival benefit requires further study. However, the fact that long-term survival is possible despite pN2 or pM1 disease encourages the authors to perform an aggressive surgical procedure with extended lymph node dissection in selected patients with hilar cholangiocarcinoma.     

Biological significance of occult micrometastases in histologically negative axillary lymph nodes in breast cancer patients using the recent American Joint Committee on Cancer breast cancer staging system

The biological significance of occult metastases in axillary lymph nodes of breast cancer patients is controversial. The purpose of the study was to determine the prognostic significance of occult micrometastases using the current American Joint Committee on Cancer (AJCC) staging system in a cohort of women with node-negative breast cancer, of whom 5% received adjuvant systemic therapy and who all had long-term follow-up. We studied a cohort of 214 consecutive histologically node-negative breast cancer patients with a median follow-up of 8 years. Blocks of the axillary lymph nodes were assessed for occult micrometastases by examination of an additional hematoxylin-eosin-stained slide and by immunohistochemical staining using an antibody to low molecular weight keratin. Occult metastases were classified according to the sixth edition of the AJCC cancer staging manual. We examined the prognostic effects of occult micrometastases and other clinicopathologic features on recurrence outside the breast with disease-free interval (DFI) and survival from breast cancer with disease-specific survival (DSS). Cytokeratin-positive tumor cells were identified in the lymph nodes in 29 of 214 cases (14%). Two cases had isolated tumor cells and no cluster larger than 0.2 mm [pN0(i+)], whereas 27 of 214 (13%) had micrometastases (larger than 0.2 mm and 相似文献   

Significance of immunohistochemically demonstrated micrometastases to lymph nodes in esophageal cancer with histologically negative nodes

BACKGROUND: We examined the prevalence, patterns, and clinical significance of nodal micrometastases in patients with esophageal cancer. METHODS: Cervical, mediastinal, and abdominal lymph nodes systematically removed from 37 patients without conventional histologic evidence of lymph node metastasis from esophageal squamous cell carcinoma were immunohistochemically examined to detect cells that were stained for cytokeratins by the monoclonal antibody cocktail AE1/AE3. Postoperative care and survival were compared in cases with and without such micrometastases. RESULTS: Nodal micrometastases were found in 14 of 37 patients (38%). Among these patients, 9, 7, and 4 had micrometastases to abdominal, mediastinal, and cervical lymph nodes, respectively. Postoperative tumor recurrence was significantly more frequent in patients with micrometastases (50%) than in those without (9%, P = .008). Overall and relapse-free survival in the former group was significantly worse than in the latter group (P = .042 and P = .002, respectively). Nodal micrometastases had an independent prognostic importance for relapse-free survival as determined by multivariate analysis. CONCLUSIONS: Metastatic tumor cells are frequently present in lymph nodes, even in patients without histologic evidence of nodal metastasis from esophageal cancer. Nodal micrometastases indicates a poorer prognosis after a curative esophagectomy procedure in histologically node-negative cases.     

Clinical value of genetically diagnosed lymph node micrometastasis for patients with oral squamous cell carcinoma

BACKGROUND: The purpose of this study was to investigate the incidence and clinical significance of genetically diagnosed lymph node micrometastasis for patients with oral squamous cell carcinoma (SCC). METHODS: A total of 495 lymph nodes obtained from 21 patients with primary oral SCCs that had p53 mutations were examined for corresponding p53 mutations in lymph nodes using mutant allele-specific amplification (MASA). RESULTS: Among 476 histologically negative nodes, 44 were scored as positive for metastasis by MASA. All 19 histologically positive lymph nodes were genetically positive. Four of the 10 pN0 cases and nine of the 11 pN-positive cases had genetically positive micrometastases. Four patients who had five or more genetically positive lymph nodes located in three or more levels, three with disease staged as pN0 or pN1, died of cancer. CONCLUSIONS: These results indicate that a high rate of micrometastasis in cervical lymph nodes of oral SCCs and patients with multiple or lower neck spread of micrometastases have a poor prognosis; they should be treated with postoperative adjuvant therapy.     

中下段直肠癌预后与淋巴结微转移的关系

目的 观察淋巴结微转移对中下段直肠癌预后的影响.方法 应用CK-20免疫组织化学技术对56例中下段直肠癌患者共计661枚淋巴结检测微转移.结果 20例(35.7%)67枚(10.1%)淋巴结检出微转移.20例检出淋巴结微转移者中10例TNM分期提高:Ⅰ→ⅢA 3例,Ⅰ→ⅢC 2例,ⅡA→ⅢB 3例,ⅢA→ⅢC 2例.Kaplan-Meier生存分析显示,淋巴结微转移阳性患者半数生存期为(36.90±3.37)个月(95%置信区间:30.29～43.51个月),明显短于淋巴结微转移阴性者的(48.72±2.25)个月(95%置信区间:44.30～53.14个月),两者差异有统计学意义(P＜0.05).结论 中下段直肠癌淋巴结微转移检测有助于更准确地进行临床病理分期.淋巴结微转移阳性者预后较差.     

Distribution of Lymph Node Metastasis Including Micrometastasis in Gastric Cancer with Submucosal Invasion

Abstract The purpose of this retrospective study was to analyze the distribution of lymph node metastases, including micrometastases, according to the location of the gastric cancer with submucosal invasion. A total of 118 patients with submucosal gastric cancer were enrolled in this study. The distribution of lymph node metastases was examined according to tumor location. Immunohistochemical examination using anti-cytokeratin antibody was performed to examine nodal micrometastases in 118 patients. Lymph node metastasis was found in 19.5% (23/118) of the patients. Significant differences were found for tumor size and depth, lymphatic invasion, and venous invasion for patients with and without nodal metastasis. The distribution of lymph node metastasis for tumors at upper or middle portions of the stomach was mainly found along the left gastric artery. The distribution of lymph node metastasis for tumors in the lower and lesser curvature varied. Immunohistochemical analysis found that 15 of 23 patients with lymph node metastasis found by histologic examination had micrometastases. The presence of two or more lymph node micrometastases was found in these 15 patients, and they were distributed in another stations, including distant nodes. The incidence of micrometastasis was 24.2% (23/95) in pN0 patients. Lymph node micrometastases were confined to regional nodes near the primary tumor. When planning minimally invasive treatment for submucosal gastric cancer, it is important to understand the distribution of lymph node metastasis, including micrometastasis, according to tumor location.     

Immunohistochemically detected micrometastases in peribronchial and mediastinal lymph nodes from patients with T1, N0, M0 pulmonary adenocarcinomas

The T1, N0, M0 subset of stage I lung adenocarcinoma is a tumor that has a 5-year disease-free survival rate of 66% to 85%. To date, there has not been a rigorous immunohistochemically detected lymph node micrometastasis study composed of patients with identical stage and type of tumors, and in which standard histologic features were incorporated into multivariate analyses. We immunohistochemically examined the peribronchial and mediastinal lymph nodes from 80 consecutively accrued patients with T1, N0, M0 adenocarcinomas and bronchioloalveolar carcinomas unselected for distant metastasis, and an additional 39 patients with similar stage and type neoplasms who were selected for their development of metastases to evaluate the prevalence of micrometastases, their association with distant metastases, and their relationship with other pathologic prognostic features. All slides were stained with keratin AE1/3. Micrometastases were confirmed with Ber-Ep4. Three immunohistochemically detected lymph node micrometastases were identified in three of 80 consecutively accrued patients (4%). These three positive stains constituted 0.5% of the 573 stains required to immunohistochemically screen all of the lymph node blocks from these patients. Among the 39 patients who were selected because they developed distant metastases, three immunohistochemically detected lymph node micrometastases from three patients were identified, which constituted 8% of patients in this group and 1% of the 280 stains required to screen all of these patients' lymph nodes. Small vessel invasion, maximum tumor dimension, and immunohistochemically detected lymph node micrometastases were independently associated with metastases on multivariate analysis. Among patients who developed metastases, there was no significant difference in the disease-free survival rate between those with and those without immunohistochemically detected lymph node micrometastases. Given the low sensitivity in terms of the number of immunohistochemical stains performed, and the prognostic significance of standard histologic features, the use of immunohistochemical screening lymph nodes from all patients with T1, N0, M0 adenocarcinomas is questionable.     

Pattern of Lymph Node Micrometastasis and Prognosis of Patients with Colorectal Cancer

Background: Studies of lymph node micrometastases in patients with colorectal cancer have ignored the prognostic significance of the number and level of lymph node micrometastases. The aim of this study was to clarify the prognostic significance of the status of lymph node micrometastases in histologically node-negative colorectal cancer.Methods: We used immunohistochemistry with anti-cytokeratin antibody CAM5.2 to examine 1013 lymph nodes in 42 patients (12 recurrent and 30 nonrecurrent) with histologically determined Dukes B colorectal cancer. Five serial 6-m sections were used for immunohistochemical staining. The frequency, tumor cell pattern, and number and level of lymph node micrometastases were compared between the recurrent and nonrecurrent groups.Results: Micrometastasis was confirmed in 16% (59/373) of lymph nodes in the recurrent group and 12% (77/640) of lymph nodes in the nonrecurrent group, and the frequency of lymph node micrometastases was 92% (11/12) in the recurrent group and 70% (21/30) in the nonrecurrent group. The tumor cell pattern in the metastatic lymph nodes was similar in the recurrent and nonrecurrent groups. Micrometastasis in four or more lymph nodes occurred more frequently in the recurrent group than in the nonrecurrent group (58% vs. 20%, P < .05), and micrometastasis to N2 or higher nodes occurred more frequently in the recurrent group than in the nonrecurrent group (92% vs. 47%, P < .01).Conclusions: The number and level of positive micrometastatic lymph nodes was significantly correlated with postoperative recurrence of histologically determined Dukes B colorectal cancer. This parameter is a useful prognostic indicator in histologically node-negative colorectal cancer and is helpful in planning adjuvant chemotherapy.