Lymph Node Harvest in Colon Cancer: Influence of Microsatellite Instability and Proximal Tumor Location
ABSTRACT BackgroundAt least 12 harvested lymph nodes are recommended for proper staging of colon cancer. The effect of tumor-related factors
associated with lymph node harvest is not well understood as data are lacking. We investigated tumor-related factors in relation
to the number of lymph nodes harvested.
MethodsPatient and tumor characteristics were investigated in relation to harvested lymph nodes (LN≥12), number of metastatic nodes,
LN ratio (LNR), and prognosis with univariate and multivariate analyses.
ResultsAn LN harvest≥12 nodes was achieved in 36% of the patients. Having<12 nodes harvested was not associated with increased
risk for locoregional recurrence, distant metastasis, or decreased survival. Tumor size>5cm, microsatellite instability
(MSI), and proximal tumor location predicted a harvest of LN≥12. The highest rate (54%) of LN≥12 was found for MSI cancers
[odds ratio (OR) 2.9, 95% confidence interval (CI) 1.3–6.5; P=0.011]. Multivariate analysis identified a proximal location as an independent factor of LN≥12 (adjusted OR 3.5, 95%
CI 1.5–8.2; P=0.003), with MSI an independent factor in stage II to III colon cancer (adjusted OR 2.6, 95% CI 1.1–6.0; P=0.026). To determine the best prognosticator, LNR was the only significant factor in the multivariate analysis (Cox proportional
hazards) with a hazard ratio (HR) of 2.9 (95% CI 1.1–7.8; P=0.038) for LNR 0.01–0.17 and an HR of 5.8 (95% CI 2.5–13.1; P<0.001).
ConclusionsProximal tumor location and microsatellite instability are associated with a higher number of lymph nodes harvested, pointing
to possible underlying genetic and immunologic mechanisms. The LNR is an independent prognostic variable for colon cancer.
Article: Adequacy of Lymph Node Staging in Colorectal Cancer: Analysis of 250 Patients and Analytical Literature Review[show abstract] [hide abstract]
ABSTRACT: Background: The extent of lymph node involvement is the most important prognostic factor in resected locoregional colorectal cancer. Currently, examination of at least 12 lymph nodes is recommended for adequate colorectal cancer staging. Objectives: The present study aimed to evaluate the adequacy of lymph node staging in 250 patients with colorectal cancer and analytical literature review. Patients and Methods: Two hundred fifty patients with histologically proven locoregional invasive colorectal adenocarcinoma from 2005 to 2011 were included. All patients were treated by standard surgical resection for their disease. Twenty-three patients with rectal cancer received neoadjuvant treatment. All potential tumor, patient and treatment variables were evaluated for their impact on the average total number of lymph node examined. Results: In this study, 147 men and 103 women with a median age of 54 (range 23-84) years were included. The median total number of lymph nodes examined was 7 (mean 9.35). Sixty-nine patients (27.6%) had adequate (≥ 12) lymph nodes examination, and twenty patients (8%) had no nodes examined. In univariate analysis, younger age, colon primary site, larger tumor size, the presence of lymphatic vascular invasion, the lack of neoadjuvant treatments, individual surgeon B and Hospital B were more associated with the average total number of lymph node examined. Conclusion: This study indicates that only less than a third of patients with colorectal cancer underwent adequate lymph nodes examination. Further investigation using careful pathologic reviewing of specimens with inadequate lymph node examined is suggested for differentiating true inadequate lymph node dissection from inadequate lymph node detection.Annals of Colorectal Research. 04/2013; 1(1):1-9.
Article: The Correlation between Microsatellite Instability and the Features of Sporadic Colorectal Cancer in the North Part of Iran[show abstract] [hide abstract]
ABSTRACT: The aim of this study was to determine the correlation between MSI and sporadic colorectal cancer in Guilan province, North part of Iran. Materials and Methods. A total of 96 patients who underwent resection for sporadic colorectal cancer in Guilan province were studied. No patients had positive family history of cancers. The frequencies of MSI were analyzed by testing the BAT-26 and BAT-25 markers. Results. MSI analysis revealed that 22.9% of the tumors (22 patients) were microsatellite instability positive and 77.1% (74 patients) were microsatellite instability negative. The highest rate of MSI (40.9%) was found in the rectal region. MSI-H status was seen more frequently in distal tumors (P=0.04, odds ratio = 3.13, 0.96–10.14). Conclusions. Distal tumor location and MSI may associate with special clinicopathological features. It seems that there may be correlation with underlying genetic and immunologic mechanismsGastroenterology Research and Practice. 11/2012;