Technique and clinical consequences of sentinel lymph node biopsy in colorectal cancer

Role of one-step nucleic acid amplification in colorectal cancer lymph node metastases detection

Current histopathological staging procedures in colorectal cancer (CRC) depend on midline division of the lymph nodes (LNs) with one section of hematoxylin and eosin staining. Cancer cells outside this transection line may be missed, which could lead to understaging of Union for International Cancer Control Stage II high-risk patients. The one-step nucleic acid amplification (OSNA) assay has emerged as a rapid molecular diagnostic tool for LN metastases detection. It is a molecular technique that can analyze the entire LN tissue using a reverse-transcriptase loop-mediated isothermal amplification reaction to detect tumor-specific cytokeratin 19 mRNA. Our findings suggest that the OSNA assay has a high diagnostic accuracy in detecting metastatic LNs in CRC and a high negative predictive value. OSNA is a standardized, observer-independent technique, which may lead to more accurate staging. It has been suggested that in stage II CRC, the upstaging can reach 25% and these patients can access postoperative adjuvant chemotherapy. Moreover, intraoperative OSNA sentinel node evaluation may allow early CRC to be treated with organ-preserving surgery, while in more advanced-stage disease, a tailored lymphadenectomy can be performed considering the presence of aberrant lymphatic drainage and skip metastases.

Role of methylene blue in detecting the sentinel lymph node in colorectal cancer: In vivo vs. ex vivo technique

The identification of sentinel lymph nodes is a valuable oncological method, which aims at mapping lymphatic drainage and has the advantage of correctly staging the disease and assessing prognosis. Lymph node invasion is an important prognostic feature. In colorectal cancer, lymphadenectomy is not influenced by the positive or negative status of the sentinel lymph node. The identification of lymph nodes with possible invasion by staining the primary tumor with methylene blue can lead to improved staging and management. In other words, the consequent administration of neoadjuvant therapy (chemotherapy) to the appropriate patients may result in lower recurrence rates. Thus, the aim of the present study was to use methylene blue to identify the sentinel node/nodes in colorectal cancer and to determine whether the dye-capturing nodes were invaded by the tumor. This is a non-randomized prospective study, in which 26 patients with colon cancer with surgical indication were enrolled. Two types of methods were utilized: in vivo (16 patients) and ex vivo (10 patients). The identification rate was 75% for the in vivo technique and 60% for the ex vivo technique, resulting in a 69.26% overall identification rate. Of 18 patients with sentinel lymph nodes identified using dye, routine histological examination detected metastases in 6 (33.33%) of these patients. In conclusion, further research should be conducted into how the clinical application of sentinel node detection can be employed in colorectal cancer.

Intra-operative tumour detection and staging in colorectal cancer surgery

AIM

Surgical resection for colorectal cancer involves segmental resection and regional lymphadenectomy. The appropriateness of this 'one-size-fits-all' strategy is questioned as bowel cancer screening programmes result in a shift to earlier stage disease. Currently, the nodal status of a colorectal cancer can only be reliably determined by histopathological examination of the resected specimen. New methods of intra-operative staging are required to allow surgical resection to be tailored to the stage of the disease.

METHOD

A literature search was performed of PubMed and Embase databases using the terms 'colon' OR 'colorectal' AND 'intra-operative detection' OR 'intra-operative staging' OR 'intra-operative detection' OR 'radioimmunoguided surgery'. Articles published between January 1980 and January 2012 were included. Technologies that have the potential to allow intra-operative staging and treatment stratification were identified and further searches performed.

RESULTS

Established techniques such as sentinel lymph node mapping and radioimmunoguided surgery have benefited from combination with other technologies to allow real-time intra-operative staging. Intra-operative fluorescence, using naturally fluorescent biomarkers or fluorescent tumour probes, probably offers the most practical means of intra-operative lymph node staging and may be facilitated using nanotechnology. Optical coherence tomography and real-time elastography have the potential to provide an in vivo'virtual biopsy'.

CONCLUSION

Technological advances may allow accurate intra-operative lymph node staging to facilitate tailored surgical resection. This may become the next paradigm shift in colorectal cancer surgery.

Ex vivo localization and immunohistochemical detection of sentinel lymph node micrometastasis in patients with colorectal cancer can upgrade tumor staging

BACKGROUND

It is not clear if sentinel lymph node (SLN) mapping can improve outcomes in patients with colorectal cancers. The purpose of this study was to determine the prognostic values of ex vivo sentinel lymph node (SLN) mapping and immunohistochemical (IHC) detection of SLN micrometastasis in colorectal cancers.

METHODS

Colorectal cancer specimens were obtained during radical resections and the SLN was identified by injecting a 1% isosulfan blue solution submucosally and circumferentially around the tumor within 30 min after surgery. The first node to stain blue was defined as the SLN. SLNs negative by hematoxylin and eosin (HE) staining were further examined for micrometastasis using cytokeratin IHC.

RESULTS

A total of 54 patients between 25 and 82 years of age were enrolled, including 32 males and 22 females. More than 70% of patients were T3 or above, about 86% of patients were stage II or III, and approximately 90% of patients had lesions grade II or above. Sentinel lymph nodes were detected in all 54 patients. There were 32 patients in whom no lymph node micrometastasis were detected by HE staining and 22 patients with positive lymph nodes micrometastasis detected by HE staining in non-SLNs. In contrast only 7 SLNs stained positive with HE. Using HE examination as the standard, the sensitivity, non-detection rate, and accuracy rate of SLN micrometastasis detection were 31.8% (7/22), 68.2% (15/22), and 72.2%, respectively. Micrometastasis were identified by ICH in 4 of the 32 patients with HE-negative stained lymph nodes, resulting in an upstaging rate 12.5% (4/32). The 4 patients who were upstaged consisted of 2 stage I patients and 2 stage II patients who were upstaged to stage III. Those without lymph node metastasis by HE staining who were upstaged by IHC detection of micrometastasis had a significantly poorer disease-free survival (p = 0.001) and overall survival (p = 0.004).

CONCLUSION

Ex vivo localization and immunohistochemical detection of sentinel lymph node micrometastasis in patients with colorectal cancer can upgrade tumor staging, and may become a factor affecting prognosis and guiding treatment.

Analysis of sentinel lymph node biopsy results in colon cancer in regard of the anthropometric features of the population and body composition assessment formulas

Purpose

The aim of the study was to assess sentinel lymph node biopsy (SLNB) results in colon cancer (CC) regarding basic anthropometric features of the studied population and their derivatives calculated using mathematical formulas.

Methods

One hundred three SLNBs in CC have been analysed. Various indicators were calculated for every patient using mathematical formulas: BMI, Roher’s index, lean body weight, body fat percentage and body weight/ideal body weight for a given height ratios using the following formulas: Broca’s, Broca’s ideal weight, Broca–Brugsch, Lorenz’s, Potton’s, Devine’s, Robinson’s, Miller’s and Hamwi. The results were compared with accuracy, sensitivity and false negative results percentage by means of ROC curves and the test for structure indicators (for determined cut-off points).

Results

No statistically significant relationship between the results and patients' sex or age were found. ROC curve analysis did not reveal statistically significant relationships between the obtained results and indicators calculated on the basis of growth and weigh (all p > 0.05). The analyses of sensitivity and accuracy with determined cut-off point, in spite of differences amounting to 19 % (analysis of lean body weight/weight ratio), showed no statistical significance for any of the relationships (all p > 0.05).

Conclusions

No indicator with high diagnostic and prognostic value has been found. The problem of qualifying patients for SLNB in CC in regard of the anthropometric features of the population and body composition assessment formulas remains open and requires further analysis on larger populations.

Ultrastaging of colon cancer by sentinel node biopsy using fluorescence navigation with indocyanine green

PURPOSE

Lymph node status is the most important prognostic factor in colon cancer, but the role of sentinel lymph node biopsy (SLNB) as a tool for identification of micrometastatic disease and extraanatomical lymph nodes for adjuvant strategies and a tailored approach still remains unclear. Indocyanine green (ICG) fluorescence detection is a new method for SLNB allowing real-time lymphography and lymph node detection. This study was designed to evaluate the feasibility of fluorescence-guided sentinel lymph node detection in colon carcinoma.

METHODS

Twenty six patients with colon adenocarcinoma were prospectively included in this study. Intraoperatively, a peritumorous injection with a mean of 2.0 ml ICG was performed, followed by lymphatic mapping and SLNB. Clinical feasibility, detection rate, and sensitivity of the method were analyzed.

RESULTS

No adverse reactions occurred due to the injection of ICG. Overall, ICG fluorescence imaging identified 1.7 sentinel lymph node (SLN) in average in 25 out of 26 patients (detection rate, 96%). Metastatic involvement of the SLN was found in nine out of 11 nodal positive patients by conventional histopathology. The sensitivity of the method was 82% for colon carcinoma, respectively.

CONCLUSION

ICG fluorescence imaging is a new, feasible method for SLNB of colon carcinoma and enables ultrastaging with improved accuracy but with limited validity due to the small number of cases. One advantage of this technique is real-time visualization of lymphatic vessels and SLNB without radiation exposure. Further, larger series are necessary to analyze the role of fluorescence-guided SLNB for colon cancer.

Current clinical status of sentinel lymph nodes in colon and proximal rectal cancer

The postoperative report of the lymph node status of colorectal cancer in clinical practice is not a given fact. Among other factors, it is dependent on the experience and technique of the surgeon as well as the pathologist. Therefore a method like sentinel lymph node biopsy (SLNB) that identifies and provides for analysis the lymph node at highest risk for tumour involvement would be highly beneficial. Unlike in breast cancer or melanoma, SLNB is more difficult to apply in colorectal cancer and is still not ready for clinical routine application for these tumor entities. However, careful patient selection and expertise of the involved specialists can improve the quality and results of SLNB in colorectal cancer. Especially in the early stage cancer patients, SLNB may be helpful to identify the earliest signs of lymphatic dissemination (thereby upstaging the patient) or to encourage a limited extent of resection.

Biomarker-based selection of therapy for colorectal cancer

Colorectal cancer (CRC) has been re-classified based on molecular analyses of various genes and proteins capable of separating morphologic types of tumors into molecular categories. The diagnosis and management of CRC has evolved with the discovery and validation of a wide variety of biomarkers designed to facilitate a personalized approach for the treatment of the disease. In addition, a number of new prognostic and predictive individual genes and proteins have been discovered that are designed to reflect the sensitivity and/or resistance of CRC to existing therapies. Multigene predictors have also been developed to predict the risk of relapse for intermediate-stage CRC after completion of surgical resection. Finally, a number of biomarkers have been proposed as specific predictors of chemotherapy and radiotherapy response and, in some instances, drug toxicity. In this article, a series of novel biomarkers are considered and compared with standard-of-care markers for their potential use as pharmacogenomic and pharmacogenetic predictors of disease outcome.

One hundred consecutive cases of sentinel lymph node mapping in colon cancer-the results of prospective, single--centre feasibility study with implementation of immunohistochemical staining

PURPOSE

Although the importance of sentinel node biopsy (SNB) in colon cancer (CC) has not been clearly established, this method is proposed as potentially enabling more appropriate staging by means of immunohistochemistry (IHS). The aim of the study was to evaluate the SNB method used in CC treatment taking into consideration the results of the IHS examination.

MATERIALS AND METHODS

In the period from May 2005 to September 2010 in the 1st Department of Surgical Oncology and General Surgery, Wielkopolska Cancer Centre, 100 SNB in CC were performed. Sentinel nodes (SN) were identified intraoperatively with the use of Patent Blue dye. In the case of negative hematoxylin and eosin staining, the SN material was subjected to immunohistochemical examination. Finally, the histopathological findings of sentinel and non-sentinel lymph nodes were compared with the results of the immunohistochemical staining.

RESULTS

At least one SN was identified in 99 of 100 patients (99%). The SN was the only place of metastases in 12.1% (12/99) of the patients. The accuracy of SNB in determining the regional lymph node status was 93.9% (93/99). The sensitivity of the method was 83.3% (30/36). The false-negative rate amounted to 16.7% (6/36). Upstaging obtained by the implementation of the immunohistochemical method was 10% (7/70).

CONCLUSIONS

The application of the immunohistochemical staining enables upstaging of some patients, potentially benefiting from adjuvant chemotherapy. For full and definitive assessment of SNB in CC, further research is required especially in terms of additional factors determining a patient's eligibility for this procedure.

Process of distant lymph node metastasis in colorectal carcinoma: implication of extracapsular invasion of lymph node metastasis

BACKGROUND

We previously demonstrated that extracapsular invasion (ECI) at a metastatic sentinel node was significantly associated with the presence of positive non-sentinel nodes in patients with breast cancer. However, the mechanism of metastatic spreading of tumor cells to distant lymph nodes in patients with colorectal carcinoma is not fully understood. In this study, we investigated the factors that may determine the likelihood of additional regional lymph node metastasis when metastasis is found in nodes at the N1 site in colorectal cancer, especially focusing on the presence of ECI.

METHODS

Two hundred and twenty-eight consecutive patients who underwent colorectal resection were identified for inclusion in this study, of which 37 (16.2%) had positive lymph nodes at the N1 site. Six of these 37 cases had additional metastasis in N2 site lymph nodes. We reviewed the clinicopathological features of these cases and performed statistical analysis of the data.

RESULTS

In the univariate analysis ECI at the N1 site was the only factor significantly associated with the presence of cancer cells in the N2 site. Other factors, including number of positive lymph nodes, lymphovascular invasion of the primary tumor, tumor size and tumor depth of invasion, were not associated with metastatic involvement at the N2 site.

CONCLUSIONS

Our results suggest that the presence of ECI at metastatic lymph nodes at the N1 site is correlated with further metastasis at the N2 site. These findings imply the possibility that ECI might indicate the ability of colorectal tumor cells to disseminate to distant lymph nodes.

Rectum-conserving surgery in the era of chemoradiotherapy

BACKGROUND

A complete pathological response occurs in 10-30 per cent of patients with locally advanced rectal cancer undergoing neoadjuvant chemoradiotherapy (CRT). The standard of care has been radical surgery with high morbidity risks and the challenges of stomata despite the favourable prognosis. This review assessed minimalist approaches (transanal excision or observation alone) to tumours with a response to CRT.

METHODS

A systematic review was performed using PubMed and Embase databases. Keywords included: 'rectal', 'cancer', 'transanal', 'conservative', 'complete pathological response', 'radiotherapy' and 'neoadjuvant'. Original articles from all relevant listings were sourced. These were hand searched for further articles of relevance. Main outcome measures assessed were rates of local recurrence and overall survival, and equivalence to radical surgery.

RESULTS

Purely conservative 'watch and wait' strategies after CRT are still controversial. Originally used for elderly patients or those who refused surgery, the data support transanal excision of rectal tumours showing a good response to CRT. A complete pathological response in the T stage (ypT0) indicates < 5 per cent risk of nodal metastases.

CONCLUSION

Rectal tumours showing an excellent response to CRT may be suitable for local excision, with equivalent outcomes to radical surgery. This approach should be the subject of prospective clinical trials in specialist centres.

Up-regulation of hnRNP A1, Ezrin, tubulin β-2C and Annexin A1 in sentinel lymph nodes of colorectal cancer

AIM: To investigate the early metastasis-associated proteins in sentinel lymph node micrometastasis (SLNMM) of colorectal cancer (CRC) through comparative proteome.

METHODS: Hydrophobic protein samples were extracted from individual-matched normal lymph nodes (NLN) and SLNMM of CRC. Differentially expressed protein spots were detected by two-dimensional electrophoresis and image analysis, and subsequently identified by matrix assisted laser desorption/ionization-time of flight mass spectrometry-mass spectrometry and Western blotting, respectively.

RESULTS: Forty proteins were differentially expressed in NLN and SLNMM, and 4 metastasis-concerned proteins highly expressed in SLNMM were identified to be hnRNP A1, Ezrin, tubulin β-2C and Annexin A1. Further immunohistochemistry staining of these four proteins showed their clinicopathological characteristics in lymph node metastasis of CRC.

CONCLUSION: Variations of hydrophobic protein expression in NLN and SLNMM of CRC and increased expression of hnRNP A1, Ezrin, tubulin β-2C and Annexin A1 in SLNMM suggest a significantly elevated early CRC metastasis.

Biomarker-based prediction of response to therapy for colorectal cancer: current perspective

The diagnosis and management of colorectal cancer (CRC) has been impacted by the discovery and validation of a wide variety of biomarkers designed to facilitate a personalized approach for the treatment of the disease. Recently, CRC has been reclassified based on molecular analyses of various genes and proteins capable of separating morphologic types of tumors into molecular categories. At the same time, a number of new prognostic and predictive single genes and proteins have been discovered that are designed to reflect sensitivity and/or resistance to existing therapies. Multigene predictors have also been developed to predict the risk of relapse for intermediate-stage CRC after completion of surgical extirpation. More recently, a number of biomarkers tested by a variety of methods have been proposed as specific predictors of chemotherapy and radiotherapy response. Other markers have been successfully used to predict toxic effects of standard therapies. In this review, a series of novel biomarkers are considered and compared with standard-of-care markers for their potential use as pharmacogenomic and pharmacogenetic predictors of disease outcome.

Distribution of the first metastatic lymph node in colon cancer and its clinical significance

INTRODUCTION

The pattern of distribution of lymph node metastasis in resected specimens of colon cancer has been rarely reported in the English literature. The aim of this study was to determine the location of the first metastatic lymph node, giving insight into the drainage pattern of colon cancer lymphatics.

METHOD

All lymph nodes in the mesentery of the resected specimen were carefully harvested and their precise locations documented. Patients with a single metastatic node in the resected specimen were included in the study.

RESULTS

Ninety-three patients with only one metastatic lymph node found on histology were studied. The mean number of lymph nodes per specimen was 22.3 (range: 8-72). The patients' first metastatic node was not directly below the tumour in 48% of cases. The first metastatic node was found in the region either along the feeding vessels (skipping the pericolic nodes) or in the pericolic area outside 5 cm on either side of the tumour edge in 18% of cases. No factors were found to be predictive for lymph node metastasis occurring elsewhere other than in the pericolic region just below the tumour.

CONCLUSION

Although there has been recent resurgence of interest in using sentinel node biopsy to limit surgical dissection to facilitate minimally access and natural orifice surgery, the present study is a warning that this may compromise oncological clearance. Radical surgery should remain standard practice for colorectal cancer.