Adjuvant therapy for colorectal cancer

Ex vivo sentinel lymph node investigation in colorectal cancer

Introduction In Brazil, about 26,000 cases of colorectal cancer are diagnosed per year. Pa- tients considered at the early stage of disease (without lymph node) evolve with tumor relapse or recurrence in up to a quarter of cases, probably due to understaging.

Objective Research on ex vivo sentinel lymph node in patients with colorectal adenocarcinoma.

Materials and methods We studied 37 patients who underwent curative surgical resection. The marker used to identify lymph nodes was patent blue dye injected into the peritu- moral submucosa of the open surgical specimen immediately after its removal from the abdominal cavity.

Results  Ex vivo identification of sentinel lymph node with marker occurred in 13 (35.1%) patients. The sensitivity was 40% and 60% false negative. The detailed histological examina- tion of sentinel lymph nodes with multilevel section and immunohistochemistry showed metastasis in one (4.3%) individual, considered ultra-staging.

Conclusion The ex vivo identification of sentinel lymph node had questionable benefits, and worse results when include patients with rectal cancer. Restaging of one patient was possible after multilevel section and immunohistochemistry of the sentinel lymph node, but more research is needed to evaluate the role of micrometastases in patients with colorectal cancer.

The role of sentinel lymph node in colon cancer evolution

INTRODUCTION

The aim of this study is to evaluate the sentinel lymph node mapping (SLNM) with methylene blue staining "ex vivo" in colon cancer, as well as calculate the upstaging obtained by the determination of micrometastases and its correlation with the evolution of the disease.

METHODS

Between 2008 and 2011, 101 patients with colon cancer undergoing resection were studied prospectively with SLNM and detection of micrometastases. The correlation of SLN micrometastases with the disease evolution was evaluated in patients with a follow-up of more than one year.

RESULTS

The SLNM rate was 92 cases (91%). Only SLN was positive for micrometastases in 9 cases, with a 14% upstaging. The incidence of false negatives was 9 patients (10%). Mean follow of N0 patients (n=74) was 38 months. The SLN- (negative) group (65 patients) had a recurrence rate of 4 patients (7%), whereas this rate was 2 patients (22%) in the group of SLN+(positive) (9 patients), but without significant differences. No differences in survival were observed.

CONCLUSIONS

SLNM is a reproducible technique without significant increase in time and costs. Upstaging was obtained in 14% of patients staged as N0 by conventional technique. At follow-up of N0 patients with SLN+there seems to be a higher rate of recurrence, which could change the guidelines of adjuvant treatment, but we must interpret the results it with caution because the sample is small.

[Sentinel lymph node biopsy technique in colon cancer. Experience in 125 cases]

INTRODUCTION

The level of lymph node involvement is the most important factor in staging colorectal cancer without metastasis. Sentinel lymph node mapping identifies the node(s) that most accurately reflect the lymph node status of patients, and intensive techniques that improve staging can be focused on these nodes. The aim of this study was to assess the efficacy of ex vivo sentinel lymph node mapping in the staging of colon cancer.

MATERIALS AND METHODS

A prospective study was conducted on 125 patients from the Alava-Txagorritxu University Hospital Health Region (Alava), who were diagnosed prior to surgery with colon cancer without distant metastasis from September 2009 to December 2011. Ex vivo sentinel lymph node mapping with methylene blue was use in these patients to study the sentinel nodes with multiple slices using immunohistochemical techniques and haematoxylin-eosin staining. A comparative study was also performed based on a control group of 170 patients staged with conventional techniques, and involving a single slice and haematoxylin-eosin staining.

RESULTS

The sentinel lymph node identification rate was 98%, with 5.6% false negatives. Upstaging occurred in 14.2% of cases compared to the group studied using conventional techniques (P=.006).

CONCLUSIONS

Ex vivo sentinel lymph node mapping with methylene blue accurately reflects the lymph node status of patients with colon cancer. This approach upstages patients classified as stages i and ii by conventional techniques to stage iii, indicating chemotherapy that may improve their prognosis.

Predictive model of outcome of targeted nodal assessment in colorectal cancer

BACKGROUND

Improvement in staging accuracy is the principal aim of targeted nodal assessment in colorectal carcinoma. Technical factors independently predictive of false negative (FN) sentinel lymph node (SLN) mapping should be identified to facilitate operative decision making.

PURPOSE

To define independent predictors of FN SLN mapping and to develop a predictive model that could support surgical decisions.

PATIENTS AND METHODS

Data was analyzed from 2 completed prospective clinical trials involving 278 patients with colorectal carcinoma undergoing SLN mapping. Clinical outcome of interest was FN SLN(s), defined as one(s) with no apparent tumor cells in the presence of non-SLN metastases. To assess the independent predictive effect of a covariate for a nominal response (FN SLN), a logistic regression model was constructed and parameters estimated using maximum likelihood. A probabilistic Bayesian model was also trained and cross validated using 10-fold train-and-test sets to predict FN SLN mapping. Area under the curve (AUC) from receiver operating characteristics curves of these predictions was calculated to determine the predictive value of the model.

RESULTS

Number of SLNs (<3; P = 0.03) and tumor-replaced nodes (P < 0.01) independently predicted FN SLN. Cross validation of the model created with Bayesian Network Analysis effectively predicted FN SLN (area under the curve = 0.84-0.86). The positive and negative predictive values of the model are 83% and 97%, respectively.

CONCLUSION

This study supports a minimum threshold of 3 nodes for targeted nodal assessment in colorectal cancer, and establishes sufficient basis to conclude that SLN mapping and biopsy cannot be justified in the presence of clinically apparent tumor-replaced nodes.

Prospective randomized study comparing sentinel lymph node evaluation with standard pathologic evaluation for the staging of colon carcinoma: results from the United States Military Cancer Institute Clinical Trials Group Study GI-01

BACKGROUND

The principal role of sentinel lymph node (SLN) sampling and ultrastaging in colon cancer is enhanced staging accuracy. The utility of this technique for patients with colon cancer remains controversial.

PURPOSE

This multicenter randomized trial was conducted to determine if focused assessment of the SLN with step sectioning and immunohistochemistry (IHC) enhances the ability to stage the regional nodal basin over conventional histopathology in patients with resectable colon cancer.

PATIENTS AND METHODS

Between August 2002 and April 2006 we randomly assigned 161 patients with stage I-III colon cancer to standard histopathologic evaluation or SLN mapping (ex vivo, subserosal, peritumoral, 1% isosulfan blue dye) and ultrastaging with pan-cytokeratin IHC in conjunction with standard histopathology. SLN-positive disease was defined as individual tumor cells or cell aggregates identified by hematoxylin and eosin (H&E) and/or IHC. Primary end point was the rate of nodal upstaging.

RESULTS

Significant nodal upstaging was identified with SLN ultrastaging (Control vs. SLN: 38.7% vs. 57.3%, P = 0.019). When SLNs with cell aggregates < or =0.2 mm in size were excluded, no statistically significant difference in node-positive rate was apparent between the control and SLN arms (38.7% vs. 39.0%, P = 0.97). However, a 10.7% (6/56) nodal upstaging was identified by evaluation of H&E stained step sections of SLNs among study arm patients who would have otherwise been staged node-negative (N0) by conventional pathologic assessment alone.

CONCLUSION

SLN mapping, step sectioning, and immunohistochemistry (IHC) identifies small volume nodal disease and improves staging in patients with resectable colon cancer. A prospective trial is ongoing to determine the clinical significance of colon cancer micrometastasis in sentinel lymph nodes.

The prognostic effect of micrometastases in previously staged lymph node negative (N0) colorectal carcinoma: a meta-analysis

BACKGROUND

The prognostic relevance of lymphatic micrometastases in colorectal carcinoma is unclear. To determine the prognostic significance of micrometastases in colorectal cancer, a meta-analysis was performed on all studies, which reported 3-year disease-free survival (DFS) and overall survival (OS).

METHODS

Published studies selected for meta-analysis contained sufficient data from which to extrapolate estimates of 3-year DFS and/or OS. From 1991-2003, 25 studies re-examined N0 lymph nodes by serial sectioning and immunohistochemical (IHC) staining or reverse transcriptase-polymerase chain reaction (RT-PCR) assay. Eight studies (566 patients) with IHC detected micrometastases and three (173 patients) with RT-PCR micrometastases were used to determine DFS and OS. Weighted estimates of 3-year survival were combined across studies within each group, and the combined survival estimates were compared across groups using a binomial test.

RESULTS

Micrometastases were identified in all IHC studies; upstaging, including N1, N1mi and N0(i+), was achieved in 32% (179/566 patients). All RT-PCR studies identified micrometastases; upstaging to N0(mol+) was achieved in 37% (64/173 patients). There was a statistically significant difference in 3-year OS between RT-PCR positive N0(mol+) patients (77.8%) and those for whom micrometastases were not detected (96.6%) (P < .001).

CONCLUSION

The prognostic value of micrometastases detected retrospectively by RT-PCR is significant in AJCC stage II colorectal patients. Studies utilizing RT-PCR performed a more complete nodal analysis when compared to studies using IHC techniques. RT-PCR may also be more specific for the detection of clinically relevant micrometastases compared to IHC detected cytokeratins. Prospective studies are needed to evaluate the potential benefit of systemic chemotherapy in patients with molecular metastases.

Detecção de linfonodo sentinela no câncer colorretal: importância, técnicas e resultados

RACIONAL: Considerando que o comprometimento linfonodal é o fator determinante no estádio, prognóstico e, conseqüentemente, na indicação de terapia adjuvante em câncer de cólon, e sendo esta responsável pelo aumento significativo na sobrevida global desses pacientes, os métodos para estádio devem conferir a maior precisão possível para que todos os pacientes com doença linfonodal maligna possam se beneficiar desta terapêutica na sua sobrevida global. O estudo do linfonodo sentinela vem progressivamente sendo mais valorizado no sentido de conferir maior precisão nesse estádio, bem como no prognóstico do câncer de cólon. OBJETIVO: Identificar o linfonodo sentinela e melhor estudar o status linfonodal no câncer de cólon. PACIENTES E MÉTODOS: Foram randomizados prospectivamente 31 pacientes com câncer de cólon em dois grupos: no primeiro, o linfonodo sentinela foi identificado usando-se corante azul patente e no segundo houve adição de colóide radioativo marcado com 99mTecnécio. RESULTADOS: Pelo menos um linfonodo sentinela foi identificado em 100% dos casos. O número médio de linfonodo sentinela por paciente foi de 1,96, variando de 1 a 3. A adição do método cintigráfico transoperatório acrescentou cinco linfonodos sentinela, que não haviam sido identificados pelo corante. Em quatro casos (12,9%) apenas o linfonodo sentinela se revelou positivo para malignidade, sendo este comprometimento identificado por hematoxilina e eosina com adição de imunoistoquímica. Nesta casuística não foi identificada drenagem linfática aberrante. CONCLUSÃO: Os métodos são viáveis, seguros, complementares e acrescentam acuidade ao estádio desses tumores.

Sentinel lymph node mapping with GI cancer

Precise evaluation of lymph node status is one of the most important factors in determining clinical outcome in treating gastro-intestinal (GI) cancer. Sentinel lymph node (SLN) mapping clearly has become highly feasible and accurate in staging GI cancer. The lunchtime symposium focused on the present status of SLN mapping for GI cancer. Dr. Kitigawa proposed a new strategy using sentinel node biopsy for esophageal cancer patients with clinically early stage disease. Dr. Uenosono reported on whether the SLN concept is applicable for gastric cancer through his analysis of more than 180 patients with cT1-2, N0 tumors. The detection rate was 95%, the false negative rate of lymph node metastasis including micro-metastasis was 4%, and accuracy was 99% in gastric cancer patients with cT1N0. Dr. Bilchik recommended the best technique for identifying SLNs in colorectal cancer: a combination of radiotracer and blue dye method, emphasizing that this technique will become increasingly popular because of the SLN concept, with improvement in staging accuracy. He stressed that this novel procedure offers the potential for significant upstaging of GI cancer. Dr. Saha emphasized that SLN mapping for colorectal cancer is highly successful and accurate in predicting the presence or absence of nodal disease with a relatively low incidence of skip metastases. It provided the "right nodes" to the pathologists for detailed analysis for appropriate staging and treatment with adjuvant chemotherapy. Although more evidence from large-scale multicenter clinical trials is required, SLN mapping may be very useful for individualizing multi-modal treatment for esophageal cancer and might be widely acceptable even for GI cancer.

Quality control issues in the management of colon cancer patients

Quality assurance in colon cancer demands a multidisciplinary effort involving general practitioners, surgeons, radiologists, gastroenterologists, medical oncologists, and pathologists, among others. Maximal improvements in survival will result when colon cancer screening, diagnosis, staging, treatment and surveillance are optimized. We seek to identify those issues most relevant to the quality of care we provide our colon cancer patients.

Lymphatic mapping and sentinel node analysis in colon cancer

Accurate staging of colon cancer is prognostically and therapeutically important. By identifying those patients who would most benefit from adjuvant chemotherapy, accurate staging should decrease recurrence rates and improve overall survival. Lymphatic mapping and sentinel node analysis allow for a focused review of the lymph nodes, which are most likely to harbor a metastasis and may make ultrastaging techniques, such as immunohistochemistry and reverse-transcriptase polymerase chain reaction, more practical. The prognostic significance of micrometastatic disease detected via ultrastaging techniques remains controversial.

Sentinel lymph node mapping in colon and rectal cancer: its impact on staging, limitations, and pitfalls

Sentinel lymph node (SLN) mapping has been widely applied in the staging of solid neoplasms including colon and rectal cancer. Since the first reported feasibility study in 1997, there have been numerous publications validating SLN mapping as a highly accurate and powerful upstaging technique for colon and rectal cancer. In addition to refining the technical aspects of this procedure, these studies have investigated the use of other tracers and operative techniques, while determining the indications, limitations, and pitfalls of SLN mapping in patients with colorectal cancers. This chapter reviews the rationale for performing SLN mapping for the accurate staging of colon and rectal cancers, and provides a brief review of the historical background of the development of the procedure. Landmark publications, which have contributed to the current status of the technique, are discussed. We will focus on the technical details of the procedure, and on the pathological evaluation of the specimen and the SLNs. The various tracers and techniques of SLN mapping in colon and rectal cancer will be discussed. We have performed SLN mapping in more than 240 consecutive patients over the past 7 years. The success rates for identifying at least one SLN for colon and rectal cancer were 100% and 90.6%, respectively. The accuracy rates were 95.8% and 100%, respectively. In terms of upstaging, 32.3% of colon cancer patients with nodal metastases and 16.7% of rectal patients with nodal metastases were upstaged by the detection of micrometastases found in the SLNs only. Finally, we will also discuss the current role as well as the future research directions for SLN mapping in colon and rectal cancer.

Accuracy of determining nodal negativity in colorectal cancer on the basis of the number of nodes retrieved on resection

BACKGROUND

Correct determination of nodal status is pivotal to accurate staging and predicting survival.

METHODS

This is a secondary analysis of INT0089, an intergroup trial of adjuvant chemotherapy for high-risk stage II and III colon cancer. A subset of patients was studied who underwent right or left hemicolectomy and from whom at least 10 lymph nodes were examined. A mathematical model was created to estimate the probability of a true negative result on the basis of the number of nodes examined. The number of nodes needed to predict nodal negativity with 85%, 50%, and 25% probability on the basis of tumor stage was calculated.

RESULTS

In this analysis, 1585 patients were studied. The average number of nodes removed at surgery was comparable between treatment groups at 18.5 (median of 16 in all groups). With this model, when 18 nodes are removed at resection, there is a <25% probability of true node negativity in T1/T2 tumors, whereas <10 nodes need to be examined in T3 and T4 tumors to achieve the same probability.

CONCLUSIONS

Tumor stage and the number of nodes retrieved at resection influence the accuracy of determining nodal status in colon cancer. Most patients are understaged. Underestimating nodal stage may influence decisions regarding adjuvant therapy, as well as overall prognosis.

Validation of sentinel node mapping in patients with colon cancer

BACKGROUND

Sentinel lymph node (SLN) mapping techniques have been validated in breast cancer and melanoma. This study summarizes our experience with SLN mapping for colon cancer.

METHODS

Fifty-five patients with colon cancer underwent intraoperative SLN mapping. One mL of 1% isosulfan blue was injected subserosally around the tumor. The first nodes highlighted with blue were identified as the SLNs. SLNs underwent multiple sectioning and immunohistochemical staining for cytokeratin. The overall learning curve was calculated.

RESULTS

Lymphatic mapping adequately identified at least 1 SLN in 45 patients (82%). SLNs adequately predicted regional status in 44 of 45 (98%) cases. In 9 of 45 cases (20%), the SLNs were the only sites of metastases. Among the 14 cases that were SLN positive, 6 of 55 patients (11%) were positive only by immunohistochemistry. Of the 31 cases with negative SLNs, 1 case had a 3.5-mm pericolonic tumor-replaced non-SLN (3% false-negative rate). The overall learning curve stabilized after five cases.

CONCLUSIONS

Intraoperative SLN mapping is a feasible technique, with a quick learning curve, and had a reasonable SLN identification rate. Negative SLNs accurately predict the status of non-SLNs 97% of the time. Eleven percent of patients were upstaged by demonstration of micrometastases and may benefit from adjuvant chemotherapy.

Intraoperative sentinel lymph node mapping in patients with colon cancer

BACKGROUND

The sentinel lymph node (SLN) mapping technique has been used in breast cancer and melanoma, and was recently described for colon cancer.

METHODS

Thirty-five patients with colon cancer underwent intraoperative SLN mapping. One milliliter of 1% isosulfan blue was injected subserosally around the tumor. The first nodal area that was highlighted with blue was identified as the SLN. All lymph nodes underwent examination with hematoxylin and eosin (H&E) stain. SLNs underwent additional sectioning and were stained with CAM 5.2.

RESULTS

Lymphatic mapping adequately identified the SLN in 25 patients (71%). In the 15 cases where the SLNs were negative for metastases, all other non-SLNs were also negative (0% false negative rate). The SLN was the only site of metastases in 6 (17%) of 35 patients. CAM 5.2 staining provided the only evidence of micrometastases in 4 (11%) of 35 patients.

CONCLUSIONS

Intraoperative SLN mapping is a feasible technique with a reasonable SLN identification rate (71%). The absence of metastases in the SLNs accurately predicts the status of the non-SLNs. Tumors in 11% of patients were upstaged by the demonstration of micrometastatic involvement, and these patients may benefit from further adjuvant chemotherapy.

Pathologic evaluation of sentinel lymph nodes in colorectal carcinoma

BACKGROUND

The identification of lymph node metastases in colorectal resection specimens is necessary for accurate tumor staging. However, routine lymph node dissection by the pathologist yields only a subset of nodes removed surgically and may not include those nodes most directly in the path of lymphatic drainage from the tumor. Intraoperative mapping of such sentinel lymph nodes (SLNs) has been reported in cases of melanoma and breast cancer. We applied a similar method to cases of colorectal carcinoma, with emphasis on the pathology of the SLNs.

METHODS

Eighty-three consecutive patients with colorectal carcinoma were evaluated after intraoperative injection of 1 to 2 mL of 1% isosulfan blue dye (Lymphazurin) into the peritumoral subserosa. Blue-stained lymph nodes were suture-tagged by the surgeon within minutes of the injection for identification by the pathologist, and a standard resection was performed. Designated SLNs were sectioned at 10 levels through the block; a cytokeratin immunostain (AE1) was also obtained. To evaluate the possibility that increased detection of metastases in the SLN might be solely due to increased histologic sampling, all initially negative non-SLNs in the first 25 cases were sectioned also at 10 levels.

RESULTS

Sentinel lymph nodes were identified intraoperatively in 82 (99%) of 83 patients and accounted for 152 (11.9%) of 1275 lymph nodes recovered, with an average of 1.9 SLNs per patient. A total of 99 positive lymph nodes (38 positive SLNs and 61 positive non-SLNs) were identified in 34 node-positive patients. The SLNs were the only site of metastasis in 17 patients (50%), while 14 patients (41%) had both positive SLNs and non-SLNs. Three patients (9%) had positive non-SLNs with negative SLNs, representing skip metastases. In patients with positive SLNs, 91 (19%) of 474 total lymph nodes and 53 (12%) of 436 non-SLNs were positive for metastasis. In patients with negative SLNs, 8 (1%) of 801 total lymph nodes and 8 (1.2%) of 687 non-SLNs were positive for metastasis. Multilevel sections of 330 initially negative non-SLNs in the first 25 patients yielded only 2 additional positive nodes (0. 6%). All patients with positive SLNs were correctly staged by a combination of 4 representative levels through the SLN(s) together with a single cytokeratin immunostain.

CONCLUSIONS

Intraoperative mapping of SLNs in colorectal carcinoma identifies lymph nodes likely to contain metastases. Focused pathologic evaluation of the 1 to 4 SLNs so identified can improve the accuracy of pathologic staging.

Technical details of sentinel lymph node mapping in colorectal cancer and its impact on staging

BACKGROUND

Sentinel lymph node (SLN) mapping for melanoma and breast cancer has greatly enhanced the identification of micrometastases in many patients, thereby upstaging a subset of these patients. The purpose of this study was to see if SLN mapping technique could be used to identify SLNs in colorectal cancer and to assess its impact on pathological staging and treatment.

METHODS

At the time of surgery, 1 ml of Lymphazurin 1% was injected subserosally around the tumor without injecting into the lumen. The first to fourth blue nodes identified were considered the SLNs, which have the highest probability to contain metastases. A standard oncological resection of the bowel was then performed. Multilevel microsections of the SLNs, including a detailed pathological examination of the entire specimen, was performed.

RESULTS

SLN was successfully identified in 85 (98.8%) of 86 patients. In 85 patients, there were 1,367 (16 per patient) lymph nodes examined, of which 140 (1.6 per patient) were identified as SLNs. In 53 (95%) of 56, of whom the SLNs were without metastases (negative), all other non-SLNs also were negative. In 29 (34% of 85) patients, SLNs were positive for metastases; in 14 of the 29 patients, other non-SLNs also were positive in addition to the SLNs. In the other 15 of the 29 patients (18% of 85 patients), SLNs were the only site of metastases, and all other non-SLNs were negative. In 7 patients (8.2% of 85 patients), micrometastases were identified only in 1 or 2 of the 10 sections of a single SLN. In five of seven patients, such micrometastases were detected by hematoxylin and eosin staining and immunohistochemistry; in the other two patients, it was detected only by immunohistochemistry. In patients with negative SLNs, the rate of occurrence of micrometastases in non-SLNs was 5 (0.4%) of 1,184 lymph nodes.

CONCLUSIONS

SLN mapping can be performed easily in colorectal cancer patients, with an accuracy of more than 95%. The identification of submicroscopic lymph node metastases by this technique may have upstaged these patients (18%) from stage I/II to stage III disease, who may then benefit from further adjuvant chemotherapy.