Analysis of micrometastatic disease in sentinel lymph nodes from resectable colon cancer: results of Cancer and Leukemia Group B Trial 80001

Lymphatic Mapping in Colon Cancer Depending on Injection Time and Tracing Agent: A Systematic Review and Meta-Analysis of Prospective Designed Studies

An optimized lymph node yield leads to better survival in colon cancer, but extended lymphadenectomy is not associated with survival benefits. Lymphatic mapping shows several colon cancers feature aberrant drainage pathways inducing local recurrence when not resected. Currently, different protocols exist for lymphatic mapping procedures. This meta-analysis assessed which protocol has the best capacity to detect tumor-draining and possibly metastatic lymph nodes. A systematic review was conducted according to PRISMA guidelines, including prospective trials with in vivo tracer application. The risk of bias was evaluated using the QUADAS-2 tool. Traced lymph nodes, total resected lymph nodes, and aberrant drainage detection rate were analyzed. Fifty-eight studies met the inclusion criteria, of which 42 searched for aberrant drainage. While a preoperative tracer injection significantly increased the traced lymph node rates compared to intraoperative tracing (30.1% (15.4, 47.3) vs. 14.1% (11.9, 16.5), p = 0.03), no effect was shown for the tracer used (p = 0.740) or the application sites comparing submucosal and subserosal injection (22.9% (14.1, 33.1) vs. 14.3% (12.1, 16.8), p = 0.07). Preoperative tracer injection resulted in a significantly higher rate of detected aberrant lymph nodes compared to intraoperative injection (26.3% [95% CI 11.5, 44.0] vs. 2.5% [95% CI 0.8, 4.7], p < 0.001). Analyzing 112 individual patient datasets from eight studies revealed a significant impact on aberrant drainage detection for injection timing, favoring preoperative over intraoperative injection (OR 0.050 [95% CI 0.010-0.176], p < 0.001) while indocyanine green presented itself as the superior tracer (OR 0.127 [95% CI 0.018-0.528], p = 0.012). Optimized lymphatic mapping techniques result in significantly higher detection of aberrant lymphatic drainage patterns and thus enable a personalized approach to reducing local recurrence.

Hematopoietic Gene Expression Regulation Through m6A Methylation Predicts Prognosis in Stage III Colorectal Cancer

Background

Methylation of N6 adenosine (m⁶A) plays important regulatory roles in diverse biological processes. The purpose of this research was to explore the potential mechanism of m⁶A modification level on the clinical outcome of stage III colorectal cancer (CRC).

Methods

Gene set variation analysis (GSVA) and gene set enrichment analysis (GSEA) were adopted to reveal the signal pathway which was most likely affected by m⁶A methylation. The linear models for microarray data (LIMMA) method and the least absolute shrink-age and selection operator (LASSO) Cox regression model were used to identify the signature. The signature can sensitively separate the patients into high and low risk indicating the relapse-free survival (RFS) time based on time-dependent receiver operating characteristic (ROC) analysis. Then, the multi-gene signature was validated in GSE14333 and the Cancer Genome Atlas (TCGA) cohort. The number of the samples in GSE14333 and TCGA cohort are 63 and 150. Finally, two nomograms were set up and validated to predict prognosis of patients with stage III CRC.

Results

The hematopoietic cell lineage (HCL) signaling pathway was disclosed through GSEA and GSVA. Seven HCL-related genes were determined in the LASSO model to construct signature, with AUC 0.663, 0.708, and 0.703 at 1-, 3-, and 5-year RFS, respectively. Independent datasets analysis and stratification analysis indicated that the HCL-related signature was reliable in distinguishing high- and low-risk stage III CRC patients. Two nomograms incorporating the signature and pathological N stage were set up, which yielded good discrimination and calibration in the predictions of prognosis for stage III CRC patients.

Conclusions

A novel HCL-related signature was developed as a predictive model for survival rate of stage III CRC patients. Nomograms based on the signature were advantageous to facilitate personalized counseling and treatment in stage III CRC.

Sentinel Lymph Node Mapping with Isosulfan Blue or Indocyanine Green in Colon Cancer Shows Comparable Results and Identifies Patients with Decreased Survival: A Prospective Single-Center Trial

BACKGROUND

Sentinel lymph node (SLN) mapping was reported to improve lymph node staging in colon cancer. This study compares isosulfan blue (IB) with indocyanine green (ICG)-based SLN-mapping and assesses the prognostic value of isolated tumor cells (ITC) and micro-metastases in upstaged patients.

METHODS

A total of 220 stage I-III colon cancer patients were included in this prospective single-center study. In 170 patients, SLN-mapping was performed in vivo with IB and in 50 patients ex vivo with ICG. Three levels of each SLN were stained with H&E. If negative for tumor infiltration, immunostaining for cytokeratin (AE1/3; cytokeratin-19) was performed.

RESULTS

SLN detection rate for IB and ICG was 100 and 98%, respectively. Accuracy and sensitivity was 88 and 75% for IB, 82 and 64% for ICG, respectively (p = 0.244). Overall, 149 (68%) patients were node negative. In these patients, ITC and micro-metastases were detected in 26% (31/129) with IB and 17% (5/29) with ICG (p = 0.469). Patients with ITC and micro-metastases did show decreased overall survival (hazard ratio = 1.96, p = 0.09) compared to node negative disease.

CONCLUSIONS

This study demonstrates a high diagnostic accuracy for both the IB and the ICG SLN-mapping. SLN-mapping upstaged a quarter of patients with node negative colon cancer, and the detected ITC and micro-metastases were an independent negative prognostic marker in multivariate analysis.

Blue dye injection does not induce dissemination of epithelial cells during SLN procedure in colon cancer patients

INTRODUCTION

The sentinel lymph node (SLN) procedure for colon cancer patients has been increasingly performed over the past decade and has shown advantages regarding lymph node staging. However, there are concerns that the manipulation of the colon, particularly the blue dye injection, results in isolated tumor cell dissemination to lymph nodes. Therefore, the objective of the present study was to evaluate whether the blue dye injection during the SLN procedure for colon cancer induces epithelial cell dissemination to the regional lymph nodes using a fake SLN procedure as a model.

METHODS

One hundred seventy-four colon cancer patients underwent open oncologic colon resection and SLN procedure according to a standardized protocol. For the fake SLN procedure, blue dye was injected ex vivo, into the subserosa of a nontumor-bearing segment of the resected colon in 37 unselected patients. Three levels of each SLN were stained with H&E and with the pancytokeratin marker AE1/AE3 and were analyzed for the presence of cytokeratin positive cells.

RESULTS

Identification of fake SLN was successful in 32 of the 37 patients (86 %). Seventy fake SLN were histologically confirmed. The median number of fake SLN was 2 per patient (range 1-8). None of the fake SLN showed any disseminated epithelial cells.

CONCLUSIONS

The present prospective study provides compelling evidence that blue dye injection during sentinel lymph node procedure for colon cancer does not induce epithelial cell dissemination to the sentinel lymph nodes. Therefore, isolated tumor cells in sentinel lymph nodes result from a true metastatic process.

Ex vivo sentinel lymph node mapping in laparoscopic resection of colon cancer

AIM

The study examined the feasibility and potential benefit of ex vivo sentinel lymph node (SLN) mapping, including multilevel sectioning (MLS) and immunohistochemistry (IHC) in colon cancer patients undergoing laparoscopic colectomy. The secondary goals were (i) to identify patient and tumour characteristics that might influence the success of the SLN technique, (ii) to investigate the extent of lymphadenectomy required to encompass tumour-positive nonsentinel lymph nodes (NSLN) and (iii) to ascertain the association of SLN status with oncological outcomes.

METHOD

SLN mapping was performed after specimen extraction using 1% Isosulfan blue. The SLNs were analysed with H&E staining after MLS, and if negative, IHC was performed. NSLNs were grouped by distance either greater than or less than 4 cm from the tumour.

RESULTS

Seventy-one patients completed the study between 2003 and 2007. Using H&E with MLS, the accuracy of SLN mapping was 76%, sensitivity was 52% and the false-negative rate was 48%. Excluding patients with clinically positive lymph nodes resulted in a significant improvement in accuracy to 81% and decreased the false-negative rate to 30%. Furthermore, as the only positive NSLN > 4 cm from the tumour was grossly positive, SLN mapping with a 4-cm mesenteric cuff would have given 100% sensitivity in patients without macroscopically involved nodes.

CONCLUSIONS

SLN mapping may be of value in selected patients. It may be possible to accurately stage patients with a 4-cm cuff of mesentery, although further validation of this proposal is required.

Review of histopathological and molecular prognostic features in colorectal cancer

Prediction of prognosis in colorectal cancer is vital for the choice of therapeutic options. Histopathological factors remain paramount in this respect. Factors such as tumor size, histological type and subtype, presence of signet ring morphology and the degree of differentiation as well as the presence of lymphovascular invasion and lymph node involvement are well known factors that influence outcome. Our understanding of these factors has improved in the past few years with factors such as tumor budding, lymphocytic infiltration being recognized as important. Likewise the prognostic significance of resection margins, particularly circumferential margins has been appreciated in the last two decades. A number of molecular and genetic markers such as KRAS, BRAF and microsatellite instability are also important and correlate with histological features in some patients. This review summarizes our current understanding of the main histopathological factors that affect prognosis of colorectal cancer.

Sentinel-lymph-node procedure in colon and rectal cancer: a systematic review and meta-analysis

BACKGROUND

No consensus exists on the validity of the sentinel-lymph-node procedure for assessment of nodal status in patients with colorectal cancer. We aimed to assess the diagnostic performance of this procedure.

METHODS

We searched Embase and PubMed databases for studies published before March 20, 2010. Eligible studies had a prospective design, a sample size of at least 20 patients, and reported the rate of sentinel-lymph-node positivity. Individual patient data were requested for localisation and T-stage stratification. A subset of reports with high methodological quality was selected and analysed.

FINDINGS

We identified 52 eligible studies, which included 3767 sentinel-lymph-node procedures (2961 [78·6%] colon and 806 [21·4%] rectal carcinomas). Most tumours 2339 (62·1%) were stage T3 or T4. 1887 (50·1%) of patients were male, 1880 (49·9%) female. Mean overall weighted-detection rate was 0·94 (95% CI 0·92-0·95), at a pooled sensitivity of 0·76 (0·72-0·80) with limited heterogeneity (χ(2)=286·08, degrees of freedom=51; p=0·003). A mean weighted upstaging of 0·15 (95% CI 0·12-0·19) was noted. Individual patient data were available from 19 studies that included 1168 patients. Analysis of these data showed no significant difference in sensitivity between colon (0·86 [95% CI 0·83-0·90]) and rectal cancer (0·82 [0·77-0·88]; p=0·23). Also, there was no dependency of sensitivity on T stage for both colon (pT1: 0·79 [95% CI 0·73-0·84], pT2: 0·76 [0·62-0·90], pT3: 0·73 [0·59-0·87], pT4: 0·73 [0·53-0·93]) and rectal cancer (T1 or T2: 0·81 [0·52-0·94] vs T3 or T4: 0·80 [0·51-0·93]). The subgroup of eight studies with high methodological quality showed a mean detection rate of 0·96 (95% CI 0·90-0·99) for colonic tumours and 0·95 (0·75-0·99) for rectal tumours, and a mean sensitivity of 0·90 (95% CI 0·86-0·93) for colonic tumours and 0·82 (0·60-0·93) for rectal tumours.

INTERPRETATION

The sentinel-lymph-node procedure shows a low sensitivity, regardless of T stage, localisation, or pathological technique. For every patient diagnosed with colon or rectal cancer without clinical evidence of lymph-node involvement or metastatic disease, this procedure in addition to conventional resection should be considered, since the prognostic information provided by this technique could be clinically significant.

FUNDING

Cancer Center Amsterdam Foundation, Amsterdam, Netherlands.

Ratio of metastatic to resected lymph nodes enhances to predict survival in patients with stage III colorectal cancer

BACKGROUND

The objective of this study was to assess the value of metastatic lymph node ratio in predicting prognosis of patients with stage III colorectal cancer.

METHODS

From 2000 to 2005 inclusively, a total of 626 patients featuring stage III colorectal cancer underwent curative resection. These patients were stratified into LNR groups: 1 (0 < LNR ≤ 0.1); 2 (0.1 < LNR ≤ 0.25); 3 (0.25 < LNR ≤ 0.5); and 4 (LNR > 0.5). The follow-up was closed in April 2010. Kaplan-Meier survival curve and log-rank test were used to evaluate the prognostic value of LNR. A Cox regression model was used for multivariate analyses.

RESULTS

With a median follow-up period of 42.2 months, 5-year overall survival for groups LNR1, LNR2, LNR3, and LNR4 was 73%, 64%, 44%, and 22%, respectively. In the multivariate analysis, the LNR was an independent prognostic factor for survival (P < 0.001). LNR remained statistically significant (P < 0.001), both in patients with colon and rectum cancer regardless of the number of lymph nodes retrieved (≥12 or < 12). The survival rate of ratio group LNR1 was better than ratio group LNR4 (P < 0.001) for patients with the same IIIB or IIIC staging.

CONCLUSIONS

LNR is an accurate prognostic method for patients with stage III colorectal cancer. We proposed an algorithm to incorporate LNR into current AJCC staging system to form new staging.

Clinical translation of ex vivo sentinel lymph node mapping for colorectal cancer using invisible near-infrared fluorescence light

Background

Sentinel lymph node (SLN) mapping in colorectal cancer may have prognostic and therapeutic significance; however, currently available techniques are not optimal. We hypothesized that the combination of invisible near-infrared (NIR) fluorescent light and ex vivo injection could solve remaining problems of SLN mapping in colorectal cancer.

Methods

The FLARE imaging system was used for real-time identification of SLNs after injection of the NIR lymphatic tracer HSA800 in the colon and rectum of (n = 4) pigs. A total of 32 SLN mappings were performed in vivo and ex vivo after oncologic resection using an identical injection technique. Guided by these results, SLN mappings were performed in ex vivo tissue specimens of 24 consecutive colorectal cancer patients undergoing resection.

Results

Lymph flow could be followed in real-time from the injection site to the SLN using NIR fluorescence. In pigs, the SLN was identified in 32 of 32 (100%) of SLN mappings under both in vivo and ex vivo conditions. Clinically, SLNs were identified in all patients (n = 24) using the ex vivo strategy within 5 min after injection of fluorescent tracer. Also, 9 patients showed lymph node involvement (N1 disease). In 1 patient, a 3-mm mesenteric metastasis was found adjacent to a tumor-negative SLN.

Conclusions

The current pilot study shows proof of principle that ex vivo NIR fluorescence-guided SLN mapping can provide high-sensitivity, rapid, and accurate identification of SLNs in colon and rectum. This creates an experimental platform to test optimized, non-FDA-approved NIR fluorescent lymphatic tracers in a clinical setting.

Pathological examination of 12 regional lymph nodes and long-term survival in stages I-III colon cancer patients: an analysis of 2,056 consecutive patients in two branches of same institution

PURPOSE

Pathologic examination of at least 12 lymph nodes (LNs) is widely accepted as a standard for colon cancer surgery. We sought to address its association with patient source, other clinicopathological factors, and survival by comparing information from two branches in a large single institution.

METHODS

Patients with stages I-III adenocarcinoma of the colon between 1998 and 2003 were identified from the Chang Gung Colorectal Tumor Registry in two branches (Linkou and Kaohsiung branches) of same institution. We used multivariate analysis to adjust for variables with P < 0.1 in univariate analyses.

RESULTS

A minimum of 12 examined nodes were observed in 80% of patients in Linkou branch versus 25% in Kaohsiung branch (P < 0.0001). Younger age, right hemicolectomy, larger tumor, higher tumor stage, higher caseload of surgeons, and patients at Linkou branch with an odds ratio (OR) as high as 23 (95% CI, 17-31) were independently associated with a higher frequency of ≥12 examined nodes. Patients with examined node number of <12 had a greater risk of recurrence within stages II and III (stage II: adjusted OR 1.88, 95% CI 1.27-2.79; stage III: adjusted OR 1.58, 95% CI 1.15-2.17) but not within stage I (OR 0.73, 95% CI 0.23-2.24).

CONCLUSIONS

The results confirm that factors influencing nodal harvest are multifactorial and the examined LN number of 12 or more is associated with an increased long-term survival in stages II-III colon cancer. It is possible to adequately sample and examine a sufficient number of nodes in the majority of colon cancer specimens by standardized conventional methods.

Lymph road mapping obtained via blue sentinel node detection to avoid middle colic artery resection for highly selected colon cancer cases: proof of a concept?

BACKGROUND

In theory, perioperative detection of lymph nodes with the injection of isosulfan blue dye should provide lymph road mapping (LRM) able to direct the resection. However, there is no supporting evidence for this theory in cases of colon cancer. We reanalysed all operative reports using the sentinel lymph node technique with blue dye injection.

MATERIALS AND METHODS

The retrospective study included 140 patients who underwent the sentinel lymph node (SLN) procedure between February 2001 and November 2007, including 70 cases in which the in vivo technique was used. In 8 cases (11%), LRM was used by the surgeon to determine the extent of resection.

RESULTS

In 5 cases, including limited or extended resection, the final pathological stage was II at the end of the follow-up period, and the patients had no recurrent disease. However, findings for 3 cases of stage III cancer were more relevant to the aims of this study. In these 3 patients, one with cancer (T3N1(3/22)) located at the hepatic flexure, and 2 with cancers (T3N2(7/41) and T2N2 (4/15)) at the splenic flexure, the middle colic artery was conserved as a result of LRM information. Of these 3 patients, 1 was alive without disease at 6-year follow-up and 2 at 5-year follow-up.

CONCLUSION

LRM obtained via blue sentinel node detection makes it possible to avoid middle colic artery resection for selected colon cancer cases. LRM seems particularly suitable in cases of colonic flexure location or prior colon surgery.

Ex vivo sentinel lymph node mapping in patients undergoing proctectomy for rectal cancer

PURPOSE

Controversy exists over the utility of sentinel lymph node mapping in the treatment of rectal cancer. The purpose of this study was to evaluate the use of ex vivo sentinel lymph node mapping in the setting of proctectomy for rectal cancer, with and without multilevel sectioning and immunohistochemistry.

METHODS

A prospective phase 2 clinical study of subjects undergoing proctectomy for rectal cancer from 2003 to 2008 was conducted. Sentinel lymph node mapping was performed with ex vivo injection of isosulfan blue. Sentinel lymph nodes were examined by hematoxylin and eosin evaluation, and when the results were negative, they were examined by multilevel sectioning and immunohistochemistry.

RESULTS

The study population consisted of 58 subjects; 88% received neoadjuvant therapy. Tumors were downstaged in 25 (49%) subjects receiving neoadjuvant therapy, 24% were clinical complete responders, and 20% were pathologic complete responders. The mean total lymph node harvest was 12.1 nodes per patient. Twenty-five subjects had positive nodal disease on final pathology. The sentinel lymph node detection rate was 85%, with a mean sentinel lymph node harvest of 2.2 nodes per subject. Fifteen (26%) subjects had sentinel lymph node nodal metastasis on routine hematoxylin and eosin examination. Neither multilevel sectioning nor immunohistochemistry evaluation improved detection of sentinel lymph node positivity. The accuracy of sentinel lymph node mapping was 71%, the sensitivity was 53%, the negative predictive value was 79%, and the false negative rate was 47%. Seven subjects were determined to have nodal disease only in the sentinel lymph node.

CONCLUSION

Ex vivo sentinel lymph node mapping is feasible after proctectomy for rectal cancer but did not improve staging. Neither multilevel sectioning nor immunohistochemistry improved the sensitivity of sentinel lymph node mapping.

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.

Diagnosing occult tumour cells and their predictive value in sentinel nodes of histologically negative patients with colorectal cancer

PURPOSE

Most studies on the sentinel node (SN) procedure in patients with colorectal cancer include immunohistochemical analysis of the SN only. To evaluate the real diagnostic accuracy of the SN procedure with immunohistochemical analysis, the presence of occult tumour cells in all histologically negative lymph nodes was compared to the presence of these cells in SNs. Also the reproducibility of diagnosing occult tumour cells (OTC) and the sensitivity of three different antibodies was assessed.

METHODS

Between November 2006 en July 2007, an ex vivo SN procedure was performed in 58 histologically N0 patients with colorectal cancer. All lymph nodes (n = 908, mean 15.7) were step-sectioned and immunohistochemistry was performed using two antibodies against cytokeratins (Cam5.2, and CK 20) and one antibody against BerEp-4.

RESULTS

OTC were identified in 19 of 58 patients, with micrometastases (0.2-2 mm) in 7 and isolated tumour cells (ITC)(<0.2 mm) in 12 patients. The overall agreement in diagnosing OTC between two independent pathologists was 86%. An SN was identified in 53 of 58 patients. All micrometastases were found in SNs. In two patients with negative SNs, ITC's were demonstrated in non-SNs (sensitivity 88%, and overall accuracy 96%).

CONCLUSION

Additional immunohistochemical analysis of histologically negative lymph nodes demonstrates occult tumour cells in 33% of the patients resulting in an upstaging rate of 12%. Occult tumour cells are predominantly found in the SN, therefore SN mapping has the potential to refine the staging system for patients with colorectal cancer.

Comparison of ex vivo and in vivo injection of blue dye in sentinel lymph node mapping for colorectal cancer

BACKGROUND

The technique of sentinel lymph node (SLN) mapping in patients with colorectal cancer varies between reports, and the optimal method has not been established. The purpose of this study was to determine the optimal injection technique for SLN mapping.

METHODS

Sixty-nine consecutive patients who underwent curative surgery for colorectal cancer were enrolled. The SLNs was identified intraoperatively by subserosal blue dye injection (in vivo) or by submucosal injection after standard colectomy (ex vivo). If negative by conventional hematoxylin and eosin staining analysis, all lymph nodes, SLNs and non-SLNs, were subjected to further analysis by multi-level section and immunohistochemical examination.

RESULTS

The in vivo and ex vivo injected groups were similar in demographic character, tumor size, and histological grade. The mean number of SLNs identified was 2.3 in the in vivo group and 2.6 in the ex vivo group (p = 0.192). The detection rate of SLNs by blue dye injection was somewhat higher in the ex vivo group than in the in vivo group: 90.6 vs. 81.1% (p = 0.219). The false-negative rate was 23.5% for the in vivo group and 13.3% for the ex vivo group (p = 0.392). The upstaging rate, which was 18.5% overall, was similar in both groups (p = 0.538).

CONCLUSIONS

These findings suggest that ex vivo blue dye injection is an effective alternative to in vivo injection for identifying SLNs in patients with colorectal cancer. Because of its simplicity and applicability in routine clinical settings, further investigation of the ex vivo mapping technique is warranted.

Identification of 12 or more lymph nodes in resected colon cancer specimens as an indicator of quality performance

BACKGROUND

: Identification of > or =12 lymph nodes in resected colon cancer specimens has been endorsed as a quality indicator.

METHODS

: The Hoag Hospital cancer registry was used to identify patients diagnosed with colon cancer. The proportion of colon cancer specimens for which > or =12 lymph nodes were identified was determined by anatomic location, stage of disease, patient age, and operating surgeon. Survival was correlated with stage and with whether > or =12 lymph nodes were identified.

RESULTS

: Pathology procedural changes in 1998 were associated with an increase in the average number of lymph nodes identified from 8.0 to 14.5 (P < .0001); therefore, analysis was limited to 574 patients who underwent surgical resection of colon adenocarcinoma during 1998 to 2005. Identification of > or =12 lymph nodes varied from 57% to 83% by 7 anatomic locations (P < .0001), from 65% to 75% by 5 age cohorts (P = .027), from 59% to 73% by 4 general stages of disease (P = .004), and from 53% to 80% among 12 surgeons who performed at least 17 resections (P = .014). The proportion of resections in which > or =12 lymph nodes were identified was higher for 3 colorectal fellowship-trained surgeons compared with the other 9 surgeons (77% vs 63%, P = .0007), and with 30 surgeons who each performed <10 resections (77% vs 51%, P < .0001). Identification of > or =12 lymph nodes was associated with better survival for patients with stage I (P = .016) and stage II (P = .021) disease.

CONCLUSIONS

: Anatomic location, colorectal surgical training, and case volume were strongly correlated with the number of lymph nodes identified. Cancer 2009. (c) 2009 American Cancer Society.

Sentinel node biopsy for the individualization of surgical strategy for cure of early-stage colon cancer

INTRODUCTION

The requirement for nodal analysis currently confounds the oncological propriety of focused purely endoscopic resection for early-stage colon cancer and complicates the evolution of innovative alternatives such as natural orifice transluminal endoscopic surgery (NOTES) and its hybrids. Adjunctive sentinel node biopsy (SNB) deserves consideration as a means of addressing this shortfall.

METHODS

Data from two prospectively maintained databases established for multicentric studies of SNB in colon cancer that employed similar methodologies were pooled to establish technique potency selectively in T1/T2 disease (both overall and under optimized conditions) and to project potential clinical impact.

RESULTS

Of 891 patients with T1-4, M0 intraperitoneal colon cancer, 225 had T1/T2 disease. Sentinel nodes were either not found or were falsely negative in 18 patients with T1/T2 cancers (8%) as compared with 17% (112/646) in those with T3/T4 disease (P = 0.001). Negative predictive value (NPV) in the former exceeded 95%, while sensitivity [including immunohistochemistry (IHC)] was 81%. In the 193 patients with T1/T2 disease recruited from those centers contributing >22 patients, sensitivity was 89% and NPV 97%. Thus, in this cohort, SNB could have correctly prompted localized resection (obviating en bloc mesenteric dissection) in 75% (144) of patients, including 59 with T1 lesions potentially amenable to intraluminal resection alone as their definitive treatment. Forty-four patients (23.4%) would still have conventional resection, leaving three patients (1.6% overall) understaged (11% false-negative rate).

CONCLUSION

These findings support the further investigation of SNB as oncological augment for localized resective techniques. Specific prospective study should pursue this goal.

Quantitative RT-PCR detection of tumor cells in sentinel lymph nodes isolated from colon cancer patients with an ex vivo approach

OBJECTIVE

To investigate quantitative RT-PCR-based detection of tumor cells in lymph nodes (LNs) isolated from colon cancer patients by ex vivo sentinel lymph node (SLN) mapping.

SUMMARY BACKGROUND DATA

Although lymph node status is among the strongest prognostic factors in colon cancer patients, 20% to 30% of node negative patients experience disease recurrence. These patients may have LN metastases that are not detected by routine examination.

METHODS

Ex vivo SLN mapping was applied to 131 prospectively recruited patients undergoing curative surgery for primary colon cancer. The SLNs were analyzed for the presence of tumor cells by routine histology and real-time RT-PCR quantitation of cytokeratin 20 (CK20) and mucin 2(MUC2) mRNA.

RESULTS

SLNs were identified in 125 (95%) of the 131 patients included.Routine histologic analysis of SLNs and other regional lymph nodes revealed LN metastases in 42 patients (N+), of which 29 (69%) had metastases detected in 1 or more SLNs (sensitivity, 69%; false negative rate, 31%).When analyzing the SLNs by quantitative RT-PCR, the sensitivity, compared with routine LN examination, was 37/42 (88%) for both the CK20 and the MUC2 mRNA markers. In addition, 46% and 27% of the patients' node negative by routine LN examination (N0) were positive for the CK20 and MUC2 mRNA markers, respectively, possibly reflecting the presence of occult tumor cells in their SLNs.

CONCLUSIONS

Quantitative RT-PCR analysis of SLNs identified N+ patients with high sensitivity and revealed a subgroup of N0 patients with potential occult LN disease.

Lymph node evaluation in early-stage colon cancer

Accurate nodal staging is of crucial importance in patients with nonmetastatic colon cancer, because it affects patient prognosis and delivery of adjuvant chemotherapy. In this article, we review the role of 2 controversial aspects of lymph node staging in colon cancer: the number of lymph nodes evaluated and sentinel lymph node (SLN) biopsy. Although it is clear that the number of lymph nodes assessed correlates with patient survival, the underlying mechanisms are far more uncertain, and thus, more research is warranted to determine whether interventions to increase nodal assessment will lead to improved patient outcomes. Sentinel lymph node biopsy does not appear to have the same advantages in the treatment of patients with colon cancer as in the treatment of patients with breast cancer or melanoma. Also, it might not improve colon cancer staging above standard pathology, and should be restricted to use in research settings.

Could lymphatic mapping and sentinel node biopsy provide oncological providence for local resectional techniques for colon cancer? A review of the literature

BACKGROUND

Endoscopic resectional techniques for colon cancer are undermined by their inability to determine lymph node status. This limits their application to only those lesions at the most minimal risk of lymphatic dissemination whereas their technical capacity could allow intraluminal or even transluminal address of larger lesions. Sentinel node biopsy may theoretically address this breach although the variability of its reported results for this disease is worrisome.

METHODS

Medline, EMBASE and Cochrane databases were interrogated back to 1999 to identify all publications concerning lymphatic mapping for colon cancer with reference cross-checking for completeness. All reports were examined from the perspective of in vivo technique accuracy selectively in early stage disease (i.e. lesions potentially within the technical capacity of endoscopic resection).

RESULTS

Fifty-two studies detailing the experiences of 3390 patients were identified. Considerable variation in patient characteristics as well as in surgical and histological quality assurances were however evident among the studies identified. In addition, considerable contamination of the studies by inclusion of rectal cancer without subgroup separation was frequent. Indeed such is the heterogeneity of the publications to date, formal meta-analysis to pool patient cohorts in order to definitively ascertain technique accuracy in those with T1 and/or T2 cancer is not possible. Although lymphatic mapping in early stage neoplasia alone has rarely been specifically studied, those studies that included examination of false negative rates identified high T3/4 patient proportions and larger tumor size as being important confounders. Under selected circumstances however the technique seems to perform sufficiently reliably to allow it prompt consideration of its use to tailor operative extent.

CONCLUSION

The specific question of whether sentinel node biopsy can augment the oncological propriety for endoscopic resective techniques (including Natural Orifice Transluminal Endoscopic Surgery [NOTES]) cannot be definitively answered at present. Study heterogeneity may account for the variability evident in the results from different centers. Enhanced capacity (perhaps to the level necessary to consider selective avoidance of en bloc mesenteric resection) by its confinement to only early stage disease is plausible although not proven. Specific study of the technique in early stage tumors is clearly essential before proffering this approach.

The efficient operation of the surgical pathology gross room

The gross room is the area where pathology specimens from operating rooms are transferred for pathology review and analysis, serving as the bridge between the treating physician and diagnostic surgical pathologist. Reaching the correct diagnosis for a specimen depends on the proper handling and processing of tissue transferred to this very busy area. We review here the basic function and management of the gross room including a brief discussion of common specimen types, biohazard exposure and safety, and collection of tissue for research.

Lymphatic mapping and sentinel node biopsy in the colonic mesentery by Natural Orifice Transluminal Endoscopic Surgery (NOTES)

INTRODUCTION

Although intraluminal and transluminal techniques can achieve localized resection of early-stage alimentary tumours, they do not designate the status of the filtering mesenteric lymph nodes. Natural orifice transluminal endoscopic surgery (NOTES) may however effect sentinel node biopsy from within the peritoneum.

METHODS

A transgastric NOTES technique was utilized in six pigs. A conventional double-channel gastroscope created both the 12mm anterior gastrotomy and the pneumoperitoneum and enabled peritoneoscopy. The sigmoid colon was fully exposed by an intracolonic magnet under extracorporeal control. Colonoscopy facilitated submucosal injection of methylene blue dye (3 ml) at the apex of the sigmoid loop under direct transgastric vision. The mesocolon was searched for blue-stained lymph channels and nodes, the latter being resected and retrieved by the intraperitoneal endoscope. At procedure end, three pigs underwent immediate laparotomy for scrutiny of the operation site while three were survived for forensic laparotomy on postoperative day 14.

RESULTS

Each procedure was a technical success. Gastrotomy, pneumoperitoneum, peritoneoscopy and sigmoid exposure were promptly achieved (mean 9.2 min). Post-injection, blue lymphatics identifying specific nodes were immediately appreciable and these could be dissected cleanly and retrieved intact per oram. Mean lymphadenectomy time was 19 (range 12-32) min. All survival animals thrived during convalescence. At laparotomy, there was neither mesentery penetration, bowel ischemia nor mesenteric hematoma/hemorrhage in any pig and no residual blue stained nodes in those sacrificed early.

CONCLUSION

Sentinel node biopsy can be performed without abdominal wall transgression. Thus potentially the oncological proprietary of local resectional techniques may be augmented while preserving their ideals and dividends.

What’s wrong with sentinel node mapping in colon cancer?

Despite near-universal embrace of the concept and clinical relevance of lymphatic mapping for sentinel node identification and analysis for cancers of the breast and integument, the same technique has struggled to a find a role in gastrointestinal cancers in general and, perhaps, in colon cancer in particular. Despite many studies demonstrating its feasibility in malignancies of the large bowel, concern is continually aroused by the variable and often unacceptably low sensitivity rates. Additionally, many confess uncertainty as to what benefit it could ever confer to patients even if it were proven sufficiently accurate given that standard surgical resection incorporates mesenteric resection anyway. However, the huge impact sentinel node mapping has had on clinical practice in certain cancers means that each of these aspects merit careful reconsideration, from very first principles.

Technique of sentinel lymph node biopsy and lymphatic mapping during laparoscopic colon resection for cancer

Background:

The utility of lymph node mapping to improve staging in colon cancer is still under evaluation. Laparoscopic colectomy for colon cancer has been validated in multi-centric trials. This study assessed the feasibility and technical aspects of lymph node mapping in laparoscopic colectomy for colon cancer.

Methods:

A total of 42 patients with histologically proven colon cancer were studied from January 2006 to September 2007. Exclusion criteria were: advanced disease (clinical stage III), rectal cancer, previous colon resection and contraindication to laparoscopy. Lymph-nodal status was assessed preoperatively by computed tomography (CT) scan and intra-operatively with the aid of laparoscopic ultrasound. Before resection, 2–3 ml of Patent Blue V dye was injected sub-serosally around the tumour. Coloured lymph nodes were marked as sentinel (SN) with metal clips or suture and laparoscopic colectomy with lymphadenectomy completed as normal. In case of failure of the intra-operative procedure, an ex vivo SN biopsy was performed on the colectomy specimen after resection.

Results:

A total number of 904 lymph nodes were examined, with a median number of 22 lymph nodes harvested per patient. The SN detection rate was 100%, an ex vivo lymph node mapping was necessary in four patients. Eleven (26.2%) patients had lymph-nodal metastases and in five (45.5%) of these patients, SN was the only positive lymph node. There were two (18.2%) false-negative SN. In three cases (7.1%) with aberrant lymphatic drainage, lymphadenectomy was extended. The accuracy of SN mapping was 95.2% and negative predictive value was 93.9%.

Conclusions:

Laparoscopic lymphatic mapping and SN removal is feasible in laparoscopic colectomy for colon cancer. The ex vivo technique is useful as a salvage technique in case of failure of the intra-operative procedure. Prospective studies are justified to determine the real accuracy and false-negative rate of the technique.

Prognostic impact of micrometastases in colon cancer: interim results of a prospective multicenter trial

OBJECTIVE

The 25% rate of recurrence after complete resection of stage II colon cancer (CC) suggests the presence of occult nodal metastases not identified by hematoxylin and eosin staining (H&E). Interim data from our ongoing prospective multicenter trial of sentinel node (SN) biopsy indicate a 29.6% rate of micrometastases (MM) identified by immunohistochemical staining (IHC) of H&E-negative SNs in CC. We hypothesized that these MM have prognostic importance.

METHODS

Between March 2001 and August 2006, 152 patients with resectable colorectal cancer were enrolled in the trial. IHC and quantitative RT-PCR (qRT) assay were performed on H&E-negative SNs. Results were correlated with disease-free survival.

RESULTS

The sensitivity of lymphatic mapping was significantly better in CC (75%) than rectal cancer (36%), P<0.05. Of 92 node-negative CC patients 7 (8%) were upstaged to N1 and 18 (22%) had IHC MM. Four patients negative by H&E and IHC were positive by qRT. At a mean follow-up of 25 months, 15 patients had died from noncancer-related causes, 12 had developed recurrence, 5 had died of CC (2 with macrometastases, 3 with MM), and 7 were alive with disease. The 12 recurrences included 4 patients with SN macrometastases and 6 with SN MM (2 by IHC, 4 by qRT). One of the 2 SN-negative recurrences had other positive lymph nodes by H&E. All patients with CC recurrences had a positive SN by either H&E/IHC or qRT. No CC patient with a negative SN by H&E and qRT has recurred (P=0.002).

CONCLUSION

This is the first prospective evaluation of the prognostic impact of MM in colorectal cancer. These results indicate that the detection of MM may be clinically relevant in CC and may improve the selection of patients for adjuvant systemic chemotherapy. Patients with CC who are node negative by cumulative detection methods (H&E/IHC and qRT) are likely to be cured by surgery alone.

Sentinel lymph node evaluation does not improve staging accuracy in colon cancer

BACKGROUND

Lymph node involvement is an important prognostic factor in colorectal cancer. Sentinel lymph node (SLN) evaluation for assessing lymph node status in colorectal cancer remains controversial. Here we evaluated the sensitivity, predictive value, and accuracy of SLN evaluation for determining lymph node status in resectable colon cancer.

METHODS

A prospective phase 2 cohort study of SLN evaluation in colon cancer was conducted from September 1998 to April 2006. Patients underwent resection and SLN mapping with 1% isosulfan blue and (m99)Tc sulfur colloid injection. SLNs were evaluated by hematoxylin and eosin (HE) staining and, if findings were negative, by additional thin HE sections and immunohistochemical (IHC) staining for pancytokeratin and MOC31. Overall survival for patients with IHC-positive disease was evaluated by Kaplan-Meier analysis and the log rank test.

RESULTS

SLNs were identified in 119 (99%) of the 120 patients eligible for the study. Median number of SLNs identified was 4 (range, 0-13). Forty-nine patients (40%) had nodal metastases on HE. The SLN accurately identified nodal metastases in 29 (59%) of these 49 patients and was negative for metastases in 22 patients (41%). SLNs in eight patients (7%) were negative by HE but positive by IHC staining. Positive IHC status did not affect survival after a median follow-up of 33 months (P = .41).

CONCLUSIONS

The low sensitivity and high false-negative rate of SLN evaluation does not support this technique for improving the accuracy of nodal staging for patients with colon cancer. The significance of IHC-positive SLNs remains uncertain.

Sentinel lymph node biopsy for gastrointestinal cancers

Sentinel lymph node biopsy (SLNB) in gastrointestinal-(GI)-tract cancer is not yet of clinical relevance. Nevertheless, the results in the upper GI-tract promise to be helpful to individualize the indication for surgical therapy. SLNB in colon cancer still fails to show high validity to predict the nodal status, but may be helpful to clarify the prognostic role of micrometastases/isolated tumor cells. In anal cancer SLNB is able to guide the indication for groin irradiation.

Is occult lymph node disease in colorectal cancer patients clinically significant? A review of the relevant literature

The clinical significance of micrometastasis of colorectal cancer (CRC) to regional lymph nodes remains controversial. In this review, we analyze publications that have evaluated the clinical significance of occult lymph node metastasis in CRC. An extensive literature search identified 19 publications that evaluated the clinical significance of micrometastatic CRC by various methods, including immunohistochemistry (IHC; n = 13) and reverse transcription-polymerase chain reaction (RT-PCR, n = 6). These studies were reviewed for methodology and findings. Significant limitations in methodology were identified, including inconsistent histological definitions of micrometastatic disease, poor sampling because of an inadequate number of lymph nodes or number of sections per lymph node analyzed, lack of conformity with respect to IHC antibody or RT-PCR marker, and inadequate power because of small sample size. Micrometastatic lymph node metastasis identified by RT-PCR was consistently found to be prognostically significant, but this was not true of micrometastatic disease identified by IHC. RT-PCR analysis of lymph nodes with specific markers can help identify pN0 (pathological-negative lymph node) CRC patients at increased risk for recurrence. The identification of occult disease by IHC techniques may also ultimately prove to be associated with worse outcome, but a number of inadequately powered studies have concluded conversely.

Is sentinel lymph node mapping in colorectal cancer a future prognostic factor? A meta-analysis

The diagnostic value of sentinel lymph node mapping (SLNM) in patients with colorectal cancer (CRC) is controversial. Prognostic factors for CRC must be detected to improve its treatment. A PubMed query (key words: colorectal cancer, sentinel node) provided 182 studies on the sentinel lymph node (SLN) for CRC, the abstracts of which were reviewed. Altogether, 48 studies dealing with the diagnostic value of SLNM were selected from PubMed, and 6 other studies were retrieved from reviews. We compared the diagnostic value of SLNM with that of conventional histopathologic examination. We used the diagnostic accuracy odds ratio (DAOR) method. Because of significant heterogeneity, we chose the random effect model (Der Simonian and Laird). Statistics were performed on 33 studies, including 1794 patients (1201 colon and 332 rectum cancers). The mean SLNM failure rate was 10%. The global sensitivity and specificity of the SLNM were, respectively, 70% and 81%. The pooled DAOR was 10.7 (95% confidence interval 7.0-16.5). That means that a patient whose SLN is invaded has 10.7 times more risk to be node-positive than an SLN-negative patient. Lymphatic mapping appears to be readily applicable to CRC. One of the main reasons for the heterogeneity is the performance of the SLNM by Saha et al., whose data had better sensitivity (90%) than those in other studies. The SLNM technique should be better standardized in future studies. Understanding the cause of false-negative SLNs (9%) is a major issue to resolve before routinely using this technique in CRC management. The prognostic implication of micrometastases found in SLNs requires further evaluation.

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.

Sentinel lymph node biopsy in colon cancer: a prospective multicenter trial

INTRODUCTION

The clinical impact of sentinel lymph node biopsy (SLNB) in colon cancer is still controversial. The purpose of this prospective multicenter trial was to evaluate its clinical value to predict the nodal status and identify factors that influence these results.

METHODS

Colon cancer patients without prior colorectal surgery or irradiation were eligible. The sentinel lymph node (SLN) was identified intraoperatively by subserosal blue dye injection around the tumor. The SLN underwent step sections and immunohistochemistry (IHC), if classified free of metastases after routine hematoxylin and eosin examination.

RESULTS

At least one SLN (median, n = 2) was identified in 268 of 315 enrolled patients (detection rate, 85%). Center experience, lymphovascular invasion, body mass index (BMI), and learning curve were positively associated with the detection rate. The false-negative rate to identify pN+ patients by SLNB was 46% (38 of 82). BMI showed a significant association to the false-negative rate (P < 0.0001), the number of tumor-involved lymph nodes was inversely associated. If only slim patients (BMI < or =24) were investigated in experienced centers (>22 patients enrolled), the sensitivity increased to 88% (14 of 16). Moreover, 21% (30 of 141) of the patients, classified as pN0 by routine histopathology, revealed micrometastases or isolated tumor cells (MM/ITC) in the SLN.

CONCLUSIONS

The contribution of SLNB to conventional nodal staging of colon cancer patients is still unspecified. Technical problems have to be resolved before a definite conclusion can be drawn in this regard. However, SLNB identifies about one fourth of stage II patients to reveal MM/ITC in lymph nodes. Further studies must clarify the clinical impact of these findings in terms of prognosis and the indication of adjuvant therapy.

Micrometastases in cervical lymph nodes from patients with squamous carcinoma of the head and neck: should they be actively sought? Maybe

Techniques are now being developed, which allow ever smaller metastatic deposits in regional lymph nodes to be detected; the question is, should they be sought, or does their presence convey no additional information for treatment of head and neck carcinoma patients at this time? Preliminary findings have suggested that the presence of micrometastases may carry with it some prognostic information, and as a consequence, the search for micrometastases would, for the foreseeable future, appear to be a fertile ground for investigation. To bring some uniformity to this project, it is suggested that these definitions be adopted: a micrometastasis measures greater than 0.2 mm but less than 2.0 mm in diameter, and smaller deposits should be designated as isolated tumor cells, which, in turn, are subdivided into those isolated tumor cells detected by light microscopy, immunohistochemistry, or molecular methods. At this juncture, the import of such micrometastases remains in the realm of the clinical investigator--it remains an open question whether the identification of micrometastases (however they may ultimately come to be defined) will prove to have an impact on the care of head and neck cancer patients.

Laparoscopic lymphatic mapping and sentinel lymph node detection in colon cancer: technical aspects and preliminary results

BACKGROUND

The utility of lymph node mapping to improve staging in colon cancer is under evaluation. Laparoscopic colectomy for colon cancer has been validated in multicentric trials. This study assessed the feasibility of lymph node mapping in laparoscopic colectomy for colon cancer.

METHODS

From March 2004 to December 2005, 22 patients were studied. Before resection, 2 to 3 ml of Patent Blue V dye was injected subserosally around the tumor. Colored lymph nodes were marked as sentinel nodes (SNs) with metal clips, and laparoscopic colectomy with lymphadenectomy was completed as normal. In SNs, multiple 4-microm slices at 50-microm intervals were stained with hematoxylin and eosin and examined. Anticytokeratin antibody immunostaining was applied in doubtful cases. Other lymph nodes were examined with multiple slices at 100- to 500-microm intervals by standard methods.

RESULTS

The SN detection rate was 100%, although ex vivo lymph node mapping was necessary for an obese patient. Five patients (22.7%) were SN positive. There was one false-negative SN (16.7%). In two cases (9.1%) with aberrant lymphatic drainage, lymphadenectomy was extended. The SN reflected the status of the regional lymph nodes in 21 patients (95.4%). Accuracy was 95.4%, and negative predictive value was 94.1%.

CONCLUSIONS

Laparoscopic lymphatic mapping and SN removal is feasible in laparoscopic colectomy for colon cancer. Although the false-negative rate was high (16.7%), the overall results are promising and justify prospective studies to determine the real accuracy and false-negative rate for the technique.

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.

Cancer and Leukemia Group B Surgery Committee

Surgeons play a vital role in the Cancer and Leukemia Group B by providing patients and specimens for studies of the common solid tumors, and more recently, by serving as investigators who conduct surgically focused research protocols and contribute to the correlative science studies in the Group. Surgical activities encompass thoracic, gastrointestinal, breast, and genitourinary cancers and melanoma. Surgical quality assurance is also an important focus. This article will describe the development and importance of a robust and vigorous surgical component to a strong cooperative group and highlight the many trials conducted by the Cancer and Leukemia Group B surgeons and their contributions to advancement of the care of the patient with solid organ malignancy.

Cancer and leukemia group B gastrointestinal cancer committee

The Cancer and Leukemia Group B Gastrointestinal Cancer Committee was organized in the late 1970s under the leadership of Michael Perry and Philip Schein and began full-scale operations in the mid-1980s. Today, it is a multidisciplinary team of surgeons, radiation and medical oncologists, statisticians, quality-of-life experts, pharmacogeneticists, basic scientists, and community oncologists who design studies that are conducted across the United States. The Committee has done trials in patients with esophageal, gastric, pancreatic, colon, rectal, and anal cancers. New initiatives are under way in hepatocellular cancer, cholangiocarcinoma, and neuroendocrine tumors originating in the gastrointestinal tract. The Committee has increasingly concentrated on translational studies using tumor blocks, germ-line DNA, and plasma to evaluate biological correlates of tumor response and clinical outcomes. A broad program of pharmacogenomics has been incorporated for virtually all studies, including trials that prospectively use polymorphisms in drug-metabolizing genes to assign treatments. Future efforts aim to evolve new standards of care, evaluate new therapies, and answer relevant biological questions in gastrointestinal cancer.