The role of sentinel lymph node mapping in colon cancer: detection of micro-metastasis, effect on survival, and driver of a paradigm shift in extent of colon resection.

Unlike in breast cancer and melanoma, sentinel lymph node mapping in colon cancer is primarily used as an aid to the pathologist for accurate nodal staging. The study was undertaken to review the incidence of micro-metastasis and its impact on survival when treated with chemotherapy. The study was also undertaken to see if SLNM could guide limited colon resection in early T stage tumor as a paradigm shift. SLNM was done by subserosal injection of a blue dye. SLNs were ultra-staged by multilevel sectioning and remaining Specimen was then examined by conventional method. For the last 245 patients the specimen was divied ex vivo into two segments as segment A containing the tumor bearing portion of the colon and SLNs with attached mesentery, while segment B include distal part of the colon with attached mesentery. Nodal staging was separately examined. Of the 354 Pts, SLNM was successful in 99.9% of Pts with an average no of SLN/ Pt = 2.8 and total nodes 17.8/pt. Survival was directly related negatively with stage and nodal status. Pts with +ve LN did much better with chemotherapy than without chemotherapy. With 245 Pts, specimen A Vs B, no Pts had +ve node in specimen B with -ve LN in specimen A. SLNM results in more node/Pt, more positive node/Pt ,and more micro-metastasis who when treated with chemotherapy survive longer. Limited segmental resection in early T stage is possible when done with guidance by SLNM without compromising biology.

Challenging the conventional treatment of colon cancer by sentinel lymph node mapping and its role of detecting micrometastases for adjuvant chemotherapy.

All colon cancer patients with lymph node (LN) positive disease are treated with chemotherapy. Patients with node negative disease are usually cured by surgery alone. Yet about 20% of patients develop recurrence within 5 years despite node negative status. This may often be the result of missed micrometastases by conventional examination. Sentinel lymph node (SLN) mapping was developed to find those nodes detected by blue dye which was ultrastaged to detect micrometastases. Consecutive patients, underwent SLN mapping with the blue dye with success rate of 99.2%. Average number of LN was 18.3, average number of SLN was 3/patient and overall nodal positivity was 45%. Ten patients had skip metastases. Overall survival of 235 patients was 84 months with survival of node negative patients 97 months versus 68 months for node positive patients. For stage I-IV patients, overall survival was as follows: stage I-115 months, stage II-90 months, stage III-84 months and stage IV-24 months respectively. Patients with micrometastases after chemotherapy had average survival of 108 months versus those without chemotherapy was 50 months. Thus, SLN mapping techniques is highly successful, easily reproducible and finds micrmoetastases in over 15% of patients which could have been missed by conventional pathological examination. These patients when treated with adjuvant chemotherapy have similar survival as those of node negative disease. Similarly, patients without any nodal metastases after SLN mapping and ultrastaging, may be considered as true node negative disease and may avoid further adjuvant chemotherapy.

Toll-like receptor expression in human non-small cell lung carcinoma: potential prognostic indicators of disease.

INTRODUCTION: Lung cancer remains the highest cause of cancer mortality worldwide. Toll-like receptors (TLR) are innate immune receptors that have both pro- and anti-tumorigenic properties. Based on findings from epidemiological studies and in rodents, we hypothesized that elevated TLR expression would be a positive prognostic indicator of disease in non-small cell lung carcinoma patients. RESULTS: Higher mRNA expression of TLR1-3 and 5-8 were significantly associated with increased overall survival (OS) when analyzed individually or as a group in both non-small cell lung carcinoma (NSCLC) patients and in the adenocarcinoma (ADC) subtype. Significant co-expression of many TLR combinations in ADC patients were also observed via RNA sequencing. Immunostaining demonstrated TLR4 and 8 significantly correlated in tumor tissue, similar to RNA. METHODS: We used kmplot.com to perform a meta-analysis on mRNA expression of TLR1-10 to determine any significant associations with OS in NSCLC and the ADC subtype. cBioportal was also used simultaneously to assess co-expression in TLR1-10 in ADC patients via RNA sequencing and to identify any molecular alterations. Lastly, immunostaining for a subset of TLRs was conducted on ADC patients. CONCLUSIONS: Expression of innate immune receptors TLR1-10 is associated with improved survival outcomes in NSCLC. Thus, further evaluation of their predictive capacity and therapeutic utility is warranted.

The prognostic value of additional malignant lesions detected by magnetic resonance imaging versus mammography.

BACKGROUND: Nodal positivity is correlated with a poorer prognosis in breast cancer. A study was composed to compare nodal positivity in patients with single versus multiple lesions found on magnetic resonance imaging (MRI) and mammogram (MMG). METHODS: A retrospective study of breast cancer patients undergoing MRI and MMG was performed. Nodal positivity was compared in patients with additional invasive lesions found on MRI versus single invasive lesions found on MRI and MMG. RESULTS: A total of 425 patients were included. The overall nodal positivity was 23.8%. Patients with single versus multiple malignant lesions had nodal positivity of 20.9% vs 31.1% (P = .04). MRI detected multiple lesions in 120 patients, 80 of which were not detected by MMG (18.8%). Comparing single lesions with additional malignant lesions detected by MRI only, nodal positivity increased from 20.9% to 51.6% (P = .0002). CONCLUSIONS: Patients with additional invasive lesions on MRI had significantly higher nodal positivity than single invasive lesions. Hence, addition of MRI in early-stage breast cancer may have prognostic value because of detection of potential node-positive patients.

Tumor size predicts long-term survival in colon cancer: an analysis of the National Cancer Data Base.

BACKGROUND: American Joint Committee on Cancer uses tumor size for "T" staging of many solid tumors for its effect on prognosis. However, tumor size has not been incorporated in tumor (T), nodal status (N), metastasis (M) staging for colon cancer. Hence, the National Cancer Data Base was used to determine whether tumor size correlates with TNM staging and survival. METHODS: For the 300,386 patients, tumor size was divided into S1 (0 to 2 cm), S2 (>2 to 4 cm), S3 (>4 to 6 cm), and S4 (>6 cm). Statistical comparison was done for TNM stage, grade, and nodal status with tumor size. Kaplan-Meier survival analysis was done for each "S" stage. RESULTS: Of the 300,386 patients, 13% were classified as S1, 39% S2, 30% S3 and 18% as S4. Right colon was the most common site (48%). Tumor size positively correlated with grade, T stage, and nodal stage. Tumor size was inversely associated with survival. CONCLUSION: Tumor size is positively correlated with important prognostic factors and negatively impacted survival.

Feline mammary basal-like adenocarcinomas: a potential model for human triple-negative breast cancer (TNBC) with basal-like subtype.

BACKGROUND: Breast cancer is one of the leading causes of cancer deaths. Triple-negative breast cancer (TNBC), an immunophenotype defined by the absence of immunolabeling for estrogen receptor (ER), progesterone receptor (PR) and HER2 protein, has a highly aggressive behavior. A subpopulation of TNBCs exhibit a basal-like morphology with immunohistochemical positivity for cytokeratins 5/6 (CK5/6) and/or epidermal growth factor receptor (EGFR), and have a high incidence of BRCA (breast cancer susceptibility) mutations. Feline mammary adenocarcinomas (FMAs) are highly malignant and share a similar basal-like subtype. The purpose of this study was to classify FMAs according to the current human classification of breast cancer that includes evaluation of ER, PR and HER2 status and expression of basal CK 5/6 and EGFR. Furthermore, we selected triple negative, basal-like FMAs to screen for BRCA mutations similar to those described in human TNBC. METHODS: Twenty four FMAs were classified according to the current human histologic breast cancer classification including immunohistochemistry (IHC) for ER, PR HER2, CK5/6 and EGFR. Genetic alteration and loss of heterozygosity of BRCA1 and BRCA2 genes were analyzed in triple negative, basal-like FMAs. RESULTS: IHC for ER, PR and HER2 identified 14 of the 24 (58%) FMAs as a triple negative. Furthermore, 11 of these 14 (79%) triple negative FMAs had a basal-like subtype. However, no genetic abnormalities were detected in BRCA1 and BRCA2 by direct sequencing and loss of heterozygosity analysis. CONCLUSION: FMAs are highly aggressive neoplasms that are commonly triple negative and exhibit a basal-like morphology. This is similar to human TNBC that are also commonly classified as a basal-like subtype. While sequencing of a select number of triple negative, basal-like FMAs and testing for loss of heterozygosity of BRCA1 and BRCA2 did not identify mutations similar to those described in human TNBC, further in-depth evaluation is required to elucidate a potential role of BRCA in the tumorigenesis of triple negative, basal-like FMAs. The strong similarities in clinical behavior, morphology and IHC phenotype suggest that triple negative, basal-like FMAs may be a suitable spontaneous animal model for studying novel therapeutic approaches against human basal-like TNBC.

Endothelin-1 enriched tumor phenotype predicts breast cancer recurrence.

Introduction. Breast cancer recurrence can develop years after primary treatment. Crosstalk between breast cancer cells and their stromal microenvironment may influence tumor progression. Our primary study aim was to determine whether endothelin-1 (ET-1) expression in tumor and stroma predicts breast cancer relapse. The secondary aim was to determine ET-1/endothelin receptor A (ETAR) role on signaling pathways and apoptosis in breast cancer. Experimental Design. Patients with histologically documented stages I-III invasive breast cancer were included in the study. ET-1 expression by immunohistochemistry (IHC) in tumor cells and stroma was analyzed. Association between ET-1 expression and clinical outcome was assessed using multivariate Cox proportional hazard model. Kaplan-Meier curves were used to estimate disease-free survival (DFS). In addition, the effect of ET-1/ETAR on signaling pathways and apoptosis was evaluated in MCF-7 and MDA-MB-231 breast cancer cells. Results. With a median followup of 7 years, ET-1 non-enriched tumor phenotype had a significant association with favorable disease-free survival (HR = 0.16; 95% CI 0.03-0.77; P value <0.02). ER negativity, advanced stage of disease and ET-1-enriched tumor phenotype were all associated with a higher risk for recurrence. Experimental study demonstrated that ET-1 stimulation promoted Akt activation in MCF-7 and MDA-MB-231 cells. Furthermore, silencing of ETAR induced apoptosis in both hormone receptor negative and hormone receptor positive breast cancer cells. Conclusions. We found ET-1 expression in tumor and stroma to be an independent prognostic marker for breast cancer recurrence. Prospective studies are warranted to examine whether ET-1 expression in tumor/stroma could assist in stratifying patients with hormone receptor positive breast cancer for adjuvant therapy.

Detection and prognostic impact of micrometastasis in colorectal cancer.

Review of literature was performed on studies with prognostic impact of micrometastasis in colorectal cancer. Among 16 studies included, micrometastasis was detected in 26.5% of patients. Most analysis revealed that micrometastasis carries a poorer prognosis compared to node negative disease (NND). The results of those studies were compared with our pilot study of 109 patients with colon cancer, showing improved prognosis of micrometastasis after being upstaged and treated with chemotherapy when compared with NND.

Nodal positivity in breast cancer correlated with the number of lesions detected by magnetic resonance imaging versus mammogram.

BACKGROUND: Magnetic resonance imaging (MRI) in breast cancer can detect more than 15% additional lesions than mammography. We investigated lymph node metastases rates in patients with multifocal or multicentric disease detected by MRI compared with patients with a single lesion detected by mammography and magnetic resonance imaging. METHODS: A retrospective analysis of breast cancer patients undergoing MRI and mammography was performed. The objective was to compare lymph node metastases rates in patients with additional lesions detected by MRI versus a single lesion detected by mammography or MRI. RESULTS: Of 413 patients, 318 were included for the study. The overall nodal metastases rate was 24.8%. MRI detected multiple lesions in 83 (26.1%) patients; 67 (21.1%) patient MRI findings were not detected by mammography. The lymph node metastases rate was 37.3% when ≥ 2 lesions were detected compared with 20.2% when a single malignant lesion was detected (P = .01). The evaluation of the 67 patients with additional lesions detected by MRI revealed 32 patients with invasive lesions, 29 with benign lesions, and 6 with in situ disease. Comparing patients with single malignant lesions with patients with additional malignant lesions detected by MRI, the lymph node metastases rate increased from 20.2% to 50% (P = .002). CONCLUSIONS: Our study shows a significant increase in the lymph node metastases rate in patients with additional malignant lesions detected by MRI. This finding suggests that MRI-detected malignant lesions are biologically significant and may predict more aggressive disease.

Comparison of nodal positivity between SLNM vs conventional surgery in colon cancer patients with <12 and ≥12 lymph nodes harvested.

BACKGROUND: Examination of ≥12 lymph nodes (LNs) ensures accurate staging in colon cancer. The aim of this study was to compare nodal positivity between sentinel LN mapping (SLNM) and conventional surgery in patients with <12 and ≥12 LNs harvested. METHODS: From 1993 to 2008, 407 and 380 patients with colon cancer underwent SLNM and conventional surgery, respectively. Total LNs harvested and nodal positivity were analyzed. Patients were grouped according to number of LNs harvested: 2 to 11, 12 to 25, or >25. RESULTS: The average numbers of LNs harvested in the groups with 2 to 11, 12 to 25, and >25 LNs harvested for SLNM and conventional surgery, respectively, were 8.3 and 7.1 (P < .0001), 17.2 and 16.5 (P = .09), and 34.2 and 32.1 (P = .40). Nodal positivity for SLNM and conventional surgery in the groups with <12 and ≥12 LNs harvested was 42% and 29% (P = .01) and 50% and 36% (P = .003), respectively. Overall nodal positivity was 47% for SLNM and 32% for conventional surgery (P < .0001). When SLNM with 2 to 11 LNs was compared with conventional surgery with 12 to 25 LNs, nodal positivity was 42% versus 36% (P = .35). CONCLUSIONS: SLNM possessed higher nodal positivity compared with conventional surgery. SLNM is a valuable adjunct to accurate nodal staging in colon cancer.

Ultrastaging of sentinel lymph nodes (SLNs) vs. non-SLNs in colorectal cancer--do we need both?

BACKGROUND: The aim of this study to analyze whether ultrastaging of initially negative nonsentinel lymph nodes (non-SLNs) would increase nodal positivity in colon cancer and rectal cancer. METHODS: After SLN mapping (SLNM), SLNs were ultrastaged by 4 hematoxylin and eosin and 1 immunohistochemistry sections. A blinded pathologist reexamined initially negative non-SLNs by 3 additional hematoxylin and eosin and 1 immunohistochemistry sections. RESULTS: In 156 colon cancer and 44 rectal cancer patients, 2,755 nodes were identified (494 SLNs and 2,261 non-SLNs). Metastases were detected in 20.9% of SLNs and 8.6% of non-SLNs (P<.0001). After ultrastaging non-SLNs, only .58% became positive for metastases in 12 patients. Of these, 10 already had positive lymph nodes, hence no change of staging occurred. Ultrastaging upstaged only 2 of 200 patients (1%). CONCLUSIONS: The chance of finding additional metastases by ultrastaging of all non-SLNs is extremely low (<1%) and of little benefit.

Predictors of occult nodal metastasis in colon cancer: results from a prospective multicenter trial.

BACKGROUND: The relationship between primary colon cancer and occult nodal metastases (OMs) detected by cytokeratin immunohistochemistry (CK-IHC) is unknown. We sought to investigate the correlation of clinicopathologic features of colon cancer with OMs and to identify predictors of OM. METHODS: Patients with colon cancer from 5 tertiary referral cancer centers enrolled in a prospective trial of staging had standard pathologic analysis performed on all resected lymph nodes (using hematoxylin and eosin staining [H&E]). Nodes negative on H&E underwent CK-IHC to detect OMs, which were defined as micrometastases (N1mic) or isolated tumor cells (N0i+). Patients who were negative on both H&E and CK-IHC were defined as node negative (NN), and those positive on H&E were node positive (NP). The relationships between tumor characteristics and OMs were analyzed using the Kruskal-Wallis and the Fisher exact test. RESULTS: OMs were identified in 23.4% (25/107) of patients. No significant differences were found in demographics, tumor location, tumor size, and number of nodes examined between groups. Compared with the NN group, patients with OMs had more tumors that were T3/T4 (72% vs 57%; P < .001), had tumors of higher grade (28% vs 12%; P = .022), and had tumors with lymphovascular invasion (16% vs 3%; P < .001). CONCLUSION: Adverse primary pathologic colon cancer characteristics correlate with OMs. In patients with negative nodes on H&E and stage T3/T4 colon cancer, lymphovascular invasion, or high tumor grade, consideration should be given to performing CK-IHC. The detection of OMs in this subset may influence decisions regarding adjuvant chemotherapy and risk stratification.

Intraperitoneal virtual biopsy by fibered optical coherence tomography (OCT) at natural orifice transluminal endoscopic surgery (NOTES).

INTRODUCTION: Fibered optical coherence tomography (OCT) in conjunction with natural orifice transluminal endoscopic surgery (NOTES) could provide a facility for rapid, in situ pathological diagnosis of intraperitoneal tissues in a truly minimally invasive fashion. MATERIALS AND METHODS: A large porcine model was established to test this hypothesis. A standard double channel gastroscope (Olympus) was used to achieve a transgastric access to the peritoneum and initiate the pneumoperitoneum. Magnetic retraction was used to display the sigmoid colon along with its mesentery. A commercially available fibered OCT probe (NIRIS system, Imalux) was inserted via a working channel of the gastroscope and used to assess intraperitoneal tissues. Separately, OCT images of human tissue specimens ex vivo were contrasted with representative standard histopathological slides. RESULTS: Intraperitoneal OCT provided clear real-time images of both the serosal and muscularis propria mural layers as well as the submucosal-muscularis interface. Examination of mesenteric lymph nodes (including sentinel nodes) allowed visualization of their subcapsular sinus. Comparison of representative cross-sections however failed to evince sufficient resolution for confident diagnosis. CONCLUSION: This approach is technically feasible and, if the technology is advanced and proven accurate in human patients, could potentially be used to individualize operative extent prior to definitive resection.

A prospective trial comparing 1% lymphazurin vs 1% methylene blue in sentinel lymph node mapping of gastrointestinal tumors.

BACKGROUND: Methylene blue (M), as a dye in sentinel lymph node mapping (SLNM), has been introduced as an alternative to lymphazurin (L) after the recent shortage of L. M has been evaluated in breast cancer in multiple studies with favorable results. Our study compares L with M in the SLNM of gastrointestinal (GI) tumors. METHODS: Between Jan 2005 and Aug 2008, 122 consecutive patients with GI tumors were enrolled. All patients (pts) underwent SLNM with either L or M by subserosal injection of 2-5 mL of dye. Efficacy and rates of adverse reactions were compared between the two dyes. Patients were prospectively monitored for adverse reactions including anaphylaxis, development of blue hives, and tissue necrosis. RESULTS: Of 122 pts, 60 (49.2%) underwent SLNM using L and 62 (50.8%) underwent SLNM using M. Colon cancer (CrCa) was the most common site in both groups. The success rate of L and M in SLNM was 96.6% and 96.7%, respectively, with similar numbers of total number of lymph nodes per pt, SLNs per pt (<3), nodal positivity, skip metastasis, and accuracy. The only adverse reaction in the L group was oxygen desaturation >5% in 5% (3/60) of pts, compared with none in the M group. Cost per vial of L was $210 vs $7 for M. CONCLUSION: The success rate, nodal positivity, average SLNs per patient, and overall accuracy were similar between L and M. Absence of anaphylaxis and lower cost make M more desirable than L in SLNM of GI tumors.

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.

Comparative analysis of bone marrow micrometastases with sentinel lymph node status in early-stage breast cancer.

Bone marrow micrometastases (BMM) and sentinel lymph node (SLN) status are both prognostic factors in breast cancer (BRCa) patients (pts). A definitive relationship between the two has not yet been proven and the data available is controversial. Thus, a retrospective study was conducted to determine the relationship of BM status and SLN status in pts with early BRCa (T1/T2). All female pts with early BRCa (T1/T2) operated upon by a single surgeon were included in the study. Prior to surgery, all pts underwent bone marrow aspiration from the posterior superior iliac spine bilaterally. Subsequently, pts underwent SLN biopsy and definitive primary breast surgery. BM samples were examined by using a Cytokeratin Detection Kit using CAM 5.2 monoclonal antibody. All pts with BMM underwent repeat BM analysis 6 months after completing all treatments. Data was collected for SLN, BM, estrogen receptor/progesterone receptor (ER/PR), and human epidermal growth factor receptor 2 (Her-2/neu) status and analyzed using chi-square (chi (2)) analysis or Fischer's exact test. A total of 270 consecutive pts with early BRCa were studied. SLN mapping was successful in all pts. SLN metastases (mets) were detected in 28.9% (78/270) pts. Of the 270 pts, 77.0% (208/270) had T1 disease. BMM were detected in 9.6% (26/270) pts, of whom 69.2% (18/26) were found to have BMM unilaterally. BMM were detected in 11.5% (9/78) pts with SLN mets versus 8.9% (17/192) in pts with node-negative disease (p = 0.65). Of the pts with T1 BRCa, BMM were observed in 9.1% (19/208) pts versus 11.3% (7/62) in pts with T2 BRCa (p = 0.6). In pts with ER/PR-negative (-ve) BRCa, BMM were found in 7.7% (2/26) pts versus 9.9% (24/242) in pts with ER/PR-positive (+ve) BRCa (p = 0.27). BMM were detected in 12.3% (9/73) pts with Her-2/neu +ve BRCa and in 8.6% (16/187) pts with Her-2/neu -ve BRCa (p = 0.11). After completion of adjuvant therapy all pts with BMM (n = 26) converted to BM negative status. We conclude that BM status did not correlate with SLN status and occurs independently of lymphatic metastasis possibly through a different mechanism. BMM occur in node-negative pts and may assist in identifying pts at high risk for disease recurrence. Obtaining bone marrow aspirate from two locations resulted in a significant increase in detection of micrometastases.

Prognostic relevance of occult nodal micrometastases and circulating tumor cells in colorectal cancer in a prospective multicenter trial.

PURPOSE: Nodal micrometastasis and circulating tumor cells detected by multimarker quantitative real-time reverse transcription-PCR (qRT-PCR) may have prognostic importance in patients with colorectal cancer. EXPERIMENTAL DESIGN: Paraffin-embedded sentinel lymph nodes from 67 patients and blood from 34 of these patients were evaluated in a prospective multicenter trial of sentinel lymph node mapping in colorectal cancer. Sentinel lymph nodes were examined by H&E staining and cytokeratin immunohistochemistry. Sentinel lymph nodes and blood were examined by a four-marker qRT-PCR assay (c-MET, melanoma antigen gene-A3 family, beta1-->4-N-acetylgalactosaminyltransferase, and cytokeratin-20); qRT-PCR results were correlated with disease stage and outcome. RESULTS: In H&E-negative sentinel lymph node patients that recurred, cytokeratin immunohistochemistry and qRT-PCR detected metastasis in 30% and 60% of patients, respectively. Disease-free survival differed significantly by multimarker qRT-PCR upstaged sentinel lymph node (P = 0.014). qRT-PCR analysis of blood for circulating tumor cells correlated with overall survival (P = 0.040). CONCLUSION: Molecular assessment for micrometastasis in sentinel lymph node and blood specimens may help identify patients at high risk for recurrent colorectal cancer, who could benefit from adjuvant therapy.

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.

Prospective multicenter trial of staging adequacy in colon cancer: preliminary results.

HYPOTHESIS: Lymph node evaluation is an important prognostic factor in colorectal cancer (CRC). A 25% recurrence rate in patients with node-negative CRC suggests that current staging practices are inadequate. Focused analysis of the sentinel node (SN) by multiple sectioning and immunohistochemistry improves staging accuracy. DESIGN: Prospective phase 2 multicenter trial. SETTING: Tertiary referral cancer centers. PATIENTS: Between March 2001 and June 2005, 132 patients were enrolled with clinical stage I and II CRC in a prospective multicenter trial (R01-CA90484). INTERVENTION: During a standard oncologic resection, lymphatic mapping was performed and the SN identified either by the surgeon or the pathologist. Hematoxylin-eosin staining was performed on all lymph nodes and immunohistochemistry, on lymph nodes negative by hematoxylin-eosin staining. MAIN OUTCOME MEASURES: Micrometastases greater than 0.2 mm but less than 2 mm and isolated tumor cells less than 0.2 mm were defined according to the sixth edition of the American Joint Committee on Cancer Cancer Staging Manual. RESULTS: The 63 men and 69 women had a median age of 74 years. Sixty-eight patients (52%) underwent a right hemicolectomy; 3 (2.3%), a transverse colectomy; 9 (7%), a left colectomy; 15 (11%), a sigmoid colectomy; 34 (26%), a low anterior resection; 1 (1%), an abdominal perineal resection; and 2 (2%), a total colectomy. Of the 111 evaluable primary tumors, 19 (17%) were T1 lesions; 17 (15%), T2; 72 (65%), T3; and 3 (2.7%), T4 tumors. Thirty-three patients (30%) were classified as stage I; 46 (41%), stage II, and 32 (29%), stage III. The SN was identified by the surgeon in 127 patients (96%) and by the pathologist in 5 patients (4%). The median number of SNs and total lymph nodes examined were 3 and 14.5, respectively. The sensitivity of lymphatic mapping and SN analysis was 88.2% and the false-negative rate, 7.4% (6/81). Of the 6 false-negative results, 4 were attributed to lymphatic channels obliterated by tumor. Upstaging occurred in 28 patients (23.6%). CONCLUSIONS: In a multicenter trial, ultrastaging of colon cancer is feasible and accurate. In stage II CRC, 24% of patients had nodal carcinoma cells not detected by conventional staging methods. Surgical technique (adequate lymph node retrieval) and focused pathological analysis may improve staging accuracy and the selection of patients for chemotherapy. The unnecessary toxicity and expense of chemotherapy may be avoided in those patients who are truly node negative.