Nodal staging score: a tool to assess adequate staging of node-negative colon cancer

STARD: How many lymph nodals needed to be dissected in corpus carcinoma?

During corpus carcinoma surgery, there is uncertainty as to how many lymph nodes should be dissected and examined to determine lymph invasion.In this study, we evaluated a beta-binominal model in data extracted from the Surveillance, Epidemiology, and End Results (SEER) database, which contains 22,372 complete records. We quantified the relationship between examined node number and the probability of missing invaded nodes. Survival curves were used for further validation.We found that for stage T1-T4, 1, 10, 23, and 37 lymph nodes, respectively, needed to be examined to minimize the missing positive nodal probability (1-nodal staging score, NSS) to less than 5%. A hypothetical lymph node examination rate was calculated. Survival rate of T2 and T3 stage samples was significantly associated with NSS, but T1 and T4 sample survival rate was not.The currently dissected nodal should be reduced to 1 to 2 for T1, remains to 10 for T2, and increases to 23 for T3.

How to Reliably Assess Nodal Status in Distal Pancreatectomy for Adenocarcinoma

OBJECTIVES

The optimal number of lymph nodes that need to be analyzed to reliably assess nodal status in distal pancreatectomy for adenocarcinoma is still unknown.

METHODS

Two hundred seventy-eight patients who underwent distal pancreatectomy for adenocarcinoma were retrieved from a retrospective French nationwide database. The relations between the number of analyzed lymph nodes and the nodal status of the tumor were studied. The beta-binomial law was used to estimate the probability of being truly node negative depending on the number of analyzed lymph nodes. Cox proportional hazard model was used for the survival analysis.

RESULTS

The median number of analyzed lymph nodes was 15. There was a positive correlation between the number of positive lymph nodes and the number of lymph nodes analyzed. The curve reached a plateau at approximately 25 lymph nodes. The beta binomial model demonstrated that an analysis of 21 negative lymph nodes shows a probability to be truly N0 at 95%. N+ status was associated with survival, but the number of lymph node analyzed was not.

CONCLUSION

At least 21 lymph nodes should be analyzed to ensure a reliable assessment of the nodal status, but this number may be hard to reach in distal pancreatectomy.

External Validation of the Pathologic Nodal Staging Score for Prostate Cancer: A Population-based Study

BACKGROUND

We sought to externally validate our pathologic nodal staging score (pNSS) model, which allows for quantification of the likelihood that a pathologically node-negative patient will not have lymph node (LN) metastasis after radical prostatectomy for prostate cancer (PCa) in a population-based cohort.

PATIENTS AND METHODS

We analyzed data from 50,598 patients treated with radical prostatectomy and pelvic LN dissection using the Surveillance, Epidemiology, and End Results database. We estimated the sensitivity of pathologic nodal staging using a β-binomial model and developed a novel pNSS model, which represents the probability that a patient's PCa has been correctly staged as node negative as a function of the number of examined LNs. These findings were compared against those from the original cohort of 7135 patients.

RESULTS

The mean and median number of LNs removed was 6.5 and 5, respectively (range, 1-89; interquartile range, 2-8), and 96.9% of the patients (n = 49,020) had stage pN0. Similar to the original cohort, the probability of missing a positive LN decreased with the increasing number of LNs examined. In both the validation and the original cohort, the number of LNs needed to correctly stage a patient's disease as node negative increased with more advanced tumor stage, higher Gleason sum, positive surgical margins, and higher preoperative prostate-specific antigen levels.

CONCLUSION

We have confirmed that the number of examined LNs needed for adequate nodal staging in PCa depends on the pathologic tumor stage, Gleason sum, surgical margins status, and preoperative prostate-specific antigen. We externally validated our pNSS in a population-based cohort, which could help to refine decision-making regarding the administration of adjuvant therapy.

Assessing the adequacy of lymph node yield for different tumor stages of colon cancer by nodal staging scores

Background

According to the current official guidelines, at least 12 lymph nodes (LNs) are qualified as an adequate sampling for colon cancer patients. However, patients evaluated with less nodes were still common in the United States, and the prevalence of positive nodal disease may be under-estimated because of the false-negative assessment. In this study, we present a statistical model that allows preoperative determination of the minimum number of lymph nodes needed to confirm a node-negative disease with certain confidence.

Methods

Adenocarcinoma colon cancer patients with stage T1-T3, diagnosed between 2004 and 2013, who did not receive neoadjuvant therapies and had at least one lymph node pathologically examined, were extracted from the Surveillance, Epidemiology and End Results (SEER) database. A beta binomial distribution was used to estimate the probability of an occult nodal disease is truly node-negative as a function of total number of LNs examined and T stage.

Results

A total of 125,306 patients met study criteria; and 47,788 of those were node-positive. The probability of falsely identifying a patient as node-negative decreased with an increasing number of nodes examined for each stage, and was estimated to be 72% for T1 and T2 patients with a single node examined and 57% for T3 patients with a single node examined. To confirm an occult nodal disease with 90% confidence, 3, 8, and 24 nodes need to be examined for patients from stage T1, T2, and T3, respectively.

Conclusions

The false-negative rate of diagnosed node negative, together with the minimum number of examined nodes for adequate staging, depend preoperatively on the clinical T stage. Predictive tools can recommend a threshold on the minimum number of examined nodes regarding to the favored level of confidence for each T stage.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3491-2) contains supplementary material, which is available to authorized users.

External validation of the pathological nodal staging score in upper tract urothelial carcinoma: A population-based study

OBJECTIVES

To externally validate our previously developed pathological nodal staging model (pNSS) that allows quantification of the likelihood that a patient with pathologic node-negative status has, indeed, no lymph node metastasis (LNM).

PATIENTS AND METHODS

We analyzed data from 2,768 patients treated with radical nephroureterectomy (RNU) and lymph node dissection (LND) using the Surveillance, Epidemiology, and End Results database from 1988 to 2010. We estimated the sensitivity of pathologic nodal staging using a beta-binomial model and developed a new pNSS. Then, we compared these findings with those of the initial cohort.

RESULTS

The mean and median numbers of lymph node (LN) removed were 5 and 2, respectively (interquartile range = 5) in the validation cohort, though 66.5% of the patients (n = 1814) were pN0. Similar to the development cohort, the probability of missing a LNM decreased as the number of nodes examined increased in the validation cohort. If only a single node was examined, 35% of patients would be misclassified as pN0 while harboring LNM. Even when 5 nodes were examined, 8% would be misclassified. The probability of having a positive node increased with advancing pathological T stage in both the cohorts. Patients with pT0-Ta-Tis-T1 disease in both cohorts would have more than a 95% chance of a correct pathologic nodal staging with 2 examined nodes. However, if a patient has pT3-T4 disease, more than 12 examined LNs are needed to reach 95% accuracy.

CONCLUSIONS

We confirmed that the number of examined nodes needed for adequate staging depends on pT category. We externally validated our previous pNSS in a population-based database, which could help in the clinical decision-making regarding adjuvant chemotherapy administration.

How Many Lymph Nodes Are Enough? Assessing the Adequacy of Lymph Node Yield for Papillary Thyroid Cancer

PURPOSE

Patients who undergo surgery for papillary thyroid cancer with only a limited lymph node examination are thought to be at risk for potentially harboring occult disease. However, this risk has not been objectively quantified and may have implications for subsequent management and surveillance.

METHODS

Data from the National Cancer Database (1998 to 2012) were used to characterize the distribution of nodal positivity of adult patients diagnosed with localized ≥ 1-cm papillary thyroid cancer who underwent thyroidectomy with one or more lymph nodes (LNs) examined. A β-binomial distribution was used to estimate the probability of occult nodal disease as a function of total number of LNs examined and pathologic tumor stage.

RESULTS

A total of 78,724 patients met study criteria; 38,653 patients had node-positive disease. The probability of falsely identifying a patient as node negative was estimated to be 53% for patients with a single node examined and decreased to less than 10% when more than six LNs were examined. To rule out occult nodal disease with 90% confidence, six, nine, and 18 nodes would need to be examined for patients with T1b, T2, and T3 disease, respectively. Sensitivity analyses limited to patients likely undergoing prophylactic central neck dissection resulted in three, four, and eight nodes needed to provide comparable adequacy of LN evaluation.

CONCLUSION

To our knowledge, our study provides the first empirically based estimates of occult nodal disease risk in patients after surgery for papillary thyroid cancer as a function of primary tumor stage and number of LNs examined. Our estimates provide an objective guideline for evaluating adequacy of LN yield for surgeons and pathologists in the treatment of papillary thyroid cancer, and especially intermediate-risk disease, for which use of adjuvant radioactive iodine and surveillance intensity are not currently standardized.

Effect of Neoadjuvant Radiation Dose and Schedule on Nodal Count and Its Prognostic Impact in Stage II-III Rectal Cancer

BACKGROUND

It is unknown how neoadjuvant treatment schedule affects lymph node count (LNC) and lymph node ratio (LNR) and how these correlate with overall survival (OS) in rectal cancer (RC).

METHODS

Data were used from the Belgian PROCARE rectal cancer registry on RC patients treated with surgery alone, short-term radiotherapy with immediate surgery (SRT), or chemoradiation with deferred surgery (CRT). The effect of neoadjuvant therapy on LNC was examined using Poisson log-linear analysis. The association of LNC and LNR with overall survival (OS) was studied using Cox proportional hazards models.

RESULTS

Data from 4037 patients were available. Compared with surgery alone, LNC was reduced by 12.3 % after SRT and by 31.3 % after CRT (p < 0.001). In patients with surgery alone, the probability of finding node-positive disease increased with LNC, while after SRT and CRT no increase was noted for more than 12 and 18 examined nodes, respectively. Per node examined, we found a decrease in hazard of death of 2.7 % after surgery alone and 1.5 % after SRT, but no effect after CRT. In stage III patients, the LNR but not (y)pN stage was significantly correlated with OS regardless of neoadjuvant therapy. Specifically, a LNR > 0.4 was associated with a significantly worse outcome.

CONCLUSIONS

Nodal counts are reduced in a schedule-dependent manner by neoadjuvant treatment in RC. After chemoradiation, the LNC does not confer any prognostic information. A LNR of >0.4 is associated with a significantly worse outcome in stage III disease, regardless of neoadjuvant therapy type.

Prognostic Effect of Ultra-Staging Node-Negative Colon Cancer Without Adjuvant Chemotherapy: A Prospective National Cancer Institute-Sponsored Clinical Trial

BACKGROUND

We recently reported, in a prospective randomized trial, that ultra-staging of patients with colon cancer is associated with significantly improved disease-free survival (DFS) compared with conventional staging. That trial did not control for lymph node (LN) number or adjuvant chemotherapy use.

STUDY DESIGN

The current international prospective multicenter cooperative group trial (ClinicalTrials.gov identifier NCT00949312; "Ultra-staging in Early Colon Cancer") evaluates the 12-LN quality measure and nodal ultra-staging impact on DFS in patients not receiving adjuvant chemotherapy. Eligibility criteria included biopsy-proven colon adenocarcinoma; absence of metastatic disease; >12 LNs staged pathologically; pan-cytokeratin immunohistochemistry (IHC) of hematoxylin and eosin (H&E)-negative LNs; and no adjuvant chemotherapy.

RESULTS

Of 445 patients screened, 203 patients were eligible. The majority of patients had intermediate grade (57.7%) and T3 tumors (64.9%). At a mean follow-up of 36.8 ± 22.1 months (range 0 to 97 months), 94.3% remain disease free. Recurrence was least likely in patients with ≥12 LNs, H&E-negative LNs, and IHC-negative LNs (pN0i-): 2.6% vs 16.7% in the pN0i+ group (p < 0.0001).

CONCLUSIONS

This is the first prospective report to demonstrate that patients with optimally staged node-negative colon cancer (≥12 LNs, pN0i-) are unlikely to benefit from adjuvant chemotherapy; 97% remain disease free after primary tumor resection. Both surgical and pathologic quality measures are imperative in planning clinical trials in nonmetastatic colon cancer.

Preoperative endoscopic tattooing to mark the tumour site does not improve lymph node retrieval in colorectal cancer: a retrospective cohort study

BACKGROUND

A direct correlation between number of lymph nodes retrieved and evaluated after a colectomy for colorectal cancer and survival of the patient has been reported, and consensus guidelines recommend to assess at least 12 lymph nodes for adequate staging. Many factors (i.e., patients' and tumour characteristics, surgeon, and pathologist) may influence the evaluation of the presence of neoplastic disease in lymph nodes as well as the total number of lymph nodes examined. Preoperative endoscopic tattooing to mark the site of the tumour has recently been suggested to facilitate the retrieval of lymph nodes in colorectal specimens. The aim of this study was to investigate its association with adequate lymphadenectomy (≥12 nodes) after colorectal resection for cancer.

RESULTS

All patients undergoing elective colorectal resection for cancer between 2009 and 2011 at the S. Anna University Hospital in Ferrara, Italy (N = 250) were retrospectively divided into two cohorts according to whether ink tattooing to mark the tumour site was performed during preoperative colonoscopy. The two cohorts were comparable regarding age, gender, body mass index, tumour location and size, TNM staging, and DNA microsatellite instability-high status. No difference between the tattoo (N = 107) and control (N = 143) groups could be detected in the rate of adequate lymphadenectomies performed (78% vs. 79%, p = 0.40). All factors known to influence lymph nodes retrieval from colorectal specimen were specifically evaluated. Rectal and colonic cancers were analysed together and separately. Full adjusted logistic regression analysis in patients who underwent colonic resection showed that right hemicolectomy (OR 4.72; CI95% 1.09-20.36) was the only factor associated to adequate lymphadenectomy. No association between ink tattooing performed preoperatively to mark the site of the tumour and adequate lymphadenectomy after colorectal resection was found with logistic regression analysis.

CONCLUSION

This study shows that preoperative ink tattooing utilized to mark the site of the tumour does not improve adequate lymphadenectomy and lymph nodes yield from colorectal cancer specimens. Further studies are therefore needed to determine if preoperative colonoscopic tattooing to mark the tumour site can refine staging.

The prognostic impact of the log odds of positive lymph nodes in colon cancer

AIM

This study aimed to investigate the prognostic impact of the log odds of positive lymph nodes (LODDS) in colon cancer.

METHOD

Four hundred and forty patients with colon cancer were divided into three each groups according to their lymph node ratio (LNR) and LODDS. Survival analysis was performed.

RESULTS

The 5-year overall survival (OS) rate was 70.2%. In univariate analysis age, pT and pN stage, tumour grade, lymphatic, venous and perineural invasion, surgical margin clearance, LNR and LODDS were significantly associated with OS. In multivariate analysis age, surgical margins, perineural invasion and LODDS were found to be independent prognostic factors. In subgroup analysis of patients with an inadequate number of examined lymph nodes (NELN) (n = 76) and node-negative patients (n = 210), LODDS retained its prognostic value, whereas the impact of LNR was not statistically significant (P = 0.063). The overall survival rates of node-negative patients in the LODDS groups 0, 1 and 2 were 81%, 74.2% and 50%, respectively (P = 0.020). LNR and LODDS classifications were both significantly associated with survival in Stage III colon cancer, but only LODDS was an independent prognostic factor.

CONCLUSION

Conventional TNM staging for nodes (pN) and LNR status cannot reliably classify node-negative patients into homogeneous groups. LODDS provides more valuable information than LNR independently of the NELN.

Lymph node count and prognosis in colorectal cancer: the influence of examination quality

Colorectal cancer guidelines recommend adjuvant chemotherapy in stage II disease when less than 12 lymph nodes are assessed. The recommendation bases on previous studies showing an association of a low lymph node count and adverse outcome. Compared to current standards, however, the quality of lymph node examination in the studies was low. We, therefore, investigated the prognostic role of <12 lymph nodes in cancers diagnosed adherent to current quality measures. Stage I-IV colorectal cancers from 1,899 patients enrolled into a population-based cohort study were investigated for the prognostic impact of a lymph node count <12. The stage specific share of patients diagnosed with ≥12 nodes (stage I-IV: 62, 85, 85, 78%, respectively) was used to compare lymph node examination quality to other studies. We found no impact of a lymph node count <12 on overall, cancer-specific or recurrence-free survival for any tumour stage. Compared to studies reporting an adverse prognostic impact of a low lymph node count in stages II and III the stage-specific shares of patients with ≥12 nodes were markedly higher in this study (85% vs. 24-58% in previous analyses) and this correlated with increased rates of stage III compared to stage II cancers. In conclusion our data indicate, that the previously reported effect of a low lymph node count on the patients' outcomes is eliminated by improved lymph node examination quality and thus question the general applicability of a 12 lymph node cut off for adjuvant chemotherapy decision making in stage II disease.

Clinical nodal staging scores for prostate cancer: a proposal for preoperative risk assessment

BACKGROUND

Pelvic lymph node dissection in patients undergoing radical prostatectomy for clinically localised prostate cancer is not without morbidity and its therapeutical benefit is still a matter of debate. The objective of this study was to develop a model that allows preoperative determination of the minimum number of lymph nodes needed to be removed at radical prostatectomy to ensure true nodal status.

METHODS

We analysed data from 4770 patients treated with radical prostatectomy and pelvic lymph node dissection between 2000 and 2011 from eight academic centres. For external validation of our model, we used data from a cohort of 3595 patients who underwent an anatomically defined extended pelvic lymph node dissection. We estimated the sensitivity of pathological nodal staging using a beta-binomial model and developed a novel clinical (preoperative) nodal staging score (cNSS), which represents the probability that a patient has lymph node metastasis as a function of the number of examined nodes.

RESULTS

In the development and validation cohorts, the probability of missing a positive lymph node decreases with increase in the number of nodes examined. A 90% cNSS can be achieved in the development and validation cohorts by examining 1-6 nodes in cT1 and 6-8 nodes in cT2 tumours. With 11 nodes examined, patients in the development and validation cohorts achieved a cNSS of 90% and 80% with cT3 tumours, respectively.

CONCLUSIONS

Pelvic lymph node dissection is the only reliable technique to ensure accurate nodal staging in patients treated with radical prostatectomy for clinically localised prostate cancer. The minimum number of examined lymph nodes needed for accurate nodal staging may be predictable, being strongly dependent on prostate cancer characteristics at diagnosis.

The impact of the lymph node ratio is greater than traditional lymph node status in stage III colorectal cancer patients

BACKGROUND

The prognostic value of nodal status in colorectal cancer (CRC) patients may be influenced by the total number of lymph nodes (LNs) harvested. This study evaluates the impact of LN ratio (LNR) on CRC patients' outcome.

METHODS

A total of 612 stage III CRC patients who underwent curative-intent surgery between 2004 and 2008 were enrolled. The measured end point was postoperative disease-free survival (DFS) and overall survival (OS).

RESULTS

The metastatic LN numbers were significantly higher in patients with more than 12 LN harvested (4.6 ± 5.81 vs. 2.7 ± 1.97, P < 0.001). The mean LNR was 22.9 ± 20 % (range = 2-100 %, median = 16.7 %). As the cutoff value of LNR was set above 17 %, the impact of the LNR on 5-year DFS became statistically significant. In univariate analysis, the 5-year DFS and OS for patients with high-LNR tumors was 54.4 and 57.3 %, respectively, significantly lower than those for patients with low-LNR tumors (72.8 and 76.4 %; P < 0.001). In multivariate analysis, the independent factors affecting the 5-year DFS and OS were tumor depth, carcinoembryonic antigen level, and LNR.

CONCLUSION

The LNR, set at the median value or 17 %, could be an independent prognostic factor for stage III CRC patients.

The impact of the lymph node ratio is greater than traditional lymph node status in stage III colorectal cancer patients

BACKGROUND

The prognostic value of nodal status in colorectal cancer (CRC) patients may be influenced by the total number of lymph nodes (LNs) harvested. This study evaluates the impact of LN ratio (LNR) on CRC patients' outcome.

METHODS

A total of 612 stage III CRC patients who underwent curative-intent surgery between 2004 and 2008 were enrolled. The measured end point was postoperative disease-free survival (DFS) and overall survival (OS).

RESULTS

The metastatic LN numbers were significantly higher in patients with more than 12 LN harvested (4.6 ± 5.81 vs. 2.7 ± 1.97, P < 0.001). The mean LNR was 22.9 ± 20 % (range = 2-100 %, median = 16.7 %). As the cutoff value of LNR was set above 17 %, the impact of the LNR on 5-year DFS became statistically significant. In univariate analysis, the 5-year DFS and OS for patients with high-LNR tumors was 54.4 and 57.3 %, respectively, significantly lower than those for patients with low-LNR tumors (72.8 and 76.4 %; P < 0.001). In multivariate analysis, the independent factors affecting the 5-year DFS and OS were tumor depth, carcinoembryonic antigen level, and LNR.

CONCLUSION

The LNR, set at the median value or 17 %, could be an independent prognostic factor for stage III CRC patients.

More adequate lymph node dissection after laparoscopic colorectal surgery

The aim of this study was to determine whether there is a difference in the amount of lymph nodes harvested during open and laparoscopic surgery and whether this might influence the subsequent offering of adjuvant chemotherapy. All patients who underwent colorectal surgery for colorectal malignancies from July 2006 to April 2008 were included in our prospective database and in the study. In the laparoscopic group, 11/55 (20%) patients with stage II tumors had <10 lymph nodes in the pathology specimen when compared with 44/110 (40%) in the open group (P=0.01). The average number of lymph nodes was 12.1 for laparoscopic as compared with 10.2 lymph nodes for open resection (P=0.009). We demonstrate a significant increase in the number of resected lymph nodes with laparoscopic surgery. Significantly more patients in the open surgery group had <10 negative lymph nodes and were subsequently offered chemotherapy for their high-risk stage II colorectal malignancies.

Lymph node evaluation for resected colorectal cancer

SUMMARY The negative impact of regional lymph node metastasis on survival from nonmetastatic colorectal cancers is proportional to the number of nodes harvested. A thorough lymph node examination by the pathologist is essential for accurate staging. Recommendations in the USA and Europe stipulate that a minimum of 12–15 lymph nodes must be examined to accurately predict regional node negativity. The prognostic separation for stage III colorectal cancer obtained by the lymph node ratio is superior to that of the absolute number of positive nodes. The extent of mesenteric resection, pathologic technique, age or tumor location may influence lymph node yield. In the future, biological significance and clinical impact on outcome of very small amounts of tumor in regional nodes could help in staging patients. The current data are considered insufficient to recommend either the routine examination of multiple tissue levels of paraffin blocks or the use of special/ancillary techniques.

What counts most in the lymph node count for colorectal cancer?

The adequate number of lymph nodes that should be examined to correctly stage colorectal cancer is still debated. Even though the guidelines state that 12 should be the minimum, there is ongoing concern that this might not be enough. Moreover, many studies have shown that this cut-off is far from universally obtained in many surgical series, whether via laparotomy or via laparoscopy. Arguments in favor of sticking to the cutoff value of 12 are weak: certainly, culling and examining as many lymph nodes as possible should increase the chances of correct staging and the consequent therapeutic consequences, decrease local recurrence and, perhaps, also increase survival (although this is not the direct consequence of gathering and examining as many lymph nodes as possible). Laparoscopy should be no different from open surgery: the same rational prevails for laparoscopic oncologic clearance to increase patient well-being and ensure good practice. What is most important, however, is to make surgeons and pathologists realize that this issue is important and that all of us should strive, in close collaboration, to achieve these goals, for the good of the patient, the person for whom the lymph node count counts most.

Prediction of true nodal status in patients with pathological lymph node negative upper tract urothelial carcinoma at radical nephroureterectomy

PURPOSE

The role of lymph node dissection is still controversial in patients treated with radical nephroureterectomy for upper tract urothelial cancer. We developed a pathological nodal staging model that allows quantification of the likelihood that a patient with pathologically node negative disease has, indeed, no lymph node metastasis.

MATERIALS AND METHODS

We analyzed data on 814 patients treated with radical nephroureterectomy and lymph node dissection, and estimated the sensitivity of pathological nodal staging using a β-binomial model. We developed a pathological nodal staging score that represents the probability that a case is correctly staged as node negative.

RESULTS

A median of 5 lymph nodes (range 1 to 46) was removed and 593 patients (73%) had pN0 disease. The probability of missing lymph node metastasis decreased as the number of nodes examined increased. If only a single node was examined, 44% of patients would have been misclassified as having pN0 disease while harboring lymph node metastasis. Even when 5 nodes were examined, 12% of patients would have been misclassified. The proportion of those with a positive node increased with advancing pathological T stage and lymphovascular invasion. Patients with pT0-Ta-Tis-T1/lymphovascular invasion had more than a 95% chance of correct pathological nodal staging with 2 examined nodes. However, if a patient had pT3-T4 and positive lymphovascular invasion, even 20 examined lymph nodes did not attain 95% accuracy.

CONCLUSIONS

Lymph node dissection provides more accurate staging and prediction of survival. The number of examined nodes needed for adequate staging depends on pT stage and lymphovascular invasion. We developed a tool to estimate the likelihood of false-negative lymph node metastasis, which could help refine clinical decision making regarding the administration of adjuvant chemotherapy.

The complexity of the count: considerations regarding lymph node evaluation in colorectal carcinoma

In patients with colorectal carcinoma, studies have reported improved survival with increasing numbers of retrieved lymph nodes. These findings are puzzling, as increased node sampling was not correlated with significant change in disease staging. Although the physiologic processes underlying this correlation between number of lymph nodes sampled and survival remain unknown, the reported correlation has caused modifications to clinical and non-clinical practices. Herein, we review the literature and discuss potential etiologies responsible for the observed increased survival statistics. Literature regarding colorectal lymph node anatomy, molecular aspects of colorectal cancer, changes in tumor characteristics and utilization of lymph node sample numbers are evaluated. In addition, we present the mathematical concepts available for probabilistic prediction of diagnostic confidence based upon sample size. From evaluation of the aggregate literature, certain facts emerge which are not easily identified within the individual studies. Colorectal carcinoma appears to encompass a number of individual disease entities with different physiologic characteristics and likelihoods of metastasis. In addition, it appears the improved survival is likely multifactorial including effects from intrinsic tumor biology and tumor-host interactions along with ever changing clinical practices. Finally, because lymph node count is dependent on a number of variables and is correlated, but unlikely to be causally associated with survival, use of this number as a quality indicator is unwarranted. Based on statistical considerations, the current recommended goal of 12-15 recovered lymph nodes without evidence of metastatic disease provides approximately 80% negative predictive value for colorectal carcinoma metastasis.

Nodal staging score: a tool for survival prediction of node-negative bladder cancer

PURPOSE

A recently developed nodal staging score (NSS) might give an estimation of the likelihood of lymph node (LN) metastasis more accurately than simple cutoff of the number of LNs removed. The study aimed to evaluate whether patients with higher NSS will have a better outcome, since the NSS may provide an accurate staging across tumor stages.

MATERIALS AND METHODS

The clinical and histopathologic data from 242 patients with LN-negative urothelial bladder cancer (pN0) were analyzed. Probability of missing positive LN of <10% (clinical NSS 90%) was set by examining 6 nodes for clinical Ta-Tis tumors, 9 nodes for cT1 tumors, and 25 nodes for cT2 tumors. Multivariate analysis by Cox's proportional hazards model was used to determine the contribution of NSS to cancer-specific survival rates of patients. Discrimination, calibration, and clinical net benefit of the Cox regression model were evaluated using a time-dependent receiver operating characteristics curve, plotting Kaplan-Meyer curve and decision curve analysis.

RESULTS

Margin status and NSS exhibited independent contributions in the Cox regression model. The predictive accuracy of the Cox regression model was 0.756. The Cox regression model successfully stratified the outcome into three different groups based on score. At 2, 5, and 8 years, the Cox regression model performed well across a wide range of threshold probabilities using decision curve analysis.

CONCLUSIONS

Our findings support the prognostic relevance of the NSS 90% cutoff in patients with LN-negative bladder cancer. The present results should be validated by prospective studies with defined LN dissection area.

Laparoscopic resection for sigmoid and rectosigmoid colon cancer performed by trainees: impact on short-term outcomes and selection of suitable patients

PURPOSE

This study aimed (1) to evaluate the impact of clinical factors, particularly operation by trainees, on the short-term outcomes of laparoscopic resection for sigmoid and rectosigmoid cancer, and (2) to determine patients suitable for operation by trainees.

METHODS

From a prospectively maintained single-institution database, we identified 133 patients who underwent laparoscopic resection for sigmoid or rectosigmoid cancer between 2007 and 2010. Gender, age, body mass index (BMI), previous abdominal surgery, tumor location, tumor size, tumor stage, extent of lymph node dissection, and primary surgeon were evaluated using univariate and multivariate analyses to determine the predictive significance of these variables on surgical outcomes including operative time, blood loss, complication, postoperative stay, and retrieved lymph nodes.

RESULTS

Multivariate analysis showed that location of the tumor in the rectosigmoid (p < 0.001), higher BMI (p < 0.001), operation by trainees (p < 0.001), male gender (p = 0.002), and greater tumor depth (p = 0.011) were independently predictive of longer operative time. Larger tumor size (p = 0.025) and higher BMI (p = 0.040) were independently predictive of greater blood loss. Larger tumor size was also related to longer postoperative stay (p = 0.001) and a greater number of retrieved lymph nodes (p = 0.001).

CONCLUSIONS

This study identified operation by trainees as an independent risk factor for longer operative time but with no negative impact on any of the other outcomes. Female patients with a low BMI, sigmoid cancer, shallow tumor depth, and/or small tumor are suitable for operation by trainees.

Log odds of positive lymph nodes in colon cancer: a meaningful ratio-based lymph node classification system

BACKGROUND

The log odds of positive lymph nodes (LODDS), defined as the log of the ratio between the numbers of positive and negative lymph nodes, has recently been proposed as a new prognostic index in surgical oncology. The aim of the present study was to investigate whether the LODDS system of lymph node classification was a more accurate prognostic tool than the tumor node metastasis (TNM) and lymph node ratio (LNR) classifications in colon cancer patients.

MATERIALS AND METHODS

Clinicopathologic data from 258 colon cancer patients who had undergone surgical resection were reviewed. Lymph node parameters were categorized according to the Internation Union Against Cancer/American Joint Cancer Commission (UICC/AJCC) TNM staging system, the LNR (LNR0 with ratio ≤ 0.05, LNR1 with 0.05 < ratio ≤ 0.20, LNR2 with ratio > 0.20), and the log odds ratio (LODDS0 ≤ -1.36, -1.36 < LODDS1 ≤ -0.53, and LODDS2 > -0.53).

RESULTS

The LODDS was able to identify patients who would have been included in different prognostic categories, according to both the TNM and LNR. In addition, LODDS was significantly related to the number of positive and negative lymph nodes, as well as the number of examined lymph nodes. In multivariate analysis, LODDS classification (LODDS0: HR 1; LODDS1: HR 3.687, p = 0.003; LODDS2: HR 9.440, p < 0.001) was identified as an independent prognostic factor.

DISCUSSION

The LODDS system is a highly reliable staging system with strong predictive ability for patient outcome. Compared with other nodal staging systems, the prognostic power of LODDS is less influenced by the number of lymph nodes dissected and examined.

Number of lymph nodes evaluated: prognostic value in pancreatic adenocarcinoma

INTRODUCTION

The impact of the number of lymph node (LN) evaluated pathologically on accurate staging is unknown. Our primary aim was to determine a minimum number of evaluated LN needed to provide accurate staging of pancreatic cancer.

METHODS

Four hundred ninety-nine patients underwent a curative pancreatectomy for pancreatic adenocarcinoma cancer from 1981-2007. The probability of understaging a patient as N0 was estimated based on the number of LN evaluated. The prognostic value of LN ratio (LNR) was assessed.

RESULTS

Survival for node-negative (pN0) patients with <11 LN examined was worse than for pN0 patients with ≥11 LNs with a hazard ratio (95 % CI) of 1.33 (1.1-1.7, p = 0.01) with 3-year survivals of 32 vs. 50%, respectively. Three-year survival for pN1 patients with <11 nodes evaluated was similar to pN1 patients with ≥11 nodes (25 vs. 30%). LNR ≥ 0.17 predicted worse survival with hazard ratio of 1.76 (1.3-2.4, p = 0.001) than LNR < 0.17; 3-year survivals were 37 vs. 19%.

CONCLUSION

Patients with "N0" disease with <11 LN evaluated pathologically have worse survival, suggesting that metastatic nodes were missed by evaluating too few nodes. For pN1 patients, LNR stratifies survival of patient cohorts more accurately. Adequate staging of pancreatic cancer requires pathologic evaluation of ≥11 LNs.

Volume of surgical activity and lymph node evaluation for patients with colorectal cancer in France

BACKGROUND

The correct examination of lymph nodes is decisive for tumour classification into stage 2 and stage 3. The aim of this specialised population-based study was to investigate the influence of clinical factors and volume of surgical activity on lymph node assessment in France for patients diagnosed with localised colorectal cancer.

METHODS

From 1997 to 2004, French digestive cancer registries recorded a total of 4197 cases of colorectal cancer. The volume of surgical activity was appreciated by the annual number of digestive surgery admissions in 2004. The probability of having at least 12 lymph nodes examined after surgical resection was analysed using a multilevel logistic regression model.

RESULTS

Only 1900 patients had more than 12 lymph nodes examined (45.2%). The percentage of patients with at least 12 lymph nodes examined after tumour resection is directly associated with the volume of surgical activity within care centres for patients diagnosed between 1997 and 2000. This association was no longer significant during the second period study (2001-2004).

CONCLUSION(S)

This population-based study reports that only 55% of colorectal patients have a sufficient number of lymph nodes examined. This insufficient number of examined lymph nodes could be considered as a potential prospect for increasing treatment quality in cancer patients in France.

Prognostic value of the lymph node ratio in stage III colorectal cancer

The nodal stage of colorectal cancer is based on the number of positive nodes. It is inevitably affected by the number of removed lymph nodes, but lymph node ratio can be unaffected. We investigated the value of lymph node ratio in stage III colorectal cancer in this study. The clinicopathologic factors and follow-up data of 145 cases of stage III colorectal cancer between January 1998 and December 2008 were analyzed retrospectively. The Pearson and Spearman correlation analyses were used to determine the correlation coefficient, the Kaplan-Meier method was used to analyze survival, and the Cox proportional hazard regression model was used for multivariate analysis in forward stepwise regression. We found that lymph node ratio was not correlated with the number of removed lymph nodes (r = -0.154, P = 0.065), but it was positively correlated with the number of positive lymph nodes (r = 0.739, P < 0.001) and N stage (r = 0.695, P < 0.001). Kaplan-Meier survival analysis revealed that tumor configuration, intestinal obstruction, serum carcinoembryonic antigen (CEA) concentration, T stage, N stage, and lymph node ratio were associated with disease-free survival of patients with stage III colorectal cancer (P < 0.05). Multivariate analysis showed that serum CEA concentration, T stage, and lymph node ratio were prognostic factors for disease-free survival (P < 0.05), whereas N stage failed to achieve significance (P = 0.664). We confirmed that lymph node ratio was a prognostic factor in stage III colorectal cancer and had a better prognostic value than did N stage.

Prognostic value of the lymph node ratio in stage III colorectal cancer

The nodal stage of colorectal cancer is based on the number of positive nodes. It is inevitably affected by the number of removed lymph nodes, but lymph node ratio can be unaffected. We investigated the value of lymph node ratio in stage III colorectal cancer in this study. The clinicopathologic factors and follow-up data of 145 cases of stage III colorectal cancer between January 1998 and December 2008 were analyzed retrospectively. The Pearson and Spearman correlation analyses were used to determine the correlation coefficient, the Kaplan-Meier method was used to analyze survival, and the Cox proportional hazard regression model was used for multivariate analysis in forward stepwise regression. We found that lymph node ratio was not correlated with the number of removed lymph nodes (r = -0.154, P = 0.065), but it was positively correlated with the number of positive lymph nodes (r = 0.739, P < 0.001) and N stage (r = 0.695, P < 0.001). Kaplan-Meier survival analysis revealed that tumor configuration, intestinal obstruction, serum carcinoembryonic antigen (CEA) concentration, T stage, N stage, and lymph node ratio were associated with disease-free survival of patients with stage III colorectal cancer (P < 0.05). Multivariate analysis showed that serum CEA concentration, T stage, and lymph node ratio were prognostic factors for disease-free survival (P < 0.05), whereas N stage failed to achieve significance (P = 0.664). We confirmed that lymph node ratio was a prognostic factor in stage III colorectal cancer and had a better prognostic value than did N stage.

Challenging the feasibility and clinical significance of current guidelines on lymph node examination in rectal cancer in the era of neoadjuvant therapy

PURPOSE

We sought to examine the feasibility and clinical significance of current guidelines on nodal assessment in patients with rectal cancer (RC) treated with neoadjuvant radiation.

METHODS

All patients with RC treated with curative surgery from 1991 to 2003 were included. Number of lymph nodes (LNs) assessed was compared between patients who received neoadjuvant therapy and surgery (NEO) and patients who underwent surgery alone (SURG). Impact of node retrieval on node positivity and disease-specific survival (DSS) in NEO patients was assessed.

RESULTS

In total, 708 patients were identified, of whom 429 (61%) were in the NEO group. These patients had significantly fewer nodes assessed than SURG patients (unadjusted mean, 10.8 v 15.5; adjusted mean difference, -5.0 nodes; P < .001). In the NEO group, 63% of patients had fewer than 12 nodes retrieved (P < .001 v SURG). The proportion of patients diagnosed with node-positive disease in the NEO group was significantly and monotonically associated with the number of lymph nodes retrieved, with no plateau in the relationship. Fewer nodes retrieved was not associated with inferior DSS.

CONCLUSION

In a tertiary cancer center, the 12-LN threshold was not relevant and often not achievable in patients with RC treated with neoadjuvant therapy. Lower LN count after neoadjuvant treatment was not associated with understaging or inferior survival. Although we support the critical importance of careful pathologic examination and adequate nodal staging, we challenge the relevance of LN count both in clinical practice and as a quality indicator in RC.

Estimating underreported N2 disease in rectal cancer patients with low lymph node counts

BACKGROUND

The variability in the number of lymph nodes examined needs to be taken into account for adequate staging. The definition of nodal staging was refined by quantifying the likelihood of N2 disease when the patient had fewer than four positive LN.

METHODS

In a retrospective study a total of 548 patients with node positive rectal cancer and curative surgery between 1990 and 2006 were identified. The misclassification of pN staging was estimated with a Bayesian computation. The prognostic value of the calculated probability, lymph node ratio (LNR), and nodal stage was assessed with Cox proportional hazard regression.

RESULTS

A probability of understaging of 40% or more indicated worse prognosis of cancer-specific survival (CSS) with hazard ratio 2.6 (95%CI: 1.8-3.9, P < 0.001). The concordance index of a multivariate model with probability of N2 disease as a prognostic factor for survival was 0.68 for all patients and 0.75 for patients with less than 10 lymph nodes examined.

CONCLUSION

Utilizing estimated probabilities of N2 disease improves our ability to predict survival, in particular in patients with low LN count. These probabilities allow for a simple rule in patient counseling and clinical decision making.

Clinical nodal staging scores for bladder cancer: a proposal for preoperative risk assessment

BACKGROUND

Radical cystectomy (RC) with pelvic lymph node dissection (LND) is the standard of care for refractory non-muscle-invasive and muscle-invasive bladder cancer. Although consensus exists on the need for LND, its extent is still debated.

OBJECTIVE

To develop a model that allows preoperative determination of the minimum number of lymph nodes (LNs) needed to be removed at RC to ensure true nodal status.

DESIGN, SETTING, AND PARTICIPANTS

We analyzed data from 4335 patients treated with RC and pelvic LND without neoadjuvant chemotherapy at 12 academic centers located in the United States, Canada, and Europe.

MEASUREMENTS

We estimated the sensitivity of pathologic nodal staging using a beta-binomial model and developed clinical (preoperative) nodal staging scores (cNSS), which represent the probability that a patient has LN metastasis as a function of the number of examined nodes.

RESULTS AND LIMITATIONS

The probability of missing a positive LN decreased with an increasing number of nodes examined (52% if 3 nodes were examined, 40% if 5 were examined, and 26% if 10 were examined). A cNSS of 90% was achieved by examining 6 nodes for clinical Ta-Tis tumors, 9 nodes for cT1 tumors, and 25 nodes for cT2 tumors. In contrast, examination of 25 nodes provided only 77% cNSS for cT3-T4 tumors. The study is limited due to its retrospective design, its multicenter nature, and a lack of preoperative staging parameters.

CONCLUSIONS

Every patient treated with RC for bladder cancer needs an LND to ensure accurate nodal staging. The minimum number of examined LNs for adequate staging depends preoperatively on the clinical T stage. Predictive tools can give a preoperative estimation of the likelihood of nodal metastasis and thereby allow tailored decision-making regarding the extent of LND at RC.

T cell subpopulations in lymph nodes may not be predictive of patient outcome in colorectal cancer

Background

The immune response has been proposed to be an important factor in determining patient outcome in colorectal cancer (CRC). Previous studies have concentrated on characterizing T cell populations in the primary tumour where T cells with regulatory effect (Foxp3+ Tregs) have been identified as both enhancing and diminishing anti-tumour immune responses. No previous studies have characterized the T cell response in the regional lymph nodes in CRC.

Methods

Immunohistochemistry was used to analyse CD4, CD8 or Foxp3+ T cell populations in the regional lymph nodes of patients with stage II CRC (n = 31), with (n = 13) or without (n = 18) cancer recurrence after 5 years of follow up, to determine if the priming environment for anti-tumour immunity was associated with clinical outcome.

Results

The proportions of CD4, CD8 or Foxp3+ cells in the lymph nodes varied widely between and within patients, and there was no association between T cell populations and cancer recurrence or other clinicopathological characteristics.

Conclusions

These data indicate that frequency of these T cell subsets in lymph nodes may not be a useful tool for predicting patient outcome.

Evaluation of lymph node numbers for adequate staging of Stage II and III colon cancer

BACKGROUND

Although evaluation of at least 12 lymph nodes (LNs) is recommended as the minimum number of nodes required for accurate staging of colon cancer patients, there is disagreement on what constitutes an adequate identification of such LNs.

METHODS

To evaluate the minimum number of LNs for adequate staging of Stage II and III colon cancer, 490 patients were categorized into groups based on 1-6, 7-11, 12-19, and ≥ 20 LNs collected.

RESULTS

For patients with Stage II or III disease, examination of 12 LNs was not significantly associated with recurrence or mortality. For Stage II (HR = 0.33; 95% CI, 0.12-0.91), but not for Stage III patients (HR = 1.59; 95% CI, 0.54-4.64), examination of ≥20 LNs was associated with a reduced risk of recurrence within 2 years. However, examination of ≥20 LNs had a 55% (Stage II, HR = 0.45; 95% CI, 0.23-0.87) and a 31% (Stage III, HR = 0.69; 95% CI, 0.38-1.26) decreased risk of mortality, respectively. For each six additional LNs examined from Stage III patients, there was a 19% increased probability of finding a positive LN (parameter estimate = 0.18510, p < 0.0001). For Stage II and III colon cancers, there was improved survival and a decreased risk of recurrence with an increased number of LNs examined, regardless of the cutoff-points. Examination of ≥7 or ≥12 LNs had similar outcomes, but there were significant outcome benefits at the ≥20 cutoff-point only for Stage II patients. For Stage III patients, examination of 6 additional LNs detected one additional positive LN.

CONCLUSIONS

Thus, the 12 LN cut-off point cannot be supported as requisite in determining adequate staging of colon cancer based on current data. However, a minimum of 6 LNs should be examined for adequate staging of Stage II and III colon cancer patients.

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.

Prognostic value of the lymph node ratio in stage III colorectal cancer: a systematic review

BACKGROUND

Although nodal invasion represents one of the most powerful prognostic indicators in colorectal cancer, marked heterogeneity exists within stage III patients. Recently, the lymph node ratio (LNR), defined as the ratio of the number of positive nodes over the total number of examined nodes, was proposed to stratify outcome in stage III patients.

METHODS

A systematic search was performed for studies examining the prognostic significance of the LNR in colon or rectal cancer. Individual studies were assessed for methodological quality and summary data extracted. Hazard ratios from multivariate analyses were entered in a fixed-effects meta-analysis model.

RESULTS

In total, 16 studies were identified including 33,984 patients with stage III colon or rectal cancer. In all identified studies, the LNR was identified as an independent prognostic factor in patients with stage III cancer of the colon or rectum. The prognostic separation obtained by the LNR was superior to that of the number of positive nodes (N stage). The pooled hazard ratios for overall and disease-free survival were 2.36 (95% confidence interval, 2.14-2.61) and 3.71 (95% confidence interval, 2.56-5.38), respectively.

CONCLUSIONS

The LNR allows superior prognostic stratification in stage III colorectal cancer and should be validated in prospective studies.