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

How Many Lymph Nodes are Enough in Thyroidectomy? A Cohort Study Based on Real-World Data

BACKGROUND

Thyroidectomy with only limited examination of lymph nodes is considered to pose potential risk for harboring occult nodal disease in patients with papillary thyroid cancer (PTC). However, the optimal number of examined lymph nodes (ELNs) in patients with PTC with clinically lateral lymph node metastasis (cN1b) remains unclear.

PATIENTS AND METHODS

Patients with cN1b PTC who underwent therapeutic neck dissection were retrospectively enrolled. A β-binomial distribution was utilized to calculate the likelihood of occult nodal disease as a function of total number of ELNs, and recurrence-free survival analysis was performed using the Kaplan-Meier method.

RESULTS

Together 982 patients met the inclusion criteria for this study, of which 853 patients had node-positive disease. The median ELN count was 23 (interquartile range 14-33). Increased ELN counts were associated with a decreased rate of occult nodal disease. The prevalence of nodal metastasis was 84%, while the corrected prevalence was 90%. The estimated probability of false-negative nodal disease was 67% for patients with PTC when only a single node was examined. Survival analysis revealed that populations with higher probability of occult nodal diseases experienced significantly higher recurrence rate. For patient with cN1b PTC, 20 ELNs were required to achieve 95% confidence of having no occult nodal disease. Minimum thresholds of 24, 14, 14, and 15 ELNs were selected for patients with pT1, pT2, pT3, and pT4 diseases, respectively.

CONCLUSIONS

Our findings robustly conclude that a minimum of 20 ELNs is essential to assess the quality of neck dissection and acquire accurate staging for patients with cN1b PTC.

How Many Lymph Nodes are Enough in Paratesticular Rhabdomyosarcoma?

BACKGROUND

Treatment strategies for paratesticular rhabdomyosarcoma (PT RMS) are based on stage, which requires accurate lymph node (LN) evaluation. Previous methodology for determining quantity of LN for negative nodal status is based on LN positivity rates, without accounting for the relationship between LNs or amongst patients. This study aims to quantify the chance of missing involved LNs based on LN yield (LNY) using a previously established methodology in comparison to current recommendations.

METHODS

Using the National Cancer Database, patients with a diagnosis of PT RMS were queried from 2004 to 2018. Patients >10 years and those ≤10 years with cN1 disease were included, based on COG guidelines for who should undergo retroperitoneal LN sampling (RPLNS). The beta-binomial model was used to calculate the rate of false negative RPLNS and identified the LNY threshold to reduce the risk of a missing an involved LN node to <10 %.

RESULTS

Sixty-two patients were included for analysis over the study period. Median LNY was 17 (IQR 9-28.75), and the median number of involved LNs was 2.5 (IQR 2-5). The median LN density was 0.27 (IQR 0.10-0.34). Application of the beta-binomial model identified that a LNY of 26 LNs corresponds to a <10 % chance of missing occult disease (Fig. 3).

CONCLUSION

Previous models estimate that sampling of 7-12 LN is adequate for accurate staging. However, the beta binomial model quantifies sampling at least 26 LNs to reduce the chance of missing occult metastatic disease to <10 % in the majority of patients. Surgeons should consider this false negative rate during RPLNS for patients with PT RMS.

LEVEL OF EVIDENCE

III.

Number of lymph nodes retrieved in patients with locally advanced rectal cancer after total neoadjuvant therapy: post-hoc analysis from the STELLAR trial

BACKGROUND

The current gold standard for extraperitoneal locally advanced rectal cancer is total neoadjuvant therapy (TNT) followed by total mesorectal excision. This research explored the number of lymph nodes in patients with locally advanced rectal cancer after TNT and its correlation with survival.

MATERIALS AND METHODS

This is a post-hoc analysis based on the STELLAR trial, including patients with locally advanced rectal cancer from 16 tertiary centres who were randomized for short-term radiotherapy followed by chemotherapy (TNT group) or long-term concurrent chemotherapy group followed by total mesorectal excision between 2015 and 2018. This lymph node-related analysis is based on the TNT group. Subgroups were differentiated based on the lymph node harvest (below the median number: limited lymphadenectomy group, and greater than/equal to the median number: extended lymphadenectomy group). The primary outcomes were overall survival and disease-free survival (DFS). Correlations with clinical/pathological variables, lymphadenectomy categories and use of adjuvant chemotherapy were explored.

RESULTS

Among the 451 patients enrolled in the STELLAR trial, 227 patients (50.3%) were assigned to the TNT group, including 29.5% females. The median number of lymph nodes retrieved in the TNT group was 11.0. Patients in the limited lymphadenectomy subgroup exhibited worse overall survival than those with extended lymphadenectomy (HR 2.95 (95% c.i. 1.47 to 5.92), P = 0.001). The overall survival was similar in the ypN0-limited and ypN1-extended subgroups (HR 0.38 (95% c.i. 0.11 to 1.30), P = 0.109). Adjuvant chemotherapy was associated with better overall survival and DFS than no adjuvant chemotherapy overall (P < 0.001) and in the limited lymphadenectomy subgroup (P < 0.001). However, there was no significant difference in overall survival or DFS with or without adjuvant chemotherapy in the extended lymphadenectomy subgroup (P = 0.887 and P = 0.192, respectively).

CONCLUSION

In the STELLAR trial, the median number of lymph nodes harvested was 11. In patients with limited lymphadenectomy, the use of adjuvant therapy after TNT was beneficial and correlated with better prognosis compared with patients who did not receive adjuvant chemotherapy.

Nodal staging score for adequacy of nodal staging in cervical cancer

Background

Cervical cancer remains the fourth most common female malignancy with increasing newly cases around the world. It is of clinical value to precisely evaluate whether false negative nodal existed and develop a nodal staging model in cervical cancer.

Materials and methods

Clinical data of cervical cancer patients was retrieved from the Surveillance, Epidemiology, and End Results database. Probability of missing nodal disease and nodal staging score (NSS) was computed to assess the nodal status of each individual.Prognostic value of NSS was assessed.

Results

A total of 9056 individuals were in this study, with 5115 squamous cell carcinoma, 2791 adenocarcinoma, 512 adenosquamous carcinoma, and 638 other type individuals. A beta-binomial model was used to compute the probability of nodal disease in four histological types, respectively. False negative probability drastically decreased as more nodes examined. To reach 0.05 of false negative probability, it required at least 17 lymph nodes in squamous cell carcinoma patients,18 in adenocarcinoma, 12 in adenosquamous carcinoma patients and 14 in other types. To reach 0.95 of NSS, it took 10 lymph nodes in squamous cell carcinoma, 6 in adenocarcinoma, 10 in adenosquamous carcinoma and 7 in other types. Significant prognostic values of NSS quartiles subsets were found in all four histological sets.

Conclusion

NSS tool enables adequate nodal staging of cervical cancer with significant prognostic value. Exact number of lymph nodes required for surgery in cervical cancer is specified based on histologic type.

Log odds of positive nodes as a prognostic factor for rectal cancer: a retrospective study

OBJECTIVE

Rectal cancer is an important cause of mortality and morbidity globally. The aim of this study was to investigate whether the log odds of positive nodes system is a better indicator than tumor node metastasis and lymph node ratio systems to determine rectum cancer prognosis, which is an important cause of mortality and morbidity globally.

METHODS

This was a single-center retrospective cross-sectional study. Data were obtained from the medical records of patients with rectum adenocarcinoma followed at Gazi University Hospital. The clinicopathological data of 128 patients with rectum adenocarcinoma who underwent low anterior resection or abdominoperineal resection between January 2010 and December 2018 was retrospectively reviewed. Patients with rectum adenocarcinoma as the first and only primary diagnosis, which was confirmed by histopathological examination, than those who had undergone complete curative resection via low anterior resection or abdominoperineal resection were included. Those with familial adenomatous polyposis or Lynch syndrome, those under 18 years of age, with a synchronous tumor, peritoneal spread, or metastatic disease at the time of diagnosis, and those with <12 lymph nodes dissected from the resection material were excluded from the study.

RESULTS

In multivariate analysis, age, perineural invasion, tumor node metastasis stage, lymph node ratio stage, and log odds of positive nodes stage were found to be independent prognostic factors (p<0.05). LODDS2 patients' mortality rates were 9.495 times higher than LODDS0 patients [hazard ratio=9.495, (95%CI 4.155-21.694), p<0.001] while LNR2 stage patients' mortality rates were 7.016 times higher than LNR0 stage patients [hazard ratio=7.016, (95%CI 3.123-15.765), p<0.001] and N2 stage patients had a 5.135 times higher risk of mortality than those who were in N0 stage [hazard ratio=5.135 (95%CI 2.451-10.756), p<0.001].

CONCLUSION

Log odds of positive nodes is a more valuable prognostic factor for rectal cancer patients than tumor node metastasis and lymph node ratio systems to determine rectum cancer prognosis.

A 3 M Evaluation Protocol for Examining Lymph Nodes in Cancer Patients: Multi-Modal, Multi-Omics, Multi-Stage Approach

Through meticulous examination of lymph nodes, the stage and severity of cancer can be determined. This information is invaluable for doctors to select the most appropriate treatment plan and predict patient prognosis; however, any oversight in the examination of lymph nodes may lead to cancer metastasis and poor prognosis. In this review, we summarize a significant number of articles supported by statistical data and clinical experience, proposing a standardized evaluation protocol for lymph nodes. This protocol begins with preoperative imaging to assess the presence of lymph node metastasis. Radiomics has replaced the single-modality approach, and deep learning models have been constructed to assist in image analysis with superior performance to that of the human eye. The focus of this review lies in intraoperative lymphadenectomy. Multiple international authorities have recommended specific numbers for lymphadenectomy in various cancers, providing surgeons with clear guidelines. These numbers are calculated by applying various statistical methods and real-world data. In the third chapter, we mention the growing concern about immune impairment caused by lymph node dissection, as the lack of CD8 memory T cells may have a negative impact on postoperative immunotherapy. Both excessive and less lymph node dissection have led to conflicting findings on postoperative immunotherapy. In conclusion, we propose a protocol that can be referenced by surgeons. With the systematic management of lymph nodes, we can control tumor progression with the greatest possible likelihood, optimize the preoperative examination process, reduce intraoperative risks, and improve postoperative quality of life.

The optimal number of examined lymph nodes for accurate staging of intrahepatic cholangiocarcinoma: A multi-institutional analysis using the nodal staging score model

BACKGROUND

This study aims to develop a nodal staging score (NSS) to determine the optimal number of lymph nodes (LNs) examined in intrahepatic cholangiocarcinoma (iCCA) patients.

METHODS

Clinicopathologic data were collected from the SEER database (development cohort, n = 2782) and seven Chinese tertiary hospitals (validation cohort, n = 363). NSS was constructed based on a binomial distribution to indicate the probability of nodal disease absence. In addition, its prognostic value was examined by survival analysis and multivariable modeling on pN0 patients.

RESULTS

A model fit was performed in node-positive patients and a subgroup analysis was performed according to clinical characteristics. Statistically significant differences were only found in the subgroups when divided by the tumor size of 3 cm. As the number of examined lymph nodes (ELNs) increased, the likelihood of missing a metastatic LN decreased. NSS escalated as ELNs increased in groups with different tumor sizes, with plateaus at 7 and 11 LNs ensuring an NSS of 90.0% for ≤3 cm and >3 cm tumors, respectively. For pN0 patients, multivariate analysis revealed that NSS was an independent prognostic factor for overall survival (OS) and recurrence-free survival (RFS).

CONCLUSIONS

For accurate staging of iCCA, the optimal number of ELNs was related to tumor size. We recommend that at least 7 and 11 LNs should be examined for tumor size ≤3 cm and >3 cm, respectively. Therefore, the NSS model could be helpful to make clinical decisions for pN0 iCCA.

Misclassification simulation extrapolation method for a Weibull accelerated failure time model

The problem of misclassification in covariates is ubiquitous in survival data and often leads to biased estimates. The misclassification simulation extrapolation method is a popular method to correct this bias. However, its impact on Weibull accelerated failure time models has not been studied. In this paper, we study the bias caused by misclassification in one or more binary covariates in Weibull accelerated failure time models and explore the use of the misclassification simulation extrapolation in correcting for this bias, along with its asymptotic properties. Simulation studies are carried out to investigate the numerical properties of the resulting estimator for finite samples. The proposed method is then applied to colon cancer data obtained from the cancer registry at Memorial Sloan Kettering Cancer Center.

Size and number of lymph nodes were risk factors of recurrence in stage II colorectal cancer

BACKGROUND

Size and number of lymph nodes (LNs) were reported to be associated with the prognosis of stage II colorectal cancer (CRC). The purpose of this study was to determine the prognostic role of the size of LNs (SLNs) measured by computer tomography (CT) and the number of retrieved LNs (NLNs) in the relapse-free survival (RFS) and overall survival (OS) among stage II CRC patients.

METHODS

Consecutive patients diagnosed with stage II CRC at Fudan University Shanghai Cancer Center (FUSCC) from January 2011 to December 2015 were reviewed, and 351 patients were randomly divided into two cohorts for cross-validation. The optimal cut-off values were obtained using X-tile program. Kaplan-Meier curves and Cox regression analyses were conducted for the two cohorts.

RESULTS

Data from 351 stage II CRC patients were analyzed. The cut-off values for SLNs and NLNs were 5.8 mm and 22, respectively, determined by the X-tile in the training cohort. In the validation cohort, Kaplan-Meier curves demonstrated SLNs (P = 0.0034) and NLNs (P = 0.0451) were positively correlated with RFS but not with OS. The median follow-up time in the training cohort and the validation cohort were 60.8 months and 61.0 months respectively. Univariate and multivariate analysis revealed that both SLNs (training cohort: Hazard Ratio (HR) = 2.361, 95% Confidence interval (CI): 1.044-5.338, P = 0.039; validation cohort: HR = 2.979, 95%CI: 1.435-5.184, P = 0.003) and NLNs (training cohort: HR = 0.335, 95%CI: 0.113-0.994, P = 0.049; validation cohort: HR = 0.375, 95%CI: 0.156-0.900, P = 0.021) were independent prognostic factors for RFS whereas not for OS.

CONCLUSION

SLNs and NLNs are independent prognostic factors for patients with stage II CRC. Patients with SLNs > 5.8 mm and NLNs ≤ 22 are apt to have higher risk of recurrence.

Development and validation of nodal staging score in pN0 patients with esophageal squamous cell carcinoma: A population study from the SEER database and a single-institution cohort

BACKGROUND

Patients with esophageal squamous cell carcinoma (ESCC) with lymph node metastasis may be misclassified as pN0 due to an insufficient number of lymph nodes examined (LNE). The purpose of this study was to confirm that patients with ESCC are indeed pN0 and to propose an adequate number for the correct nodal stage using the nodal staging score (NSS) developed by the beta-binomial model.

METHODS

A total of 1249 patients from the Surveillance, Epidemiology, and End Results (SEER) database between 2000 and 2017, and 1404 patients diagnosed with ESCC in our database between 2005 and 2018 were included. The NSS was developed to assess the probability of pN0 status based on both databases. The effectiveness of NSS was verified using survival analysis, including Kaplan-Meier curves and Cox models.

RESULTS

Many patients were misclassified as pN0 based on our algorithm due to insufficient LNE. As the number of LNE increased, false-negative findings dropped; accordingly, the NSS increased. In addition, NSS was an independent prognostic indicator for pN0 in patients with ESCC in the SEER database (hazard ratio [HR] 0.182, 95% confidence interval [CI] 0.046-0.730, p = 0.016) and our database (HR 0.215, 95% CI 0.055-0.842, p = 0.027). A certain number of nodes must be examined to achieve 90% of the NSS.

CONCLUSIONS

NSS could determine the probability of true pN0 status for patients, and it was sufficient in predicting survival and obtaining adequate numbers for lymphadenectomy.

Pathologic node-negative lung cancer: Adequacy of lymph node yield and a tool to assess the risk of occult nodal disease

INTRODUCTION

Accurate lymph node (LN) staging is crucial for prognostication in NSCLC. Diagnosis of pN0 disease is based on the absence of positive LNs, irrespective of the number of LNs excised, and is thus susceptible to sampling error. Tumors that are assumed to be pN0 may in fact be understaged. We developed a tool to quantify the risk of occult nodal disease (OND) among patients with pN0 NSCLC in terms of the number of LNs examined.

METHODS

Patients treated surgically for stage I-III primary NSCLC between 2004 and 2014 (n = 49,356) were extracted from the Surveillance, Epidemiology, and End Results database. The probability of missing a positive node in terms of the number of LNs examined was modeled using a beta-binomial model. A mathematical tool was then used to calculate the negative predictive value (NPV) corresponding to the number of LNs examined. Ranging from 0 to 100%, higher NPV reflects greater confidence in the pN0 diagnosis and a lower probability of OND.

RESULTS

The median number of LNs examined was 7 for N0, 10 for N1/N2, and 8 for N3 disease. The probability of missing a positive node decreased as LNs examined increased. Additionally, higher T stage required more LNs to confirm an N0 diagnosis. After accounting for false-negative diagnoses, the prevalence of node-positive disease was readjusted from 16% to 22% among patients with T1 disease. According to our tool, with 10 LNs examined, the NPV was 85% (15% probability of OND) for a patient with T3 disease, compared with 95% (5% probability of OND) for a patient with T1 disease.

CONCLUSIONS

Accurate pN0 diagnosis depends on the number of LNs examined. The proposed tool offers the ability to quantify, in a patient-specific manner, the confidence in a diagnosis of node-negative disease on the basis of the number of LNs examined.

Prediction of Cervical Lymph Nodes Metastasis in Papillary Thyroid Carcinoma (PTC) Using Nodal Staging Score (NSS)

Background

Cervical lymph node metastasis is commonly seen in papillary thyroid carcinoma. Surgery is the preferred treatment for PTC with cervical lymph node metastasis. There is no alternate ultrasound, neck CT, and thyroglobulin (Tg) methods to assess the occult lymph node metastasis. For moderate-and high-risk PTC, the number of lymph nodes to be dissected should be increased to remove the occult lymph node metastasis.

Objective

This study was designed to develop a nodal staging score model to predict the likelihood of lymph node metastasis in papillary thyroid carcinoma (PTC), and further guide the treatments. Material and Methods. Data were collected from the SEER database. Patients with PTC from 2000 to 2005 were selected. The beta-binomial model was adopted to establish a nodal staging score (NSS)-based model. The NSS-based model was built according to gender, age, extrathyroidal invasion, tumor multifocality, tumor size, and T stage of the patients. A total of 12,431 PTC patients were included in our study. Various types of lymph nodes were examined based on various categories (incidence, risk assessment) to evaluate the results.

Results

5,959 (47.9%) patients in the study were positive and 6,472 (52.1%) were confirmed negative for lymph node metastasis. The corrected incidence of lymph node metastasis was higher than that of direct calculation, regardless of the factors that affected lymph node metastasis. There were significant differences in the OS of PTC patients among the four groups and T stage (p is less than 0.05), indicating that cervical lymph node metastasis would have an impact on the prognosis of patients.

Conclusion

In conclusion, an NSS-based model base on a variety of clinicopathological factors can be used to predict lymph node metastasis. It is important to evaluate the risk of occult lymph node metastasis in the treatment of PTC.. Since, this statistical model can describe the risk of occult lymph node metastasis in patients; therefore, it can be used as basis for decision-making related to the number of lymph nodes that can be dissected in operations.

Pathological Nodal Staging Score for Gastric Signet Ring Cell Carcinoma: A Clinical Tool of Adequate Nodal Staging

Background: Gastric signet ring cell carcinoma (GSRCC) is a subset of gastric cancer with distinct histological and inconsistent prognosis outcome. Currently, the association between the adequate regional lymph node and proper nodal staging in GSRCC is rarely noticed. Materials and methods: Clinical data of GSRCC were retrieved from the Surveillance, Epidemiology, and End Results database. Beta-binomial distribution model was employed for the estimation of the probability of missing nodal disease, followed by the development of a nodal staging score (NSS). Results: A total of 561 GSRCC patients were included in this study, with 193 in lymph node-negative and 368 in lymph node-positive diagnoses. As the number of examined lymph nodes increased, the probability of missing nodal disease decreased rapidly, with T stage-specific curves. The probability of missing nodal disease in T4 was lower than that in T1. NSS calculation indicated that T1 stage patients commonly had NSS > 0.8. However, with the NSS of T2−T4 to reach 0.8, the number of examined lymph node was required to be larger than 12 in T2, 17 in T3 and 27 in T4. NSS ≥ 0.75 (quantile 75%) subgroup in T2−T4 subgroups tended to have better outcome; however, without significant prognostic value. Conclusions: NSS is served as a reliable and feasible tool in adequate nodal staging of GSRCC with statistical basis and provides further evidence for clinical decision making.

A More Extensive Lymphadenectomy Enhances Survival After Neoadjuvant Chemoradiotherapy in Locally Advanced Esophageal Adenocarcinoma

OBJECTIVE

We sought to determine the extent of lymphadenectomy that optimizes staging and survival in patients with locally advanced EAC treated with neoadjuvant chemoradiotherapy followed by esophagectomy.

SUMMARY OF BACKGROUND DATA

Several studies have found that a more extensive lymphadenectomy leads to better disease-specific survival in patients treated with surgery alone. Few studies, however, have investigated whether this association exists for patients treated with neoadjuvant chemoradiotherapy.

METHODS

We examined our prospective database and identified patients with EAC treated with neoadjuvant chemoradiotherapy followed by esophagectomy between 1995 and 2017. Overall survival (OS) and DFS were estimated using Kaplan-Meier methods, and a multivariable Cox proportional hazards model was used to identify independent predictors of OS and DFS. The relationship between the total number of nodes removed and 5-year OS or DFS was plotted using restricted cubic spline functions.

RESULTS

In total, 778 patients met the inclusion criteria. The median number of excised nodes was 21 (interquartile range, 16-27). A lower number of excised lymph nodes was independently associated with worse OS and DFS (OS: hazard ratio, 0.98; confidence interval, 0.97-1.00; P = 0.013; DFS: hazard ratio, 0.99; confidence interval, 0.98-1.00; P = 0.028). Removing 25 to 30 lymph nodes was associated with a 10% risk of missing a positive lymph node. Both OS and DFS improved with up to 20 to 25 lymph nodes removed, regardless of treatment response.

CONCLUSIONS

The optimal extent of lymphadenectomy to enhance both staging and survival after chemoradiotherapy, regardless of treatment response, is approximately 25 lymph nodes.

A Mathematical Model to Assess the Effect of Residual Positive Lymph Nodes on the Survival of Patients With Papillary Thyroid Microcarcinoma

Background

Active surveillance (AS) has been considered the first-line management for patients with clinical low-risk papillary thyroid microcarcinoma (PTMC) who often have lymph node micrometastasis (m-LNM) when diagnosed. The "low-risk" and "high prevalence of m-LNM" paradox is a potential barrier to the acceptance of AS for thyroid cancer by both surgeons and patients.

Methods

Patients diagnosed with PTMC who underwent thyroidectomy with at least one lymph node (LN) examined were identified from a tertiary center database (n = 5,399). A β-binomial distribution was used to estimate the probability of missing nodal disease as a function of the number of LNs examined. Overall survival (OS) probabilities of groups with adequate and inadequate numbers of LNs examined were estimated using the Kaplan-Meier method in the Surveillance, Epidemiology, and End Results (SEER) database (n = 15,340). A multivariable model with restricted cubic splines was also used to verify the association of OS with the number of LNs examined.

Results

The risk of residual m-LNM (missed nodal disease) ranged from 31.3% to 10.0% if the number of LNs examined ranged from 1 and 7 in patients with PTMC. With 7 LNs examined serving as the cutoff value, the intergroup comparison showed that residual positive LNs did not affect OS across all patients and patients aged ≥55 years (P = 0.72 and P = 0.112, respectively). After adjusting for patient and clinical characteristics, the multivariate model also showed a slight effect of the number of LNs examined on OS (P = 0.69).

Conclusions

Even with the high prevalence, OS is not significantly compromised by persistent m-LNM in the body of patients with low-risk PTMC. These findings suggest that the concerns of LNM should not be viewed as an obstacle to developing AS for thyroid cancer. For patients with PTMC who undergo surgery, prophylactic central LN dissection does not provide a survival benefit.

Misclassification of nodal stage in gastric cancer: 16 lymph nodes is not enough

Background

In gastric cancer, nodal stage plays an important role. Insufficient lymph node harvesting or incomplete examination may lead to misclassification and affect postoperative strategy and group survival. This study’s objective was to determine the minimum number of examined lymph nodes needed in gastric cancer and compare this to the minimum lymph node count according to the current Union for International Cancer Control (UICC) classification using real world data.

Methods

Based on anatomical data, expected mean lymph node counts and their 95% confidence intervals for complete D2 lymphadenectomy were calculated. Using stochastic analysis, a threshold for correct classification in 95% of cases was determined. Survival data of nodal negative gastric cancer patients was extracted from the Surveillance, Epidemiology, and End Results (SEER)-Database for 2010–2017. Patients reaching at least the calculated theoretical threshold were compared to the minimum threshold according to the current UICC classification.

Results

The expected lymph node count was 30 (95% CI: 28–32; range 17–52), corresponding to a 27 lymph nodes. In nodal negative patients with exactly 16 and at least 27 examined lymph nodes, relative 5 year survival was 79 and 89% in T1/T2 and 39 and 64% T3/T4 gastric cancer, respectively. Theoretically, when only 16 lymph nodes are analyzed, nodal negative staging may be incorrect in up to 47% of cases.

Conclusions

A minimum threshold of 16 examined lymph nodes cannot be justified. Retrospective analysis confirmed systematic misclassification of patients with insufficient lymphadenectomy in nodal negative gastric cancer patients. Correct lymphadenectomy and thorough examination of the surgical specimen is mandatory.

Stepwise Improvement of Surgical Quality in Robotic Lateral Pelvic Node Dissection: Lessons From 100 Consecutive Patients With Locally Advanced Rectal Cancer

BACKGROUND

Lateral pelvic node dissection has significant technical difficulty and a high incidence of surgical morbidity. A steep learning curve is anticipated in performing lateral pelvic node dissection. However, no study has previously analyzed the learning curve and surgical skill acquisition for this complex procedure.

OBJECTIVES

We aimed to evaluate the learning process for performing robotic total mesorectal excision with lateral pelvic node dissection in patients with rectal cancer.

DESIGN

This is a retrospective analysis of a prospectively collected database.

SETTING

This study was conducted at a tertiary cancer center.

PATIENTS

A total of 100 patients who underwent robotic total mesorectal excision with lateral pelvic node dissection between 2011 and 2017 were included.

MAIN OUTCOME MEASURES

A cumulative sum analysis was calculated based on the number of unilateral retrieved lateral pelvic nodes. Operative time, estimated bloodloss, lateral pelvic node metastatic rate, postoperative morbidities, and local recurrence were also analyzed.

RESULTS

Cumulative sum modeling suggested 4 learning phases: learning I (33 patients), learning II (19 patients), consolidation (30 patients), and competence (18 patients). In the consolidation and competence phases, we adopted fluorescence imaging and standardized the surgical procedure on the basis of anatomical planes. The competence phase had the greatest number of unilateral retrieved lateral pelvic nodes (12.8 vs 4.9, 8.2, and 10.4; p < 0.001). Urinary complications, including urinary retention and postoperative α-blocker usage, were more frequently observed in learning phase I than in the competence phase (39.4% vs 16.7%, p = 0.034). During the median follow-up of 44.2 months, local recurrence in the pelvic sidewall was observed in 4 patients from learning phase I and in 1 patient from learning phase II.

LIMITATIONS

This study was limited by its retrospective design.

CONCLUSION

Completeness of the lateral pelvic node dissection procedure increased with the surgeon's experience and as new imaging systems and surgical technique standardization were implemented. Further studies are warranted to determine the oncologic outcomes associated with each phase. See Video Abstract at http://links.lww.com/DCR/B774.

MEJORA GRADUAL DE LA CALIDAD QUIRRGICA EN LA DISECCIN LINFTICA PLVICA LATERAL ROBTICA LECCIONES DE PACIENTES CONSECUTIVOS CON CNCER DE RECTO LOCALMENTE AVANZADO

ANTECEDENTES:La disección linfática pélvica lateral tiene una dificultad técnica significativa y una alta incidencia de morbilidad quirúrgica. Se prevé una curva de aprendizaje muy pronunciada al realizar la disección linfática pélvica lateral. Sin embargo, ningún estudio ha analizado previamente la curva de aprendizaje y la adquisición de habilidades quirúrgicas para este procedimiento.OBJETIVOS:Nuestro objetivo fue evaluar el proceso de aprendizaje para realizar la escisión total de mesorrecto robótica con disección linfática pélvica lateral en pacientes con cáncer de recto.DISEÑO:Este es un análisis retrospectivo de una base de datos recopilada prospectivamente.AJUSTE:Este estudio se realizó en un centro oncológico terciario.PACIENTES:Un total de 100 pacientes fueron sometidos a escisión total de mesorrecto robótica con disección linfática pélvica lateral entre 2011 y 2017.PRINCIPALES MEDIDAS DE DESENLACE:Se calculó un análisis de suma acumulativa basado en el número unilateral de ganglios pélvicos laterales recuperados. También se analizaron el tiempo operatorio, la pérdida de sangre estimada, la tasa de metástasis ganglionares pélvicas laterales, las morbilidades postoperatorias y la recidiva local.RESULTADOS:El modelado total acumulativo sugirió cuatro fases de aprendizaje: aprendizaje I (33 pacientes), aprendizaje II (19 pacientes), consolidación (30 pacientes) y competencia (18 pacientes). En las fases de consolidación y competencia, adoptamos imágenes de fluorescencia y estandarizamos el procedimiento quirúrgico basado en planos anatómicos, respectivamente. La fase de competencia tuvo el mayor número de ganglios pélvicos laterales recuperados unilateralmente (12,8 frente a 4,9, 8,2 y 10,4; p < 0,001). Las complicaciones urinarias, incluida la retención urinaria y el uso posoperatorio de bloqueadores beta, se observaron con más frecuencia en la fase de aprendizaje I que en la fase de competencia (39,4% frente a 16,7%, p = 0,034). Durante la mediana de seguimiento de 44,2 meses, se observó una recidiva local en la pared lateral pélvica en cuatro pacientes de la fase de aprendizaje I y en un paciente de la fase de aprendizaje II.LIMITACIONES:Este estudio estuvo limitado por su diseño retrospectivo.CONCLUSIÓNES:La completitud del procedimiento de disección linfática pélvica lateral aumentó con la experiencia del cirujano y a medida que se implementaron nuevos sistemas de imágenes y estandarización de técnicas quirúrgicas. Se necesitan más estudios para determinar los resultados oncológicos asociados con cada fase. Consulte Video Resumen en http://links.lww.com/DCR/B774.

Lymph Nodes With Germinal Centers Are Not Associated With Tumor Response After Neoadjuvant Treatment in Locally Advanced Rectal Cancer

In patients with locally advanced rectal cancer, neoadjuvant radiotherapy or chemoradiotherapy followed by total mesorectal excision as a standard of care. We aimed to explore the number, size, germinal centers, extracapsular invasion of lymph nodes (LN), and their impact on overall survival and disease free survival. Furthermore we also investigated the characteristics of lymph nodes in patients who received neoadjuvant therapy and those who underwent surgery between 2011 and 2018. The count and measurement of lymph nodes was assessed by careful visual inspection and manual palpation. The predictive cut-off value of the lymph node ratio (LNR) was determined based on the receiver operating characteristic (ROC), method and the survival outcomes based on Kaplan-Meier curves. We found that the size and the number of lymph nodes decreased significantly after neoadjuvant treatment. The mean LN for patients who received neoadjuvant therapy was 12.68 ± 6.69 and for patients who did not receive neoadjuvant therapy was 16.29 ± 5.61 ( P = .012). The average size for patients who received neoadjuvant therapy followed by surgery was 3.30 ± 1.10 versus 4.22 ± 1.18 mm for control group (surgery only) ( P < .001), an LNR of 0.13 (sensitivity: 86%, specificity: 47%, AUC: 60%, 95% CI, 0.41%-0.76%) predicted recurrence and metastasis. Presence of lymph nodes with germinal centers was significantly associated with absence of vascular invasion, nodal tumor deposits, distant metastasis, and lower age group (<50 years). However there was no association seen between overall survival and relapse free, total number of lymph nodes enlarged and extracapsular invasion in positive nodes.

Finally there is no association between lymph nodes with germinal centers and tumor response after neoadjuvant treatment in locally advanced rectal cancer.

Risk probability model for residual metastatic lymph node in patients with papillary thyroid microcarcinoma undergoing cervical central lymph node dissection

To establish a risk probability model for residual metastatic lymph nodes in patients with papillary thyroid microcarcinoma (PTMC) after cervical central lymph node dissection (CLND). The clinical data of patients with PTMC treated in the First Affiliated Hospital of Kunming Medical University from 2007 to 2020 were retrospectively reviewed. All patients underwent thyroidectomy with CLND, and at least one lymph node was examined. Based on the distribution characteristics of metastatic lymph nodes from this retrospective cohort, a probabilistic model for the risk of residual metastatic lymph node was established. β-Binomial distribution was used to estimate the probability of residual metastatic lymph node as a function of the number of lymph nodes examined. Among 5399 patients included in the probabilistic model, central lymph node metastases were observed in 1664 cases (30.8%). After model correction, the real lymph node metastasis rate increased from 30.8% to 38.9%. The probability of false negative of central lymph node was estimated to be 31.3% for patients with a single node examined, while decreased to 10.0% and 4.9% when 7 and 12 nodes were examined, respectively. In the sensitivity analysis limited to patients with or without Hashimoto thyroiditis, the performance of probability model was also satisfactory. The established risk probability model in this study quantifies the risk of residual metastatic lymph nodes after CLND in patients with PTMC, which can be used as complementary indicators for the risk of recurrence/persistence disease at postoperative evaluation. The study also provides a new method to evaluate the impact of residual metastatic lymph nodes on the prognosis of tumor patients through retrospective data.

Stage II colon cancer staging using the number of retrieved lymph nodes may be superior to current TNM staging for prognosis stratification: the Japanese study group for postoperative follow-up of colorectal cancer

PURPOSE

The purpose of the study was to compare staging of stage II colon cancer using the number of retrieved lymph nodes (RN) to current TNM staging for stratification of prognosis.

METHODS

The subjects were 6307 patients with stage II colon cancer who underwent curative resection at 24 Japanese institutions. The cutoff for the number of RN was established using Akaike information criterion (AIC) values for relapse-free survival (RFS) and overall survival (OS). Comparison of survival using TNM and T + RN (TRN) staging was performed using a Cox proportional hazards regression model.

RESULTS

AIC was lowest for 14 retrieved lymph nodes for RFS and OS. This number was used as the cutoff. In multivariate analysis, age (≥ 69), male gender, V1, CEA (> 5), pT (T4a, T4b), and RN-L were independent factors associated with RFS and OS. Six combinations of pT and RN categories were used to establish three subgroups: TRN stages IIA, IIB, and IIC. The 5-year RFS was 83.9%, 72.3%, and 71.8% in TNM stages IIA, IIB, and IIC; and 86.0%, 76.9%, and 60.3% in TRN stages IIA, IIB, and IIC. The 5-year OS was 90.0%, 81.3%, and 82.6% for the TNM stages; and 91.6%, 85.0%, and 71.9% for the TRN stages. The AIC for RFS was lower for TRN (22,318.2) than for TNM (22,390.6), and that for OS was also lower for TRN (16,285.3) than for TNM (16,355.1).

CONCLUSION

Stage II colon cancer staging using the number of retrieved lymph nodes may be superior to current TNM staging for prognosis stratification.

Evaluating the adequacy of nodal status in node-negative gallbladder cancer with T1b-T2 stages: use of nodal staging score

BACKGROUND

The study aimed at establishing a nodal staging score (NSS) to quantify the likelihood that pathologic node-negative gallbladder cancer (GBC) patients are indeed free of lymph node (LN) metastasis.

METHODS

Clinicopathological data of 1374 GBC patients with T1b-T2 stages were collected from the Surveillance, Epidemiology and End Result database (design cohort [DC], n = 1289) and the First Affiliated Hospital of Sun Yat-sen University (validation cohort [VC], n = 85). NSS was derived from the count of examined LNs (ELNs) and T stage by using a beta-binomial model, and represented the probability that a node-negative patient is correctly staged. The prognostic value of NSS in node-negative GBC was evaluated by survival analysis.

RESULTS

The probability of missing a nodal disease in node-negative GBC patients with T1b-T2 stages (pT1bN0 and pT2N0) decreased as the number of ELNs increased. NSS increased as the number of ELNs increased. For pT1bN0 and pT2N0 patients, examination of 5 and 27 lymph nodes could ensure an NSS of 90.0%, respectively. Multivariate analysis revealed that NSS was an independent predictor for overall survival in pT1bN0 and pT2N0 GBC patients (DC, HR:0.53, 95%CI: 0.42-0.66, p < 0.001; VC, HR: 0.33, 95%CI: 0.14-0.76, p = 0.009).

CONCLUSION

NSS could evaluate the adequacy of nodal staging and predict the prognosis in pT1bN0 and pT2N0 GBC patients, and hence was helpful to guide their treatment strategies.

Use of Nodal Staging Score in Evaluating the Accuracy of Pathologic Nodal Status in Node-Negative Ampullary Carcinoma

BACKGROUND

The minimum number of lymph nodes (LNs) that should be resected for accurate nodal staging in patients with ampullary carcinoma (AC) remains controversial. This study aimed to establish a nodal staging score (NSS) to evaluate whether a pathological node-negative AC patient is indeed free of a nodal disease.

METHODS

A total of 2539 AC patients with stages I-III were retrieved from the Surveillance, Epidemiology and End Result database (design cohort [DC], n = 2382) and First Affiliated Hospital of Sun Yat-sen University (validation cohort [VC], n = 157). NSS was developed to represent the probability that a node-negative patient was correctly staged as a function of the number of examined LNs (ELNs) and pathologic T stage with a beta-binomial model. Its prognostic value in node-negative patients was assessed by survival analysis.

RESULTS

The probability of missing a metastatic LN decreased as the number of the ELNs increased. NSS was escalated as the number of ELNs increased. For patients with early-stage (T1-T2) and late-stage (T3-T4) tumors, examining 7 and 33 lymph nodes could ensure an NSS of 80.0%, respectively. Multivariate analysis showed that higher NSS was an independent favorable prognostic factor for overall survival in node-negative patients with AC (DC, p < 0.001; VC, p = 0.001).

CONCLUSIONS

NSS model could be used to evaluate the accuracy of nodal staging and predict the prognosis of node-negative AC patients. It could assist in making clinical strategies in node-negative AC patients.

Role of Lymph Node Resection and Histopathological Evaluation in Accurate Staging of Nonfunctional Pancreatic Neuroendocrine Tumors: How Many Are Enough?

BACKGROUND

Nodal involvement has been identified as one of the strongest prognostic factors in patients with nonfunctional pancreatic neuroendocrine tumors (NF-PanNETs). Sufficient lymphadenectomy and evaluation is vital for accurate staging. The purpose of this study was to identify the optimal number of examined lymph nodes (ELN) required for accurate staging.

METHODS

The SEER database was used to identify patients with resected NF-PanNETs between 2004 and 2014. The distributions of positive lymph nodes (PLN) ratio and total lymph nodes were used to develop a mathematical model. The sensitivity of detecting nodal disease at each cutoff of ELN was estimated and used to identify the optimal cutoff for ELN.

RESULTS

A total of 1098 patients were included in the study of which 391 patients (35.6%) had nodal disease. The median ELN was 12 (interquartile range [IQR]: 7-19.5), and the median PLN was 2 (IQR: 1-4) for patients with nodal disease. With an increase in ELN, the sensitivity of detecting nodal disease increased from 12.0% (ELN: 1) to 92.2% (ELN: 20), plateauing at 20 ELN (< 1% increase in sensitivity with an additional ELN). This sensitivity increase pattern was similar in subgroup analyses with different T stages.

CONCLUSIONS

The sensitivity of detecting nodal disease in patients with NF-PanNETs increases with an increase in the number of ELN. Cutoffs for adequate nodal assessment were defined for all T stages. Utilization of these cutoffs in clinical settings will help with patient prognostication and management.

Impact of Examined Lymph Node Count for Esophageal Squamous Cell Carcinoma in Patients who Underwent Right Transthoracic Esophagectomy

BACKGROUND

The impact of the number of examined lymph nodes (ELNs) on stage correction and prognostication in patients with esophageal squamous cell carcinoma (ESCC) who underwent right transthoracic esophagectomy is still unclear.

METHODS

Patients with ESCC who underwent right transthoracic esophagectomy at Sun Yat-sen University Cancer Center between January 1997 and December 2013 were retrospectively enrolled. The Cox proportional hazards regression model was used to determine the effect of ELN count on overall survival. The impact of ELN count on stage correction was evaluated using the hypergeometric distribution and Bayes theorem and β-binomial distribution estimation, respectively. The threshold of ELNs was determined using the LOWESS smoother and piecewise linear regression.

RESULTS

Among the 875 included patients, greater ELNs were associated with a higher rate of nodal metastasis. Significant association between staging bias and the number of ELNs is only observed through the Bayes method. The ELN count did not impact 90-day mortality but significantly impacted long-term survival (adjusted hazard ratio [aHR] 0.986), especially in those patients with node-negative disease (aHR 0.972). In patients with node-negative disease, cut-point analysis showed a threshold ELN count of 21.

CONCLUSIONS

A greater number of ELNs is associated with more accurate node staging and better long-term survival in resected ESCC patients. We recommended harvesting at least 21 LNs to acquire accurate staging and long-term survival information for patients with declared node-negative disease using the right thoracic approach.

Application of clockwise modularized laparoscopic lymphadenectomy in the suprapancreatic area, a propensity score matching study and comparison with open gastrectomy

BACKGROUND

Suprapancreatic lymphadenectomy is the essence of D2 radical gastric cancer surgery. The present study aimed to describe clockwise modularized laparoscopic lymphadenectomy in the suprapancreatic area.

METHODS

The data from gastric cancer patients who underwent surgical treatment from September 2016 to December 2018 were collected. Patients were divided into clockwise modularized lymphadenectomy (CML) and traditional open gastrectomy (OG) groups according to the surgical treatment strategy. The propensity score matching method was utilized to balance the baseline characteristics between the two groups.

RESULTS

Finally, 551 gastric cancer patients were included in the present study. Following propensity score matching, 106 pairs of patients in the CML group and OG group were included in the final analysis. The CML group had more total examined lymph nodes (36, IQR 28-44.74 vs. 29, IQR 29-39.5, p = 0.002) and no. 9 station nodes (2, IQR 1-5 vs. 2, IQR 1-3, p = 0.007) than the OG group. There was less intraoperative blood loss (30, IQR 20-80 ml vs. 80, IQR 50-80 ml, p < 0.001) and a longer surgical duration (262.5 min, IQR 220-303.25 min vs. 232, IQR 220-255 min, p < 0.001) in the CML group than in the OG group. The incidence of postoperative complications (19.8% vs. 16.0%, p = 0.591) and postoperative hospital stay (8, IQR 7-9 days vs. 8, IQR 7-9 days, p = 0.452) were comparable between the CML and OG groups.

CONCLUSION

Laparoscopic lymphadenectomy for gastric cancer surgery is technically demanding. Clockwise modularized laparoscopic lymphadenectomy in the suprapancreatic area can attain similar effects as traditional open surgery and without an increase in postoperative adverse events.

Lymph node yield in pediatric, adolescent and young adult Renal Cell Carcinoma - How many are enough?

PURPOSE

Pediatric, adolescent and young adult (PAYA) patients with renal cell carcinoma (RCC) have a high rate of LN involvement, yet data to guide surgical lymph node (LN) management in this group is limited. The objective is to describe a LN yield threshold to quantify the chance of missing occult LN involvement at ≤10% in PAYAs with RCC.

MATERIALS & METHODS

The National Cancer Database was queried for patients aged ≤30 y with unilateral, non-metastaticRCC from 2004 to 2013. The probability of a false negative LN sampling was determined on the cohort of patients who had at least one positive LNand ≥ 2 LNs examined. For a given LN yield, the probability that a positive LN exists but none were found was estimated using a beta-binomial model.

RESULTS

We identified 112 patients meeting study criteria. Median age was 24 y and median tumor size was 9.5 cm (IQR 5.8-14). The median number of LNs sampled was 7 (IQR 4-12) and the median number of LNs positive was 4 (IQR 2-7). To achieve ≤10% probability of a false-negativeLN sampling, the beta-binomial model estimated that 5 LNs (95% CI4-7) must be sampled.

CONCLUSIONS

The desired LN yield to reduce the risk of a false-negativeLN sampling in PAYAs with RCC to ≤10% is 5. This is in keeping with prior studies identifying a LN yield of 6-10 to achieve the same. These data may be used to standardize surgical guidelines when treating PAYAs with renal tumors.

LEVEL OF EVIDENCE

II.

Superior prognosis stratification for stage III colon cancer using log odds of positive lymph nodes (LODDS) compared to TNM stage classification: the Japanese study group for postoperative follow-up of colorectal cancer

OBJECTIVES

The aim of this study is to examine whether prognosis stratification in staging of Stage III colon cancer using T factor and log odds of positive lymph nodes (LODDS) categories is superior to that of the TNM staging system.

MATERIALS AND METHODS

The subjects were 5,919 patients with Stage III colon cancer who underwent curative resection at 24 Japanese institutions. Univariate analysis of LODDS categories and clinicopathologic factors was conducted using a Cox proportional hazards regression model for cancer-specific survival (CSS). Independent prognostic factors for CSS were extracted in multivariate analysis using factors with significance in univariate analysis. Effect sizes of risk factors for CSS were compared using the LogWorth statistic. Combinations of T factor and LODDS categories were used to create L-stage subgroups A, B and C. Stratification of prognosis with L-stage and TNM was compared using the Akaike information criterion (AIC).

RESULTS

In multivariate analysis, LODDS was identified as an independent prognostic factor, together with age, maximum tumor diameter, histopathological grade, L, V, pT, and pN. The LogWorth of LODDS was 17.149, which was the second highest after pT (31.562), and that of pN was 7.434. The 5-year CSS was 96.5%, 88.5%, and 66.6% in TNM stages IIIA, IIIB, and IIIC, respectively, and 96.0%, 87.6%, and 59.3% in L-stage A, B, and C, respectively (p < 0.0001). AICs for TNM and L-stage were 14,795.5 and 14,707.8, respectively.

CONCLUSIONS

Prognosis stratification of the stage classification for Stage III colon cancer was superior with L-stage compared to TNM stage classification.

Nodes staging score to quantify lymph nodes for examination in gastric cancer

The lymph nodal invasion diagnosis is critical for therapeutic-decision and follows up in gastric cancer. However, the number of nodes to be examined for nodal invasion diagnosis is still under controversy, and the model for quantifying risk of missing positive node is currently not reported yet. We analyzed the nodal invasion status of 13,857 gastric cancer samples with records of primary tumor stage, the number of examined and positive lymph nodes in the surveillance, epidemiology, and end results (SEER) database, fitting a beta-binomial model. The nodes need to be examined with different primary tumor stage were determined based on the model. Overall, examining 11 lymph nodes reduces the probability of missing positive nodes to <10%, and the currently median nodes dissected is adequate (12 nodes). While the number of nodes demands to be dissected for T1, T2, T3, and T4 subgroups are 6, 19, 40, and 66, respectively. The currently implemented median value for these samples was 12, 12, 13, and 16, separately. It implies that the number of nodes to be examined is sufficient for early gastric cancer (T1), but it is inadequate for middle and advanced gastric cancer (T2-T3). The clinical significance of nodal staging score was validated with survival information. In summary, we first quantified the lymph nodes to be examined during surgery using a beta-binomial model, and validated with survival information.

How many lymph nodes should be dissected in esophagectomy with or without neoadjuvant therapy to get accurate staging?

It is essential to dissect an adequate number of lymph nodes (LNs) to ensure staging accuracy during esophagectomy with or without neoadjuvant therapy. We developed a statistical model to quantify the probability of precise nodal staging based on previous studies. Esophageal cancer patients who underwent esophagectomy were retrospectively reviewed in the Surveillance, Epidemiology, and End Results database. A β-binomial distribution was adopted to estimate the number of understaged patients based on the numbers of positive and examined LNs. Using 6,252 patients, we estimated a 90% confidence of accurate N0 staging could be achieved by examining 17 LNs without neoadjuvant therapy. To obtain similar accuracy in N1 and N2, 20 and 25 LNs should be examined. For patients with neoadjuvant therapy, 18, 19, and 28 LNs could achieve the same accuracy. Staging accuracy was a significant prognostic factor. We found when 90% confidence had been achieved, patient survival did not improve with more LNs examined and the ratio and log odds of positive LNs did not have significant prognostic values. The statistical model we developed for precise staging in patients with different N stages is of great value in guiding lymphadenectomy. It provided risk assessment for underestimated LN metastases and guided subsequent adjuvant treatment.

How many lymph nodes are enough? Assessing the adequacy of lymph node yield for staging in favorable histology wilms tumor

PURPOSE

Current investigational priorities in the treatment of favorable histology Wilms tumor (FHWT) center on accurate staging and risk-stratification. The extent of lymph node (LN) sampling has not been clearly defined; its importance cannot be overstated as it guides adjuvant therapy. The identification of a minimum LN yield to minimize the risk of harboring occult metastatic disease could help development of surgical guidelines. This study focuses on using the beta-binomial distribution to estimate the risk of occult metastatic disease in patients with FHWT.

MATERIALS & METHODS

The National Cancer Database was queried for patients with unilateral FHWT from 2004 to 2013. Data were used to characterize nodal positivity for patients who underwent surgery and had ≥1 positive LN and ≥2 LNs examined. The probability of missing a positive LN (i.e., false negative) for a given LN yield was calculated using an empirical estimation and the beta-binomial model. Patients were then stratified by tumor size.

RESULTS

422 patients met study criteria. To limit the chance of missing a positive LN to ≤10%, the empirical estimation and beta-binomial model estimated that 6 and 10 LNs needed to be sampled, respectively. Tumor size did not influence the result. Internal validation showed little variation to maintain a false negative rate ≤ 10%.

CONCLUSIONS

Using mathematical modeling, it appears that the desired LN yield in FHWT to reduce the risk of false-negative LN sampling to ≤10% is between 6 and 10. The current analysis represents an objective attempt to determine the desired surgical approach to LN sampling to accurately stage patients with FHWT.

LEVEL OF EVIDENCE

II.

Quantifying the number of lymph nodes for examination in breast cancer

OBJECTIVE

Examining the correct number of lymph nodes when diagnosing breast cancer invasion is still a problem. This work aimed to develop a qualification model that estimates the possibility of missing nodes and the number of lymph nodes that need to be examined.

METHODS

By analyzing lymph node invasion of 303,760 breast cancer samples with primary tumor stage and the number of examined and positive lymph nodes from the Surveillance, Epidemiology and End Results database using a beta-binomial model, the number of nodes that should be examined was quantified in different stages.

RESULTS

In general, to reduce the possibility of missing positive nodes to less than 10%, 21 lymph nodes should be examined; thus, the current median of dissected nodes (12) is not adequate. The number of nodes needed to be dissected for stages T1, T2, and T3 are 8, 37, and 87, respectively. Currently, the median number of node dissections for these stages were 12, 13, and 14, respectively. The clinical significance of the nodal staging score was validated with survival information.

CONCLUSION

Currently, the number of lymph nodes dissected in breast cancer are excessive for T1 but insufficient for T2 and T3.

Accuracy of nodal staging is influenced by sidedness in colon cancer

Background

Adequate lymph node (LN) sampling is critical for accurate nodal staging in colon cancer (CC), particularly for T3N0 disease as current guidelines recommend considering adjuvant chemotherapy when less than 12 LNs are examined. The impact of sidedness on nodal staging accuracy in patients with T3N0 disease has not been previously studied.

Methods

Patients with pathologic T3 CC were identified from a prospective multicenter international trial of ultrastaging in CC. The probability of true nodal negativity (TNN) based on the number of LN examined was calculated for right and left CC. These results were then validated in a cohort of patients with similar inclusion criteria selected from the National Cancer Database (NCDB) between 2006 and 2014.

Results

Three hundred and seventy patients met the inclusion criteria in the trial cohort; 48% were LN-negative. Of 153,945 patients in the NCDB, 57% were LN-negative. The probability of TNN when 12 LNs were examined was 68% for right and 64% for left CC in the trial cohort and 77% and 72% in the NCDB. The number of LNs needed to achieve any given probability of TNN was significantly different between right and left CC in both the trial (P<0.001) and the NCDB (P<0.001).

Conclusions

In both a prospective multicenter trial and the NCDB, sidedness influences the number of LNs needed to predict nodal negativity in CC. Current guidelines regarding the minimum number of LNs needed to accurately stage patients with T3N0 CC may need to be re-evaluated by taking into consideration the tumor sidedness.

Positron Emission Tomography/Computed Tomography-Based Assessments of Androgen Receptor Expression and Glycolytic Activity as a Prognostic Biomarker for Metastatic Castration-Resistant Prostate Cancer

Importance

Androgen receptor-signaling inhibitor (ARSi) drugs prolong life in metastatic castration-resistant prostate cancer (mCRPC), but such tumors eventually become resistant and progress. Comprehensive positron emission tomography/computed tomography (PET/CT) imaging using fluoro-2-D-deoxyglucose F 18 ([18F]-FDG) for glycolysis (Glyc) and fluorodihydrotestosterone F 18 ([18F]-FDHT) for androgen receptor (AR) expression determine heterogeneity of imaging phenotypes, which may be useful in distinguishing patients who will benefit from ARSi drugs from those who need alternative treatments.

Objective

To test the hypothesis that PET/CT-based assessments of AR expression and glycolytic activity would reveal heterogeneity affecting prognosis.

Design, Setting, and Participants

Between April 6, 2007, and October 4, 2012, patients with mCRPC underwent imaging with both [18F]-FDG and [18F]-FDHT at Memorial Sloan Kettering Cancer Center. The patients were naive to ARSi treatment with enzalutamide or abiraterone acetate and were referred during documented disease progression. Image-directed biopsy determined the presence or absence of prostate cancer at positive imaging sites.

Interventions

PET/CT imaging was performed with [18F]-FDHT and [18F]-FDG; select individual lesions were biopsied to correlate imaging phenotype with histologic findings.

Main Outcomes and Measures

All metabolically active lesions were interpreted as [18F]-FDHT-positive (AR1) or [18F]-FDHT-negative (AR0) and as [18F]-FDG-positive (Glyc1) or [18F]-FDG-negative (Glyc0). Correlation was performed with overall survival for both individual lesion imaging phenotype as well as patient-specific imaging phenotype.

Results

The mean (SD) age of the 133 patients was 68 (8.6) years. Imaging phenotypes of 2405 PET/CT-positive lesions (median, 12.0 per patient) included 1713 (71.2%) AR1Glyc1, 386 (16.0%) AR1Glyc0, and 306 (12.7%) AR0Glyc1. On multivariate analysis, each phenotype had an independent negative impact effect on survival, most pronounced for AR0Glyc1 lesions (hazard ratio [HR], 1.11; 95% CI, 1.05-1.16; P < .001), followed by AR1Glyc1 lesions (HR, 1.05; 95% CI, 1.03-1.06; P < .001) and AR1Glyc0 lesions (HR, 1.03; 95% CI, 1.00-1.05; P = .048). When sorted by lesion type, 4 patient-specific groups emerged: (1) concordant, with all AR1Glyc1 (34 patients [25.6%]); (2) AR predominant, with AR1Glyc1 and varying numbers of AR1Glyc0 (33 [24.8%]); (3) Glyc predominant, with AR1Glyc1 and varying numbers of AR0Glyc1 (40 [30.1%]); and (4) mixed, with AR1Glyc1 plus a mixture of varying numbers of AR1Glyc0 and AR0Glyc1 (26 [19.5%]).

Conclusions and Relevance

Heterogeneity of PET/CT imaging phenotype has clinical relevance on a lesion and individual patient level. With regard to mCRPC lesions, most express ARs, consistent with initial benefit of ARSi drugs. On a patient basis, 49% (groups 3 and 4) had at least 1 AR0Glyc1 lesion-the imaging phenotype with the most negative effect on survival, possibly due to ARSi resistance.

Development and external validation of a pathological nodal staging score for patients with clear cell renal cell carcinoma

OBJECTIVES

To develop and externally validate a model that quantifies the likelihood that a pathologically node-negative patient with clear cell renal cell carcinoma (cRCC) has, indeed, no lymph node metastasis (LNM).

PATIENTS AND METHODS

Data from 1389 patients treated with radical nephrectomy (RN) and lymph node dissection (LND) were analyzed. For external validation, we used data from 2270 patients in the Surveillance, Epidemiology and End Results (SEER) database. We estimated the sensitivity of pathologic nodal staging using a beta-binomial model and developed a pathological nodal staging score (pNSS), which represents the probability that a patient is correctly staged as node negative as a function of the number of examined lymph nodes (LNs).

RESULTS

The mean and median number of LNs removed were 7.0 and 5.0 (standard deviation, SD 6.6; interquartile range, IQR 7.0) in the development cohort and 5.6 and 2.0 (SD 8.6, IQR 5.0) in the validation cohort, respectively. The probability of missing a positive LN decreased with increasing number of LNs examined. In both the validation and the development cohort, the number of LNs needed for correctly staging a patient as node negative increased with higher pathological tumor stage and Fuhrman grade.

CONCLUSIONS

The number of examined LNs needed for adequate nodal staging in cRCC depends on pathological tumor stage and Fuhrman grade. We developed here and then externally validated a pNSS, which could help to refine patient counseling, decision-making regarding risk-stratified surveillance regimens and inclusion criteria for clinical trials of adjuvant therapy.

Clinical Implications of Lymph Node Metastasis in Colorectal Cancer: Current Status and Future Perspectives

Lymph node metastasis is regarded as an indubitable prognostic factor for predicting disease recurrence and survival in patients with colorectal cancer. Lymph node status based on examination of a resected specimen is a key element of the current staging system and is also a crucial factor to determine use of adjuvant chemotherapy after surgical resection. However, the current tumor-node-metastasis (TNM) staging system only incorporates the number of metastatic lymph nodes in the N category. Numerous attempts have been made to supplement this simplified N staging including lymph node ratio, distribution of metastatic lymph nodes, tumor deposits, or extracapsular invasion. In addition, several attempts have been made to identify more specific prognostic factors in resected colorectal specimens than lymph node status. In this review, we will discuss controversies in lymph node staging and factors that may influence survival beyond lymph node status.

Contemporary Validation of a Nomogram Predicting Colon Cancer Recurrence, Revealing All-Stage Improved Outcomes

Background

The Memorial Sloan Kettering Cancer Center (MSK) colon cancer recurrence nomogram is a risk calculator that provides patients and clinicians with individualized prediction of recurrence following curative resection of colon cancer. Although validated on multiple separate cohorts, the nomogram requires periodic updating as patient care changes over time. The aim of this study was to evaluate the nomogram’s accuracy in a contemporary cohort and modify the tool to reflect improvements in outcome related to advances in colon cancer therapy.

Methods

A contemporary patient cohort was compiled, including consecutive colon cancer patients undergoing curative resection for stage I–III colon adenocarcinoma at MSK from 2007 to 2014. The nomogram’s predictive accuracy was assessed by concordance index and calibration plots of predicted vs actual freedom from recurrence at 5 years after surgery.

Results

Data from a total of 999 eligible patients with complete records were used for validation. Median follow-up among survivors was 37 months. The concordance index was 0.756 (95% confidence interval = 0.707 to 0.805), indicating continued discriminating power, but the calibration plot revealed that the nomogram overestimated recurrence risk. Recalibration of the nomogram by estimating a new baseline freedom-from-recurrence function restored the nomogram’s accuracy.

Conclusion

The updated nomogram retains the original nomogram’s variables but includes a lower baseline estimation of recurrence risk, reflecting improvements in outcomes for all stages of colon cancer, likely resulting from advances in imaging and integration of multiple treatment modalities.

Nodal staging score and adequacy of nodal staging

Aims

The number of lymph nodes (LNs) excised in patients with pathologic N0 is limited, and it is very likely that there will be recessive node disease after surgery, so they are at risk of understaging. The purpose of the present study is to develop a nodal staging score (NSS) in a mathematical way to assess the likelihood that a pathologic N0 gastric cancer (GCa) patient has, indeed, no occult nodal disease after surgery.

Patients and methods

A total of 14,033 stage I-III GCa patients were identified from Surveillance, Epidemiology and End Results database for analysis. A beta-binomial model was fitted to calculate the probability of missing a nodal disease. This probability is then used to calculate the NSS.

Results

The probability of missing a nodal disease is decreased with increasing LNs examined across all pT stages. Seven and 24 LNs removed and examined was enough for an NSS of 90% in pT1 and pT2 patients, respectively, ensuring a high confidence of correct nodal negative classification. Twenty-three and 31 LNs examined in pT3 and pT4 patients could also maintain the NSS at 80%, respectively. NSS had a significant impact on patients' survival across all pT stages (all Ps <0.0001).

Conclusion

The probability that GCa patients are free of true nodal disease could be provided by NSS-based prediction, which is conducive to postoperative decision and survival surveillance. In addition, NSS can define a subtle standard on how many LNs examined are enough for adequate staging dependent on pT stages. However, at least 16 LNs examined is the standard recommendation to date.

Pathological nodal staging score for rectal cancer patients treated with radical surgery with or without neoadjuvant therapy: a postoperative decision tool

Background

Lymph node status can predict the prognosis of patients with rectal cancer treated with surgery. Thus, we sought to establish a standard for the minimum number of lymph nodes (LNs) examined in patients with rectal cancer by evaluating the probability that pathologically negative LNs prove positive during surgery.

Patients and methods

We extracted information of 31,853 patients with stage I–III rectal carcinoma registered between 2004 and 2013 from the Surveillance, Epidemiology, and End Results database and divided them into two groups: the first group was SURG, including patients receiving surgery directly and the other group was NEO, encompassing those underwent neo-adjuvant therapy. Using a beta-binomial model, we developed nodal staging score (NSS) based on pT/ypT stage and the number of LNs retrieved.

Results

In both cohorts, the false-negative rate was estimated to be 16% when 12 LNs were examined, but it dropped to 10% when 20 LNs were evaluated. In the SURG cohort, to rule out 90% possibility of false staging, 3, 7, 28, and 32 LNs would be necessarily examined in patients with pT1–4 disease, respectively. While in the NEO cohort, 4, 7, 12, and 16 LNs would be included for examination in patients with ypT1–4 disease to guarantee an NSS of 90%.

Conclusion

By determining whether a rectal cancer patient with negative LNs was appropriately staged, the NSS model we developed in this study may assist in tailoring postoperative management.

Determining the optimal number of examined lymph nodes for accurate staging of pancreatic cancer: An analysis using the nodal staging score model

INTRODUCTION

The aim of this study was to determine the optimal number of examined lymph nodes (ELNs) for accurate staging of pancreatic cancer using the nodal staging score model.

MATERIALS AND METHODS

Clinicopathological data for patients with resected pancreatic cancer were collected from SEER database (development cohort [DC]) and Fudan University Shanghai Cancer Center database (validation cohort [VC]). Multivariable models were constructed to assess how the number of ELNs was associated with stage migration and overall survival (OS). Using the β-binomial distribution, we developed a nodal staging score model from the DC and tested it with the VC.

RESULTS

Both cohorts exhibited significant proportional increases from node-negative to node-positive disease (DC: odds ratio [OR], 1.047; P < 0.001; VC: OR, 1.035; P < 0.001) and improved OS (DC: hazard ratio [HR], 0.982; P < 0.001; VC: HR, 0.979; P < 0.001) as ELNs increased. Nodal staging scores escalated separately as ELNs increased for different tumor (T) stages, with plateaus at 16, 21, and 23 LNs (cut-offs) for T1, T2, and T3 tumors, respectively. Multivariable analysis indicated that examining more LNs than the corresponding cut-off value was a significant survival predictor (DC: HR, 0.813; P < 0.001; VC: HR, 0.696; P = 0.028).

CONCLUSION

The optimal number of ELNs for adequate staging of pancreatic cancer was related to T stage. We recommend examining at least 16, 21, and 23 LNs for T1, T2, and T3 tumors, respectively, as a nodal staging quality measure for both surgery and pathological analysis.

How to evaluate the adequacy of staging for nodal-negative epithelial ovarian cancer? Use of nodal staging score

OBJECTIVE

No guideline has been provided to assess the minimal number of lymph nodes (LNs) that should be dissected for accurate staging in patients with epithelial ovarian cancer (EOC). The aim of the study was to develop a nodal staging score (NSS) as an index to assess whether a pathologic (p)N0 EOC patient is indeed free of a nodal disease.

METHODS

A total of 16,361 EOC patients staged I-III between 2004 and 2013 were identified from the Surveillance, Epidemiology and End Result database. With a β-binomial model, NSS was calculated to assess the probability of true-negative findings of LN status.

RESULTS

With an increased number of LNs examined, the probability of missing a nodal disease decreased and varied among different pT stages. Given 1 LN examined, an NSS of 93.76% calculated could ensure a high adequacy of nodal-negative classification for pT1N0 EOC patients. For pT2N0 patients, 5 LNs examined could guarantee an NSS of 90% for adequate staging. Likewise, 11 and 29 LNs examined in pT3N0 patients could maintain NSS at the level of 80% and 90%, respectively. Our study suggested the optimal number of LNs that could be examined and stratified by the pT stages for EOC patients based on this statistical model derived from large pathologic data of clinical surgery patients.

CONCLUSION

NSS, as an auxiliary tool, not only could assist the International Federation of Gynecology and Obstetrics staging more precisely, but also would provide a statistical basis for postoperative evaluation for further clinical decision-making.

The lymph node status as a prognostic factor in colon cancer: comparative population study of classifications using the logarithm of the ratio between metastatic and nonmetastatic nodes (LODDS) versus the pN-TNM classification and ganglion ratio systems

Background

pN stage in the TNM classification has been the “gold standard” for lymph node staging of colorectal carcinomas, but this system recommends collecting at least 12 lymph nodes for the staging to be reliable. However, new prognostic staging systems have been devised, such as the ganglion quotients or lymph node ratios and natural logarithms of the lymph node odds methods. The aim of this study was to establish and validate the predictive and prognostic ability of the lymph node ratios and natural logarithms of the lymph node odds staging systems and to compare them to the pN nodal classification of the TNM system in a population sample of patients with colon cancer.

Methods

A multicentric population study between January 2004 and December 2007. The inclusion criteria were that the patients were: diagnosed with colon cancer, undergoing surgery with curative intent, and had a complete anatomopathological report. We excluded patients with cancer of the rectum or caecal appendix with metastases at diagnosis. Survival analysis was performed using the Kaplan–Meier actuarial method and the Log-Rank test was implemented to estimate the differences between groups in terms of overall survival and disease-free survival. Multivariate survival analysis was performed using Cox regression.

Results

We analysed 548 patients. For the overall survival, the lymph node ratios and natural logarithms of the lymph node odds curves were easier to discriminate because their separation was clearer and more balanced. For disease-free survival, the discrimination between the pN0 and pN1 groups was poor, but this phenomenon was adequately corrected for the lymph node ratios and natural logarithms of the lymph node odds curves which could be sufficiently discriminated to be able to estimate the survival prognosis.

Conclusions

Lymph node ratios and natural logarithms of the lymph node odds techniques can more precisely differentiate risk subgroups from within the pN groups. Of the three methods tested in this study, the natural logarithms of the lymph node odds was the most accurate for staging non-metastatic colon cancer. Thus helping to more precisely adjust and individualise the indication for adjuvant treatments in these patients.

CUSUM charts in the quality control of colon cancer lymph node analysis: a population-registry study

Background

The most important determinant of survival in patients with colon cancer is the presence or absence of regional lymph node metastases. This factor is consistently associated with long-term and disease-specific survival. Cumulative summation of differences (CUSUM) charts can help to discriminate abnormalities that cannot be explained by the general variability of a process. We used CUSUM charts to analyse the quality of nodal analysis in colon cancer and to use a population-registry cancer database to estimate the optimal number of lymph nodes for adequate prognostic analysis.

Methods

This was a multicentre population-registry cancer study from January 2004 to December 2007. We used these data to produce the different CUSUM curves, focusing on the main variables. To calculate survival, we used the Kaplan–Meier method.

Results

In this study, we examined 548 patients. The CUSUM curves were calculated for overall mortality, specific mortality, and recurrence according to (1) the number of lymph nodes analysed and affected and (2) compared the ratio of the number of lymph nodes affected to the number analysed. Finally, the lymph node ratio was compared to the overall survival CUSUM curve.

Discussion

This CUSUM control chart analysis reinforces the unquestionable importance of analysing at least 12 lymph nodes in patients with colon cancer in order to accurately estimate their prognosis. However, our findings indicate that the analysis of at least 20 lymph nodes is a more appropriate cutoff point for accomplishing the demanding objective of diagnosing a high-quality prognosis in colon cancer patients.

A statistical tool for risk assessment as a function of the number of lymph nodes retrieved from rectal cancer patients

AIM

Although a minimum of 12 lymph nodes (LNs) has been recommended for examination in colorectal cancer patients there remains considerable debate with regard to rectal cancer. Inadequacy of examined LNs could lead to understaging and inappropriate treatment as a consequence. We describe a statistical tool that allows an estimate of the probability of false-negative nodes.

METHOD

A total of 26 778 patients diagnosed between 2004 and 2013 with rectal adenocarcinoma [tumour stage (T stage) 1-3] who did not receive neoadjuvant therapies and had at least one histologically assessed LN were extracted from the Surveillance, Epidemiology and End Results (SEER) database. A statistical tool using beta-binomial distribution was developed to estimate the probability of missing a positive node as a function of the total number of LNs examined and T stage.

RESULTS

The probability of falsely identifying a patient as node-negative decreased with increasing number of nodes examined for each stage. It was estimated to be 72%, 66% and 52% for T1, T2 and T3 patients, respectively, with a single node examined. To confirm an occult nodal disease with 90% confidence, 5, 9 and 29 nodes need to be examined for patients from stages T1, T2 and T3, respectively.

CONCLUSION

The false-negative rate of the examined LNs in rectal cancer was verified to be dependent preoperatively on the clinical T stage. A more accurate nodal staging score was developed to recommend a threshold for the minimum number of examined nodes with regard to the favoured level of confidence.

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.