Clinical value of station 4R node dissection in esophageal squamous cell carcinoma

BACKGROUND

Many controversies still exist concerning the optimal extent of lymphadenectomy during esophagectomy in esophageal squamous cell carcinoma (ESCC). The objective of this study was to explore the characteristics of 4R metastasis and evaluate the clinical value of 4R node dissection in ESCC.

METHODS

A total of 736 ESCC patients who underwent radical esophagectomy between 2005 and 2013 were retrospectively collected, among which 393 ones underwent 4R dissection. Propensity score matching (PSM) method was applied to reduce the effects of confounding variables between the 4R dissection and non-dissection groups to analyze overall survival.

RESULTS

Patients showed a low 4R metastasis rate of 5.1% (20/393) (5.2%, 5.8%, and 1.8% for upper, middle, and lower tumors, respectively). Correlation analyses identified that 4R metastasis was significantly associated with station 2R metastasis (p < 0.001) and pathologic tumor-node-metastasis (pTNM) stage (p < 0.001). All 4R metastases were observed in stages IIIB and IVA. Moreover, patients with station 4R dissection failed to achieve significantly improved overall survival compared with those without 4R dissection, regardless of tumor stage (overall: p = 0.696; stage 0-IIIA: p = 0.317; stage IIIB-IVA: p = 0.619).

CONCLUSION

4R metastasis is likely to be associated with more aggressive disease, and routine 4R node dissection might not be necessary for ESCC patients.

Pararespiratory and paradigestive lymph node metastases in esophageal squamous cell carcinoma: predicting survival and refining the N staging system

BACKGROUND

The site of lymph node metastasis (LNM) may affect the prognosis of patients with esophageal squamous cell carcinoma (ESCC). To investigate the prognoses of pararespiratory and paradigestive LNM and to propose a novel N (nN) staging system that integrates both the LNM site and count.

METHODS

This study was a multicenter, large-sample, retrospective cohort study that included ESCC patients with LNM between January 2014 and December 2019 from three Chinese institutes. Patients were set into training (two institutes) and external validation (one institute) cohorts. The primary outcomes were survival differences in LNM site and the development of novel nodal staging system. The overall survival (OS) of patients with pararespiratory LNM only (Group A), paradigestive LNM only (Group B), and both sites (Group C) was evaluated by Kaplan-Meier. Cox proportional hazards models were used to identify the independent prognostic factors. An nN staging system considering both the LNM site and count was developed and evaluated by the area under the receiver operating characteristic curve (AUC).

RESULTS

In total, 1313 patients were included and split into training (n = 1033) and external validation (n = 280) cohorts. There were 342 (26.0%), 568 (43.3%) and 403 (30.7%) patients in groups A, B and C, respectively. The OS of patients with pararespiratory and patients with paradigestive LNM presented significant differences in the training and validation cohorts (P < 0.050). In the training cohort, LNM site was an independent prognostic factor (hazard ratio: 1.58, 95% confidence intervals: 1.41-1.77, P < 0.001). The nN staging definition: nN1 (1-2 positive pararespiratory/paradigestive LNs), nN2 (3-6 pararespiratory LNs or 1 pararespiratory with 1paradigestive LN), nN3 (3-6 LNs with ≥ 1 paradigestive LN), nN4 (≥ 7 LNs). Subsets of patients with different nN stages showed significant differences in OS (P < 0.050). The prognostic model of the nN staging system presented higher performance in the training and validation cohorts at 3-year OS (AUC, 0.725 and 0.751, respectively) and 5-year OS (AUC, 0.740 and 0.793, respectively) than the current N staging systems.

CONCLUSIONS

Compared to pararespiratory LNM, the presence of paradigestive LNM is associated with worse OS. The nN staging system revealed superior prognostic ability than current N staging systems.

Defining a minimum number of examined lymph nodes improves the prognostic value of lymphadenectomy in pancreas ductal adenocarcinoma

BACKGROUND

Lymph node (LN) metastasis is associated with decreased survival following resection for pancreatic ductal adenocarcinoma (PDAC). In N0 disease, increasing total evaluated LN (ELN) correlates with improved outcomes suggesting patients may be understaged when LNs are undersampled. We aim to assess the optimal number of examined lymph nodes (ELN) following pancreatectomy.

METHODS

Data from 1837 patients undergoing surgery were prospectively collected. The binomial probability law was utilized to analyze the minimum number of examined LNs (minELN) and accurately characterize each histopathologic stage. LN ratio (LNR) was compared to American Joint Committee on Cancer (AJCC) guidelines.

RESULTS

As ELN total increased, the likelihood of finding node positive disease increased. An evaluation based upon the binomial probability law suggested an optimal minELN of 12 for accurate AJCC N staging. As the number of ELNs increased, the discriminatory capacity of alternative strategies to characterize LN disease exceeded that offered by AJCC N stage.

CONCLUSION

This is the first study dedicated to optimizing histopathologic staging in PDAC using models of minELN informed by the binomial probability law. This study highlights two separate cutoffs for ELNs depending upon prognostic goal and validates that 12 LNs are adequate to determine AJCC N stage for the majority of patients.

Endobronchial Ultrasound Improves Evaluation of Recurrent Laryngeal Nerve Lymph Nodes in Esophageal Squamous Cell Carcinoma Patients

BACKGROUND

The bilateral recurrent laryngeal nerve (RLN) lymph nodes are the most common metastatic site for esophageal squamous cell carcinoma (ESCC); however, the RLNs are susceptible to injury during dissection. Clinically, there is an urgent need to determine an effective diagnostic method for RLN nodes to help achieve selective nodal dissection and avoid potential serious complications by performing more conservative surgery for those with nonmetastatic nodes. Here, we innovatively applied endobronchial ultrasonography (EBUS) and investigated its diagnostic performance for preoperative evaluation of RLN nodes in ESCC patients.

PATIENTS AND METHODS

All 81 enrolled ESCC patients underwent preoperative EBUS and CT examinations. The ability of EBUS and CT to detect RLN node metastasis was evaluated based on the resulting sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV).

RESULTS

The diagnostic performance of EBUS was superior to that of CT; in particular, EBUS of the left RLN (L-RLN) nodes presented the best sensitivity, specificity, PPV, NPV, and accuracy compared with EBUS evaluations of the right RLN (R-RLN) nodes, CT of the L-RLN and R-RLN nodes. Moreover, EBUS combined with CT increased the NPV relative to that of EBUS or CT alone, promoting the ability to identify true-negative RLN nodes. In particular, the NPVs of the combined modality were 100% for both the L- and R-RLN nodes in early-T-stage (T1-T2) ESCC.

CONCLUSIONS

EBUS is an efficient tool for RLN node evaluation, and the combination with CT may provide better guidance for selective RLN node dissection in ESCC patients.

Histone deacetylase 6 expression in metastatic lymph nodes is a valuable prognostic marker for resected node-positive esophageal squamous cell cancer

Background

Histone deacetylase 6 (HDAC6) exerts enzymatic deacetylation activity on histones and on non-histone substrates and plays a key role in microtubule dynamics and chaperone activities. In addition, previous studies have demonstrated its role in cancer progression. However, its clinical significance in esophageal squamous cell cancer (ESCC) has not been elucidated. We investigated the correlation of HDAC6 expression and clinical outcome in a group of T3N1–3M0 surgically resected ESCCs.

Methods

Tissue microarrays were conducted on 209 surgically resected T3N1–3M0 ESCC tumors, including 163 pairs of primary tumors (PTs) and their corresponding metastatic lymph nodes (MLNs). Immunohistochemistry was utilized to evaluate HDAC6 protein levels. The relationship between patient outcomes and HDAC6 expression was analyzed statistically.

Results

The level of HDAC6 expression in ESCC MLNs was found to be significantly lower than that in PTs (P<0.001). Patients with lower MLN HDAC6 expression demonstrated improved overall survival (P=0.011) and disease-free survival (P=0.012) than those with higher HDAC6 expression. HDAC6 expression levels in PTs revealed no prognostic significance. Multivariate analysis showed that the MLN HDAC6 expression level was an independent prognostic factor for both overall survival (HR 1.456, P=0.029) and disease-free survival (HR 1.432, P=0.033).

Conclusion

High expression of HDAC6 in MLNs but not in PTs suggests a poor prognosis for patients with resected T3N1–3M0 ESCC. We should take into account the protein expression of MLNs when assessing prognosis in patients with lymph-node involvement.

Strategies of nodal staging of the TNM system for esophageal cancer

The 8^th edition of UICC/AJCC TNM staging for esophageal cancer will start in use since 2018. The nodal staging in this version of TNM system remains unchanged from the 7^th edition that based on the number of lymph nodes (LN) involved, except the limited revision of the regional LN map. In this review, N staging revision was evaluated from its initially simple definition of negative (N0) and positive (N1) LN(s) to the current positive node number based proposal. Meanwhile the disadvantages of current N staging were discussed. The refined nodal staging system in view of the number of metastatic node stations was introduced; as well as the extent and station of metastatic node could better reflect the disease progression and prognosis. The controversy on N staging of esophagogastric junction cancer was also discussed. Other reported N staging associated elements including LN ratio and lymphatic vessel invasion were reviewed and evaluated.