Lymph node metastases and prognosis in oesophageal carcinoma--a systematic review

Impact of lymph node metastasis on immune microenvironment and prognosis in colorectal cancer liver metastasis: insights from multiomics profiling

BACKGROUND

This study aimed to investigate the prognostic impact of lymph node metastasis (LNM) on patients with colorectal cancer liver metastasis (CRLM) and elucidate the underlying immune mechanisms using multiomics profiling.

METHODS

We enrolled patients with CRLM from the US Surveillance, Epidemiology, and End Results (SEER) cohort and a multicenter Chinese cohort, integrating bulk RNA sequencing, single-cell RNA sequencing and proteomics data. The cancer-specific survival (CSS) and immune profiles of the tumor-draining lymph nodes (TDLNs), primary tumors and liver metastasis were compared between patients with and without LNM. Pathological evaluations were used to assess immune cell infiltration and histological features.

RESULTS

The CRLM patients with LNM had significantly shorter CSS than patients without LNM in two large cohorts. Our results showed that nonmetastatic TDLNs exhibited a greater abundance of immune cells, including CD4+ T cells, CD8+ T cells, and CD19+ B cells, whereas metastatic TDLNs were enriched with fibroblasts, endothelial cells, and macrophages. Immunohistochemical analysis confirmed elevated levels of CD3+ T cells, CD8+ T cells, and CD19+ B cells in nonmetastatic TDLNs. The presence of nonmetastatic TDLNs was associated with enhanced antitumor immune responses in primary tumors, characterized by a higher Klintrup-Makinen (KM) grade and the presence of tertiary lymphoid structures. Furthermore, liver metastasis in patients with nonmetastatic TDLNs were predominantly of the desmoplastic growth pattern (dHGP), while those with metastatic TDLNs were predominantly of the replacement growth pattern (rHGP).

CONCLUSIONS

This research highlights the adverse prognostic impact of LNM on patients with CRLM and reveals potential related mechanisms through multiomics analysis. Our research paves the way for further refinement of the AJCC TNM staging system for CRLM in clinical practice.

Omission of lymph node dissection along the recurrent laryngeal nerve for lower thoracic esophageal squamous cell carcinoma with short esophageal invasion

BACKGROUND

Esophagectomy with lymphadenectomy is the primary treatment for esophageal squamous cell carcinoma (ESCC). However, intensive dissection of lymph nodes (LNs) along the recurrent laryngeal nerve (RLN) is associated with RLN palsy and pulmonary complications leading to poor survival. Therefore, this study aimed identify the risk factors for LNs metastasis along the RLN in patients with ESCC.

METHODS

The present study included 168 patients with lower thoracic esophageal and esophagogastric junction (EGJ) squamous cell carcinoma who underwent esophagectomy with total mediastinal lymphadenectomy at Kobe University Hospital. Left/Right cervical paraesophageal (101 L/R), left/right recurrent nerve (106 recL/R), and left tracheobronchial LNs (106 tbL) were defined as LNs along the RLN. We evaluated the pathological distance between the proximal tumor boundary and the EGJ using images of the fixed specimen (PB-EGJ length).

RESULTS

LN metastasis along the RLN was observed in 19 (11%) patients. The percentage of patients with a longer PB-EGJ length and cLNs metastasis was higher in the LNs metastasis along the RLN positive-group than in the RLN-negative group (p = 0.0075 and p = 0.013, respectively). The incidence of LNs metastasis along the RLN was 0% (95% confidence interval [CI] = 0-7.7%) when the PB-EGJ length was <4 cm. Univariate analysis showed that patients with cLNs metastasis negative had a low risk for LNs metastasis along the RLN (odds ratio = 0.26 and 95% CI = 0.083-0.82).

CONCLUSIONS

Patients with a PB-EGJ length <4 cm and negative for cLNs metastasis may be candidates for the omission of lymphadenectomy along the RLN.

The number of resected lymph nodes from the upper mediastinal area predicts long-term outcomes of esophageal squamous cell carcinoma after minimally invasive esophagectomy

BACKGROUND

The total number of resected lymph nodes (LNs) is an important determinant of longer survival after esophagectomy for esophageal squamous cell carcinoma (ESCC). However, the resected LN counts from areas that affect long-term outcomes remain unclear.

METHODS

This study included 406 patients who underwent minimally invasive esophagectomies (MIEs) at Kobe University Hospital. Resected LN counts were evaluated in the following areas: upper mediastinal (UM), middle mediastinal (MM), lower mediastinal (LM), and abdominal (Abd). Cut-off values for LN counts from each area were determined using receiver operating characteristics analysis of the survival status. Cox proportional hazards regression analyses were performed to identify prognostic factors.

RESULTS

The cut-off values for large or small numbers of resected LN counts in the UM, MM, LM, and Abd areas were 4, 8, 5, and 18, respectively, in patients with upper and middle thoracic (Ut/Mt) ESCC and 7, 6, 5, and 24, respectively, in patients with lower thoracic (Lt) ESCC. Multivariate analysis in patients with Ut/Mt ESCC revealed that tumor invasion depth, LN metastasis, and the resected LN count from the UM area were independent risk factors for overall survival [hazard ratio (HR), 7.04; 95% confidence interval (CI) 4.47-11.1; HR, 4.01; 95% CI 1.96-8.21; HR, 2.18; 95% CI 1.24-3.82, respectively]. In patients with Lt ESCC, tumor invasion depth, LN metastasis, and pulmonary complications were independent risk factors for overall survival (HR, 4.23; 95% CI 2.14-8.35; HR, 3.83; 95% CI 1.75-8.38; HR, 2.80; 95% CI 1.38-5.65, respectively). Resected LN counts from no areas were prognostic factors.

CONCLUSION

The number of resected LNs from the UM area influenced the survival outcomes of patients with Ut/Mt ESCC after MIE.

SMAD4 and KCNQ3 alterations are associated with lymph node metastases in oesophageal adenocarcinoma

Metastasis in oesophageal adenocarcinoma (OAC) is an important predictor of survival. Radiological staging is used to stage metastases in patients, and guide treatment selection, but is limited by the accuracy of the approach. Improvements in staging will lead to improved clinical decision making and patient outcomes. Sequencing studies on primary tumours and pre-cancerous tissue have revealed the mutational landscape of OAC, and increasingly cheap and widespread sequencing approaches offer the potential to improve staging assessment. In this work we present an analysis of lymph node metastases found by radiological and pathological sampling, identifying new roles of the genes SMAD4 and KCNQ3 in metastasis. Through transcriptomic analysis we find that both genes are associated with canonical Wnt pathway activity, but KCNQ3 is uniquely associated with changes in planar cell polaritiy associated with non-canonical Wnt signalling. We go on to validate our observations in KCNQ3 in cell line and xenograph systems, showing that overexpression of KCNQ3 reduces wound closure and the number of metastases observed. Our results suggest both genes as novel biomarkers of metastatic risk and offer new potential routes to drug targeting.

Dissecting the inflammatory tumor microenvironment of esophageal adenocarcinoma: mast cells and natural killer cells are favorable prognostic factors and associated with less extensive disease

PURPOSE

Esophageal adenocarcinoma (EAC) remains a challenging and lethal cancer entity. A promising target for new therapeutic approaches, as demonstrated by the success of immune checkpoint inhibitors, are tumor-associated immune cells and the tumor microenvironment (TME). However, the understanding of the TME in esophageal cancer remains limited and requires further investigation.

METHODS

Over 900 EAC samples were included, including patients treated with primary surgery and neoadjuvant (radio-)chemotherapy. The immune cell infiltrates of mast cells (MC), natural killer cells (NK cells), plasma cells (PC), and eosinophilic cells (EC) were assessed semi-quantitatively and correlated with histopathological parameters and overall survival (OS).

RESULTS

A high presence of all four immune cell types significantly correlated with a less extensive tumor stage and a lower frequency of lymph node metastasis, and, in case of NK cells, with less distant metastasis. The presence of MC and NK cells was favorably associated with a prolonged OS in the total cohort (MC: p < 0.001; NK cells: p = 0.004) and patients without neoadjuvant treatment (MC: p < 0.001; NK cells: p = 0.01). NK cells were a favorable prognostic factor in the total cohort (p = 0.007) and in the treatment-naïve subgroup (p = 0.04). Additionally, MC were a favorable prognostic factor in patients with lymph node metastasis (p = 0.009).

CONCLUSION

Our results indicate a complex and important role of mast cells, NK cells, and the other assessed immune cells in the tumor microenvironment of EAC. Therefore, they are one further step to a better understanding of the immune cell environment and the potential therapeutic implications in this cancer entity.

Role of m6A modification in immune microenvironment of digestive system tumors

Digestive system tumors are huge health problem worldwide, largely attributable to poor dietary choices. The role of RNA modifications in cancer development is an emerging field of research. RNA modifications are associated with the growth and development of various immune cells, which, in turn, regulate the immune response. The majority of RNA modifications are methylation modifications, and the most common type is the N6-methyladenosine (m6A) modification. Here, we reviewed the molecular mechanism of m6A in the immune cells and the role of m6A in the digestive system tumors. However, further studies are required to better understand the role of RNA methylation in human cancers for designing diagnostic and treatment strategies and predicting the prognosis of patients.

Lymphatic Drainage System and Lymphatic Metastasis of Cancer Cells in the Mouse Esophagus

BACKGROUND

Lymphatic metastasis is commonly seen in patients with esophageal squamous cell carcinoma (ESCC). Both lymphatic metastasis and the number of involved nodes are prognostic for post-operative survival. To better understand lymphatic metastasis of ESCC, there is a need to develop proper animal models.

AIMS

This study is aimed to characterize the morphology and function of the lymphatic drainage system in the mouse esophagus.

METHODS

Immunostaining and fluorescence imaging were used to visualize the lymphatic drainage system in the mouse esophagus. Tracers and cancer cells were orthotopically inoculated into the submucosa of the mouse esophagus to mimic lymphatic metastasis of T1 ESCC.

RESULTS

Using immunostaining of a lymphatic vessel marker (LYVE1), we found that lymphatic vessels were located in the submucosa and muscularis propria of the mouse esophagus, similar to the human esophagus. In the esophagus of ProxTom mice expressing tdTomato in the lymphatic vessels, we discovered a microscopic meshwork of lymphatic vessels. Functionally, orthotopically inoculated tracers (Indian ink and FITC-dextran) were drained from the submucosa into peri-esophageal lymph nodes via lymphatic vessels. Orthotopically inoculated mouse cancer cells (LLC-eGFP, MOC2) metastasized from the submucosa to lymphatic vessels, peri-esophageal lymph nodes, and distant organs (liver and lung) in immunocompetent mice. Similarly, in immunodeficient mice, orthotopically inoculated human ESCC cells (KYSE450-eGFP-Luc) metastasized via the same route.

CONCLUSION

We have characterized the morphology and function of the lymphatic drainage system of the mouse esophagus. These observations lay a foundation for mechanistic and therapeutic studies on lymphatic metastasis of T1 ESCC.

Integrating Preoperative Computed Tomography and Clinical Factors for Lymph Node Metastasis Prediction in Esophageal Squamous Cell Carcinoma by Feature-Wise Attentional Graph Neural Network

PURPOSE

This study aimed to propose a regional lymph node (LN) metastasis prediction model for patients with esophageal squamous cell carcinoma (ESCC) that can learn and adaptively integrate preoperative computed tomography (CT) image features and nonimaging clinical parameters.

METHODS AND MATERIALS

Contrast-enhanced CT scans taken 2 weeks before surgery and 20 clinical factors, including general, pathologic, hematological, and diagnostic information, were collected from 357 patients with ESCC between October 2013 and November 2018. There were 999 regional LNs (857 negative, 142 positive) with pathologically confirmed status after surgery. All LNs were randomly divided into a training set (n = 738) and a validation set (n = 261) for testing. The feature-wise attentional graph neural network (FAGNN) was composed of (1) deep image feature extraction by the encoder of 3-dimensional UNet and high-level nonimaging factor representation by the clinical parameter encoder; (2) a feature-wise attention module for feature embedding with learnable adaptive weights; and (3) a graph attention layer to integrate the embedded features for final LN level metastasis prediction.

RESULTS

Among the 4 models we constructed, FAGNN using both CT and clinical parameters as input is the model with the best performance, and the area under the curve (AUC) reaches 0.872, which is better than manual CT diagnosis method, multivariable model using CT only (AUC = 0.797), multivariable model with combined CT and clinical parameters (AUC = 0.846), and our FAGNN using CT only (AUC = 0.853).

CONCLUSIONS

Our adaptive integration model improved the metastatic LN prediction performance based on CT and clinical parameters. Our model has the potential to foster effective fusion of multisourced parameters and to support early prognosis and personalized surgery or radiation therapy planning in patients with ESCC.

Research Progress on the Predicting Factors and Coping Strategies for Postoperative Recurrence of Esophageal Cancer

Esophageal cancer is one of the malignant tumors with poor prognosis in China. Currently, the treatment of esophageal cancer is still based on surgery, especially in early and mid-stage patients, to achieve the goal of radical cure. However, esophageal cancer is a kind of tumor with a high risk of recurrence and metastasis, and locoregional recurrence and distant metastasis are the leading causes of death after surgery. Although multimodal comprehensive treatment has advanced in recent years, the prediction, prevention and treatment of postoperative recurrence and metastasis of esophageal cancer are still unsatisfactory. How to reduce recurrence and metastasis in patients after surgery remains an urgent problem to be solved. Given the clinical demand for early detection of postoperative recurrence of esophageal cancer, clinical and basic research aiming to meet this demand has been a hot topic, and progress has been observed in recent years. Therefore, this article reviews the research progress on the factors that influence and predict postoperative recurrence of esophageal cancer, hoping to provide new research directions and treatment strategies for clinical practice.

Non-Coding RNAs of Extracellular Vesicles: Key Players in Organ-Specific Metastasis and Clinical Implications

Extracellular vesicles (EVs) are heterogeneous membrane-encapsulated vesicles released by most cells. They act as multifunctional regulators of intercellular communication by delivering bioactive molecules, including non-coding RNAs (ncRNAs). Metastasis is a major cause of cancer-related death. Most cancer cells disseminate and colonize a specific target organ via EVs, a process known as "organ-specific metastasis". Mounting evidence has shown that EVs are enriched with ncRNAs, and various EV-ncRNAs derived from tumor cells influence organ-specific metastasis via different mechanisms. Due to the tissue-specific expression of EV-ncRNAs, they could be used as potential biomarkers and therapeutic targets for the treatment of tumor metastasis in various types of cancer. In this review, we have discussed the underlying mechanisms of EV-delivered ncRNAs in the most common organ-specific metastases of liver, bone, lung, brain, and lymph nodes. Moreover, we summarize the potential clinical applications of EV-ncRNAs in organ-specific metastasis to fill the gap between benches and bedsides.

Comparisons of minimally invasive esophagectomy and open esophagectomy in lymph node metastasis/dissection for thoracic esophageal cancer

BACKGROUND

The study aimed to clarify the characteristics of lymph node metastasis (LNM) and to compare the oncologic outcomes of minimally invasive esophagectomy (MIE) with open esophagectomy (OE) in terms of lymph node dissection (LND) in thoracic esophageal cancer patients.

METHODS

The data from esophageal cancer patients who underwent MIE or OE from January 2016 to January 2019 were retrospectively reviewed. The characteristics of LNM in thoracic esophageal cancer were discussed, and the differences in numbers of LND, LND rate, and LNM rate/degree of upper mediastinum between MIE and OE were compared.

RESULTS

For overall characteristics of LNM in 249 included patients, the highest rate of LNM was found in upper mediastinum, while LNM rate in middle and lower mediastinum, and abdomen increased with the tumor site moving down. The patients were divided into MIE ( n  = 204) and OE groups ( n  = 45). In terms of number of LND, there were significant differences in upper mediastinum between MIE and OE groups (8 [5, 11] vs. 5 [3, 8], P  < 0.001). The comparative analysis of regional lymph node showed there was no significant difference except the subgroup of upper mediastinal 2L and 4L group (3 [1, 5] vs. 0 [0, 2], P  < 0.001 and 0 [0, 2] vs. 0, P  = 0.012, respectively). Meanwhile, there was no significant difference in terms of LND rate except 2L (89.7% [183/204] vs. 71.1% [32/45], P  = 0.001) and 4L (41.2% [84/204] vs . 22.2% [10/45], P  = 0.018) groups. For LNM rate of T3 stage, there was no significant difference between MIE and OE groups, and the comparative analysis of regional lymph node showed that there was no significant difference except 2L group (11.1% [5/45] vs . 38.1% [8/21], P  = 0.025). The LNM degree of OE group was significantly higher than that of MIE group (27.2% [47/173] vs . 7.6% [32/419], P  < 0.001), and the comparative analysis of regional LNM degree showed that there was no significant difference except 2L (34.7% [17/49] vs . 7.7% [13/169], P  < 0.001) and 4L (23.8% [5/21] vs . 3.9% [2/51], P  = 0.031) subgroups.

CONCLUSION

MIE may have an advantage in LND of upper mediastinum 2L and 4L groups, while it was similar to OE in other stations of LND.

Factors influencing quality of lymphadenectomy in minimally invasive esophagectomy: a US-based analysis

NCCN guidelines suggest that at least 15 lymph nodes (LN) should be evaluated at the time of esophagectomy to consider the lymphadenectomy 'adequate'. Despite these guidelines, this may not always be achieved in practice. The purpose of this study was to determine factors associated with adequate lymphadenectomy among patients receiving minimally invasive esophagectomy (MIE). Patients receiving MIE in the National Cancer Database from 2010 to 2016 were identified. Patients with metastatic disease were excluded. The primary endpoint was adequate lymphadenectomy, defined as >15 or greater LN evaluated. Factors associated with adequate lymphadenectomy and overall survival were evaluated in univariable and multivariable analyses. Categorical variables were assessed using chi-squared, and continuous variables were assessed with rank-sum test. Survival was evaluated using the Kaplan-Meier method. A total of 6,539 patients underwent MIE between 2010 and 2016 (5,024 thoracoscopic-laparoscopic MIE and 1,515 robotic-assisted MIE). A total of 3,527 patients (53.9%) received adequate lymphadenectomy. Receiving MIE at an academic center (odds ratio [OR] 1.37, 95% confidence interval [CI] 1.15-1.63, P < 0.001), institutional volume of MIE (OR 1.01, 95% CI 1.008-1.011, P < 0.001), and presence of clinical nodal disease (OR 1.17, 95%CI 1.02-1.33, P = 0.025) were associated with adequate lymphadenectomy. Patients with >15 LN removed had increased overall survival (46.6 vs. 41.5 months, P < 0.001). Adequate lymphadenectomy (hazard ratio [HR] 0.77, 95%CI 0.71-0.85, P < 0.001), receiving surgery at an academic center (HR 0.87, 95%CI 0.78-0.96, P = 0.007) and private insurance status (HR 0.88, 95%CI 0.81-0.98, P = 0.02) were independently associated with improved survival. Nearly half of patients receiving MIE do not receive adequate lymphadenectomy as defined by NCCN guidelines. Receiving MIE at an academic center with high procedural volume and the presence of nodal disease were independently associated with adequate lymphadenectomy. Adequate lymphadenectomy was associated with improved survival. These findings suggest that providers performing esophagectomy should follow guideline-based recommendations for lymphadenectomy.

Development and validation of a nomogram model for the prediction of 4L lymph node metastasis in thoracic esophageal squamous cell carcinoma

Objectives

The left tracheobronchial (4L) lymph nodes (LNs) are considered as regional LNs for esophageal squamous cell carcinoma (ESCC), but there is a controversy about routine prophylactic 4L LN dissection for all resectable ESCCs. This study aimed to develop a nomogram for preoperative prediction of station 4L lymph node metastases (LNMs).

Methods

A total of 522 EC patients in the training cohort and 370 in the external validation cohort were included. The prognostic impact of station 4L LNM was evaluated, and multivariable logistic regression analyses were performed to identify independent risk factors of station 4L LNM. A nomogram model was developed based on multivariable logistic regression analysis. Model performance was evaluated in both cohorts in terms of calibration, discrimination, and clinical usefulness.

Results

The incidence of station 4L LNM was 7.9% (41/522) in the training cohort. Patients with station 4L LNM exhibited a poorer 5-year overall survival rate than those without (43.2% vs. 71.6%, p < 0.001). In multivariate logistic regression analyses, six variables were confirmed as independent 4L LNM risk factors: sex (p = 0.039), depth of invasion (p = 0.002), tumor differentiation (p = 0.016), short axis of the largest 4L LNs (p = 0.001), 4L conglomeration (p = 0.006), and 4L necrosis (p = 0.002). A nomogram model, containing six independent risk factors, demonstrated a good performance, with the area under the curve (AUC) of 0.921 (95% CI: 0.878-0.964) in the training cohort and 0.892 (95% CI: 0.830-0.954) in the validation cohort. The calibration curve showed a good agreement on the presence of station 4L LNM between the risk estimation according to the model and histopathologic results on surgical specimens. The Hosmer-Lemeshow test demonstrated a non-significant statistic (p = 0.691 and 0.897) in the training and validation cohorts, which indicated no departure from the perfect fit. Decision curve analysis indicated that the model had better diagnostic power for 4L LNM than the traditional LN size criteria.

Conclusions

This model integrated the available clinical and radiological risk factors, facilitating in the precise prediction of 4L LNM in patients with ESCC and aiding in personalized therapeutic decision-making regarding the need for routine prophylactic 4L lymphadenectomy.

The Least Nodal Disease Burden Defines the Minimum Number of Nodes Retrieved for Esophageal Squamous Cell Carcinoma

Background

Clinically, a single positive lymph node (SPLN) should indicate the least nodal disease burden in node-positive patients with esophageal squamous cell carcinoma (ESCC) and may also be used to define the minimum number of examined lymph nodes (NELNs) in ESCC patients.

Methods

Data from three Chinese cohorts of 2448 ESCC patients who underwent esophagectomy between 2008 and 2012 were retrospectively analyzed. Based on lymph node status, patients were divided into two groups: N0 ESCC and SPLN ESCC. A Cox proportional hazards regression model was used to determine the minimum NELNs retrieved to maximize survival for ESCC patients with localized lymph node involvement. The results were then validated externally in the SEER database.

Results

A total of 1866 patients were pathologically diagnosed with N0 ESCC, and 582 patients were diagnosed with SPLN ESCC. The overall survival rate of patients with N0 ESCC was significantly better than that of patients with SPLN ESCC (HR 1.88, 95% CI 1.64-2.13, P<0.001), but no significant difference was found between SPLN ESCC patients with ≥ 20 lymph nodes harvested and N0 ESCC patients (HR 1.20, 95% CI 0.95-1.52, P=0.13). Analysis of patients selected from the SEER database showed the same trend, and no significant difference was observed between N0 ESCC patients and SPLN ESCC patients with ≥ 20 lymph nodes retrieved (HR: 1.02, 95% CI 0.72-1.43, P=0.92).

Conclusions

A minimum of 20 lymph nodes retrieved should be introduced as a quality indicator for ESCC patients with localized lymph node involvement.

The Lymph Node Microenvironment May Invigorate Cancer Cells With Enhanced Metastatic Capacities

Cancer metastasis, a typical malignant biological behavior involving the distant migration of tumor cells from the primary site to other organs, contributed majorly to cancer-related deaths of patients. Although constant efforts have been paid by researchers to elucidate the mechanisms of cancer metastasis, we are still far away from the definite answer. Recently, emerging evidence demonstrated that cancer metastasis is a continuous coevolutionary process mediated by the interactions between tumor cells and the host organ microenvironment, and epigenetic reprogramming of metastatic cancer cells may confer them with stronger metastatic capacities. The lymph node served as the first metastatic niche for many types of cancer, and the appearance of lymph node metastasis predicted poor prognosis. Importantly, multiple immune cells and stromal cells station and linger in the lymph nodes, which constitutes the complexity of the lymph node microenvironment. The active cross talk between cancer cells and immune cells could happen unceasingly within the metastatic environment of lymph nodes. Of note, diverse immune cells have been found to participate in the formation of malignant properties of tumor, including stemness and immune escape. Based on these available evidence and data, we hypothesize that the metastatic microenvironment of lymph nodes could drive cancer cells to metastasize to further organs through epigenetic mechanisms.

The Role of Magnetic Resonance Imaging in the Management of Esophageal Cancer

Esophageal cancer (EC) is the eighth more frequent cancer worldwide, with a poor prognosis. Initial staging is critical to decide on the best individual treatment approach. Current modalities for the assessment of EC are irradiating techniques, such as computed tomography (CT) and positron emission tomography/CT, or invasive techniques, such as digestive endoscopy and endoscopic ultrasound. Magnetic resonance imaging (MRI) is a non-invasive and non-irradiating imaging technique that provides high degrees of soft tissue contrast, with good depiction of the esophageal wall and the esophagogastric junction. Various sequences of MRI have shown good performance in initial tumor and lymph node staging in EC. Diffusion-weighted MRI has also demonstrated capabilities in the evaluation of tumor response to chemoradiotherapy. To date, there is not enough data to consider whole body MRI as a routine investigation for the detection of initial metastases or for prediction of distant recurrence. This narrative review summarizes the current knowledge on MRI for the management of EC.

Can Lymphovascular Invasion be Predicted by Preoperative Contrast-Enhanced CT in Esophageal Squamous Cell Carcinoma?

Objective: To explore whether preoperative contrast-enhanced computed tomogrpahy (CT) can predict lymphovascular invasion (LVI) in esophageal squamous cell carcinoma (ESCC), and provide a reliable reference for the formulation of clinical individualized treatment plans. Methods: This retrospective study enrolled 228 patients with surgically resected and pathologically confirmed ESCC, including 36 patients with LVI and 192 patients without LVI. All patients underwent contrast-enhanced CT (CECT) scan within 2 weeks before the operation. Tumor size (including tumor length and maximum tumor thickness), tumor-to-normal wall enhancement ratio (TNR), and gross tumor volume (GTV) were obtained. All clinical features and CECT-derived parameters associated with LVI were analyzed by univariate and multivariate analysis. The independent predictors for LVI were identified, and their combination was built by multivariate logistic regression analysis, using the significant variables from the univariate analysis as inputs. Results: Univariate analysis of clinical features and CECT-derived parameters revealed that age, TNR, and clinical N stage (cN stage) were significantly associated with LVI. The multivariable analysis results demonstrated that age (odds ratio [OR]: 5.32, 95% confidence interval [CI]: 2.224-12.743, P<.001), TNR (OR: 5.399, 95% CI: 1.609-18.110, P  =  .006), and cN stage (cN1: OR: 2.874, 95% CI: 1.182-6.989, P  =  .02; cN2: OR: 6.876, 95% CI: 2.222-21.227) were identified to be independent predictors for LVI. The combination of age, TNR, and cN stage achieved a relatively higher area under the curve (AUC) (0.798), accuracy (ACC) (65.4%), sensitivity (SEN) (69.4%), specificity (SPE) (79.7%), positive predictive value (PPV) (77.4%), and negative predictive value (NPV) (71.6%). Conclusions: The combination of clinical features and CECT-derived parameters may be effective in predicting LVI status preoperatively in ESCC.

Exosomal and intracellular miR-320b promotes lymphatic metastasis in esophageal squamous cell carcinoma

Cancer-cell-released exosomal microRNAs (miRNAs) are important mediators of cell-cell communication in the tumor microenvironment. In this study, we sequenced serum exosome miRNAs from esophageal squamous cell carcinoma (ESCC) patients and identified high expression of miR-320b to be closely associated with peritumoral lymphangiogenesis and lymph node (LN) metastasis. Functionally, miR-320b could be enriched and transferred by ESCC-released exosomes directly to human lymphatic endothelial cells (HLECs), promoting tube formation and migration in vitro and facilitating lymphangiogenesis and LN metastasis in vivo as assessed by gain- and loss-of-function experiments. Furthermore, we found programmed cell death 4 (PDCD4) as a direct target of miR-320b through bioinformatic prediction and luciferase reporter assay. Re-expression of PDCD4 could rescue the effects induced by exosomal miR-320b. Notably, the miR-320b-PDCD4 axis activates the AKT pathway in HLECs independent of vascular endothelial growth factor-C (VEGF-C). Moreover, overexpression of miR-320b promotes the proliferation, migration, invasion, and epithelial-mesenchymal transition progression of ESCC cells. Finally, we demonstrate that METTL3 could interact with DGCR8 protein and positively modulate pri-miR-320b maturation process in an N6-methyladenosine (m6A)-dependent manner. Therefore, our findings uncover a VEGF-C-independent mechanism of exosomal and intracellular miR-320b-mediated LN metastasis and identify miR-320b as a novel predictive marker and therapeutic target for LN metastasis in ESCC.

Lymph Node Involvement in Oesophageal Carcinoma: A Single-Centre Observational Study From Western India

Introduction

Lymph node involvement is the most important predictor of prognosis in oesophageal cancer. The present study describes our single-centre experience of lymphadenopathy in oesophageal carcinoma cases at a tertiary care centre in the Marathwada region of Maharashtra state in western India.

Methods

This descriptive study included 31 patients who were operated for oesophageal carcinoma at the State Cancer Hospital in Marathwada from August 2015 to September 2017. Thirty patients underwent three-field lymph node dissections, and one patient underwent Ivor Lewis surgery with two-field lymph node dissections. Three-field lymph node dissections were through a thoracotomy, followed by laparotomy and left cervical incision. The lymphatic metastases were categorised as (a) adjacent node metastases, (b) multiple levels of lymph node metastases, and (c) skip node metastases. The histopathological assessment of the removed specimen and lymph nodes was done. Pathologists evaluated the character and depth of the primary tumour and its invasion and node involvement. The location and numbers of positive and negative nodes were recorded.

Results

A total of 31 patients were included in the study, of which 17 had lymph node involvement. A total of 946 lymph nodes were dissected and examined, and the average number of lymph nodes removed per patient was 30.51. Among the 28 squamous cell carcinoma cases, lymph node involvement was found in 14 cases (50%) whereas, in adenocarcinoma, all the three cases showed lymph node involvement. In 11 cases of squamous cell carcinoma, thoracic lymph nodes were involved, whereas abdominal lymph nodes were involved in nine and cervical lymph nodes in two cases. Thoracic lymph nodes were involved in two cases of adenocarcinoma and abdominal lymph nodes were involved in one case of adenocarcinoma.

Conclusions

Squamous cell carcinoma was the predominant type, and lymph node metastasis was observed in 50% of these cases. Thoracic lymph nodes were more commonly involved. Tumour staging T2 and T3 had an increasing percentage of lymph nodes involved. Lymph node involvement was more in moderately differentiated and undifferentiated oesophageal cancers.

CircIMMP2L promotes esophageal squamous cell carcinoma malignant progression via CtBP1 nuclear retention dependent epigenetic modification

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive cancers. The two major lethal causes of ESCC are diagnosis at an advanced stage and lymph node metastasis (LNM). Circular RNAs (circRNAs) play critical regulatory roles in cancer progression, though, largely through unclear mechanisms. However, the character of circRNAs in the malignant progression of ESCC remains unclear.

METHODS

The circRNA microarray was used to explore the circRNAs that were differentially expressed between ESCC and paired adjacent normal tissues. The function of circIMMP2L was validated by gain or loss of function assays. Pull-down, RNA immunoprecipitation assays were used to demonstrate the biological mechanism of circIMMP2L. Tissue microarray (TMA), specimen, and paired plasma were investigated to evaluate the clinical significance of circIMMP2L.

RESULTS

CircIMMP2L, commonly upregulated in tumor and plasma from advanced-stage ESCC patients and LNM patients, predicts poorer patient survival. CircIMMP2L was also found to be a significant indicator for LNM, even in the T1 stage of ESCC. CircIMMP2L depletion suppressed the malignant progression of ESCC both in vitro and in vivo. Mechanistically, cytoplasmic circIMMP2L interacted with CtBP1 and facilitated the nuclear retention of CtBP1 in a CtBP2-independent manner. Moreover, circIMMP2L promoted the interaction of CtBP1 with HDAC1 in the nucleus, which is essential for epigenetic remodeling and transcriptional suppression of E-cadherin and p21.

CONCLUSIONS

These findings demonstrated that circIMMP2L promotes the malignant progression of ESCC mediated by CtBP1 nuclear retention and is a robust biomarker for the diagnosis, prognosis, and LNM in ESCC. Further, the findings extend our knowledge about the mechanism of circRNA regulation of gene transcription through epigenetics.

Prognostic impact of lymph node metastasis along the left gastric artery in esophageal squamous cell carcinoma

BACKGROUND

Although the incidence of lymph node (LN) metastasis (LNM) along the left gastric artery is high, its relationship with the prognosis in postoperative patients with esophageal squamous cell carcinoma (ESCC) is rarely reported. This study clarified the prognostic impact of LNM along the left gastric artery in postoperative patients with ESCC.

METHODS

This study assessed data of 1521 patients with ESCC who underwent esophagectomy at the Sun Yat-sen University Cancer Center between March 1992 and March 2012. A chi-squared test and Mann-Whitney U test were used to explore the preliminary correlation between clinical factors and LNM along the left gastric artery. Univariate and multivariate Cox regression analyses were used to assess whether LNM along the left gastric artery was an independent predictor of overall survival. Kaplan-Meier analysis and the log-rank test were used to present a classifying effect based on LN status.

RESULTS

LNM was observed in 598 patients (39.3%) and was found along the branches of the left gastric artery in 256 patients (16.8%). The patients were classified into two groups based on the presence of LNM along the left gastric artery. Patients without LNM along the left gastric artery had better cancer-specific survival than those with positive LNs (P <  0.001).

CONCLUSIONS

This study indicated that LNM along the left gastric artery was an important independent prognostic factor for long-term survival among ESCC patients (P = 0.011).

Prognostic Role of Nodal Skip Metastasis in Thoracic Esophageal Squamous Cell Carcinoma: A Large-Scale Multicenter Study

BACKGROUND

Nodal-skip metastasis (NSM) is found in esophageal squamous cell carcinoma (ESCC), but its prognostic role is controversial. This study aimed to investigate the prognostic value of NSM for thoracic ESCC patients.

METHODS

Categorization of NSM was according to the N groupings of Japan Esophagus Society (JES) staging system, which is dependent on tumor location. Using the Kaplan-Meier method and Cox-regression analysis, this study retrospectively analyzed the overall survival (OS) for 2325 ESCC patients after radical esophagectomy at three high-volume esophageal cancer centers. Predictive models also were constructed.

RESULTS

The overall NSM rate was 20% (229/1141): 37.4% in the in upper, 12.9% in the middle, and 22.2% in the lower thoracic ESCC. The patients with NSM always had a better prognosis than those without NSM. Furthermore, NSM was an independent prognostic factor for thoracic ESCC patients (hazard ratio [HR], 0.633; 95% confidence interval [CI], 0.499-0.803; P < 0.001). By integrating the prognostic values of NSM and N stage, the authors proposed the new N staging system. The categories defined by the new N staging system were more homogeneous in terms of OS than those defined by the current N system. Moreover, the new N system was shown to be an independent prognostic factor also for thoracic ESCC patients (HR, 1.607; 95% CI, 1.520-1.700; P < 0.001). Overall, the new N system had slightly better homogeneity, discriminatory ability, and monotonicity of gradient than the current N system.

CONCLUSIONS

This study emphasized the prognostic power of NSM and developed a modified node-staging system to improve the efficiency of the current International Union for Cancer Control (UICC)/American Joint Committee on Cancer (AJCC) N staging system.

Development and validation of nomograms to intraoperatively predict metastatic patterns in regional lymph nodes in patients diagnosed with esophageal cancer

BACKGROUND

An accurate intraoperative prediction of lymph node metastatic risk can help surgeons in choosing precise surgical procedures. We aimed to develop and validate nomograms to intraoperatively predict patterns of regional lymph node (LN) metastasis in patients with esophageal cancer.

METHODS

The prediction model was developed in a training cohort consisting of 487 patients diagnosed with esophageal cancer who underwent esophagectomy with complete LN dissection from January 2016 to December 2016. Univariate and multivariable logistic regression were used to identify independent risk factors that were incorporated into a prediction model and used to construct a nomogram. Contrast-enhanced computed tomography reported LN status and was an important comparative factor of clinical usefulness in a validation cohort. Nomogram performance was assessed in terms of calibration, discrimination, and clinical usefulness. An independent validation cohort comprised 206 consecutive patients from January 2017 to December 2017.

RESULTS

Univariate analysis and multivariable logistic regression revealed three independent predictors of metastatic regional LNs, three independent predictors of continuous regional LNs, and two independent predictors of skipping regional LNs. Independent predictors were used to build three individualized prediction nomograms. The models showed good calibration and discrimination, with area under the curve (AUC) values of 0.737, 0.738, and 0.707. Application of the nomogram in the validation cohort yielded good calibration and discrimination, with AUC values of 0.728, 0.668, and 0.657. Decision curve analysis demonstrated that the three nomograms were clinically useful in the validation cohort.

CONCLUSION

This study presents three nomograms that incorporate clinicopathologic factors, which can be used to facilitate the intraoperative prediction of metastatic regional LN patterns in patients with esophageal cancer.

Prediction of lymph node metastases using pre-treatment PET radiomics of the primary tumour in esophageal adenocarcinoma: an external validation study

OBJECTIVES

To improve clinical lymph node staging (cN-stage) in oesophageal adenocarcinoma by developing and externally validating three prediction models; one with clinical variables only, one with positron emission tomography (PET) radiomics only, and a combined clinical and radiomics model.

METHODS

Consecutive patients with fluorodeoxyglucose (FDG) avid tumours treated with neoadjuvant therapy between 2010 and 2016 in two international centres (n = 130 and n = 60, respectively) were included. Four clinical variables (age, gender, clinical T-stage and tumour regression grade) and PET radiomics from the primary tumour were used for model development. Diagnostic accuracy, area under curve (AUC), discrimination and calibration were calculated for each model. The prognostic significance was also assessed.

RESULTS

The incidence of lymph node metastases was 58% in both cohorts. The areas under the curve of the clinical, radiomics and combined models were 0.79, 0.69 and 0.82 in the developmental cohort, and 0.65, 0.63 and 0.69 in the external validation cohort, with good calibration demonstrated. The area under the curve of current cN-stage in development and validation cohorts was 0.60 and 0.66, respectively. For overall survival, the combined clinical and radiomics model achieved the best discrimination performance in the external validation cohort (X² = 6.08, df = 1, p = 0.01).

CONCLUSION

Accurate diagnosis of lymph node metastases is crucial for prognosis and guiding treatment decisions. Despite finding improved predictive performance in the development cohort, the models using PET radiomics derived from the primary tumour were not fully replicated in an external validation cohort.

ADVANCES IN KNOWLEDGE

This international study attempted to externally validate a new prediction model for lymph node metastases using PET radiomics. A model combining clinical variables and PET radiomics improved discrimination of lymph node metastases, but these results were not externally replicated.

Development of a Novel Serum Exosomal MicroRNA Nomogram for the Preoperative Prediction of Lymph Node Metastasis in Esophageal Squamous Cell Carcinoma

Preoperative prediction of lymph node (LN) metastasis is accepted as a crucial independent risk factor for treatment decision-making for esophageal squamous cell carcinoma (ESCC) patients. Our study aimed to establish a non-invasive nomogram to identify LN metastasis preoperatively in ESCC patients. Construction of the nomogram involved three sequential phases with independent patient cohorts. In the discovery phase (N = 20), LN metastasis-associated microRNAs (miRNAs) were selected from next-generation sequencing (NGS) assay of human ESCC serum exosome samples. In the training phase (N = 178), a nomogram that incorporated exosomal miRNA model and clinicopathologic was developed by multivariate logistic regression analysis to preoperatively predict LN status. In the validation phase (n = 188), we validated the predicted nomogram's calibration, discrimination, and clinical usefulness. Four differently expressed miRNAs (chr 8-23234-3p, chr 1-17695-5p, chr 8-2743-5p, and miR-432-5p) were tested and selected in the serum exosome samples from ESCC patients who have or do not have LN metastasis. Subsequently, an optimized four-exosomal miRNA model was constructed and validated in the clinical samples, which could effectively identify ESCC patients with LN metastasis, and was significantly superior to preoperative computed tomography (CT) report. In addition, a clinical nomogram consisting of the four-exosomal miRNA model and CT report was established in training cohort, which showed high predictive value in both training and validation cohorts [area under the receiver operating characteristic curve (AUC): 0.880 and 0.869, respectively]. The Hosmer–Lemeshow test and decision curve analysis implied the nomogram's clinical applicability. Our novel non-invasive nomogram is a robust prediction tool with promising clinical potential for preoperative LN metastasis prediction of ESCC patients, especially in T1 stage.

Neoadjuvant and Definitive Radiochemotherapeutic Approaches in Esophageal Cancer: A Retrospective Evaluation of 122 Cases in Daily Clinical Routine

INTRODUCTION

Esophageal cancer (EC) is a common malignant tumor entity with increasing occurrence. The incidence of esophageal adenocarcinoma (AC), particularly, is constantly rising in the Western world. The mainstays of therapy with curative intent for EC in advanced stages are neoadjuvant radiochemotherapy (neoRCT) with surgery and definitive radiochemotherapy (defRCT).

METHODS

We examined our internal files to identify patients suffering from EC. Palliative cases were excluded. Statistical testing was performed by χ2 test, Student's t test, Kaplan-Meier analyses, and the Mann-Whitney U test.

RESULTS

One hundred and twenty-two cases were included. Histology revealed squamous cell carcinoma in 92 cases and AC in 23 cases. Ninety-five patients underwent defRCT, 27 underwent neoRCT, and 114 (in both therapy regimes) received simultaneous chemotherapy. There was no difference in the overall survival (OS) (p = 0.654; HR 1.145; 95% CI 0.629-2.086) or and progression-free survival (PFS) (p = 0.912) of patients who underwent neoRCT or defRCT. Median OS was 13.5 (2-197) months for defRCT patients and 19.5 (2-134) months for neoRCT patients (p = 0.751). Karnofsky index (KI) with a cut-off of 70% was strongest, but not a significant parameter for OS (p = 0.608) or PFS (p = 0.137).

CONCLUSION

defRCT is a valid and an equal alternative to neoRCT for patients suffering from EC. Selection of patients for therapy is of crucial relevance. Further studies and improvements in follow-up are needed when neoRCT has been completed before surgery, in order to spare the patient undergoing operative treatment if there is complete remission. The identification of valid markers urgently needed to limit treatment side effects.

The Number of Negative Lymph Nodes is Positively Associated with Survival in Esophageal Squamous Cell Carcinoma Patients in China

Background

There is a controversial relationship between the negative lymph nodes (NLNs) and survival in patients with esophageal squamous cell carcinoma (ESCC). This study investigates the implications of total number of NLNs on thoracic ESCC patient prognosis.

Methods

579 thoracic ESCC patients were categorized into four groups (0-9, 10-14, 15-19 and ≥20 NLNs). Univariate analysis was done by the log-rank tests while multivariate analysis was undertaken using Cox regression models. Survival analysis was determined employing the Kaplan-Meier method.

Results

When the numbers of NLNs were 9 or less, 10 to 14, 15 to 19 and 20 or more, patients of 3-year survival rates were 21.7%, 40.0%, 61.2% and 77.5%, respectively (P<0.001). In the node-negative and node-positive subgroups, 3-year survival rates were 34.9% and 14.3%, 50.9% and 19.3%, 65.6% and 51.8%, 81.4% and 68.9% respectively (P<0.001). Gender, tumor length, tumor differentiation, T and N stage as well as the total NLNs were found to be significantly linked to survival rates. Multivariate analysis showed tumor length, T stage, N stage and total NLNs were independent prognostic factors for ESCC patients.

Conclusion

NLNs numbers is a significant independent prognostic indicator for thoracic ESCC patients' survival after curative esophagectomy.

Discordant nodal staging identifies intermediate-risk group for overall survival in patients with cT3 oesophageal adenocarcinoma

OBJECTIVES

Oesophageal adenocarcinoma has a poor prognosis and relies on multi-modality assessment for accurate nodal staging. The aim of the study was to determine the prognostic significance of nodal concordance between PET/CT and EUS in oesophageal adenocarcinoma.

METHODS

Consecutive patients with oesophageal adenocarcinoma staged between 2010 and 2016 were included. Groups comprising concordant node-negative (C-ve), discordant (DC), and concordant node-positive (C+ve) patients were analysed. Survival analysis using log-rank tests and Cox proportional hazards model was performed. The primary outcome was overall survival. A p value < 0.05 was considered statistically significant.

RESULTS

In total, 310 patients (median age = 66.0; interquartile range 59.5-72.5, males = 264) were included. The median overall survival was 23.0 months (95% confidence intervals (CI) 18.73-27.29). There was a significant difference in overall survival between concordance groups (X² = 44.91, df = 2, p < 0.001). The hazard ratios for overall survival of DC and C+ve patients compared with those of C-ve patients with cT3 tumours were 1.21 (95% CI 0.81-1.79) and 1.79 (95% CI 1.23-2.61), respectively. On multivariable analysis, nodal concordance was significantly and independently associated with overall survival (HR 1.44, 95% CI 1.12-1.83, p = 0.004) and performed better than age at diagnosis (HR 1.02, 95% CI 1.003-1.034, p = 0.016) and current cN-staging methods (HR 1.20, 95% CI 0.978-1.48, p = 0.080).

CONCLUSIONS

Patients with discordant nodal staging on PET/CT and EUS represent an intermediate-risk group for overall survival. This finding was consistent in patients with cT3 tumours. These findings will assist optimum treatment decisions based upon perceived prognosis for each patient.

KEY POINTS

• Clinicians are commonly faced with results of discordant nodal staging in oesophageal adenocarcinoma. • There is a significant difference in overall survival between patients with negative, discordant, and positive lymph node staging. • Patients with discordant lymph node staging between imaging modalities represent an intermediate-risk group for overall survival.

Reliability of clinical nodal status regarding response to neoadjuvant chemoradiotherapy compared with surgery alone and prognosis in esophageal cancer patients

Background: Clinical nodal (cN) staging is a key element in treatment decisions in patients with esophageal cancer (EC). The reliability of cN status regarding the effect on response and survival after neoadjuvant chemoradiotherapy (nCRT) with esophagectomy was evaluated in determining the up- and downstaged pathological nodal (pN) status after surgery alone. Material and methods: From a prospective database, we included all 395 EC patients who had surgery with curative intent with or without nCRT between 2000 and 2015. All patients were staged by a standard pretreatment protocol: 16-64 mdCT, 18 F-FDG-PET or 18 F-FDG-PET/CT and EUS ± FNA. After propensity score matching on baseline clinical tumor and nodal (cT/N) stage and histopathology, a surgery-alone and nCRT group (each N = 135) were formed. Clinical and pathological N stage was scored as equal (cN = pN), downstaged (cN > pN) or upstaged (cN < pN). Prognostic impact on disease free survival (DFS) was assessed with multivariable Cox regression analysis (factors with p value <.1 on univariable analysis). Results: The surgery-alone and nCRT group did not differ in cT/N status. Pathologic examination revealed equal staging (32 vs. 27%), nodal up (43 vs. 16%) and downstaging (25 vs. 56%), respectively (p < .001). Nodal up-staging was common in cT3-4a tumors and adenocarcinomas in the surgery-alone group, while nodal downstaging was found in half of cT1-2 and cT3-4 regardless of tumortype after nCRT. Prognostic factors for DFS were pN (p = .002) and lymph-angioinvasion (p = .016) in surgery-alone, and upper abdominal cN metastases (p = .012) and lymph node ratio (p = .034) in the nCRT group. Conclusions: Despite modern staging methods, correct cN staging remains difficult in EC. Nodal overstaging (cN > pN) occurred more often than understaging impeding an adequate assessment of pathologic complete response and prognosis after nCRT.

Prognostic significance of middle paraesophageal lymph node metastasis in resectable esophageal squamous cell carcinoma: A STROBE-compliant retrospective study

Lymph node metastasis (LNM) of esophageal squamous cell carcinoma (ESCC) has important prognostic significance. In this study, we examined the correlations between lymph node metastatic sites and prognosis in patients with resectable ESCC.A total of 960 patients who received curative esophagectomy with systemic lymphadenectomy between 1996 and 2014 were included in the retrospective analysis. The Kaplan-Meier method and log-rank test were used to perform the survival analysis. The prognostic significance of LNM site was evaluated by Cox regression analysis.The LNM in middle paraesophageal (P < .001), subcarinal (P < .001), lower paraesophageal (P < .001), recurrent laryngeal nerve (P = .012), paratracheal (P = .014), and perigastric (P < .001) sites were associated with poor prognosis in univariate analysis. In multivariate analysis, only middle paraesophageal LNM (MPLNM, P = .017; HR, 1.33; 95%CI, 1.05-1.67) was the independent factor for worse prognosis. Additionally, patients with MPLNM had a lower 5-year survival rate (15.6%) than those with LNM at other sites. Furthermore, upper or middle tumor location and relatively late pN stage were associated with increased risk of MPLNM.Our findings suggested MPLNM could be a characteristic indicating the worst prognosis. Preoperative examinations should identify the existences of MPLNM, especially on patients with risk factors. And patients with MPLNM should be considered for more aggressive multidisciplinary therapies.

Gross tumor volume is an independent prognostic factor in patients with postoperative locoregional recurrence of esophageal squamous cell carcinoma

Many cases of esophageal squamous cell carcinoma (ESCC) involve lymph node and distant metastases after esophagectomy, and most patients relapse within 2 years. Intensity-modulated radiotherapy (IMRT) is an important treatment for these cases of recurrence in ESCC and is widely used in clinical practice. A retrospective study of 137 postoperative patients with locoregional recurrences of ESCC who received IMRT was carried out. Kaplan-Meier survival curves and log-rank tests of univariate analysis was performed to assess whether there was a significant association between demographic and clinical features and death after recurrence. For multivariate analysis, the statistically significant results from the Kaplan-Meier method were subjected to Cox regression analysis. A total of 109 male and 28 female patients were included. There were 21 (15.3%), 58 (42.3%), 36 (26.3%), 3 (2.2%), 17 (12.4%), and 2 (1.5%) recurrences in the anastomotic, supraclavicular, mediastinal, tumor bed, polyregional, and abdominal regions, respectively. Univariate analysis showed that the gross tumor volume (GTV) of radiation (<27 vs. ≥27 cm³) and the number of lymph nodes were significantly associated with survival. The survival rates of patients at 1, 2, 3 and 5 years with GTV<27 cm³ were 72.7, 51.5, 37.1 and 25.9%, respectively, and with GTV≥27 cm³ were 63.7, 26.9, 17.9 and 0%, respectively. The significant independent prognostic factor was GTV [<27 vs. ≥27 cm³; hazard ratio (HR), 1.746; 95% confidence interval (CI), 1.112–2.741]. In conclusion, GTV of radiation (<27 vs. ≥27 cm³) is an independent factor in predicting locoregional recurrence after ESCC. Patients with GTV<27 cm³ are likely to have a better prognosis.

Discrepancy Between the Clinical and Final Pathological Findings of Lymph Node Metastasis in Superficial Esophageal Cancer

BACKGROUND

Recent advances in endoscopic examinations have resulted in the detection of a larger number of early esophageal cancers; however, there have been many cases with clinically negative but pathologically positive lymph node metastasis (LNM). In this study, we aimed to evaluate the discrepancy between the clinical and pathological diagnoses of LNM in patients with cT1a-MM/cT1b N0M0 esophageal cancer, and assess LNM size in these patients to clarify the presence of LNM that cannot be detected with current modalities.

METHODS

This study included 50 patients who underwent surgery for cT1a-MM/cT1b N0M0 thoracic esophageal squamous cell carcinoma between January 2012 and November 2016 at our institution. The maximum size of involved LNs and metastatic nests were measured, and the distribution of LNM was investigated.

RESULTS

Of the 50 patients, 13 (26%) had LNM on pathological examination. Lymphatic invasion was significantly more frequent in the LNM-positive group than in the LNM-negative group (p = 0.005). The median sizes of 28 involved LNs and metastatic nests were 3 and 1.6 mm, respectively. Of these LNs, 20 (71%) were classified as micrometastases (≤ 2 mm). The involved nodes were distributed across three fields.

CONCLUSIONS

There was a discrepancy between the clinical and final pathological findings of LNM in patients with cT1a-MM/cT1b N0M0 esophageal cancer. The detection of involved nodes with current modalities in these patients was difficult because of the small size of LNM. Therefore, continued strong consideration for extended LN dissection is necessary in these patients to ensure appropriate diagnosis and treatment.

Neoadjuvant versus definitive chemoradiation in patients with squamous cell carcinoma of the esophagus

Background

Multimodal treatment with neoadjuvant chemoradiation followed by surgery (nCRT + S) is the treatment of choice for patients with locally advanced or node-positive esophageal squamous cell carcinoma (E-SCC). Those who are unsuitable or who decline surgery can be treated with definitive chemoradiation (dCRT). This study compares the oncologic outcome of nCRT + S and dCRT in E-SCC patients.

Methods

Between 2011 and 2017, 95 patients with E-SCC were scheduled for dCRT or nCRT+ S with IMRT at our department. Patients undergoing dCRT received at least 50 Gy and those undergoing nCRT + S received at least 41.4 Gy. All patients received simultaneous chemotherapy with either carboplatin and paclitaxel or cisplatin and 5-fluoruracil. We retrospectively compared baseline characteristics and oncologic outcome including overall survival (OS), progression-free survival (PFS) and site of failure between both treatment groups.

Results

Patients undergoing dCRT were less likely to have clinically suspected lymph node metastases (85% vs. 100%, p = 0.019) than patients undergoing nCRT + S and had more proximally located tumors (median distance from dental arch to cranial tumor border 20 cm vs. 26 cm, p < 0.001). After a median follow up of 25.6 months for surviving patients, no significant differences for OS and PFS were noticed comparing nCRT + S and dCRT. However, the rate of local tumor recurrence was significantly higher in patients treated with dCRT than in those treated with nCRT + S (38% vs. 10%, p = 0.002). Within a multivariate Cox regression model, age, tumor location, and tumor grading were the only independent parameters affecting OS and PFS. In addition to that, proximal tumor location was the only parameter independently associated with an increased risk for local treatment failure.

Conclusion

In E-SCC patients treated with either dCRT or nCRT + S, a higher rate of local tumor recurrence was seen in patients treated with dCRT than in patients treated with nCRT + S. There was at least a trend towards an improved OS and PFS in patients undergoing nCRT + S. However, this should be interpreted with caution, because proximal tumor location was the only parameter independently affecting the risk of local tumor recurrence.

Feasibility and strategy of common hepatic artery lymph node dissection in thoracolaparoscopic esophagectomy for thoracic esophageal squamous cell cancer

Controversy about the adequate extent of lymph node (LN) dissection persists in surgery for thoracic esophageal squamous cell carcinoma (ESCC). The present study estimates the feasibility and strategy of common hepatic artery LN dissection during ESCC surgery.The clinical data of 482 patients with ESCC, who underwent thoracolaparoscopic esophagectomy at Fujian Medical University Union Hospital, were retrospectively selected. Among the 482 ESCC patients, 224 patients underwent thoracolaparoscopic esophagectomy with routine common hepatic artery LN dissection (cohort 1), while 258 patients underwent the same procedure without common hepatic artery LN dissection (cohort 2). The proposed operation method was introduced to safely dissect the common hepatic artery LN. Both univariate and multivariate analyses were performed to analyze the clinicopathological factors correlated to the common hepatic artery LN metastasis.The main postoperative complications were pneumonia, anastomotic leakage, vocal cord palsy and cardiovascular disease. There was no significant difference in the incidence of major postoperative complications between the 2 cohorts (P >.05), and the incidence was similar in a number of reports. The metastatic rate of common hepatic artery LNs was 4.91%, which was relatively lower. Based on the logistic regression analysis of 5 factors, tumor location and T classification were risk factors for common hepatic artery LN metastasis (P <.05).Routine common hepatic artery LN dissection is safe and feasible during a thoracolaparoscopic esophagectomy for ESCC. Although the metastatic rate is lower, common hepatic artery LN dissection should be performed for lower thoracic ESCCs, especially for tumors that invade the outer membrane.

Novel imaging techniques in staging oesophageal cancer

The survival of oesophageal cancer is poor as most patients present with advanced disease. Radiological staging of oesophageal cancer is complex but is fundamental to clinical management. Accurate staging investigations are vitally important to guide treatment decisions and optimise patient outcomes. A combination of baseline computed tomography (CT), endoscopic ultrasound (EUS) and positron emission tomography (PET) are currently used for initial treatment decisions. The potential value of these imaging modalities to re-stage disease, monitor response and alter treatment is currently being investigated. This review presents an essential update on the accuracy of oesophageal cancer staging investigations, their use in re-staging after neo-adjuvant therapy and introduces evolving imaging techniques, including novel biomarkers that have clinical potential in oesophageal cancer.

External validation of a prognostic model incorporating quantitative PET image features in oesophageal cancer

AIM

Enhanced prognostic models are required to improve risk stratification of patients with oesophageal cancer so treatment decisions can be optimised. The primary aim was to externally validate a published prognostic model incorporating PET image features. Transferability of the model was compared using only clinical variables.

METHODS

This was a Transparent Reporting of a multivariate prediction model for Individual Prognosis Or Diagnosis (TRIPOD) type 3 study. The model was validated against patients treated with neoadjuvant chemoradiotherapy according to the Neoadjuvant chemoradiotherapy plus surgery versus surgery alone for oesophageal or junctional cancer (CROSS) trial regimen using pre- and post-harmonised image features. The Kaplan-Meier method with log-rank significance tests assessed risk strata discrimination. A Cox proportional hazards model assessed model calibration. Primary outcome was overall survival (OS).

RESULTS

Between 2010 and 2015, 449 patients were included in the development (n = 302), internal validation (n = 101) and external validation (n = 46) cohorts. No statistically significant difference in OS between patient quartiles was demonstrated in prognostic models incorporating PET image features (X² = 1.42, df = 3, p = 0.70) or exclusively clinical variables (age, disease stage and treatment; X² = 1.19, df = 3, p = 0.75). The calibration slope β of both models was not significantly different from unity (p = 0.29 and 0.29, respectively). Risk groups defined using only clinical variables suggested differences in OS, although these were not statistically significant (X² = 0.71, df = 2, p = 0.70).

CONCLUSION

The prognostic model did not enable significant discrimination between the validation risk groups, but a second model with exclusively clinical variables suggested some transferable prognostic ability. PET harmonisation did not significantly change the results of model validation.

A comprehensive methylation signature identifies lymph node metastasis in esophageal squamous cell carcinoma

Treatment modalities in esophageal squamous cell carcinoma (ESCC) depend largely on lymph node metastasis (LNM) status. With suboptimal detection sensitivity of existing imaging techniques, we propose a methylation signature which identifies patients with LNM with greater accuracy. This would allow precise stratification of high-risk patients requiring more aggressive treatment from low-risk ESCC patients who can forego radical surgery. An unbiased genome-wide methylation signature for LNM detection was established from an initial in silico discovery phase. The signature was tested in independent clinical cohorts comprising of 249 ESCC patients. The prognostic potential of the methylation signature was compared to clinical variables including LNM status. A 10-probe LNM associated signature (LNAS) was developed using stringent bioinformatics analyses. The area under the curve values for LNAS risk scores were 0.81 and 0.88 in the training and validation cohorts respectively, in association with lymphatic vessel invasion and tumor stage. High LNAS risk-score was also associated with worse overall survival [HR (95% CI) 3 (1.8-4.8), p < 0.0001 training and 3.9 (1.5-10.2), p = 0.001 validation cohort]. In conclusion, our novel methylation signature is a powerful biomarker that identifies LNM status robustly and is also associated with worse prognosis in ESCC patients.

LncRNA-ECM is overexpressed in esophageal squamous cell carcinoma and promotes tumor metastasis

The aim of the present study was to investigate the expression of long non-coding(lnc) RNA-extracellular matrix (ECM) in esophageal squamous cell carcinoma (ESCC) and its effect on ESCC metastasis. Using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), the expression of lncRNA-ECM in ESCC tissues was investigated and compared with that in corresponding adjacent tissues. In addition, the expression of lncRNA-ECM in the human ESCC cell lines TE-1, EC9706, KYSE150, Eca109 and KYSE30 was also detected and compared with that in the normal esophageal mucosal epithelial cell line HET-1A. The clinicopathological association between lncRNA-ECM and ESCC was assessed. Silencing and overexpression of lncRNA-ECM in ESCC TE-1 and Eca109 cells determined the correlation between lncRNA-ECM expression and ESCC invasion and metastasis. The possible target genes of lncRNA-ECM were predicted and verified by bioinformatics analysis and experimental results. The expression level of intercellular adhesion molecule 1 (ICAM1) was detected in ESCC tissues by RT-qPCR and the correlation between the expression of ICAM1 and lncRNA-ECM was analyzed. Changes in the expression of ICAM1 in ESCC TE-1 and Eca109 cell lines were evaluated after knocking down lncRNA-ECM and transfection of lncRNA-ECM overexpression plasmids. The expression level of lncRNA-ECM in the tissues of ESCC with lymph node metastasis were significantly increased compared with ESCC with no lymph metastasis (P<0.05). LncRNA-ECM silencing notably reduced the invasion and metastasis of TE-1 and Eca109 cells, while lncRNA-ECM overexpression promoted the invasion and metastasis of the two cell lines. The expression level of ICAMI was directly correlated with the expression of lncRNA-ECM, suggesting that ICAM1 may be the downstream target gene of lncRNA-ECM. LncRNA-ECM was revealed as being overexpressed in ESCC. LncRNA-ECM expression was positively correlated with metastasis and may affect the metastasis of ESCC through ICAMI regulation. These findings indicate that lncRNA-ECM may be promising as a novel biomarker for the diagnosis and prediction of prognosis for ESCC, and it may also serve as a novel therapeutic target for ESCC.

Radiomics nomogram outperforms size criteria in discriminating lymph node metastasis in resectable esophageal squamous cell carcinoma

OBJECTIVES

To determine the value of radiomics in predicting lymph node (LN) metastasis in resectable esophageal squamous cell carcinoma (ESCC) patients.

METHODS

Data of 230 consecutive patients were retrospectively analyzed (154 in the training set and 76 in the test set). A total of 1576 radiomics features were extracted from arterial-phase CT images of the whole primary tumor. LASSO logistic regression was performed to choose the key features and construct a radiomics signature. A radiomics nomogram incorporating this signature was developed on the basis of multivariable analysis in the training set. Nomogram performance was determined and validated with respect to its discrimination, calibration and reclassification. Clinical usefulness was estimated by decision curve analysis.

RESULTS

The radiomics signature including five features was significantly associated with LN metastasis. The radiomics nomogram, which incorporated the signature and CT-reported LN status (i.e. size criteria), distinguished LN metastasis with an area under curve (AUC) of 0.758 in the training set, and performance was similar in the test set (AUC 0.773). Discrimination of the radiomics nomogram exceeded that of size criteria alone in both the training set (p <0.001) and the test set (p=0.005). Integrated discrimination improvement (IDI) and categorical net reclassification improvement (NRI) showed significant improvement in prognostic value when the radiomics signature was added to size criteria in the test set (IDI 17.3%; p<0.001; categorical NRI 52.3%; p<0.001). Decision curve analysis supported that the radiomics nomogram is superior to size criteria.

CONCLUSIONS

The radiomics nomogram provides individualized risk estimation of LN metastasis in ESCC patients and outperforms size criteria.

KEY POINTS

• A radiomics nomogram was built and validated to predict LN metastasis in resectable ESCC. • The radiomics nomogram outperformed size criteria. • Radiomics helps to unravel intratumor heterogeneity and can serve as a novel biomarker for determination of LN status in resectable ESCC.

Additional value of EUS in oesophageal cancer patients staged N0 on PET/CT: validation of a prognostic model

Background

Lymph node metastases are a major prognostic indicator in oesophageal cancer. Radiological staging largely influences treatment decisions and is becoming more reliant on PET and CT. However, the sensitivity of these modalities is suboptimal and is known to under-stage disease. The primary aim of this study was to validate a published prognostic model in oesophageal cancer patients staged N0 with PET/CT, which showed that EUS nodal status was an independent predictor of survival. The secondary aim was to assess the prognostic significance of pathological lymph node metastases in this cohort.

Methods

An independent validation cohort included 139 consecutive patients from a regional upper gastrointestinal cancer network staged N0 with PET/CT between 1st January 2013 and 31st June 2015. Replicating the original study, two Cox regression models were produced: one included EUS T-stage and EUS N-stage, and one included EUS T-stage and EUS N0 versus N+. The primary outcome of the prognostic model was overall survival (OS). Kaplan–Meier analysis assessed differences in OS between pathological node-negative (pN0) and node-positive (pN+) groups. A p value of < 0.05 was considered statistically significant.

Results

The mean OS of the validation cohort was 29.8 months (95% CI 27.1–35.2). EUS T-stage was significantly and independently associated with OS in both models (p = 0.011 and p = 0.012, respectively). EUS N-stage and EUS N0 versus N+ were not significantly associated with OS (p = 0.553 and p = 0.359, respectively). There was a significant difference in OS between pN0 and pN+ groups (χ² 13.315, df 1, p < 0.001).

Conclusion

Lymph node metastases have a significant detrimental effect on OS. This validation study did not replicate the results of the developed prognostic model but the continued benefit of EUS in patients staged N0 with PET/CT was demonstrated. EUS remains a valuable component of a multi-modality approach to oesophageal cancer staging.

Building CT Radiomics Based Nomogram for Preoperative Esophageal Cancer Patients Lymph Node Metastasis Prediction

PURPOSE: To build and validate a radiomics-based nomogram for the prediction of pre-operation lymph node (LN) metastasis in esophageal cancer. PATIENTS AND METHODS: A total of 197 esophageal cancer patients were enrolled in this study, and their LN metastases have been pathologically confirmed. The data were collected from January 2016 to May 2016; patients in the first three months were set in the training cohort, and patients in April 2016 were set in the validation cohort. About 788 radiomics features were extracted from computed tomography (CT) images of the patients. The elastic-net approach was exploited for dimension reduction and selection of the feature space. The multivariable logistic regression analysis was adopted to build the radiomics signature and another predictive nomogram model. The predictive nomogram model was composed of three factors with the radiomics signature, where CT reported the LN number and position risk level. The performance and usefulness of the built model were assessed by the calibration and decision curve analysis. RESULTS: Thirteen radiomics features were selected to build the radiomics signature. The radiomics signature was significantly associated with the LN metastasis (P<0.001). The area under the curve (AUC) of the radiomics signature performance in the training cohort was 0.806 (95% CI: 0.732-0.881), and in the validation cohort it was 0.771 (95% CI: 0.632-0.910). The model showed good discrimination, with a Harrell’s Concordance Index of 0.768 (0.672 to 0.864, 95% CI) in the training cohort and 0.754 (0.603 to 0.895, 95% CI) in the validation cohort. Decision curve analysis showed our model will receive benefit when the threshold probability was larger than 0.15. CONCLUSION: The present study proposed a radiomics-based nomogram involving the radiomics signature, so the CT reported the status of the suspected LN and the dummy variable of the tumor position. It can be potentially applied in the individual preoperative prediction of the LN metastasis status in esophageal cancer patients.

Nomogram and recursive partitioning analysis to predict overall survival in patients with stage IIB-III thoracic esophageal squamous cell carcinoma after esophagectomy

We have developed statistical models for predicting survival in patients with stage IIB-III thoracic esophageal squamous cell carcinoma (ESCC) and assessing the efficacy of adjuvant treatment. From a retrospective review of 3,636 patients, we created a database of 1,004 patients with stage IIB-III thoracic ESCC who underwent esophagectomy with or without postoperative radiation. Using a multivariate Cox regression model, we assessed the prognostic impact of clinical and histological factors on overall survival (OS). Logistic analysis was performed to identify factors to include in a recursive partitioning analysis (RPA) to predict 5-year OS. The nomogram was evaluated internally based on the concordance index (C-index) and a calibration plot. The median survival time in the training dataset was 30.9 months, and the 5-year survival rate was 33.9%. T stage, differentiated grade, adjuvant treatment, tumor location, lymph node metastatic ratio (LNMR), and the presence of vascular carcinomatous thrombi were statistically significant predictors of 5-year OS. The C-index of the nomogram was 0.70 (95% CI 0.67-0.73). RPA resulted in a three-class stratification: class 1, LNMR ≤ 0.15 with adjuvant treatment; class 2, LNMR ≤ 0.15 without adjuvant treatment and LNMR > 0.15 with adjuvant treatment; and class 3, LNMR > 0.15 without adjuvant treatment. The three classes were statistically significant for OS (P < 0.001). Thus, the nomogram and RPA models predicted the prognosis of stage IIB-III ESCC patients and could be used in decision-making and clinical trials.

DNA polymerase iota (Pol ι) promotes invasion and metastasis of esophageal squamous cell carcinoma

DNA polymerase iota (Pol ι) is an error-prone DNA polymerase involved in translesion DNA synthesis (TLS) that contributes to the accumulation of DNA mutations. We recently showed that Pol ι is overexpressed in human esophageal squamous cell cancer (ESCC) tissues which promotes ESCC' progression. The present study was aimed at investigating the molecular mechanisms by which Pol ι enhances the invasiveness and metastasis of ESCC cells. We found that the expression of Pol ι is significantly higher in ESCCs with lymph node metastasis compared to those without lymph node metastasis. Kaplan-Meier analysis revealed an inverse correlation between Pol ι expression and patient prognosis. The expression levels of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9), two essential regulators of cells' invasiveness, were positively associated with Pol ι expression in ESCC tissues. Ectopic expression of Pol ι enhanced the motility and invasiveness of ESCC cells as evaluated by wound-healing and transwell assays, respectively. A xenograft nude mouse model showed that Pol ι promotes the colonization of ESCC cells in the liver, lung and kidney. Signaling pathway analysis identified the JNK-AP-1 cascade as a mediator of the Pol ι-induced increase in the expression of MMP-2/9 and enhancement of ESCC progression. These data demonstrate the underlying mechanism by which Pol ι promotes ESCC progression, suggesting that Pol ι is a potential novel prognostic biomarker and therapeutic target for ESCC.

Patterns of failure and clinical outcomes of definitive radiotherapy for cervical esophageal cancer

Purpose

Because of the scarcity of cervical esophageal cancer (CEC), data for this disease entity is limited. We aim to evaluate the outcomes, prognostic factors and failure patterns of CEC treated by contemporary radiotherapy (RT).

Methods

We retrospectively analyzed 86 CEC patients consecutively treated between 2007 and 2015 by definitive RT with or without concurrent chemotherapy. RT was mainly delivered with Intensity Modulated Irradiation Therapy (IMRT) or Volumetric-Modulated Arc Therapy (VMAT). Statistical analyses were performed on survival, prognostic factors and failure patterns.

Results

The median follow-up time was 19.4 months. The 3-year overall survival (OS), local regional failure free survival (LRFFS), distant metastatic free survival (DMFS), and progression free survival (PFS) were 53.6%, 57.9%, 81.5% and 41.5%, respectively. Independent predictors for poorer OS were N stage, hoarseness and recurrent laryngeal nerve lymph node (RLN) involvement, and predictors for LRFFS were N stage and EQD2 (equivalent dose in 2 Gy fraction) to gross tumor volume (GTV), with ≥ 66Gy achieving local control of 94.7%. Patients receiving elective nodal irradiation (ENI) had better nodal regional control than those receiving involved field irradiation (IFI). 31 (36%) patients had treatment failure and 15 (17.4%), 8 (9.3%) and 14 (16.2%) patients had local, regional, and distant failure, respectively. 86.7% (13/15) local failures were within GTV, and supraclavicular region (62.5%, 5/8) was the most common regional failure site. No severe toxicities were observed.

Conclusions

Our results seem to indicate that good locoregional control might be achieved for CEC with adequate radiation dose and treatment planning approaches.

Sterilization of tumor-positive lymph nodes of esophageal cancer by neo-adjuvant treatment is associated with worse survival compared to tumor-negative lymph nodes treated with surgery first

BACKGROUND AND OBJECTIVES

Lymph node (LN) involvement by esophageal cancer is associated with compromised long-term prognosis. This study assessed whether LN downstaging by neoadjuvant treatment (NAT) might offer a survival benefit compared to patients with a priori negative LN.

METHODS

Patients undergoing esophagectomy for cancer between 2005 and 2014 were screened for inclusion. Group 1 included cN0 patients confirmed as pN0 who were treated with surgery first, whereas group 2 included patients initially cN+ and down-staged to ypN0 after NAT. Survival analysis was performed with the Kaplan-Meier and Cox regression methods.

RESULTS

Fifty-seven patients were included in our study, 24 in group 1 and 33 in group 2. Group 2 patients had more locally advanced lesions compared to a priori negative patients, and despite complete LN sterilization by NAT they still had worse long-term survival. Overall 3-year survival was 86.8% for a priori LN negative versus 63.3% for downstaged patients (P = 0.013), while disease-free survival was 79.6% and 57.9%, respectively (P = 0.021). Tumor recurrence was also earlier and more disseminated for the down-staged group.

CONCLUSIONS

Downstaged LN, despite the systemic effect of NAT, still inherit an increased risk for early tumor recurrence and worse long-term survival compared to a priori negative LN.

Nodal skip metastasis in thoracic esophageal squamous cell carcinoma: a cohort study

BACKGROUND

Nodal skip metastasis is a prognostic factor in some sites of malignancies, but its role in esophageal cancer is still unclear. The present study aimed to investigate occurrence and effect of nodal skip metastases in thoracic esophageal squamous cell carcinoma.

METHODS

All 578 patients undergoing esophagectomy for thoracic esophageal squamous cell carcinoma at the Center for Esophageal Diseases located in Padova between January 1992 and December 2010 were retrospectively evaluated. Selection criteria were R0 resection, pathological M0 stage and pathological lymph node involvement. Patients receiving neoadjuvant therapy were excluded.

RESULTS

The selection identified 88 patients with lymph node involvement confirmed by pathological evaluation. Sixteen patients (18.2%) had nodal skip metastasis. Adjusting for the number of lymph node metastases, patient with nodal skip metastasis had similar 5-year overall survival (14% vs. 13%, p = 0.93) and 5-year disease free survival (14% vs. 9%, p = 0.48) compared to patients with both peritumoral and distant lymph node metastases. The risk difference of nodal skip metastasis was: -24.1% (95% C.I. -43.1% to -5.2%) in patients with more than one lymph node metastasis compared to those with one lymph node metastasis; -2.3% (95% C.I. -29.8% to 25.2%) in middle thoracic esophagus and -23.0% (95% C.I. -47.8% to 1.8%) in lower thoracic esophagus compared to upper thoracic esophagus; 18.1% (95% C.I. 3.2% to 33.0%) in clinical N0 stage vs. clinical N+ stage.

CONCLUSIONS

Nodal skip metastasis is a common pattern of metastatic lymph involvement in thoracic esophageal squamous cell carcinoma. However, neither overall survival nor disease free survival are associated with nodal skip metastasis occurrence.