Mapping patterns of metastatic lymph nodes for postoperative radiotherapy in thoracic esophageal squamous cell carcinoma: a recommendation for clinical target volume definition

Patterns of Lymph Node Recurrence after Esophagectomy of pT2-3 N0M0 Esophageal Squamous Cell Carcinoma

PURPOSE

This study aims to elucidate the distribution patterns of lymph node recurrence (LNR) in patients with pT2-3N0M0 esophageal squamous cell carcinoma (ESCC) following esophagectomy.

METHODS

A comprehensive retrospective analysis was conducted on 96 pT2-3N0M0 ESCC patients who experienced postoperative LNR at our institution between January 2010 and August 2019. LNR sites were systematically categorized into cervical, mediastinal, and abdominal regions. Computed tomography imaging was digitally reconstructed to precisely map recurrence locations, followed by rigorous statistical analysis of distribution patterns.

RESULTS

The final cohort comprised 96 patients with confirmed LNR, with males constituting 79.2% of the sample and a median age of 61 years. Mediastinal LNR was determined to be the most prevalent (69.8%), followed by cervical (43.8%) and abdominal (33.3%) regions. Cervical recurrences were predominantly identified in lymph node station 104R/L (7.8%), while mediastinal recurrences were predominantly localized to station 106recR (14.5%) and station 105 (10.4%), and abdominal recurrences were concentrated in stations 16a2 (3.6%) and 9 (3.6%). Computerized tomography reconstruction demonstrated a distinctive "T"-shaped distribution of LNR in the cervical and upper mediastinal regions in proximity to major vascular structures. The primary tumor location was not found to significantly influence LNR distribution patterns (P > 0.05).

CONCLUSIONS

LNR in pT2-3N0M0 ESCC predominantly manifests in cervical and upper mediastinal lymph nodes. Administering targeted adjuvant radiotherapy to high-risk patients may be an effective strategy for enhancing therapeutic outcomes. Prospective multicenter studies are warranted to validate these preliminary findings.

Value of Computed Tomography Scan for Detecting Lymph Node Metastasis in Early Esophageal Squamous Cell Carcinoma

BACKGROUND

The necessity of computed tomography (CT) scan for detecting potential lymph node metastasis (LNM) in early esophageal squamous cell carcinoma (ESCC) before endoscopic and surgical treatments is under debate.

METHODS

Patients with histologically proven ESCC limited to the mucosa or submucosa were examined retrospectively. Diagnostic performance of CT for detecting LNM was analyzed by comparing original CT reports with pathology reports. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were calculated.

RESULTS

A total of 625 patients from three tertiary referral hospitals were included. The rate of pathologically confirmed LNM was 12.5%. Based on original CT reports, the sensitivity, specificity, accuracy, PPV, and NPV of CT to determine LNM in T1 ESCC were 41.0%, 83.2%, 77.9%, 25.8%, and 90.8% respectively. For mucosal cancers (T1a), these parameters were 50.0%, 81.7%, 80.9%, 6.8%, and 98.4%, respectively. For submucosal cancers (T1b), they were 40.0%, 85.0%, 75.0%, 43.0%, and 83.3%, respectively. Additionally, the diagnostic performance of CT for LNM was relatively better for ESCC in the lower esophagus. Pathologically, 69.2% of patients with LNM did not exhibit lymphovascular invasion (LVI), and the sensitivity of CT for recognizing LNM in these patients (33.3%) was lower than those with LVI (58.3%).

CONCLUSIONS

Computed tomography can detect nearly half of the LNM cases in early ESCC with high specificity. The performance of CT further improved in LNM cases with LVI. Therefore, we conclude that routine preoperative CT for the assessment of potential LNM risk in patients with early ESCC is necessary.

Salvage radiotherapy for locoregional recurrence of esophageal cancer after surgery

OBJECTIVE

There is no consensus on the optimal treatment for patients with locoregional recurrence of esophageal cancer after surgery. The objective of this study was to investigate the outcomes and prognostic factors associated with salvage radiotherapy in patients with locoregional recurrence of esophageal cancer after surgery.

METHODS

We reviewed 80 patients with locoregional recurrence of esophageal cancer after surgery who were treated with radiotherapy. The median dose was 60 Gy, and 29 patients (36%) received elective nodal irradiation. Fifty-three patients (66%) received concurrent chemotherapy (mostly 5-fluorouracil and cisplatin) during radiotherapy. Overall survival, progression-free survival and in-field recurrence rate were assessed.

RESULTS

The median follow-up period was 17 months. Two-year overall survival, progression-free survival and in-field recurrence rate were 50.3%, 23.5% and 41.3%, respectively. On multivariate analysis, a maximum diameter of locoregional recurrence lesions <30 mm was associated with higher overall survival (P = 0.044). Disease-free interval between surgery and locoregional recurrence >14 months was associated with higher PFS (P = 0.003). Late grade 3 toxicities occurred in three patients (3.8%). No grade 4 or higher toxicity was observed.

CONCLUSIONS

Salvage radiotherapy demonstrated efficacy in achieving in-field control with acceptable toxicity. However, the high rate of out-of-field metastases led to poor progression-free survival and overall survival, particularly in cases involving large lesions and a short disease-free interval. A prospective study is warranted to establish a treatment strategy, particularly considering the combined use of effective anti-cancer drugs.

Supraclavicular lymph node metastasis should not be defined as regional lymph node metastasis in cervical and upper thoracic esophageal squamous cell carcinoma

The importance of supraclavicular lymph node (SCLN) metastasis in cervical and upper thoracic esophageal squamous cell carcinoma (ESCC) has not been determined. The aim of the present study was to provide a detailed definition of the range of SCLN regions and to explore whether SCLNs should be considered as a regional lymph nodes for patients with cervical and upper thoracic ESCC. A retrospective analysis was performed on 230 patients with locally advanced cervical or upper thoracic ESCC who underwent radical radiotherapy and chemotherapy. The range of SCLN regions was defined in detail on contrast enhanced computed tomography images of the neck. According to whether the patient had lymph node metastasis in the supraclavicular region, the included patients were divided into two groups, and the survival differences and reasons for treatment failure between the two groups were analyzed. Of the 230 patients with ESCC, 71 (30.87%) exhibited lymph node metastases in the supraclavicular region. The median overall survival time of ESCC patients with and without SCLN metastasis was 17 and 30 months, respectively (P<0.001). After propensity score matching (PSM), the median overall survival time of ESCC patients with and without SCLN metastasis was 17 and 28 months, respectively (P<0.001). During the follow-up period, there were a total of 101 cases of failure of treatment in the irradiation field, 6 cases had esophageal metastasis in the non-irradiated field and 27 cases had regional lymph node metastasis in the non-irradiated field. In addition, there were 33 cases of metastasis to the distant lymph nodes or organs. There was no significant difference in the local treatment failure rate between the groups with or without SCLN metastasis in both the irradiation field and the non-irradiation field, but the probability of distant metastasis in the SCLN metastasis group was significantly higher than that in the group without SCLN metastasis (P=0.025). In conclusion, patients with cervical and upper thoracic ESCC with SCLN metastasis have a poor prognosis and the median overall survival time is closer to that of metastatic ESCC than ESCC with regional lymph node metastasis; therefore, SCLNs should not be defined as regional lymph nodes in patients with cervical and upper thoracic ESCC.

Deep Learning and Registration-Based Mapping for Analyzing the Distribution of Nodal Metastases in Head and Neck Cancer Cohorts: Informing Optimal Radiotherapy Target Volume Design

We introduce a deep-learning- and a registration-based method for automatically analyzing the spatial distribution of nodal metastases (LNs) in head and neck (H/N) cancer cohorts to inform radiotherapy (RT) target volume design. The two methods are evaluated in a cohort of 193 H/N patients/planning CTs with a total of 449 LNs. In the deep learning method, a previously developed nnU-Net 3D/2D ensemble model is used to autosegment 20 H/N levels, with each LN subsequently being algorithmically assigned to the closest-level autosegmentation. In the nonrigid-registration-based mapping method, LNs are mapped into a calculated template CT representing the cohort-average patient anatomy, and kernel density estimation is employed to estimate the underlying average 3D-LN probability distribution allowing for analysis and visualization without prespecified level definitions. Multireader assessment by three radio-oncologists with majority voting was used to evaluate the deep learning method and obtain the ground-truth distribution. For the mapping technique, the proportion of LNs predicted by the 3D probability distribution for each level was calculated and compared to the deep learning and ground-truth distributions. As determined by a multireader review with majority voting, the deep learning method correctly categorized all 449 LNs to their respective levels. Level 2 showed the highest LN involvement (59.0%). The level involvement predicted by the mapping technique was consistent with the ground-truth distribution (p for difference 0.915). Application of the proposed methods to multicenter cohorts with selected H/N tumor subtypes for informing optimal RT target volume design is promising.

Effect of contrast medium on early detection and analysis of mediastinal lymph nodes in computed tomography

OBJECTIVE

This study aimed to evaluate the diagnostic efficiency of contrast-to-noise and signal-to-noise ratios created by the contrast medium in detecting lymph nodes.

METHODS

In this study, 57 short-axis subcentimeter lymph nodes in 40 cardiac computed tomography patients with noncontrast- and contrast-enhanced phases were evaluated. The contrast-to-noise ratios and signal-to-noise ratios of noncontrast- and contrast-enhanced lymph node-mediastinal fat and aortic-mediastinal fat tissues were determined. In addition, lymph nodes in noncontrast- and contrast-enhanced series were evaluated subjectively.

RESULTS

There was a significant difference in lymph node-mediastinal fat signal-to-noise values between the contrast and noncontrast phases (p=0.0002). In the contrast phase, aortic density values were found to be 322.04±18.51 HU, lymph node density values were 76.41±23.41 HU, and mediastinal adipose tissue density values were -65.73±22.96 HU. Aortic-mediastinal fat contrast-to-noise ratio value was 20.23±6.92 and the lymph node-mediastinal fat contrast-to-noise ratio value was 6.43±2.07. A significant and moderate correlation was observed between aortic-mediastinal fat and lymph node-mediastinal fat contrast-to-noise ratio values in the contrast phase (r=0.605; p<0.001). In the contrast-enhanced series, there was a significant increase in the subjective detection of lymph nodes (p=0.0001).

CONCLUSION

In the detection of paratracheal lymph nodes, the contrast agent increases the detection of short-axis subcentimeter lymph nodes quantitatively and qualitatively. Contrast enhances and facilitates the detection of paratracheal lymph nodes.

Lymph drainage and cervical fascia anatomy-oriented differential nodal CTV delineation at the supraclavicular region for esophageal cancer and nasopharyngeal cancer

PURPOSE

To determine the differences in supraclavicular lymph node metastasis between esophageal cancer (EC) and nasopharyngeal cancer (NPC) and explore the feasibility of differential supraclavicular clinical target volume (CTV) contouring between these two diseases based on the involvement of different fascial spaces.

MATERIALS AND METHODS

One hundred patients with supraclavicular nodes positive for EC or NPC were enrolled, and their pre-treatment images were reviewed. The distribution patterns of nodes between the two diseases were compared in the context of node levels defined by the 2017 Japanese Esophageal Society and 2013 International Consensus on Cervical Lymph Node Level Classification. Grouping supraclavicular nodes based on sub-compartments formed by the cervical fascia was discussed, and the feasibility of differential CTV contouring based on the differences in the involvement of these sub-compartments between EC and NPC was explored.

RESULTS

The 2013 Consensus on cervical node levels and 2017 Japanese Esophageal Society node station could not practically guide supraclavicular CTV contouring. We divided the supraclavicular space into six sub-compartments: the para-esophageal space (PES), carotid sheath space (CSS), sub-thyroid pre-trachea space (STPTS), pre-vascular space (PVS), and vascular lateral space (VLS) I and II. EC mainly spread to the PES, STPTS, CSS, and VLS I, whereas NPC tended to spread to the CSS, VLS I, and VLS II. These combinations of sub-compartments may help constitute the supraclavicular CTVs for EC and NPC.

CONCLUSIONS

The fascia anatomy-based sub-compartments sufficiently distinguished metastasis to the supraclavicular space between EC and NPC, thus facilitating differential CTV contouring between these two diseases.

Prediction of Individual Lymph Node Metastatic Status in Esophageal Squamous Cell Carcinoma Using Routine Computed Tomography Imaging: Comparison of Size-Based Measurements and Radiomics-Based Models

BACKGROUND

Lymph node status is vital for prognosis and treatment decisions for esophageal squamous cell carcinoma (ESCC). This study aimed to construct and evaluate an optimal radiomics-based method for a more accurate evaluation of individual regional lymph node status in ESCC and to compare it with traditional size-based measurements.

METHODS

The study consecutively collected 3225 regional lymph nodes from 530 ESCC patients receiving upfront surgery from January 2011 to October 2015. Computed tomography (CT) scans for individual lymph nodes were analyzed. The study evaluated the predictive performance of machine-learning models trained on features extracted from two-dimensional (2D) and three-dimensional (3D) radiomics by different contouring methods. Robust and important radiomics features were selected, and classification models were further established and validated.

RESULTS

The lymph node metastasis rate was 13.2% (427/3225). The average short-axis diameter was 6.4 mm for benign lymph nodes and 7.9 mm for metastatic lymph nodes. The division of lymph node stations into five regions according to anatomic lymph node drainage (cervical, upper mediastinal, middle mediastinal, lower mediastinal, and abdominal regions) improved the predictive performance. The 2D radiomics method showed optimal diagnostic results, with more efficient segmentation of nodal lesions. In the test set, this optimal model achieved an area under the receiver operating characteristic curve of 0.841-0.891, an accuracy of 84.2-94.7%, a sensitivity of 65.7-83.3%, and a specificity of 84.4-96.7%.

CONCLUSIONS

The 2D radiomics-based models noninvasively predicted the metastatic status of an individual lymph node in ESCC and outperformed the conventional size-based measurement. The 2D radiomics-based model could be incorporated into the current clinical workflow to enable better decision-making for treatment strategies.

Effect of Adjuvant Radiation Dose on Survival in Patients with Esophageal Squamous Cell Carcinoma

Background: For patients with esophageal squamous cell carcinoma (ESCC) treated with surgery alone, the incidence of local-regional recurrence remains unfavorable. Postoperative radiotherapy (PORT) has been associated with increased local-regional recurrence-free survival (LRFS), although its application is limited by concerns of PORT-related toxicities. Methods: Among 3591 patients with ESCC analyzed in this study, 2765 patients with T3-4N0 and T1-4N1-3 lesions and specific local-regional status information were analyzed in a subsequent analysis of adjuvant radiation dose (aRTD) effect. Application of the restricted cubic spline regression model revealed a non-linear relationship between aRTD and survival/radiotoxicity. Linear regression analysis (LRA) was performed to evaluate correlations between LRFS and overall survival (OS)/ disease-free survival (DFS). Results: For patients staged T1−2N0, T1−2N1−3, T3−4N0, and T3−4N1−3, 5-year OS in PORT and non-PORT groups were 77.38% vs. 72.91%, p = 0.919, 52.35% vs. 46.60%, p = 0.032, 73.41% vs. 61.19%, p = 0.005 and 38.30% vs. 25.97%, p < 0.001. With aRTD escalation, hazard ratios (HRs) of OS/DFS declined until aRTD exceeded 50Gy, then increased, whereas that of LRFS declined until aRTD exceeded 50 Gy, then remained steady. HR of treatment-related mortality was stable until aRTD exceeded 50 Gy, then increased. LRA revealed strong correlations between LRFS and OS/DFS (r = 0.984 and r = 0.952, respectively). An absolute 1% advancement in LRFS resulted in 0.32% and 0.34% improvements in OS and DFS. Conclusions: An aRTD of 50Gy was well-tolerated, with favorable survival resulting from PORT-related LRFS improvement in patients staged T3−4N0 or T1-4N1−3. Further stratification analyses based on tumor burden would help determine potential PORT-beneficiaries.

Recommendations of the clinical target volume for the para-aortic region based on the patterns of lymph node metastasis in patients with biliary tract cancer

BACKGROUND

Even though the clinical target volume (CTV) in biliary tract cancer (BTC) patients has been proposed by several previous studies, the para aortic CTV for BTC is still not well-defined. The objective of this study was to determine the precise delineation of the para aortic CTV for BTC according to the distribution pattern and failure pattern of lymph nodes.

METHODS

Computed tomography (CT)-, magnetic resonance imaging (MRI)- or positron emission tomography-computed tomography (PET-CT)-generated images of patients with BTC from 2015 to 2020 were analyzed retrospectively. The distribution patterns of lymph nodes in different regions were summarized. The diagnosed para aortic lymph nodes (PALNs) were manually mapped to standard axial CT images. The asymmetric CTV expansions from the para aortic were defined according to the distance from the volumetric centre of lymph node to the most proximal border of aorta.

RESULTS

A total of 251 positive lymph nodes were found in the study cohort (n = 61 patients, 92 PALN). All PALNs were projected onto axial CT image of the standard patient. PALNs were concentrated in the 16a2 and 16b1 regions, and the involvement rates were 17% and 13% respectively. Therefore, the upper boundary of 16a2 and the lower boundary of 16b1 were defined as the cranial and caudal border of para aortic CTV, respectively. For the study cohort, the mean distance from the volume center of all lymph nodes in 16a2 and 16b1 to the proximal border of the aorta was 9 mm (range 4-24) in the front, 7 mm (range 3-14) on the left, and 12 mm (range 5-29) on the right. For the validation cohort (n=19 patients, 56 PALN), the mean distance from the center of the lymph node to the border of the aorta were both 10 mm on the left (range 5-20) and right (range 6-23). The mean distance in front of the aorta was 9 mm (range 5-23). Finally, a CTV expansion from the aorta of 18 mm in the front, 12 mm on the left, and 24 mm on the right resulted in 96% (73/76) coverage of PALNs in the study cohort. At the time of the validation, the described CTV could include 96% (47/49) of recurrent PALNs in the validation cohort.

CONCLUSIONS

The involvement rates of PALNs in 16a2 and 16b1 were the highest. Based on the distribution of PALNs, a new para-aortic CTV was defined to construct a more accurate target volume for adjuvant radiotherapy in BTC.

Development and Validation of Novel Nomograms to Predict the Overall Survival and Cancer-Specific Survival of Cervical Cancer Patients With Lymph Node Metastasis

Objective

The objective of this study was to establish and validate novel individualized nomograms for predicting the overall survival (OS) and cancer-specific survival (CSS) in cervical cancer patients with lymph node metastasis.

Methods

A total of 2,956 cervical cancer patients diagnosed with lymph node metastasis (American Joint Committee on Cancer, AJCC N stage=N1) between 2000 and 2018 were included in this study. Univariate and multivariate Cox regression models were applied to identify independent prognostic predictors, and the nomograms were established to predict the OS and CSS. The concordance index (C-index), calibration curves, and receiver operating characteristic (ROC) curves were applied to estimate the precision and discriminability of the nomograms. Decision-curve analysis (DCA) was used to assess the clinical utility of the nomograms.

Results

Tumor size, log odds of positive lymph nodes (LODDS), radiotherapy, surgery, T stage, histology, and grade resulted as significant independent predictors both for OS and CSS. The C-index value of the prognostic nomogram for predicting OS was 0.788 (95% CI, 0.762–0.814) and 0.777 (95% CI, 0.758–0.796) in the training and validation cohorts, respectively. Meanwhile, the C-index value of the prognostic nomogram for predicting CSS was 0.792 (95% CI, 0.767–0.817) and 0.781 (95% CI, 0.764–0.798) in the training and validation cohorts, respectively. The calibration curves for the nomograms revealed gratifying consistency between predictions and actual observations for both 3- and 5-year OS and CSS. The 3- and 5-year area under the curves (AUCs) for the nomogram of OS and CSS ranged from 0.781 to 0.828. Finally, the DCA curves emerged as robust positive net benefits across a wide scale of threshold probabilities.

Conclusion

We have successfully constructed nomograms that could predict 3- and 5-year OS and CSS of cervical cancer patients with lymph node metastasis and may assist clinicians in decision-making and personalized treatment planning.

Postoperative lymphatic recurrence distribution and delineation of the radiation field in lower thoracic squamous cell esophageal carcinomas: a real-world study

Background

To study lymphatic recurrence distribution after radical surgery in the real world and guide clinical tumor volume delineation for regional lymph nodes during postoperative radiotherapy for lower thoracic squamous cell esophageal carcinomas.

Methods

We enrolled patients who underwent radical esophagectomy, without radiation before or after surgery, at 3 cancer hospitals. Patients were classified into groups according to tumor locations. We included patients with tumors in the lower thoracic segment and analyzed the postoperative lymph node recurrence mode. A cutoff value of 10% was used to differentiate high-risk lymph node drainage areas from others.

Results

We enrolled 1905 patients in the whole study series, including 652 thoracic esophageal carcinomas that met our inclusion criteria; there were 241 cases of lower thoracic esophageal carcinomas. 1st, 2nd, 4th, 7th, 8th groups of lymph nodes, according to the 8th edition of the AJCC classification, displayed as high-risk recurrence areas, representing 17.8%, 23.9%, 11.7%, 10.9% and 12.2% of lymph node recurrence. Stage III-IV tumors located in the lower segment of the thoracic esophagus showed a tendency to recur in the left gastric nodes (7.9%) and celiac nodes (10.6%).

Conclusions

According to our results, we recommended including the 4th, 7th and 8th groups of lymph nodes in the radiation field, and for patients with stage III-IV disease, the 17th and 20th groups of nodes should be irradiated during postoperative treatment. Whether including 1st/2nd groups in preventive irradiation needed more proofs.

Mapping of Cervical and Upper Mediastinal Lymph Node Recurrence for Guiding Clinical Target Delineation of Postoperative Radiotherapy in Thoracic Esophageal Squamous Cell Carcinoma

Background

The lower neck and upper mediastinum are the major regions for postoperative radiotherapy (PORT) in thoracic esophageal squamous cell carcinoma (TESCC). However, there is no uniform standard regarding the delineation of nodal clinical target volume (CTVnd). This study aimed to map the recurrent lymph nodes in the cervical and upper mediastinal regions and explore a reasonable CTVnd for PORT in TESCC.

Methods

We retrospectively reviewed patients in our hospital with first cervical and/or upper mediastinal lymph node recurrence (LNR) after upfront esophagectomy. All of these recurrent lymph nodes were plotted on template computed tomography (CT) images with reference to surrounding structures. The recurrence frequency at different stations was investigated and the anatomic distribution of recurrent lymph nodes was analyzed.

Results

A total of 119 patients with 215 recurrent lymph nodes were identified. There were 47 (39.5%) patients with cervical LNR and 102 (85.7%) patients with upper mediastinal LNR. The high-risk regions were station 101L/R, station 104L/R, station 106recL/R, station 105 and station 106pre for upper TESCC and station 104L/R, station 106recL/R, station 105, station 106pre and station 106tbL for middle and lower TESCCs. LNR in the external group of station 104L/R was not common, and LNR was not found in the narrow spaces where the trachea was in close contact with the innominate artery, aortic arch and mediastinal pleura. LNR below the level of the cephalic margin of the superior vena cava was also not common for upper TESCC.

Conclusions

The CTVnd of PORT in the cervical and upper mediastinal regions should cover station 101L/R, station 104L/R, station 106recL/R, station 105 and station 106pre for upper TESCC and station 104L/R, station 106recL/R, station 105, station 106pre and station 106tbL for middle and lower TESCCs. Based on our results, we proposed a useful atlas for guiding the delineation of CTVnd in TESCC.

Para-aortic lymph node metastasis in lower Thoracic Esophageal Squamous Cell Carcinoma after Radical Esophagectomy: a CT-based atlas and its clinical implications for Adjuvant Radiotherapy

Background: Our previous work showed that para-aortic lymph node (PALN) metastasis was the major failure pattern in lower thoracic esophageal squamous cell carcinoma (LTESCC) patients who presented abdominal LN failure after curative surgery. We thereby aim to generate a computerized tomography (CT)-based documentation of PALNs and to propose a clinical target volume (CTV) for this region. Methods: Sixty-five patients were enrolled. The epicentre of each PALN was drawn onto an axial CT image of a standard patient with reference to the surrounding anatomical landmarks. A CTV for PALN was generated based on the final result of node distribution, and was evaluated for dosimetric performance in three simulated patients. Results: All the studied 248 LNs were below the level of 1.0 cm above the celiac artery (CA), and 94.76% were above the bottom of vertebra L3. Horizontally, 93.33% of the LNs in the celiac level were located within an expansion of 1.5 cm on the CA, and 94.12% of the LNs in the superior mesenteric artery (SMA) level were within 1.5 cm on the left side of the SMA. Below the SMA, all the LNs were behind the left renal vein, left to the right border of the inferior vena cava, and 98.51% of the LNs were medial to the lateral surface of the left psoas major. The proposed CTV could cover 92.74% of the LNs and was dosimetrically feasible. Conclusions: The proposed CTV is the first one to focus on the high-risk area of abdominal failure in LTESCC patients after surgery and can serve as a reference in the adjuvant radiotherapy for LTESCC patients.

Postoperative Radiotherapy for Thoracic Esophageal Carcinoma with Upfront R0 Esophagectomy

Multidisciplinary therapies can improve the survival of patients with locally advanced esophageal carcinoma. However, the determination of the optimal modality is still a controversial subject. Many randomized controlled trials in the late 20th century showed that there was no survival benefit when postoperative radiotherapy was added to surgery for esophageal carcinoma. As a result, the treatment modality shifted thereafter to neoadjuvant therapies. Even so, these trials are criticized for many limitations and an increasing number of studies (mainly nonrandomized controlled trials) has indicated that postoperative radiotherapy/chemoradiotherapy can improve the survival of patients with a poor prognosis after R0 esophagectomy. Additionally, a large number of patients with locally advanced esophageal carcinoma still choose upfront surgery in the clinical practice due to many reasons. Therefore, postoperative radiotherapy seems to be a feasible treatment for these patients with a poor prognosis, particularly in the new era of conformal radiotherapy. Here, we review published studies on postoperative radiotherapy/chemoradiotherapy, and we discuss the clinical issues related to postoperative radiotherapy, such as the indication, target volume, total radiation dosage, time interval and complications of postoperative radiotherapy with or without chemotherapy, to make recommendations of postoperative radiotherapy for both current practice and future research in esophageal carcinoma.

Risk Factors and Patterns of Abdominal Lymph Node Recurrence After Radical Surgery for Locally Advanced Thoracic Esophageal Squamous Cell Cancer

Background

We aimed to identify the suitable indication and delineate the target volume based on the pattern of abdominal lymph node recurrence (ALNR) after radical surgery for guiding postoperative radiotherapy in thoracic esophageal squamous cell cancer (TESCC).

Methods

Clinical data of patients with locally advanced TESCC after radical surgery without perioperative anti-tumor therapies from June 2011 to June 2016 were reviewed. Logistic regression analysis was used to find out the high-risk factors of ALNR. The pattern of ALNR was analysed and a template CT in the Pinnacle treatment plan system was used to reconstruct the distribution of the sites of ALNR.

Results

A total of 63 (19.57%) patients with 276 lymph nodes of ALNR were identified in 322 patients. Univariate logistic regression indicated that pathological tumor location, width of tumor, T stage, N stage, TNM stage, ratio of lymph node metastasis (LNM), vessel carcinoma embolus, cancerous node, LNM in the middle and lower mediastinum, LNM in the abdominal region, ratio of LNM in the abdominal region were risk factors of ALNR. Multivariate logistic regression analysis showed that only LNM in the abdominal region was an independent risk factor. The odds ratio was 7.449 (95% CI=2.552–22.297, P<0.001). Station 16a2, station 9, station 16b1, and station 8 were the major regions of ALNR. The recurrence rates were 10.56%, 9.63%, 7.14% and 5.28% in these stations, respectively.

Conclusion

Positive pathological abdominal lymph nodes should be the major indication for abdominal irradiation in postoperative radiotherapy for locally advanced TESCC. We recommended that the target volume includes station 8, station 9, station 16a2 and station 16b1 and proposed a specific delineation of the clinical target volume based on the distribution of ALNR on template CT images.