Re-evaluating the optimal radiation dose for definitive chemoradiotherapy for esophageal squamous cell carcinoma

Current and future on definitive concurrent chemoradiotherapy for inoperable locally advanced esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is an aggressive and fatal disease that is usually diagnosed when the chances for surgical intervention has been missed. Definitive concurrent chemoradiotherapy (dCRT) is the first choice of treatment for inoperable locally advanced esophageal squamous cell carcinoma (LA-ESCC). Nevertheless, the local recurrence rate for esophageal cancer patients undergoing dCRT remains high at 40-60%, with a 5-year overall survival rate of solely 10-30%. Immunotherapy in combination with dCRT is a promising treatment for inoperable LA-ESCC, for that improved long-term survival is expected. The present review provides a comprehensive overview of the evolutionary trajectory of dCRT for LA-ESCC, delineates notable relevant clinical studies, addresses unresolved concerns regarding the combination of dCRT with immunotherapy, and highlights promising directions for future research. When dCRT is combined with immunotherapy, the following aspects should be carefully explored in the future studies, including the optimal irradiation dose, segmentation scheme, radiotherapy technique, timing, sequence and duration of radiotherapy, and the selection of chemotherapeutic and immunologic drugs. In addition, further investigations on the mechanisms of how dCRT combined with immunotherapy exerts synergistic anti-tumor effects and molecular biomarkers ensuring precise screening of ESCC patients are needed.

The impact of radiation dose on the efficacy of definitive chemoradiotherapy in patients with locally advanced esophageal carcinoma: a systematic review and meta-analysis

To investigate the impact of radiation dose on the efficacy of definitive chemoradiotherapy(dCCRT) in patients with locally advanced esophageal carcinoma. PubMed, EMBASE, Cochrane Central Register of Controlled Trials, Wanfang, and Chinese National Knowledge Infrastructure(CNKI) were searched for eligible studies. Studies that compared high-dose radiation(HD-RT) group with low-dose radiation(LD-RT) group using modern radiotherapy techniques for locally advanced esophageal carcinoma patients in dCCRT were identified. The hazard ratios (HR) for overall survival (OS), progression-free survival (PFS), and the odds ratios (OR) for clinical complete response (cCR), local-regional failure (LRF), distant metastasis (DM), and grade≥3 AEs. Meta-analysis was performed when relevant data were available. Eleven studies involving 1943 patients were included for analyses. The results showed that the HD-RT group had better OS (pooled HR 0.78 [0.70, 0.87], p < .00001), PFS (pooled HR 0.72 [0.55, 0.94], p = .01), cCR (OR 1.52 [1.13, 2.05], p = .005), and LRF (OR 0.60 [0.45, 0.80], p = .0004). In addition, there were no significant differences between the two groups in terms of DM (OR 1.43 [1.00, 2.04], p = .05), grade 3-5 radiation pneumonitis (OR 1.38 [0.71, 2.68], p = .35), grade 3-5 radiation esophagitis (OR 1.36 [0.88, 2.10], p = .17), grade 3-5 other esophageal toxicities(stenosis/fistula/hemorrhage) (OR 1.22 [0.75, 2.00], p = .43), and treatment-related death (OR 1.40 [0.73, 2.68], p = .31). High-dose radiotherapy in definitive CCRT for patients with locally advanced esophageal carcinoma is associated with improved PFS, OS, cCR, and LC with no increase of grade≥3AEs. Simultaneously, we await the preliminary and final results of several ongoing dose-escalation randomized trials. Furthermore, future studies should provide personalized radiotherapy doses for these patients.

Definitive radiotherapy in patients with clinical T1N0M0 esophageal squamous cell carcinoma: A multicenter retrospective study (KROG 21-10)

PURPOSE

To assess the failure pattern and analyze the treatment scheme of definitive radiation therapy (RT) for T1N0M0 esophageal squamous cell carcinoma (ESCC).

METHODS

We performed a multi-institutional retrospective analysis in T1N0M0 ESCC patients who underwent definitive RT from 2010 to 2019. Patterns of failure were demonstrated as in-, and out-field locoregional, and distant metastasis. In the analysis, freedom-from locoregional recurrence (FFLRR) and their association with clinicopathologic factors were evaluated. Propensity score matching in cT1b patients was done.

RESULTS

168 patients were included with a median follow-up of 34.0 months, and 26 cT1a, 116 cT1b disease. The rates of 3-year all and locoregional recurrence for cT1a were 30.5% and 24.1% and those for cT1b were 27.1% and 25.9%, respectively. Among 116 cT1b patients, 69 patients received elective nodal irradiation (ENI) and 47 received involved field irradiation (IFI). After propensity score matching, the 3-year FFLRR rate was 84.5%. There was no difference between ENI and IFI in FFLRR (P = 0.831) and OS (P = 0.525). The 3-year FFLRR was 83.8% (95% Confidence interval (CI), 61.8-93.8%) in IFI group and 85.3% (95% CI, 65.1-94.3%) in ENI group. In multivariate analysis, concurrent chemotherapy use was marginally associated with FFLRR (Hazard ratio, 0.16; P = 0.064).

CONCLUSION

cT1a patients who cannot receive endoscopic resection showed similar failure rates as cT1b patients, questioning the staging accuracy and raised the need for thorough treatment like chemoradiotherapy. In cT1b patients, IFI with 50 to 60 Gy and concurrent chemotherapy could be reasonable.

Caution against simultaneous integrated boost radiotherapy for upper thoracic esophageal squamous cell carcinoma: results from a single-arm phase II trial

PURPOSE

To explore the feasibility and safety of simultaneous integrated boost technology (SIB) with elective nodal irradiation (ENI) to the cervical and upper mediastinal lymph node (LN) regions in upper thoracic esophageal squamous cell carcinoma (ESCC).

MATERIAL AND METHODS

Patients with pathologically proven unresectable upper thoracic ESCC were assigned 50.4 Gy/28 fractions (F) to the clinical target volume (encompassing the ENI area of cervical and upper mediastinal LN regions) and a boost of 63 Gy/28 F to the gross tumor volume. Chemotherapy consisted of courses of concurrent cisplatin (20 mg/m2) and docetaxel (20 mg/m2) weekly for 6 weeks. The primary endpoint was toxicity.

RESULTS

Between Jan 2017 and Dec 2019, 28 patients were included. The median follow-up time for all patients was 24.6 months (range 1.9-53.5). Radiation-related acute toxicity included esophagitis, pneumonia and radiodermatitis, all of which were well managed and reversed. Late morbidity included esophageal ulcer, stenosis, fistula and pulmonary fibrosis. Grade III esophageal stenosis and fistula was seen in 11% (3/28) and 14% (4/28) patients, respectively. The cumulative incidence rate of late esophageal toxicity was 7.7%, 19.2% and 24.6% at 6, 12 and 18 months, respectively. There was significant difference of the occurrence of severe late esophageal toxicity among the different volume levels of the esophagus, and cervical and upper mediastinal LNs which received ≥ 63 Gy stratified by the tertiles (p = 0.014).

CONCLUSIONS

Despite the acceptably tolerated acute toxicity of SIB in concurrent CRT with ENI to the cervical and upper mediastinal LN regions for upper thoracic ESCC, the incidence of severe late esophageal toxicity was relatively high. Cautions are provided against easy clinical application of SIB (50.4 Gy/28F to the CTV, 63 Gy/28F to the GTV) in upper thoracic ESCC. Further exploration on dose optimization is warranted.

Cardiac Substructures Dosimetric Predictors for Cardiac Toxicity After Definitive Radiotherapy in Esophageal Cancer

PURPOSE

To investigate the predictive value of the cardiac substructures (CSs) dosimetric parameters for cardiac toxicity after definitive radiation therapy in locally advanced esophageal cancer.

METHODS AND MATERIALS

Between August 2010 and January 2016, 716 patients with stage 2-3 esophageal cancer receiving definitive radiation therapy at 2 institutions were divided into training (n = 432) and external validation (n = 284) cohorts. Dose-volume histogram parameters for the whole heart (WH) and CSs were extracted. Competing risks and Cox regressions analyses were performed. The predictive performance of the models was evaluated using the area under the receiver operating characteristic curve (AUC) and the Brier score.

RESULTS

With a median follow-up of 93 months, 68 patients (15.7%) developed grade ≥3 cardiac events (G3+ CEs), with a median of 13.5 months to the first event. Multivariable analysis showed left ventricle, left anterior descending (LAD), and mean left circumflex (LCX) variables were significantly associated with G3+ CEs. The AUCs and Brier scores demonstrated favorable predictive accuracies of the models integrating these CS variables when predicting G3+ CEs in the training and validation cohorts. However, compared with the WH variables, the CS variables did not significantly improve the prediction of G3+ CEs. Nevertheless, when G3+ acute coronary syndrome and/or congestive heart failure (ACS/CHF) CE was the outcome of interest, models based on the LAD or LCX variables were superior to the WH variable models in training and validation cohorts.

CONCLUSIONS

Models based on CS variables showed favorable predictive accuracy for G3+ CEs. The LAD and LCX variables significantly improved the prediction of G3+ ACS/CHF events compared with the WH variables. Radiation doses to CSs, such as LCX and LAD, should be monitored to help reduce the occurrence of significant CEs in patients with esophageal cancer undergoing definitive radiation therapy.

TWIST1 activates cancer stem cell marker genes to promote epithelial-mesenchymal transition and tumorigenesis in esophageal squamous cell carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is one of the deadliest cancers worldwide. Overexpression of EMT master transcription factors can promote differentiated cells to undergo cancer reprogramming processes and acquire a stem cell-like status.

METHODS

The KYSE-30 and YM-1 ESCC cell lines were transduced with retroviruses expressing TWIST1 or GFP and analyzed by quantitative reverse transcription PCR (qRT-PCR), chromatin immunoprecipitation (ChIP), and immunostaining to investigate the correlation between TWIST1 and stemness markers expression. Cells expressing TWIST1 were characterized for mRNA candidates by qRT-PCR and for protein candidates by Flow cytometry and Immunocytochemistry. TWIST1-ESCC cells were also evaluated for apoptosis and drug resistance.

RESULTS

Here we identify a role for TWIST1 in the establishment of ESCC cancer stem cell (CSC)-like phenotype, facilitating the transformation of non-CSCs to CSCs. We provide evidence that TWIST1 expression correlates with the expression of CSC markers in ESCC cell lines. ChIP assay results demonstrated that TWIST1 regulates CSC markers, including CD44, SALL4, NANOG, MEIS1, GDF3, and SOX2, through binding to the E-box sequences in their promoters. TWIST1 promoted EMT through E-cadherin downregulation and vimentin upregulation. Moreover, TWIST1 expression repressed apoptosis in ESCC cells through upregulation of Bcl-2 and downregulation of the Bax protein, and increased ABCG2 and ABCC4 transporters expression, which may lead to drug resistance.

CONCLUSIONS

These findings support a critical role for TWIST1 in CSC-like generation, EMT progression, and inhibition of apoptosis in ESCC. Thus, TWIST1 represents a therapeutic target for the suppression of esophageal cell transformation to CSCs and ESCC malignancy.

A Phase III Multicenter Randomized Clinical Trial of 60 Gy versus 50 Gy Radiation Dose in Concurrent Chemoradiotherapy for Inoperable Esophageal Squamous Cell Carcinoma

PURPOSE

In this multicenter phase 3 trial, the efficacy and safety of 60 Gy and 50 Gy doses delivered with modern radiotherapy technology for definitive concurrent chemoradiotherapy (CCRT) in patients with inoperable esophageal squamous cell carcinoma (ESCC) were evaluated.

PATIENTS AND METHODS

Patients with pathologically confirmed stage IIA‒IVA ESCC were randomized 1:1 to receive conventional fractionated 60 Gy or 50 Gy to the tumor and regional lymph nodes. Concurrent weekly chemotherapy (docetaxel 25 mg/m2; cisplatin 25 mg/m2) and two cycles of consolidation chemotherapy (docetaxel 70 mg/m2; cisplatin 25 mg/m2 days 1‒3) were administered.

RESULTS

A total of 319 patients were analyzed for survival, and the median follow-up was 34.0 months. The 1- and 3-year locoregional progression-free survival (PFS) rates for the 60 Gy group were 75.6% and 49.5% versus 72.1% and 48.4%, respectively, for the 50 Gy group [HR, 1.00; 95% confidence interval (CI), 0.75‒1.35; P = 0.98]. The overall survival rates were 83.7% and 53.1% versus 84.8% and 52.7%, respectively (HR, 0.99; 95% CI, 0.73‒1.35; P = 0.96), whereas the PFS rates were 71.2% and 46.4% versus 65.2% and 46.1%, respectively (HR, 0.97; 95% CI, 0.73‒1.30; P = 0.86). The incidence of grade 3+ radiotherapy pneumonitis was higher in the 60 Gy group (nominal P = 0.03) than in the 50 Gy group.

CONCLUSIONS

The 60 Gy arm had similar survival endpoints but a higher severe pneumonitis rate compared with the 50 Gy arm. Fifty Gy should be considered as the recommended dose in CCRT for ESCC.

Intensity-modulated radiotherapy with more than 60 Gy improved the survival of inoperable patients with locally advanced esophageal squamous cell carcinoma: A population-based real-world study

Intensity-modulated radiotherapy (IMRT) is widely applied during the treatment of esophageal squamous cell carcinoma (ESCC), but the optimal radiation dose still lacks a consensus. The aim of this study was to explore the optimal radiation dose for inoperable locally advanced ESCC patients treated with IMRT in a real-world clinical setting.A total of 90 inoperable ESCC patients with locally advanced stages of II-IVA treated with IMRT in our institute between February 1, 2014 and June 30, 2019 were included in this retrospective study. Sixty patients had received >60 Gy (high dose group) and 30 patients had received ≤60 Gy (low dose group). The median radiation dose was 66 Gy (range: 61-70 Gy) and 50.2 Gy (range: 40-60 Gy), respectively. Concurrent chemotherapies were platinum-based regimens.The median progression free survival (PFS) and overall survival (OS) of all patients were 7.6 and 14.1 months, respectively. Patients in the high dose group exhibited a significantly better PFS (1-year PFS 34.6% vs 22.8%; 2-year PFS 11.9% vs 0%, P = .008) and OS (1-year OS 57.5% vs 39.5%; 2-year OS 31.4% vs 15.8%, P = .007). The median PFS in the high and low dose groups were 8.1 and 6.1 months, and the median OS were 15.4 and 8.5 months, respectively. Multivariate Cox analysis showed that radiation dose (>60 Gy vs ≤60 Gy) was independently prognostic factor for OS (HR: 0.44; 95% CI: 0.22-0.89; P = .021), but not for PFS (HR: 0.56; 95% CI: 0.31-1.02; P = .058). There was no significant difference in treatment-related toxicities of grade ≥3 between the 2 groups (P = .402).This retrospective study confirmed that higher radiation dose (>60 Gy) resulted in better survival outcomes for inoperable patients with locally advanced ESCC treated with IMRT.

Comparison of Pathologic Complete Response Rates and Oncologic Outcomes in Patients With Surgically Resectable Esophageal Cancer Treated With Neoadjuvant Chemoradiation to 50.4 Gy vs 41.4 Gy

Background

Excellent outcomes and high rates of pathologic complete response (pCR) have been reported in patients with operable esophageal carcinoma using 41.4 Gy of radiation with concurrent carboplatin and paclitaxel. With pCR rates similar to studies using higher doses, it remains unclear whether doses greater than 41.4 Gy result in improved outcomes. This study aims to compare pCR rates and oncologic outcomes in patients treated with neoadjuvant chemoradiation to 50.4 Gy vs 41.4 Gy.

Methods

We reviewed the charts of patients with operable esophageal carcinoma who were treated with neoadjuvant chemoradiation followed by oncologic resection. Our primary endpoint was the pCR rate. Secondary endpoints were overall survival, progression-free survival (PFS), and toxicity. 

Results

We identified 43 patients meeting inclusion criteria. Nineteen patients were treated with 41.4 Gy and 24 were treated with 50.4 Gy. Cohorts were well-matched, except for a significantly higher percentage of patients with adenocarcinoma (AC) (89.5% vs 54.2%, p = 0.02), usage of intensity-modulated radiation therapy (IMRT) (100% vs 47.6%; p = 0.002), and usage of carboplatin, plus paclitaxel (100% vs 75%; p = 0.003) in the 41.4 Gy group. The pCR rate for the cohort was 44.2%. No differences in the pCR rate (41.7% vs 47.4%), three-year overall survival (OS) (73.7% vs 77.5%), or three-year PFS (52.8% vs 43.7%) were observed. Late toxicity rates also did not vary significantly (p = 0.2). No grade 4 or 5 events were observed.

Conclusion

In this small series, there were no differences in the pCR rate, PFS, or OS between those treated with 50.4 Gy and 41.4 Gy. Larger, multi-institutional series are needed to validate these findings.

Definitive chemoradiotherapy versus esophagectomy in patients with clinical T1bN0M0 esophageal squamous cell carcinoma: A retrospective study

BACKGROUND AND PURPOSE

This study aimed to determine the equivalence between definitive chemoradiotherapy (DCRT) and radical esophagectomy in clinical T1bN0M0 esophageal squamous cell carcinoma (ESCC).

MATERIALS AND METHODS

Among 282 patients with cT1bN0M0 ESCC, 238 underwent radical esophagectomy and 44 underwent DCRT. Both treatments were retrospectively compared overall survival (OS), progression-free survival (PFS), and complications.

RESULTS

The DCRT group exhibited poorer patient characteristics than the surgery group, especially with mean age (73 vs. 63 years), Eastern Cooperative Oncology Group (ECOG) status, and Charlson Comorbidity Index (p < 0.001, each). The median follow-up duration was 49.5 (range, 0.4-97.0) and 45.5 months (range, 5.0-112.0) in the surgery and DCRT groups, respectively. In the DCRT group, clinical complete response was achieved in 43 patients (97.7%) at 1 month after treatment. The 5-year OS rates were 75.8% and 68.8% (p = 0.135) and the 5-year PFS were 63.8% and 57.8% (p = 0.637) for the surgery and DCRT groups, respectively. Local recurrence rates were identical between the two groups (11.4% and 11.4%), but the distant metastasis rate was lower in the DCRT group (n = 1, 2.27% vs. n = 29, 12.15%). Grade 3-4 hematologic toxicities were observed in 11 patients (25%) of the DCRT group, and 56 patients (23.5%) in the surgery group showed grade 3-5 surgical complications, including mortality (n = 5).

CONCLUSION

Based on the non-inferior survival rates, recurrence patterns, and complication rates without critical surgical mortality, DCRT was comparable to esophagectomy for cT1bN0 esophageal squamous cell carcinoma.

Results of a Phase 1/2 Trial of Chemoradiotherapy With Simultaneous Integrated Boost of Radiotherapy Dose in Unresectable Locally Advanced Esophageal Cancer

Importance

Effective treatment options for locally advanced esophageal cancer are limited, and rates of local recurrence after standard chemoradiotherapy remain high.

Objective

To evaluate toxic effects, local control, and overall survival rates after chemoradiotherapy with a simultaneous integrated boost of radiotherapy dose to the gross tumor and nodal disease for patients with unresectable locally advanced esophageal cancer.

Design, Setting, and Participants

A phase 1/2, single-arm trial was conducted in 46 patients from April 28, 2010, to April 9, 2015 (median follow-up, 52 months [range, 2-86 months]), at a tertiary academic cancer center. Outcomes of the study patients were compared with those of 97 similar patients treated at the same institution from January 10, 2010, to December 5, 2014, as part of the interim analysis. Statistical analysis was performed from December 15, 2018, to February 12, 2019.

Interventions

Chemoradiotherapy with a simultaneous integrated boost of radiotherapy dose (50.4 Gy to subclinical areas at risk and 63.0 Gy to the gross tumor and involved nodes, all given in 28 fractions) with concurrent docetaxel and capecitabine or fluorouracil.

Main Outcomes and Measures

Toxic effects, local (in-field) control, and overall survival rates.

Results

All 46 patients (11 women and 35 men; median age, 65.5 years [range, 37.3-84.4 years]) received per-protocol therapy, as intensity-modulated photon therapy (39 [85%]) or intensity-modulated proton therapy (7 [15%]); 11 patients (24%) ultimately underwent resection. No patients experienced grade 4 or 5 toxic effects; the 10 acute grade 3 toxic events were esophagitis (4), dysphagia (3), and anorexia (3) and the 3 late grade 3 toxic events were all esophageal strictures. The actuarial local recurrence rates were 22% (95% CI, 11%-35%) at 6 months, 30% (95% CI, 18%-44%) at 1 year, and 33% (95% CI, 20%-46%) at 2 years. Overall, 15 patients (33%) experienced local failure, at a median interval of 5 months (range, 1-24 months). The median overall survival time was 21.5 months (range, 2.3-86.4 months). Exploratory comparison with a 97-patient contemporaneous institutional cohort receiving standard-dose (non-simultaneous integrated boost) chemoradiotherapy showed superior local control (hazard ratio, 0.49; 95% CI, 0.26-0.92; P = .03) and overall survival (hazard ratio, 0.66; 95% CI, 0.47-0.94; P = .02) in the group that received chemoradiotherapy with a simultaneous integrated boost.

Conclusions and Relevance

These findings suggest that chemoradiotherapy with a simultaneous integrated boost of radiotherapy dose for locally advanced esophageal cancer is well tolerated, with encouraging local control, and thus warrants further study.

Trial Registration

ClinicalTrials.gov identifier: NCT01102088.

An Extracellular Matrix-Based Signature Associated With Immune Microenvironment Predicts the Prognosis and Therapeutic Responses of Patients With Oesophageal Squamous Cell Carcinoma

Evidence has suggested that the cancer-associated extracellular matrix (ECM) could be recognised as immune-related biomarkers that modulate tumour progression and expansion. However, the ECM-associated immune effect on esophageal squamous cell carcinoma (ESCC) prognosis and therapy has not been well characterised. In our study, we first constructed an ECM-related signature including four genes CST1, NELL2, ADAMTSL4, and ANGPTL7 by multivariate Cox regression analyses. This signature could serve as a marker to evaluate the prognosis of patients with ESCC and was successfully validated in testing and combined (training plus testing) cohorts. We also found that there were significant different therapeutic responses to chemotherapy and targeted drugs between the high-risk and low-risk groups of patients defined by the signature. Furthermore, the expression of four genes and immune function analysis suggested that this ECM-related signature gene might play important roles in the changes of the tumour microenvironment. In conclusion, our findings demonstrated that the ECM-related signature might serve as an independent prognostic factor and provide a potential biomarker for chemotherapy responses for patients with ESCC.

Enhanced KRT13 gene expression bestows radiation resistance in squamous cell carcinoma cells

Cancer metastasis and recurrence are potentially lethal. A small number of cancer cell groups called cancer stem cells (CSCs) have both stem cell capacity and cancer-forming ability and are reported to play important roles in cancer metastasis and recurrence. These CSCs are considered to be radiation-resistant (RR). Therefore, understanding the biological effects of radiation on squamous cell carcinoma (SCC) cell lines in vitro and in vivo might be worthwhile to circumvent radiation resistance. Currently, there are no reports on the establishment of RR-SCC cells in serum-free defined culture, which mimics biological mechanisms and prevents instability of using serum in the culture medium. We isolated radiation-resistant strains, designated A431-LDR and A431-HDR, from A431 cells derived from vulval SCC and irradiated them with a total dose of 60 Gy at a low-dose rate (2.2 Gy/d) (RM1000) and a high-dose rate (5 Gy/5.75min) in serum-free defined culture. These cells exhibited high sphere-forming and migration ability in vitro and high tumor-forming ability in nude mice xenografts. Overexpression of KRT13 in A431-RR cells might play a role in its radiation-resistant characteristics. These cells might be useful not only to study cancer stem cells but also to study the circumvention of radiation resistance by novel cancer treatment modalities.

Ribosomal S6 protein kinase 4 promotes radioresistance in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive cancers and is highly resistant to current treatments. ESCC harbors a subpopulation of cells exhibiting cancer stem-like cell (CSC) properties that contribute to therapeutic resistance including radioresistance, but the molecular mechanisms in ESCC CSCs are currently unknown. Here, we report that ribosomal S6 protein kinase 4 (RSK4) plays a pivotal role in promoting CSC properties and radioresistance in ESCC. RSK4 was highly expressed in ESCC CSCs and associated with radioresistance and poor survival in patients with ESCC. RSK4 was found to be a direct downstream transcriptional target of ΔNp63α, the main p63 isoform, which is frequently amplified in ESCC. RSK4 activated the β-catenin signaling pathway through direct phosphorylation of GSK-3β at Ser9. Pharmacologic inhibition of RSK4 effectively reduced CSC properties and improved radiosensitivity in both nude mouse and patient-derived xenograft models. Collectively, our results strongly suggest that the ΔNp63α/RSK4/GSK-3β axis plays a key role in driving CSC properties and radioresistance in ESCC, indicating that RSK4 is a promising therapeutic target for ESCC treatment.

The efficacy and safety of definitive concurrent chemoradiotherapy for non-operable esophageal cancer

Objective

To report outcomes and toxicity in patients who received definitive concurrent chemoradiation (DCCRT) for non‐operable esophageal cancer (EC) in the modern era, and to identify markers of overall and disease‐free survival (OS/DFS).

Methods

We conducted a retrospective cohort study of patients with unresectable EC who received DCCRT at our institution between 1/2008 and 1/2019. Descriptive statistics were used to report disease‐control outcomes and CTCAE v4.0–5.0 toxicities. Univariable and multivariable Cox regression, and stepwise regression were used to identify associations with survival.

Results

At a median follow‐up of 19.5 months, 130 patients with adenocarcinoma (AC) (62%) or squamous cell carcinoma (SCC) (38%) were evaluable (Stage II‐III: 92%). Patients received carboplatin/paclitaxel (75%) or fluorouracil‐based (25%) concurrent chemotherapy. Median total RT dose was 50.4 Gy (range, 44.7–71.4 Gy) delivered in 28 fractions (24–35). Locoregional and distant recurrence occurred in 30% and 35% of AC, and 24% and 33% of SCC, respectively. Median OS and DFS were 22.9 and 10.7 months in AC, and 25.7 and 20.2 months in SCC, respectively. On stepwise regression, tumor stage, feeding tube during DCCRT, and change in primary tumor PET/CT SUVmax were significantly associated with OS and DFS. Most severe toxicities were acute grade 4 hematologic cytopenia (6%) and radiation dermatitis (1%). Most common acute grade 3 toxicities were hematologic cytopenia (35%), dysphagia (23%), and anorexia (19%).

Conclusions

Treatment of non‐operable EC with DCCRT has acceptable toxicity and can provide multi‐year disease control for some patients, even in AC. Continued follow‐up and investigation in large studies would be useful.

Dose escalation of 3D radiotherapy is effective for esophageal squamous cell carcinoma: a multicenter retrospective analysis (3JECROG R-03)

Background

To evaluate the impact of radiation dose escalation on overall survival (OS) in patients with non-metastatic esophageal squamous cell carcinoma (ESCC) treated with radical radiotherapy.

Methods

The clinical data of ESCC patients treated with three-dimensional (3D) radiotherapy alone or chemoradiotherapy were collected from multiple institutes and retrospectively analyzed. Patients who received radiation dose ≥40 Gy were included. Radiation dose as a continuous variable was entered into the Cox regression model by using penalized spline regression to allow for a nonlinear relationship between radiation dose and OS to be identified. Patients were stratified into five groups according to EQD₂. The Kaplan-Meier method was used to assess the OS in different dose groups. Univariate and multivariate analyses were performed to evaluate the factors associated with OS.

Results

A total of 2,469 patients were included from 10 institutes across China. The median follow-up time was 58.3 months [95% confidence interval (CI): 56.4–60.2 months]. The median OS and PFS time were 24.3 months (95% CI: 22.5–26.2 months) and 18.0 months (95% CI: 16.4–19.6 months), respectively. The risk of death decreased sharply with a dose up to 60 to 62 Gy, before increasing slightly after the dose was elevated beyond 62 Gy. Multivariate analysis indicated that the chance of death was significantly decreased in patients who received radiotherapy doses of 60–62 Gy [P=0.028, hazard ratio (HR) 0.85, 95% CI: 0.73–0.98)], compared with those who received radiotherapy doses of 40–60 Gy.

Conclusions

Our results reveal radiation dose is a significant prognostic factor of survival for ESCC patients. Higher radiation dose contributes to much more favorable survival outcomes for ESCC patients receiving radical radiotherapy by modern techniques, and 60 Gy or above might be the most optimal radiation dose.

A multicenter prospective phase III clinical randomized study of simultaneous integrated boost intensity-modulated radiotherapy with or without concurrent chemotherapy in patients with esophageal cancer: 3JECROG P-02 study protocol

BACKGROUND

Since the development of three-dimensional conformal radiotherapy and intensity-modulated radiotherapy (IMRT), no prospective study has investigated whether concurrent chemoradiotherapy (SIB-IMRT with 60 Gy) remains superior to radiotherapy (SIB-IMRT) alone for unresectable esophageal cancer (EC). Furthermore, the optimal therapeutic regimen for patients who cannot tolerate concurrent chemoradiotherapy is unclear. We recently completed a phase I/II radiation dose-escalation trial using simultaneous integrated boost (SIB), elective nodal irradiation, and concurrent chemotherapy for unresectable EC. We now intend to conduct a prospective, phase III, randomized study of SIB-IMRT with or without concurrent chemotherapy. We aim to find a safe, practical, and effective therapeutic regimen to replace the conventional segmentation (1.8-2.0 Gy) treatment mode (radiotherapy ± chemotherapy) for unresectable EC.

METHODS

This two-arm, open, randomized, multicenter, phase III trial will recruit esophageal squamous cell carcinoma patients (stage IIA-IVB [UICC 2002]; IVB only with metastasis to the supraclavicular or celiac lymph nodes). In all, 164 patients will be randomized using a 1:1 allocation ratio, and stratified by study site and disease stage, especially the extent of lymph node metastasis. Patients in the SIB arm will receive definitive SIB radiotherapy (95% planning target volume/planning gross tumor volume, 50.4 Gy/59.92 Gy/28 f, equivalent dose in 2-Gy fractions = 60.62 Gy). Patients in the SIB + concurrent chemotherapy arm will receive definitive SIB radiotherapy with weekly paclitaxel and a platinum-based drug (5-6 weeks). Four cycles of consolidated chemoradiotherapy will also be recommended. The primary objective is to compare the 1-year, 2-year, and 3-year overall survival of the SIB + chemotherapy group and SIB groups. Secondary objectives include progression-free survival, local recurrence-free rate, completion rate, and adverse events. Detailed radiotherapy protocol and quality-assurance procedures have been incorporated into this trial.

DISCUSSION

In unresectable, locally advanced EC, a safe and effective total radiotherapy dose and reasonable segmentation doses are required for the clinical application of SIB-IMRT + two-drug chemotherapy. Whether this protocol will replace the standard treatment regimen will be prospectively investigated. The effects of SIB-IMRT in patients with poor physical condition who cannot tolerate definitive chemoradiotherapy will also be investigated.

TRIAL REGISTRATION

clinicaltrials.gov ( NCT03308552 , November 1, 2017).

The efficacy and safety of simultaneous integrated dose reduction in clinical target volume with intensity-modulated radiotherapy for patients with locally advanced esophageal squamous cell carcinoma

Background

Compelling research to explore the effectiveness of simultaneous integrated dose reduction in clinical target volume (CTV) with intensity-modulated radiotherapy (SIR-IMRT) for locally advanced esophageal squamous cell carcinoma (ESCC) are limited. This study aimed to compare the clinical efficacy and treatment-related toxicity between SIR-IMRT and conventional IMRT (C-IMRT) in the treatment of ESCC.

Methods

From March 2010 to September 2016, the clinical data of 257 patients with ESCC who received definitive IMRT in the Tianjin Medical University Cancer Institute and Hospital were collected and retrospectively analyzed. Among these patients, 137 patients received C-IMRT with a prescribed dose of 60 Gy in 30 fractions for planning target volume (PTV), while 120 patients received SIR-IMRT with a prescribed dose of 60 Gy in 30 fractions for the planning gross tumor volume (PGTV) and a prescribed dose of 54 Gy in 30 fractions for PTV. All of the patients received definitive IMRT with elective nodal irradiation. Locoregional control, survival, treatment toxicity and dose to organs at risk (OAR) were compared between the groups.

Results

Patients who received SIR-IMRT showed a similar locoregional failure rate compared to the C-IMRT group (27.5% versus 29.9%, P=0.668). The 1-, 2- and 3-year overall survival (OS) rates were 71.5%, 44.3%, 44.3% vs. 77.9%, 52.1%, 32.9% in the C-IMRT and SIR-IMRT groups, respectively (P=0.825). No significant differences were observed in PFS and LRRFS between the two groups (P=0.880 and P=0.216, respectively). The dose of lung V30 and the maximum dose of spinal cord in the C-IMRT group were significantly higher than those in the SIR-IMRT group (P=0.013, P=0.047). The incidence of acute radiation esophagitis was significantly lower in the SIR-IMRT group (P=0.046), although no statistical difference was observed in the incidence of acute severe adverse events between the two groups.

Conclusions

SIR-IMRT offers an effective and safe option for patients with unresectable ESCC who receive definitive RT. Further prospective and larger sample size studies are warranted to confirm our results.

High vs. Low Radiation Dose of Concurrent Chemoradiotherapy for Esophageal Carcinoma With Modern Radiotherapy Techniques: A Meta-Analysis

Purpose: The aim of this study was to evaluate the clinical benefit of different radiation doses in concurrent chemoradiotherapy (CCRT) for esophageal carcinoma using modern radiotherapy techniques. Methods: A systematic review was conducted by screening PubMed, EMBASE, Cochrane Central Register of Controlled Trials, SCOPUS, Wanfang, and Chinese National Knowledge Infrastructure (CNKI) databases with prespecified searching strategy. Studies which compared high radiation dose group with low-dose radiation group using modern radiotherapy techniques for esophageal cancer patients in CCRT were identified. The hazard ratios (HR) for overall survival (OS) and the odds ratios (OR) for local-regional failure (LRF), distant metastasis (DM), and toxicities were considered as the outcomes of interest. R 3.6.2 software was used for statistical analysis. Results: Twelve studies involving 10,896 patients were included for analyses. The results showed that the high-dose group had better OS (HR = 0.79, 95% CI = 0.70-0.90, P = 0.0004) and the local-regional control (OR = 0.59, 95% CI = 0.46-0.76, P < 0.0001), especially for patients who were diagnosed with squamous cell carcinoma (SCC). The subgroup analyses further indicated that ≥ circa 60 Gy can significantly improve the OS (HR = 0.73, 95% CI = 0.68-0.80, P < 0.0001) as well as the local-regional control (OR = 0.54, 95% CI = 0.40-0.74, P < 0.0001) as compared with < circa 60 Gy. Another subgroup analysis comparing ≤ 50.4 Gy with > 50.4 Gy showed no substantial difference in OS (HR = 0.98, 95% CI = 0.93-1.03, P = 0.43). In addition, there are no significant differences between the two groups in grade 3-5 radiation pneumonitis (OR = 1.05, 95% CI = 0.54-2.05, P = 0.89), grade 3-5 radiation esophagitis (OR = 1.40, 95% CI = 0.93-2.11, P = 0.11), treatment-related death (OR = 1.60, 95% CI = 0.70-3.66, P = 0.27), and DM (OR = 1.21, 95% CI = 0.92-1.59, P = 0.17). Conclusions: For esophageal carcinoma receiving CCRT with modern radiation techniques, evidence suggested that high-dose radiotherapy, especially ≥circa 60 Gy, had potentials to improve the OS and local-regional control without increase in severe toxicities when compared with low-dose radiotherapy. The result needs to be confirmed by randomized clinical trials.

Chemoradiotherapy vs radiotherapy for nonoperative early stage esophageal cancer: A seer data analysis

Background

The benefit of endoscopic treatment (ET) and esophagectomy for early esophageal cancer (EC) has been sufficiently recognized. Radiotherapy (RT) is the main treatment modality for patients who do not undergo surgery. The effectiveness of adding chemotherapy (CT) to RT remains unclear. This study aimed to evaluate the impact of chemoradiotherapy (CRT) and RT alone on overall survival (OS) and cancer‐specific survival (CSS) in early EC patients not undergoing surgery.

Methods

Data collected between 2004 and 2015 were obtained from the national Surveillance, Epidemiology, and End Results (SEER) database. All the samples were randomly grouped into the training cohort or the verification cohort. The training cohort was split into subgroups by stage, age, and histology. Stage was based on the American Joint Committee on Cancer (AJCC) 6th edition published in 2004. The Kaplan‐Meier method and Cox proportional hazards modeling were used to compare OS and CSS. The performance of the nomogram was measured by a concordance index (C‐index) and the calibration curve.

Results

Data for a total of 5332 patients were obtained from the SEER database. A total of 3736 patients (stage I: n = 1277; stage IIA: n = 1484; stage IIB: n = 975) were used for the training cohort. Multivariate Cox regression analysis showed that age, sex, histology, grade, therapy, reasons for no surgery, and year of diagnosis were independent predictors of OS. The survival curve of patients treated with CRT showed a significant survival benefit compared to that in patients treated by RT alone in stage I, stage IIA, and stage IIB. CRT was also found to be related to better survival than RT in patients at a younger age (<65) and an older age (≥65) with squamous cell carcinoma or adenocarcinoma.

Conclusions

Compared with RT, CRT results in better OS and CSS in early EC patients who do not undergo surgery.

Do Higher Radiation Doses with Concurrent Chemotherapy in the Definitive Treatment of Esophageal Cancer Improve Outcomes? A Meta-Analysis and Systematic Review

Background: To investigate the effects and safety profile of radiation dose escalation utilizing computerized tomography (CT) based radiotherapy techniques (including 3-Dimensional conformal radiotherapy, intensity-modulated radiotherapy and proton therapy) in the definitive treatment of patients with esophageal carcinoma (EC) with definitive concurrent chemoradiotherapy (dCCRT). Methods: All relevant studies utilizing CT-based radiation planning, comparing high-dose (≥ 60 Gy) versus standard-dose (50.4 Gy) radiation for patients with EC were analyzed for this meta-analysis. Results: Eleven studies including 4946 patients met the inclusion criteria, with 96.5% of patients diagnosed with esophageal squamous cell carcinoma (ESCC). The high-dose group demonstrated a significant improvement in local-regional failure (LRF) (OR 2.199, 95% CI 1.487-3.253; P<0.001), two-year local-regional control (LRC) (OR 0.478, 95% CI 0.309-0.740; P=0.001), two-year overall survival (OS) (HR 0.744, 95% CI 0.657-0.843; P<0.001) and five-year OS (HR 0.683, 95% CI 0.561-0.831; P<0.001) rates relative to the standard-dose group. In addition, there was no difference in grade ≥ 3 radiation-related toxicities and treatment-related deaths between the groups. Conclusion: Under the premise of controlling the rate of toxicities, doses of ≥ 60 Gy in CT-based dCCRT of ESCC patients might improve locoregional control and ultimate survival compared to the standard-dose dCCRT. While our review supports a dose-escalation approach in these patients, multiple ongoing randomized trial initial and final reports are awaited to evaluate the effectiveness of this strategy.

YY1-induced upregulation of FOXP4-AS1 and FOXP4 promote the proliferation of esophageal squamous cell carcinoma cells

Esophageal squamous cell carcinoma (ESCC) belongs to one of the most common malignant tumors worldwide and possesses high mortality. Long non-coding RNAs (lncRNAs) have been demonstrated to be essential biological participants in the progression of ESCC. On the basis of bio-informatics prediction, forkhead box P4 antisense RNA 1 (FOXP4-AS1) and forkhead box P4 (FOXP4) were upregulated in esophageal carcinoma samples and were positively correlated with each other. The present study aimed to explore the function of FOXP4-AS1 and FOXP4 in ESCC cells. Function assays disclosed that knockdown of FOXP4-AS1 or FOXP4 efficiently suppressed cell proliferation and induced cell apoptosis. Moreover, FOXP4-AS1 positively regulated FOXP4 by interacting with insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) to stabilize FOXP4 messenger RNA. In addition, FOXP4-AS1 could upregulate the expression of FOXP4 by sponging miR-3184-5p. Finally, we found that Yin Yang 1 (YY1) is a transcription factor that can transcriptionally activate both FOXP4-AS1 and FOXP4 in ESCC cells. In a word, YY1-induced upregulation of FOXP4-AS1 and FOXP4 promote the proliferation of ESCC cells.

Effect of modern high-dose versus standard-dose radiation in definitive concurrent chemo-radiotherapy on outcome of esophageal squamous cell cancer: a meta-analysis

Background and objectives

Radiation Therapy Oncology Group (RTOG) 94–05 has demonstrated that higher dose radiation didn’t improve outcome of patients with esophageal cancer (EC). However, several retrospective studies showed that a higher dose radiation based on modern radiotherapy techniques could improve overall survival (OS) and local control rate (LCR) of patients with EC, especially esophageal squamous cell cancer (ESCC). As trials have provided updated and controversial data, we performed this updated meta-analysis to investigate whether high-dose (> = 60 Gy) radiotherapy in definitive concurrent chemo-radiotherapy (CCRT) could yield benefit compared to standard dose radiotherapy.

Methods

A systematic literature search was carried out in the database of MEDLINE, PubMed and Embase. All studies published between 1 January 1990 and 31 December 2018 on the association between radiation dose and curative efficiency in EC were included in this meta-analysis. The hazard ratio (HR) was used to evaluate the time-to-event data employing RevMan version 5.3.

Results

Eight articles with a total of 3736 patients were finally included. Results indicated that there was a significant benefit in favor of high dose radiotherapy (HD-RT) regarding OS (HR = 0.78, 95%CI: 0.72–0.84, p < 0.001; 2-year OS risk ratio (RR) = 1.25, 95%CI: 1.14–1.37, p < 0.001), progression-free survival (PFS) (P = 0.001, HR = 0.7, 95%CI: 0.57–0.87) and LRFS (P < 0.001, HR = 0.52, 95%CI: 0.36–0.74) .

Conclusions

HD-RT (> = 60 Gy) based on modern radiotherapy techniques in definitive CCRT appears to improve OS, PFS amd LRFS compared to the SD-RT in patients with ESCC.

Higher Doses of Neoadjuvant Radiation for Esophageal Cancer Do Not Affect the Pathologic Complete Response Rate or Survival: A Propensity-Matched Analysis

BACKGROUND

Traditional neoadjuvant therapy for esophageal cancer has used chemoradiation doses greater than 45 Gy. This study aimed to examine the dose of preoperative radiation in relation to the pathologic complete response (pCR) rate and overall survival (OS) for patients with resectable esophageal cancer.

METHODS

The National Cancer Database was queried for all patients with esophageal or gastroesophageal junction cancer who received neoadjuvant chemoradiation (CRT) followed by esophagectomy between 2006 and 2015. The radiation doses were divided into four ranges based on Grays (Gy) received: less than 39.6 Gy, 39.60-44.99 Gy, 45-49.99 Gy, and 50 Gy or more.

RESULTS

The inclusion criteria were met by 10,293 patients. All patients received neoadjuvant CRT, with 689 patients (6.7%) receiving less than 39.6 Gy, 973 patients (9.5%) receiving 39.6-44.9 Gy, 3837 patients (37.3%) receiving 45-49.9 Gy, and 4794 patients (46.6%) receiving 50 Gy or more. The overall pCR rate was 17.2% (1769/10,293) and was significantly lower for those who received less than 39.6 Gy of radiation than for those who received 39.6 Gy or more (13.9% [96/689] vs. 17.4% [1673/9604]; p = 0.017). The median OS of 37.2 months was significantly better for those who received 39.6 Gy or more than for those who received less than 39.6 Gy (38 vs. 29.6 months (p < 0.0001). The pCR and OS did not differ between the three higher radiation doses (39.6-44.9 vs. 45-49.9 Gy vs. ≥ 50 Gy; pCR [p = 0.1] vs. OS [p = 0.097]). The patients who received 39.6-44.9 Gy were propensity matched with those who received 45 Gy or more of radiation. There remained no difference in pCR (p = 0.375) or OS (p = 0.957).

CONCLUSIONS

In the United States, the heterogeneity in neoadjuvant CRT dosing is significant, with 84% of patients receiving more than 45 Gy. The benefit of neoadjuvant CRT in terms of pCR and overall  survival is seen with doses of 39.6 Gy or more, but not with doses higher than 45 Gy.

Analyzing the impact of neoadjuvant radiation dose on pathologic response and survival outcomes in esophageal and gastroesophageal cancers

Background

The optimal neoadjuvant radiation therapy (RT) dose prior to esophagectomy is unknown. We compared patients receiving lower-dose RT (LD-RT) of 41.4-45 Gy versus those receiving higher-dose RT (HD-RT) of 50-54 Gy.

Methods

Patients with non-metastatic esophageal or gastroesophageal cancer diagnosed from 2004 to 2015 who underwent neoadjuvant chemoradiation (CRT) followed by esophagectomy were identified using the National Cancer Database (NCDB) and divided into LD-RT and HD-RT groups. Logistic regression was used to evaluate predictors of HD-RT utilization and propensity score matching. Overall survival (OS) was compared between HD-RT and LD-RT groups using Cox regression. Logistic regression was performed with respect to pathologic complete response (pCR), positive surgical margins, postoperative mortality, and readmission rates.

Results

We identified 7,996 patients meeting inclusion criteria, of which 5,732 (71.7%) received HD-RT. At median follow-up of 3.3 years, 3-year OS was 48.7% for HD-RT versus 48.4% for LD-RT (P=0.734). pCR rates were 20.3% with HD-RT versus 16.3% with LD-RT [odds ratio (OR) 1.24; 95% CI: 1.06-1.44; P=0.006]. There were no statistically significant differences between HD-RT and LD-RT with respect to positive margins, 90-day postoperative mortality, or readmission rates. In a separate analysis of patients treated with CRT alone and no subsequent esophagectomy, HD-RT was associated with improved OS (HR 0.83; 95% CI: 0.78-0.88; P<0.001).

Conclusions

Our analysis suggests that 41.4-45 and 50-54 Gy dose regimens are similar in survival and postoperative outcomes. However, in cases of equivocal resectability, a higher RT dose of 50-54 Gy may be preferred.

Upregulation of long noncoding RNA SNHG20 promotes cell growth and metastasis in esophageal squamous cell carcinoma via modulating ATM-JAK-PD-L1 pathway

Increasing evidence have proved that long noncoding RNAs (lncRNAs) play significant roles in tumorigenesis and development of various cancers. However, the effect of small nucleolar RNA host gene 20 (SNHG20) on the progression of esophageal squamous cell carcinoma (ESCC) remains to be discovered. Herein, we aim to find out the function and the possible mechanism of SNHG20 in ESCC progression. In our study, we demonstrate that SNHG20 is markedly upregulated in ESCC tissues and cell lines. Besides, the level of SNHG20 is closely associated with tumor size, lymph node metastasis, TNM stage, and tumor grade. In addition, SNHG20 level is an independent predictor for clinical outcomes of ESCC patients. Then the gain- and loss-of-function assays reveal that SNHG20 overexpression promotes cell proliferation, migration, invasion, and epithelial-mesenchymal transition as well as represses apoptosis, whereas depletion of SNHG20 exhibits opposite effects. Moreover, we uncover that SNHG20 modulates the expression of ataxia telangiectasia-mutated kinase (p-ATM), p-JAK1/2, and programmed cell death 1 ligand 1 (PD-L1) in ESCC cells and ATM upregulation restores the suppressive effect of SNHG20 inhibition on ESCC progression. Therefore, we conclude that SNHG20 serves as a carcinogen in ESCC by promoting growth and metastasis via ATM-JAK-PD-L1 pathway, supplying a possibly effective therapeutic target for ESCC.

Confirmation of the prognostic value of pretherapeutic tumor SUR and MTV in patients with esophageal squamous cell carcinoma

PURPOSE

The prognosis for patients with inoperable esophageal carcinoma is still poor and the reliability of individual therapy outcome prediction based on clinical parameters is not convincing. In a recent publication, we were able to show that PET can provide independent prognostic information in such a patient group and that the tumor-to-blood standard uptake ratio (SUR) can improve the prognostic value of tracer uptake values. The present investigation addresses the question of whether the distinctly improved prognostic value of SUR can be confirmed in a similar patient group that was examined and treated at a different site.

METHODS

¹⁸F-FDG PET/CT was performed in 147 consecutive patients (115 male, 32 female, mean age: 62 years) with newly diagnosed esophageal squamous cell carcinoma prior to definitive radiochemotherapy. In the PET images, the metabolic active volume (MTV) of the primary tumor was delineated with an adaptive threshold method. For the resulting ROIs, SUV_max and total lesion glycolysis (TLG = MTV × SUV_mean) were computed. The blood SUV was determined by manually delineating the aorta in the low-dose CT. SUR values were computed as ratio of tumor SUV and blood SUV. Univariate Cox regression and Kaplan-Meier analysis with respect to overall survival (OS), distant-metastases-free survival (DM), and locoregional control (LRC) was performed. Additionally, a multivariate Cox regression including clinically relevant parameters was performed.

RESULTS

Univariate Cox regression revealed MTV, TLG, and SUR_max as significant prognostic factors for OS. MTV as well as TLG were significant prognostic factors for LRC while SUR_max showed only a trend for significance. None of the PET parameters was prognostic for DM. In univariate analysis, SUV_max was not prognostic for any of the investigated clinical endpoints. In multivariate analysis (T-stage, N-stage, MTV, and SUR_max), MTV was an independent prognostic factor for OS and showed a trend for significance for LRC. SUR_max was not an independent predictor for OS or LRC. When including the PET parameters separately in multivariate analysis, MTV as well as SUR_max were prognostic factors for OS indicating that SUR_max is independent from the clinical parameters but not from MTV. In addition, MTV was an independent prognostic factor for LRC in this separate analysis.

CONCLUSIONS

Our study revealed a clearly improved prognostic value of tumor SUR compared to tumor SUV and confirms our previously published findings regarding OS. Furthermore, SUR delivers prognostic information beyond that provided by the clinical parameters alone, but does not add prognostic information beyond that provided by MTV in this patient group. Therefore, our results suggest that pretherapeutic MTV is the parameter of choice for PET-based risk stratification in the considered setting but further investigations are necessary to demonstrate that this suggestion is correct.

REV7 confers radioresistance of esophagus squamous cell carcinoma by recruiting PRDX2

Radiotherapy has been widely used for the clinical management of esophageal squamous cell carcinoma. However, radioresistance remains a serious concern that prevents the efficacy of esophageal squamous cell carcinoma (ESCC) radiotherapy. REV7, the structural subunit of eukaryotic DNA polymerase ζ, has multiple functions in bypassing DNA damage and modulating mitotic arrest in human cell lines. However, the expression and molecular function of REV7 in ESCC progression remains unclear. In this study, we first examined the expression of REV7 in clinical ESCC samples, and we found higher expression of REV7 in ESCC tissues compared to matched adjacent or normal tissues. Knockdown of REV7 resulted in decreased colony formation and increased apoptosis in irradiated Eca‐109 and TE‐1 cells coupled with decreased tumor weight in a xenograft nude mouse model postirradiation. Conversely, overexpression of REV7 resulted in radioresistance in vitro and in vivo. Moreover, silencing of REV7 induced increased reactive oxygen species levels postirradiation. Proteomic analysis of REV7‐interacting proteins revealed that REV7 interacted with peroxiredoxin 2 (PRDX2), a well‐known antioxidant protein. Existence of REV7‐PRDX2 complex and its augmentation postirradiation were further validated by immunoprecipitation and immunofluorescence assays. REV7 knockdown significantly disrupted the presence of nuclear PRDX2 postirradiation, which resulted in oxidative stress. REV7‐PRDX2 complex also assembled onto DNA double‐strand breaks, whereas REV7 knockdown evidently increased double‐strand breaks that were unmerged by PRDX2. Taken together, the present study sheds light on REV7‐modulated radiosensitivity through interacting with PRDX2, which provides a novel target for ESCC radiotherapy.

Three-dimensional conformal radiation therapy alone for esophageal squamous cell carcinoma: 10-year survival outcomes

Background

Concurrent chemoradiation is the standard treatment for locally advanced esophageal squamous cell carcinoma (SCC). We conducted a phase II study to explore the effect of three‐dimensional conformal radiotherapy (3‐DCRT) alone for patients with locally advanced esophageal SCC. This study aimed to analyze the long‐term survival outcomes.

Methods

Between November 2004 and April 2007, 30 patients with thoracic esophageal SCC underwent late‐course sequential boost 3‐DCRT at Fudan University Shanghai Cancer Center. The planning target volume (PTV1) comprised a 1.2–1.5 cm lateral margin around the gross tumor volume and a 3.0 cm margin, superior and inferior to the gross tumor volume. PTV2 encompassed the gross tumor volume with a margin of 0.5–0.7 cm. The PTV1 dose delivered was 50 Gy, and the PTV2 dose was a boost dose of 16 Gy, resulting in a total dose of 66 Gy. No chemotherapy was administered.

Results

The median follow‐up time was 30 months for all patients, and 132 months for patients who were alive. The median overall survival was 27 months (95% confidence interval [CI] 18.9–35.0). The 2‐, 5‐, and 10‐year overall survival rates were 56.6%, 33.3%, and 26.6%, respectively. The median progression‐free survival was 14 months (95% CI 7.7–20.2 months), and the 2‐, 5‐, and 10‐year progression‐free survival rates were 33.3%, 30.0%, and 26.6%, respectively. No severe late toxicity was observed in long‐term survivors.

Conclusion

Late‐course sequential boost 3‐DCRT is safe and feasible with promising long‐term outcomes for esophageal SCC.

Definitive radiotherapy dose escalation with chemotherapy for treating non-metastatic oesophageal cancer

The locoregional failure rate remains high after concurrent chemoradiotherapy with standard-dose radiotherapy (RT, 50–50.4 Gy) for oesophageal cancer (EC). This retrospective study evaluated whether RT dose escalation was effective among 115 consecutive patients with non-metastatic EC (July 2003 to November 2016). Forty-four patients received an RT dose of <66 Gy and 71 patients received ≥66 Gy, with most patients receiving concurrent cisplatin plus fluorouracil. The median follow-up was 12 months for all patients (52 months for 18 surviving patients). The ≥66 Gy group had significantly higher 3-year rates of overall survival (17.9% vs. 32.1%, p = 0.026) and local progression-free survival (46.1% vs. 72.1%, p = 0.005), but not disease progression-free survival (11.4% vs. 21.9%, p = 0.059) and distant metastasis-free survival (49% vs. 52.6%, p = 0.852). The ≥66 Gy group also had significantly better 5-year overall survival compared with 41.4–65.9 Gy. The only significant difference in treatment-related toxicities involved acute dermatitis (7% vs. 28%, p = 0.009). Inferior overall survival was associated with poor performance status, clinical N2–3 stage and not receiving maintenance chemotherapy. In conclusion, patients with inoperable EC experienced better survival outcomes and acceptable toxicities if they received higher dose RT (≥66 Gy) rather than lower dose RT (<66 Gy).

Dose-escalated radiotherapy improved survival for esophageal cancer patients with a clinical complete response after standard-dose radiotherapy with concurrent chemotherapy

Purpose

For esophageal cancer patients with a clinical complete response (cCR) after standard-dose radiotherapy with concurrent chemotherapy, data on the survival outcomes and recurrence patterns remain scarce. To evaluate the impact of dose escalation on overall survival for this subset of patients, we carried out the current investigation.

Materials and methods

Medical records of 80 esophageal cancer patients with a cCR after standard-dose radiotherapy with concurrent chemotherapy at our center from 2010 to 2014 were allocated into the standard-dose group (50.4 Gy, observation group) or the radiation dose-escalation group (59.4 Gy, control group). In this cohort study, we compared the outcomes between the 2 groups.

Results

There were no differences in patient characteristics between the 2 groups. The median recurrence-free survival and overall survival times for all patients were 38 and 54 months, respectively. Patients in the control group had significantly better 5-year recurrence-free survival rate (12% vs 0%, p=0.019) and 5-year overall survival rate (42.8% vs 21.0%, p=0.028) than the observation group. Additionally, local control rate was significantly higher in the control group (p=0.04), and ~60% of treatment failures were local failures even for patients achieving cCR after chemoradiotherapy. There were no significant differences in treatment-related toxicities between the groups.

Conclusion

The results of the current study suggest that for esophageal cancer patients with a cCR after standard-dose radiotherapy with concurrent chemotherapy, those with dose-escalated radiotherapy showed significantly better local control, recurrence-free survival, and overall survival than patients receiving 50.4 Gy radiotherapy.

Synchronous Supraglottic and Esophageal Squamous Cell Carcinomas Treated with a Monoisocentric Hybrid Intensity-Modulated Radiation Technique

Risk factors for squamous cell carcinomas (SCCs) of the head and neck (HN) and esophagus are similar. As such, synchronous primary tumors in these areas are not entirely uncommon. Definitive chemoradiation (CRT) is standard care for locally advanced HNSCC and is a preferred option for inoperable esophageal SCC. Simultaneous treatment of both primaries with CRT can present technical challenges. We report a case of synchronous supraglottic and esophageal SCC primary tumors, highlighting treatment with a monoisocentric hybrid radiation technique and normal tissue toxicity considerations.

Acquired Adult Aerodigestive Fistula: Classification and Management

BACKGROUND

Acquired aerodigestive fistulae (ADF) are rare, but associated with a high mortality rate. We present our experience of the diagnosis, management and outcomes of patients with ADFs treated at a tertiary centre. Utilising our findings, we propose an anatomical classification system, demonstrating how specific features of an ADF may determine management.

METHODS

A clinical database was searched and 48 patients with an ADF were identified. A classification system was developed based on anatomical location of the ADF and differences in clinico-pathological features based on this categorisation were performed, with the chi-squared test used for inferential analyses and Kaplan-Meier curves with log-rank test to assess survival.

RESULTS

Twenty (41.6%) patients developed an ADF secondary to malignancy, with previous radiotherapy (18.7%), post-operative anastomotic dehiscence and endotherapy (14.6% each) representing other causes. Thirty-one patients were managed with tracheal and/or oesophageal stents and eight underwent surgical repair. The classification system demonstrated benign causes of ADF were either proximally or distally sited, whilst a malignant cause resulted in mid-tracheal fistulae (p = 0.001), with the latter associated with poorer survival. ADFs over 20 mm in size were associated with poor survival (p = 0.011), as was the use of previous radiotherapy. Proximal and distal ADFs were associated with improved survival (p = 0.006), as were those patients managed surgically (p = 0.001).

CONCLUSION

By classifying ADFs, we have demonstrated that anatomical location correlates with the size, history of malignancy, previous radiotherapy and aetiology of ADF, which can affect management. The proposed classification system will aid in formulating multi-modality individualised treatment plans.

Radiotherapy for esophageal carcinoma: dose, response and survival

Esophageal cancer (EC) is an extremely aggressive, lethal malignancy that is increasing in incidence worldwide. At present, definitive chemoradiotherapy is accepted as the standard treatment for locally advanced EC. The EC guidelines recommend a radiation dose of 50.4 Gy for definitive treatment, yet the outcomes for patients who have received standard-dose radiotherapy remain unsatisfactory. However, some studies indicate that a higher radiation dose could improve local tumor control, and may also confer survival benefits. Some studies, however, suggest that high-dose radiotherapy does not bring survival benefit. The available data show that most failures occurred in the gross target volume (especially in the primary tumor) after definitive chemoradiation. Based on those studies, we hypothesize that at least for some patients, more intense local therapy may lead to better local control and survival. The aim of this review is to evaluate the radiation dose, fractionation strategies, and predictive factors of response to therapy in functional imaging for definitive chemoradiotherapy in esophageal carcinoma, with an emphasis on seeking the predictive model of response to CRT and trying to individualize the radiation dose for EC patients.

What is the optimal radiation dose for non-operable esophageal cancer? Dissecting the evidence in a meta-analysis

The standard radiation dose 50.4 Gy with concurrent chemotherapy for localized inoperable esophageal cancer as supported by INT-0123 trail is now being challenged since a radiation dose above 50 Gy has been successfully administered with an observable dose-response relationship and insignificant untoward effects. Therefore, to ascertain the treatment benefits of different radiation doses, we performed a meta-analysis with 18 relative publications. According to our findings, a dose between 50 and 70 Gy appears optimal and patients who received ≥ 60 Gy radiation had a significantly better prognosis (pooled HR = 0.78, P = 0.004) as compared with < 60 Gy, especially in Asian countries (pooled HR = 0.75, P = 0.003). However, contradictory results of treatment benefit for ≥ 60 Gy were observed in two studies from Western countries, and the pooled treatment benefit of ≥ 60 Gy radiation was inconclusive (pooled HR = 0.86, P = 0.64). There was a marginal benefit in locoregional control in those treated with high dose (> 50.4/51 Gy) radiation when compared with those treated with low dose (≤ 50.4/51 Gy) radiation (pooled OR = 0.71, P = 0.06). Patients that received ≥ 60 Gy radiation had better locoregional control (OR = 0.29, P = 0.001), and for distant metastasis control, neither the > 50.4 Gy nor the ≥ 60 Gy treated group had any treatment benefit as compared to the groups that received ≤ 50.4 Gy and < 60 Gy group respectively. Taken together, a dose range of 50 to 70 Gy radiation with CCRT is recommended for non-operable EC patients. A dose of ≥ 60 Gy appears to be better in improving overall survival and locoregional control, especially in Asian countries, while the benefit of ≥ 60 Gy radiation in Western countries still remains controversial.

Interim 18F-FDG-PET/CT during chemo-radiotherapy in the management of oesophageal cancer patients. A systematic review

Oesophageal cancer is an aggressive disease. The possibility to early stratify patients as responsive and non-responsive with a non-invasive method is extremely appealing. The uptake of Fluorodeoxyglucose (¹⁸F-FDG) in tumours, provided by positron emission tomography (PET) images, has been proved to be useful to assess the initial staging of the disease, recurrence, and response to chemotherapy and chemo-radiotherapy (CRT). In the last years, efforts have been focused on the possibility to use ad interim ¹⁸F-FDG-PET/CT (PET_int) to evaluate response during radiation therapy. However, controversial findings have been reported, although some relevant results would support its use for individual therapeutic decision. The present review assembles the comprehensive literature of the last decade to evaluate whether and in which cases PET_int may offer predictive potential in oesophageal cancer. All the analysed studies (13 studies, 697 patients) denoted PET_int as a challenging examination for early assessment of outcomes during CRT. In particular, 8 studies advocated the predictivity of PET_int, whilst 5 did not find any correlation between the interim variation of PET parameters and the pathological complete response and/or the clinical outcome. The reasons that possibly have caused contradictions among the studies demand further research with prospective and uniform protocols and methods of analysis to assess the predictive and prognostic value of PET_int in oesophageal cancer.

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.

Improved survival with higher radiation dose for esophageal squamous cell carcinoma patients treated with definitive chemoradiotherapy

Purpose

The optimal radiation dose for patients with esophageal squamous cell carcinoma (ESCC) has long been debated. We undertook the retrospective study to evaluate the survival impact of high dose vs standard dose in patients with stage II–III esophageal cancer treated with definitive chemoradiotherapy (CRT).

Results

A total of 137 patients were included in our study, 63 patients classified as standard-dose group and 74 as high-dose group. For the 63 patients in the standard-dose group, the median PFS and the 1-, 2-, and 3-year PFS rates were 12.6 months, 58.0%, 26.0% and 12.0%, respectively; for the 74 patients in the high-dose group, they were 20.0 months, 80.1%, 31.0% and 20.0%, respectively (P = 0.013). The median OS of the patients in the standard-dose group and high-dose group groups were 19.0 months and 26.6 months, respectively, and the 1-, 2- and 3-year survival rates were 78.0%, 39.0%, and 24.0% , and 89.0%, 61.0%, and 30.0%, respectively (P = 0.037). Besides the rate of grade ≥ 3 acute irradiation esophagitis in the high-dose group (10.5% versus. 2.2%, P < 0.01), there were no significantly differ of treatment-related toxicities between the two groups.

Materials and Methods

According to the radiation dose, patients from 2010 to 2014 were allocated into either the standard-dose group (50–50.4 Gy) or the high-dose group (≥ 59.4 Gy). Overall survival (OS), progression-free survival (PFS) and treatment-related toxicities were assessed and compared between the two groups.

Conclusions

Our findings suggest that higher radiation dose could perform better outcomes for esophageal squamous cell carcinoma patients.

The impact of histology on recurrence patterns in esophageal cancer treated with definitive chemoradiotherapy

BACKGROUND

To assess the impact of histology on recurrence patterns and survival outcomes in patients with esophageal cancer (EC) treated with definitive chemoradiotherapy (CRT).

METHODS

We analyzed 590 consecutive EC patients who received definitive CRT from 1998 to 2014, including 182 patients (30.8%) with squamous cell carcinoma (SCC) and 408 (69.2%) with adenocarcinoma. Recurrence pattern and timing, survival, and potential prognostic factors were compared.

RESULTS

After a median follow-up time of 58.0months, the SCC group demonstrated a comparable locoregional recurrence rate (42.9% vs. 38.0%, P=0.264) but a significantly lower distant failure rate (27.5% vs. 48.0%, P<0.001) than adenocarcinoma group. No significant difference was found in overall survival or locoregional failure-free survival between groups, whereas the SCC group was associated with significantly more favorable recurrence-free survival (P=0.009) and distant metastasis-free survival (P<0.001). The adenocarcinoma group had higher hematogenous metastasis rates of bone, brain, and liver, whereas the SCC group had a marginally higher regional recurrence rate. Among patients who received salvage surgery after locoregional recurrence, no significant difference in survival was found between groups (P=0.12).

CONCLUSIONS

The patterns and sites of recurrence, survival outcomes, and prognostic factors were significantly different between esophageal SCC and adenocarcinoma.

Recent advances in intensity modulated radiotherapy and proton therapy for esophageal cancer

INTRODUCTION

Radiotherapy is an important component of the standard of care for esophageal cancer. In the past decades, significant improvements in the planning and delivery of radiation techniques have led to better dose conformity to the target volume and improved normal tissue sparing. Areas covered: This review focuses on the advances in radiotherapy techniques and summarizes the availably dosimetric and clinical outcomes of intensity-modulated radiation therapy (IMRT), volumetric modulated arc therapy, proton therapy, and four-dimensional radiotherapy for esophageal cancer, and discusses the challenges and future development of proton therapy. Expert commentary: Although three-dimensional conformal radiotherapy is the standard radiotherapy technique in esophageal cancer, the retrospectively comparative studies strongly suggest that the dosimetric advantage of IMRT over three-dimensional conformal radiotherapy can translate into improved clinical outcomes, despite the lack of prospective randomized evidence. As a novel form of conventional IMRT technique, volumetric modulated arc therapy can produce equivalent or superior dosimetric quality with significantly higher treatment efficiency in esophageal cancer. Compared with photon therapy, proton therapy has the potential to achieve further clinical improvement due to their physical properties; however, prospective clinical data, long-term results, and cost-effectiveness are needed.

Dose escalation of definitive radiation is not associated with improved survival for cervical esophageal cancer: a National Cancer Data Base (NCDB) analysis

For cervical esophageal cancer (CEC), National Comprehensive Cancer Network guidelines support RT to 50-50.4 Gy with chemotherapy but acknowledge higher doses may be appropriate. This study uses the National Cancer Database (NCDB) to characterize RT practices and identify if a dose-response relationship exists for overall survival (OS) for definitive treatment of CEC. We queried the NCDB for patients diagnosed with Stage I-III CEC from 2004 to 2013, and selected patients receiving definitive RT with doses between 50 and 74 Gy. Using multivariate logistic regression, the database was analyzed to determine factors associated with use of RT > 50.4 Gy. Patients were then stratified into three dose categories. Predictors of OS were analyzed with univariate and multivariate methods using the Kaplan-Meier curves, the log-rank test, and the Cox proportional hazards analysis. We stratified 789 patients with CEC who were treated with definitive radiation ± chemotherapy: 50-50.4 Gy ('standard'), >50.4 and <66 Gy ('medium'), and 66-74 Gy ('high'). Of these patients, 215 (27%) received standard doses, 375 (48%) received medium doses, and 199 (25%) received high doses. Patients with Medicaid insurance and those with Stage II disease were less likely (P < 0.05) to receive >50.4 Gy. Sex, histology, distance to treatment facility, and academic/community facility type were not significantly associated with receipt of >50.4 Gy. There was no association between dose and OS for the medium or high groups when using univariate analysis or analysis adjusted for demographic, facility, and clinical attributes. Stage III disease and the Charlson-Deyo scores of 1 or 2 were associated with higher mortality (P < 0.05), while female sex and use of chemotherapy were associated with lower mortality (P < 0.01). Nearly three-fourths of CEC patients in the United States are treated with RT > 50.4 Gy. Higher radiation doses were not associated with increased OS in CEC patients in the NCDB.

Radiation Dose Escalation in Esophageal Cancer Revisited: A Contemporary Analysis of the National Cancer Data Base, 2004 to 2012

PURPOSE

To evaluate the effect of radiation dose escalation on overall survival (OS) for patients with nonmetastatic esophageal cancer treated with concurrent radiation and chemotherapy.

METHODS AND MATERIALS

Patients diagnosed with stage I to III esophageal cancer treated from 2004 to 2012 were identified from the National Cancer Data Base. Patients who received concurrent radiation and chemotherapy with radiation doses of ≥50 Gy and did not undergo surgery were included. OS was compared using Cox proportional hazards regression and propensity score matching.

RESULTS

A total of 6854 patients were included; 3821 (55.7%) received 50 to 50.4 Gy and 3033 (44.3%) received doses >50.4 Gy. Univariate analysis revealed no significant difference in OS between patients receiving 50 to 50.4 Gy and those receiving >50.4 Gy (P=.53). The dose analysis, binned as 50 to 50.4, 51 to 54, 55 to 60, and >60 Gy, revealed no appreciable difference in OS within any group compared with 50 to 50.4 Gy. Subgroup analyses investigating the effect of dose escalation by histologic type and in the setting of intensity modulated radiation therapy also failed to reveal a benefit. Propensity score matching confirmed the absence of a statistically significant difference in OS among the dose levels. The factors associated with improved OS on multivariable analysis included female sex, lower Charlson-Deyo comorbidity score, private insurance, cervical/upper esophagus location, squamous cell histologic type, lower T stage, and node-negative status (P<.01 for all analyses).

CONCLUSIONS

In this large national cohort, dose escalation >50.4 Gy did not result in improved OS among patients with stage I to III esophageal cancer treated with definitive concurrent radiation and chemotherapy. These data suggest that despite advanced contemporary treatment techniques, OS for patients with esophageal cancer remains unaltered by escalation of radiation dose >50.4 Gy, consistent with the results of the INT-0123 trial. Furthermore, these data highlight that many radiation oncologists have not embraced the concept that dose escalation does not improve OS. Although local control, not investigated in the present study, might benefit from dose escalation, novel therapies are needed to improve the OS of patients with esophageal cancer.

Improving Outcomes for Esophageal Cancer using Proton Beam Therapy

Radiation therapy (RT) plays an essential role in the management of esophageal cancer. Because the esophagus is a centrally located thoracic structure there is a need to balance the delivery of appropriately high dose to the target while minimizing dose to nearby critical structures. Radiation dose received by these critical structures, especially the heart and lungs, may lead to clinically significant toxicities, including pneumonitis, pericarditis, and myocardial infarction. Although technological advancements in photon RT delivery like intensity modulated RT have decreased the risk of such toxicities, a growing body of evidence indicates that further risk reductions are achieved with proton beam therapy (PBT). Herein we review the published dosimetric and clinical PBT literature for esophageal cancer, including motion management considerations, the potential for reirradiation, radiation dose escalation, and ongoing esophageal PBT clinical trials. We also consider the potential cost-effectiveness of PBT relative to photon RT.

Cancer stem cells in oesophageal squamous cell carcinoma: Identification, prognostic and treatment perspectives

Cancer stem cells (CSCs) are a vital subpopulation of cells to target for the treatment of cancers. In oesophageal squamous cell carcinoma (ESCC), there are several markers such as CD44, ALDH, Pygo2, MAML1, Twist1, Musashi1, Side population (SP), CD271 and CD90 that have been proposed to identify the cancer stem cells in individual cancer masses. It has also been demonstrated that stem cell markers like ALDH1, HIWI, Oct3/4, ABCG2, SOX2, SALL4, BMI-1, NANOG, CD133 and podoplanin are associated with patient's prognosis, pathological stages, cancer recurrence and therapy resistance. Finding new cancer stem cell targets or designing drugs to manipulate the known molecular targets in CSCs could be useful for improvements in clinical outcomes of the disease. To conclude, data suggest that CSCs in oesophageal squamous cell carcinoma are related to resistance to therapy and poor prognosis of patients with ESCC. Therefore, innovative insights into CSC biology and CSC-targeted therapies will help to achieve more effective management of patients with oesophageal squamous cell carcinoma.