Essential risk factors for operative mortality in elderly esophageal cancer patients registered in the National Clinical Database of Japan.

BACKGROUND: With the aging of society and increasingly longer of life expectancy, elderly patients with esophageal cancer are more commonly encountered. This study aimed to identify the risk factors for operative mortality after esophagectomy in elderly patients. METHODS: We used data from the National Clinical Database of Japan. After cleaning the data, 10,633 records obtained from 861 hospitals were analyzed. A risk model for operative mortality was developed using risk factors from the entire study population. Then, odds ratios (OR) were compared between age categories using this risk model. RESULTS: In this study, 1959 (18.4%) patients were ≥ 75 years (defined as "elderly" in this study). Eighteen variables, including T4b, N2-N3, and M1 in the TNM classification, were included in the risk model for operative mortality. The ORs increased in age categories < 65, 65-74, and ≥ 75 years for N2-N3 (1.172, 1.200, and 1.588, respectively), and M1 (2.189, 3.164, and 4.430, respectively). Based on these results, we also focused on residual tumors, which are caused by extensive tumor development. The operative mortality in the elderly group with residual tumors increased to more than twice than that in the non-elderly groups (15.9 vs. 5.5 or 6.5%) and was much higher than that in elderly patients without residual tumors (15.9 vs. 4.6%). CONCLUSION: We should carefully select the treatment for elderly patients with highly advanced tumors, which result in N2-N3 and M1, to avoid unfavorable short-term outcomes. In addition, R0 resection is important in preventing operative mortality among elderly patients.

[S-methyl-11C]-L-methionine positron emission tomography/computed tomography imaging parameters to evaluate early response for esophageal cancer with neoadjuvant carbon ion radiotherapy.

This study aimed to evaluate the uptake of the clinical effectiveness of [S-methyl-11C]-L-methionine positron emission tomography/computed tomography (MET PET/CT) in patients with esophageal cancer and to investigate MET PET/CT imaging parameters to assess early response for esophageal cancer with neoadjuvant carbon ion radiotherapy (CIRT). MET PET/CT scans were performed in nineteen patients before and 3 weeks after completion of CIRT. After Surgery, the effect of neoadjuvant CIRT was investigated by examining the relationship between each parameter of MET uptake and the histological assessment (grade and tumor residual ratio). Four parameters of MET uptake were the maximum and minimum standardized uptake values of pre and post CIRT (pre-SUVmax, pre-SUVmean, post-SUVmax, and post-SUVmean). MET PET/CT imaging of esophageal cancer was clearly demonstrated. The post-SUVmax was the most suitable parameter. When the cutoff value was set as post-SUVmax = 6.21, the sensitivity, the specificity, and the accuracy of Grades 3 were 100.0%, 63.6%, and 78.9%, respectively. And there was a positive relationship between the tumor residual ratio and post-SUVmax (R2 = 0.38, p < 0.005). MET PET/CT is clinically useful for the assessment of early response to neoadjuvant CIRT in esophageal cancer. Particularly, post-SUVmax is considered a promising PET imaging parameter.

Indocyanine green conjugated phototheranostic nanoparticle for photodiagnosis and photodynamic therapy.

BACKGROUND: Phototheranostics represents a highly promising paradigm for cancer therapy, although selecting an appropriate optical imager and sensitizer for clinical use remains challenging. METHODS: Liposomally formulated phospholipid-conjugated indocyanine green, denoted as LP-iDOPE, was developed as phototheranostic nanoparticle and its cancer imaging-mediated photodynamic reaction, defined as the immune response induced by photodynamic and photothermal effects, was evaluated with a near-infrared (NIR)-light emitting diode (LED) light irradiator. RESULTS: Using in vivo NIR fluorescence imaging, we demonstrated that LP-iDOPE was selectively delivered to tumor sites with high accumulation and a long half-life. Following low-intensity NIR-LED light irradiation on the tumor region of LP-iDOPE accumulated, effector CD8+ T cells were activated at the secondary lymphoid organs, migrated, and subsequently released cytokines including interferon-γ and tumor necrosis factor-α, resulting in effective tumor regression. CONCLUSIONS: Our anti-cancer strategy based on tumor-specific LP-iDOPE accumulation and low-intensity NIR-LED light irradiation to the tumor regions, i.e., photodynamic reaction, represents a promising approach to noninvasive cancer therapy.

Diagnostic performance of diffusion-weighted magnetic resonance imaging in assessing lymph node metastasis of esophageal cancer compared with PET.

BACKGROUND: Although diffusion-weighted magnetic resonance imaging (DWI) for detecting lymph node (LN) metastasis is reported to be a successful modality for primary malignant tumors, there are few studies relating to esophageal cancer. This study aimed to clarify the diagnostic performance of DWI for assessing LN metastasis compared with positron emission tomography (PET) in patients with esophageal squamous cell cancer (eSCC). METHODS: Seventy-six patients with histologically proven eSCC who underwent curative esophagectomy without neoadjuvant treatment were reviewed retrospectively. Harvested LNs were divided into 1229 node stations with 94 metastases. Diagnostic abilities and prognostic significance were compared. RESULTS: In a station-by-station evaluation, the sensitivity was higher in DWI than PET (67% vs. 32%, P < 0.001). DWI showed more than 80% sensitivity for middle- and large-sized cancer nests and large area of cancer nests. The DWI-N0 group had a better 5-year relapse-free survival rate than the DWI-N+ group (78.5% vs. 34.2%, P < 0.001), as did the PET-N0 group. DWI-N status was an independent prognostic factor (hazard ratio [HR], 2.642; P = 0.048), as was PET-N status (HR 2.481; P = 0.033). CONCLUSIONS: DWI, which depends on cancer cell volume followed by elevated intranodal density, is a non-invasive modality and showed higher sensitivity than PET. It has clinical impact in predicting postoperative survival for patients with eSCC alongside its diagnostic ability and has significant performance in clinical practice.

A 3-Year Overall Survival Update From a Phase 2 Study of Chemoselection With DCF and Subsequent Conversion Surgery for Locally Advanced Unresectable Esophageal Cancer.

BACKGROUND: A multicenter phase 2 trial analysed chemoselection with docetaxel plus 5-fluorouracil and cisplatin (DCF) induction chemotherapy (ICT) and subsequent conversion surgery (CS) for locally advanced unresectable esophageal cancer. This study presents updated 3-year analyses to further characterize the impact of DCF-ICT followed by CS. METHODS: Esophageal cancer patients with clinical T4 disease, unresectable supraclavicular lymph node metastasis, or both were eligible for this study. The treatment starts with DCF-ICT, followed by CS if the cancer is resectable, or by concurrent chemoradiation if it is not resectable. This updated analysis presents 3-year overall survival (OS), 3-year progression-free survival (PFS), and pattern of relapse. RESULTS: The median follow-up period for the patients surviving without death was 39.3 months. The estimated 1-year OS was 66.7%, and the lower limit of the 80% confidence interval (CI) was 54.6%. The estimated 3-year OS was 46.6% (95% CI 34.2-63.5%). The OS for the patients who underwent R0 resection (n = 19) was significantly longer than for those who did not (3-year OS: 71.4% vs. 30.1%). The estimated 1-year PFS was 50.6%, and the 3-year PFS was 39.6%. The PFS for R0 was significantly longer than for non-R0 (3-year PFS: 61.3% vs 25.0%). Recurrence or progression at the primary site was observed in 31% of the non-R0 group. The rate of distant metastasis did not differ significantly between the non-R0 and R0 groups (21% vs 16%). CONCLUSIONS: Long-term follow-up evaluation confirmed that DCF chemoselection aimed at CS is feasible and promising in terms of survival for patients with locally advanced esophageal cancer.

Is Oral Mucositis Occurring During Chemotherapy for Esophageal Cancer Patients Correctly Judged? EPOC Observational Cohort Study.

BACKGROUND/AIM: Oral mucositis (OM) is one of the frequent adverse events experienced by patients receiving chemotherapy. Most diagnoses of OM are based on complaints from patients. The aim of this study was to develop a tool to diagnose OM accurately. MATERIALS AND METHODS: A central review system (CRS) was created to allow judgment when the patient background is completely unknown. The primary endpoint was the rate of grade 2 or higher OM, and the secondary endpoint was the difference in grade between each institution's clinician judgement and that of the CRS. RESULTS: In total, 53 patients were registered from four institutions. CRS successfully detected grade 2 or higher OM in 16 (30.2%) of the 53 patients. The detection rate of all grades of OM was 41.5% (22 of 53 patients) by each institution's clinician judgement and 84.9% (45 of 53 patients) by CRS judgement (p<0.0001). CONCLUSION: OM during chemotherapy may be underestimated.

Genome-wide ChIP-seq data with a transcriptome analysis reveals the groups of genes regulated by histone demethylase LSD1 inhibition in esophageal squamous cell carcinoma cells.

Expression of genes is controlled by histone modification, histone acetylation and methylation, but abnormalities of these modifications have been observed in carcinogenesis and cancer development. The effect of the lysine-specific histone demethylase 1 (LSD1) inhibitor, a demethylating enzyme of histones, is thought to be caused by controlling the expression of genes. The aim of the present study is to elucidate the efficacies of the LSD1 inhibitor on the gene expression of esophageal cancer cell lines using chromatin immunoprecipitation (ChIP)-Seq. A comprehensive analysis of gene expression changes in esophageal squamous cell carcinoma (ESCC) cell lines induced by the LSD1 inhibitor NCL1 was clarified via analysis using microarray. In addition, ChIP-seq analysis was conducted using a SimpleChIP plus Enzymatic Chromatin IP kit. NCL1 strongly suppressed the proliferation of T.Tn and TE2 cells, which are ESCC cell lines, and further induced apoptosis. According to the combinatory analysis of ChIP-seq and microarray, 17 genes were upregulated, and 16 genes were downregulated in both cell lines. The comprehensive gene expression study performed in the present study is considered to be useful for analyzing the mechanism of the antitumor effect of the LSD1 inhibitor in patients with ESCC.

Salvage Carbon-ion Radiotherapy for Isolated Lymph Node Recurrence Following Curative Resection of Esophageal Cancer.

AIM: Evaluation of the therapeutic efficacy of carbon-ion radiation therapy for isolated lymph node recurrence following curative resection of esophageal cancer. MATERIALS AND METHODS: Ten cases with lymph node recurrence after esophageal cancer surgery were treated with carbon-ion radiation therapy. A total of 48.0 Gy [relative biologic effectiveness (RBE)] was delivered over 3 weeks with a daily dose of 4.0 Gy (RBE). RESULTS: The median follow-up duration was 27.1 months (range=3-92.0 months) after carbon-ion radiation therapy. The local control rates at 2, 3 and 5 years were 92.4%. The overall survival rates at 2, 3 and 5 years were 70.0%, 58.3% and 21.9%. The median survival period was 45.3 months after carbon-ion radiation therapy. There were no toxicities of grade 3 or higher. CONCLUSION: Carbon-ion radiation therapy may be a safe and effective treatment option for isolated lymph node recurrence after radical surgery for esophageal cancer.

The effect of an elemental diet on oral mucositis of esophageal cancer patients treated with DCF chemotherapy: a multi-center prospective feasibility study (EPOC study).

PURPOSE: Oral mucositis (OM) is one of the most uncomfortable adverse events experienced by cancer patients undergoing chemotherapy. Previous reports have revealed that the oral administration of an elemental diet (ED) may prevent OM. However, the incidence of OM has not been accurately determined by specialized diagnostic methods and the effects of an ED on OM remain unclear. We investigated the dose that could feasibly be administered and its effects with regard to the suppression of OM in esophageal cancer patients undergoing chemotherapy. METHODS: We performed a prospective multi-center feasibility study of the administration of an ED (160 g/day) with 2 cycles of docetaxel/cisplatin/5-FU (DCF) chemotherapy. We assessed compliance to the ED for 49 days and the incidence of OM according to the amount of the ED that was orally administered. The incidence of OM was graded by a dental specialist who was experienced in dental oncology using a central OM review system. RESULTS: Fourteen of 20 patients (70%) were able to complete the orally administered ED (160 g/day) during the course of chemotherapy. Three patients (15%) could not take the ED orally for 9, 14, and 21 days, respectively, while 1 patient (5%) took the ED orally at an average dose of 80 g/day for 35 days. The remaining 2 patients (10%) could not take the 80 g/day dose for 11 and 12 days, respectively. The incidence of grade ≥ 2 OM in the ED completion group (15.4%, 2 of 13 patients) was significantly lower than that in the non-completion group (66.7%, 4 of 6 patients) (p = 0.046). CONCLUSIONS: An ED might be a one of the test treatment to reduce the incidence of OM in esophageal cancer patients treated with DCF and should be evaluated in further randomized study. CLINICAL TRIAL: The date of submission: Dec 08th, 2017.

The concentration of programmed cell death-ligand 1 in the peripheral blood is a useful biomarker for esophageal squamous cell carcinoma.

BACKGROUND: We determined the serum concentrations of Programmed cell death-1 (PD-1) and its ligands (PD-L1 and PD-L2) in patients with esophageal squamous cell carcinoma (ESCC). METHODS: Blood samples were collected from 85 patients with histologically proved ESCC. Serum levels of PD-1, PD-L1, and PD-L2 were measured using enzyme linked immunosorbent assays. Correlations between serum PD-1, PD-L1, and PD-L2 concentration and tumor depth, number of lymph node metastases, organ metastasis status, or disease stage were assessed and five-year survival rates according to clinicopathological characteristics were calculated. RESULTS: The concentration of PD-1 was not differed according to tumor progression. On the other hand, the average concentration of PD-L1 in patients with T3/T4 disease was 15.6 (12.2-18.3) pg/mL (25-75%), and this was significantly higher than that in patients with Tis/T1/T2 disease (p = 0.020). Similarly, PD-L1 levels were significantly higher in patients with positive lymph nodes than in cases with negative lymph node involvement (p = 0.006) and were higher in patients with organ metastasis (p = 0.123) and in more advanced stage (p = 0.006). Similar tendency was observed regarding PD-L2 concentrations. PD-L2 concentration was higher in T3, T4 cases (p = 0.008), in LN positive cases (p = 0.032), and in more advanced stage (p = 0.024). CONCLUSION: Our data showed that a concentration of PD-L1 in peripheral blood was high in advanced cancer and high concentration of PD-L1 predicted disease progression and also poor survival in patients with ESCC.

Disturbed alternative splicing of FIR (PUF60) directed cyclin E overexpression in esophageal cancers.

Overexpression of alternative splicing of far upstream element binding protein 1 (FUBP1) interacting repressor (FIR; poly(U) binding splicing factor 60 [PUF60]) and cyclin E were detected in esophageal squamous cell carcinomas (ESCC). Accordingly, the expression of FBW7 was examined by which cyclin E is degraded as a substrate via the proteasome system. Expectedly, FBW7 expression was decreased significantly in ESCC. Conversely, c-myc gene transcriptional repressor FIR (alias PUF60; U2AF-related protein) and its alternative splicing variant form (FIRΔexon2) were overexpressed in ESCC. Further, anticancer drugs (cis-diaminedichloroplatinum/cisplatin [CDDP] or 5-fluorouracil [5-FU]) and knockdown of FIR by small interfering RNA (siRNA) increased cyclin E while knockdown of FIRΔexon2 by siRNA decreased cyclin E expression in ESCC cell lines (TE1, TE2, and T.Tn) or cervical SCC cells (HeLa cells). Especially, knockdown of SAP155 (SF3b1), a splicing factor required for proper alternative splicing of FIR pre-mRNA, decreased cyclin E. Therefore, disturbed alternative splicing of FIR generated FIR/FIRΔexon2 with cyclin E overexpression in esophageal cancers, indicating that SAP155 siRNA potentially rescued FBW7 function by reducing expression of FIR and/or FIRΔexon2. Remarkably, Three-dimensional structure analysis revealed the hypothetical inhibitory mechanism of FBW7 function by FIR/FIRΔexon2, a novel mechanism of cyclin E overexpression by FIR/FIRΔexon2-FBW7 interaction was discussed. Clinically, elevated FIR expression potentially is an indicator of the number of lymph metastases and anti-FIR/FIRΔexon2 antibodies in sera as cancer diagnosis, indicating chemical inhibitors of FIR/FIRΔexon2-FBW7 interaction could be potential candidate drugs for cancer therapy. In conclusion, elevated cyclin E expression was, in part, induced owing to potential FIR/FIRΔexon2-FBW7 interaction in ESCC.

Antitumor effects of metformin are a result of inhibiting nuclear factor kappa B nuclear translocation in esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC) is an intractable digestive organ cancer that has proven difficult to treat despite multidisciplinary therapy, and a new treatment strategy is demanded. Metformin is used for type 2 diabetes mellitus and its antitumor effects have been reported recently. Metformin exerts antitumor effects in various respects, such as inhibiting inflammation, tumor growth and epithelial-mesenchymal transition (EMT). However, few reports have described the efficacy of metformin on ESCC, and their findings have been controversial. We analyzed the antitumor effects of metformin and clarified its effects on anti-inflammation, growth suppression and EMT inhibition. Activation of nuclear factor kappa B (NF-κB), the major transcription factor induced by inflammation, was investigated by immunostaining. We found that localization of NF-κB in the nucleus was reduced after metformin treatment. This suggests that metformin inhibited the activation of NF-κB. Metformin inhibited tumor growth and induced apoptosis in ESCC cell lines. Associated with EMT, we examined cell motility by a wound healing assay and the epithelial marker E-cadherin expression of various ESCC cell lines by western blotting. Metformin inhibited cell motility and induced E-cadherin expression. In conclusion, metformin showed multiple antitumor effects such as growth suppression, invasion inhibition, and control of EMT by inhibiting NF-κB localization on ESCC. Further exploration of the marker of treatment efficacy and combination therapy could result in the possibility for novel treatment to use metformin on ESCC.

ZNF750 Expression Is a Potential Prognostic Biomarker in Esophageal Squamous Cell Carcinoma.

OBJECTIVE: ZNF750, a transcriptional regulator of epidermal differentiation, has been identified as a tumor suppressor in esophageal squamous cell carcinoma (ESCC). The aim of the present study was to investigate the clinical and prognostic significance of ZNF750 expression and to evaluate the effect of ZNF750 knockdown on cell proliferation, migration, and invasion in ESCC. METHODS: A total of 124 patients with ESCC who underwent curative esophagectomy were evaluated in this study. The expression of ZNF750 in surgical specimens was immunohistochemically assessed and used in the analysis of clinicopathological features and overall survival (OS). The molecular role of ZNF750 was investigated by ZNF750 knockdown using small interfering RNA (siRNA) in ESCC cell lines. RESULTS: Low ZNF750 expression had a significant correlation with positive lymph node metastasis (p = 0.028). Furthermore, there was a significant relationship between low expression of ZNF750 in ESCC and a poor OS, and a multivariate analysis showed that low ZNF750 expression was an independent prognostic factor (p = 0.020). The cell growth, migration, and invasion were significantly increased by downregulation of ZNF750. CONCLUSIONS: The low expression of ZNF750 was significantly associated with a poor prognosis, and ZNF750 expression may, therefore, be a reliable prognostic biomarker in ESCC.

Endoscopic occlusion with silicone spigots for the closure of refractory esophago-bronchiole fistula after esophagectomy.

A 65-year-old man with cT1bN0M0 stage I middle thoracic esophageal cancer underwent subtotal esophagectomy and gastric tube reconstruction through the posterior mediastinal route after preoperative carbon-ion radiotherapy and chemotherapy in a clinical trial. Anastomotic leakage occurred, but it spontaneously improved. At six months after the operation, he was rehospitalized with a cough and dysphagia. An esophago-bronchiole fistula and stenosis of the gastric tube were observed. He first underwent stent placement in the gastric tube. Two weeks later, the syringeal epithelium was burned by argon plasma coagulation after stent removal. Endoscopic occlusion was then performed for the fistula with two guidewire-assisted silicone spigots. Two weeks later, he was discharged on an oral diet, and he has not developed recurrence of the fistula or cancer for three years. This is the first report of endoscopic occlusion with a guidewire-assisted silicone spigot through the esophagus.

Comparison of Efficacy of Self-Expandable Metallic Stent Placement in the Unresectable Esophageal Cancer Patients.

This is a retrospective study to evaluate the prevention of complications of metallic stent placement in patients with unresectable advanced esophageal cancer. A total of 87 patients were treated with 4 types of metal stents in the esophagus over a period of 18 years. Stent placement was technically successful. The most common prior treatment was chemoradiotherapy. There were no significant differences in the rate of patients with no complications among the prior treatments. Approximately, 30% of patients had the most common chest pain in complications. Stent placement within one month after the completion of chemoradiotherapy should be avoided for the prevention of the chest pain. There was no significant difference in the rate of patients with no complications by lesion location. The rate of no complications was higher for the Niti-S stent than the Gianturco Z-stent or Ultraflex stent. Of note, no complications were noted for the Niti-S ultrathin stent at all. Among cases of stent-related death, the most common type of complication was respiratory disorder caused by the stent that seems to be thick and hard. Therefore, the stent with thin and flexible characteristics like the Niti-S ultrathin stent will solve the various problems of esophageal stent placement.

ZNF750 Expression as a Novel Candidate Biomarker of Chemoradiosensitivity in Esophageal Squamous Cell Carcinoma.

OBJECTIVE: ZNF750, an epidermal differentiation regulator, has been suggested to act as a tumor suppressor of esophageal squamous cell carcinoma (ESCC). Although a correlation between the epidermal differentiation gene and resistance to chemoradiotherapy (CRT) has been posited, no data regarding the ZNF750 status in ESCC have been reported. The aim of the present study was to evaluate the relationship between ZNF750 expression and response to CRT in ESCC. METHODS: Eighty-seven patients who had been pathologically diagnosed with ESCC were evaluated in the present study. All patients underwent neoadjuvant CRT, followed by curative esophagectomy. The expression of ZNF750 in pretreatment biopsy samples was immunohistochemically investigated and compared to the histopathological effectiveness of CRT in surgical specimens. RESULTS: High expression of ZNF750 was closely correlated with good sensitivity to CRT (p = 0.016). A univariate analysis showed that high/intermediate expression of ZNF750 was a significant predictive factor for good sensitivity to CRT (p = 0.006). High/intermediate expression of ZNF750 (30% or more) remained an independent predictive factor for sensitivity to CRT in a multivariate analysis (p = 0.033). CONCLUSIONS: ZNF750 expression predicts sensitivity to CRT and can be a biomarker that reliably predicts the response of ESCC to CRT.

Naso-esophageal extraluminal drainage for postoperative anastomotic leak after thoracic esophagectomy for patients with esophageal cancer.

Postoperative anastomotic leaks and subsequent mediastinal abscess are serious complications. The purpose of this study was to assess the efficacy of naso-esophageal extraluminal drainage after thoracic esophagectomy with gastric conduit reconstruction using a posterior mediastinal route. About 50 of 365 patients (13.7%) with esophageal cancer and postoperative anastomotic leak after curative esophagectomy was investigated. Beginning in June 2009, naso-esophageal extraluminal drainage by inserting a naso-esophageal aspiration tube into the abscess cavity when percutaneous abscess drainage was introduced which was ineffective or technically impossible. Twenty-five patients underwent naso-esophageal extraluminal drainage concomitantly with enteral nutrition. Twenty-one (84%) patients had major leaks, one (4%) minor leak and three (12%) had endoscopically proven conduit necrosis. None of the naso-esophageal extraluminal drainage cases (100%) required reintervention or reoperation and all experienced complete cure (100%) during hospitalization. Endoscopic balloon dilatation was performed for four patients after discharge because of anastomotic stricture. Patients with leaks were divided into two groups: current group (n = 32), treated after June 2009, and preceding group (n = 18), treated prior to the introduction of naso-esophageal extraluminal drainage. Significantly more patients in the preceding group suffered respiratory failure (28% vs. 61%, p = 0.024), and higher reoperation rate (0% vs. 17%, p = 0.042) and hospital mortality (0% vs. 22%, p = 0.013). In the current group, 31 (97%) patients experienced complete cure during hospitalization. Naso-esophageal extraluminal drainage and concomitant enteral nutritional support are less invasive, and effective and powerful methods to treat even major leakage after esophagectomy. These methods may be an alternative management to improve mortality for patients with esophageal cancer.

Heterogeneity of Glucose Metabolism in Esophageal Cancer Measured by Fractal Analysis of Fluorodeoxyglucose Positron Emission Tomography Image: Correlation between Metabolic Heterogeneity and Survival.

BACKGROUND: Intratumoral heterogeneity is a well-recognized characteristic feature of cancer. The purpose of this study is to assess the heterogeneity of the intratumoral glucose metabolism using fractal analysis, and evaluate its prognostic value in patients with esophageal squamous cell carcinoma (ESCC). METHODS: 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) studies of 79 patients who received curative surgery were evaluated. FDG-PET images were analyzed using fractal analysis software, where differential box-counting method was employed to calculate the fractal dimension (FD) of the tumor lesion. Maximum standardized uptake value (SUVmax) and FD were compared with overall survival (OS). RESULTS: The median SUVmax and FD of ESCCs in this cohort were 13.8 and 1.95, respectively. In univariate analysis performed using Cox's proportional hazard model, T stage and FD showed significant associations with OS (p = 0.04, p < 0.0001, respectively), while SUVmax did not (p = 0.1). In Kaplan-Meier analysis, the low FD tumor (<1.95) showed a significant association with favorable OS (p < 0.0001). In wthe multivariate analysis among TNM staging, serum tumor markers, FD, and SUVmax, the FD was identified as the only independent prognostic factor for OS (p = 0.0006; hazards ratio 0.251, 95% CI 0.104-0.562). CONCLUSION: Metabolic heterogeneity measured by fractal analysis can be a novel imaging biomarker for survival in patients with ESCC.