Published papers

Background: As a first step to prevent recurrent laryngeal nerve (RLN) palsy, we have developed an artificial intelligence (AI)-based anatomical recognition system for critical anatomical structures in robot-assisted minimally invasive esophagectomy (RAMIE). In the present study, we investigated whether AI would enable surgeons to rapidly recognize the RLN. Patients and Methods: Five surgical videos of RAMIE were used to validate the AI. The confidence level (CL) was established as a new criterion to define how confidently surgeons recognize the RLN and stratified into three levels: CL0 is the level when looking for RLN candidates; CL1, after recognizing a candidate but before confirming it as the RLN; CL2, after confirming that the candidate is the RLN. Eight trainee surgeons watched the original and AI-enhanced videos with an interval of > 4 weeks, and they were instructed to declare the RLN’s location at the start of CL1 and CL2. The time to CL1 and CL2 from the beginning of RLN lymph node dissection with and without AI were compared. Results: In all cases, the average time to CL1 and CL2 of the right and left RLN recognition was reduced by using AI. Particularly, in the right RLN recognition, significant differences were found between the surgeons using and not using AI (CL1, 134 vs. 178 s, p < 0.001; CL2, 233 vs. 325 s, p < 0.001). Conclusions: This study demonstrated that AI would enable surgeons not only to rapidly identify the RLN but also to enhance their confidence in its identification.

Objective: To examine the association of BMI with mortality and related outcomes after oncologic esophagectomy. Summary Background Data: Previous studies showed that high BMI was a risk factor for anastomotic leakage and low BMI was a risk factor for respiratory complications after esophagectomy. However, the association between BMI and in-hospital mortality after oncologic esophagectomy remains unclear. Methods: Data for patients who underwent esophagectomy for esophageal cancer between July 2010 and March 2019 were extracted from a Japanese nationwide inpatient database. Multivariate regression analyses and restricted cubic spline analyses were used to investigate the associations between BMI and short-term outcomes, adjusting for potential confounders. Results: Among 39,406 eligible patients, in-hospital mortality, major complications, and multiple complications (≥2 major complications) occurred in 1069 (2.7%), 14,824 (37.6%), and 3621 (9.2%), respectively. Compared with normal weight (18.5-22.9 kg/m2), severe underweight (<16.0 kg/m2), mild/moderate underweight (16.0-18.4 kg/m2), and obese (â ‰¥27.5 kg/m2)were significantly associated with higher in-hospital mortality [odds ratio 2.20 (95% confidence interval 1.65-2.94), 1.25 (1.01-1.49), and 1.48 (1.05-2.09), respectively]. BMI showed U-shaped dose-response associations with mortality, major complications, and multiple complications. BMI also showed a reverse J-shaped association with failure to rescue (death after major complications). Conclusions: Both high BMI and low BMI were associated with mortality, major complications and multiple complications after esophagectomy for esophageal cancer. Patients with low BMI were more likely to die once a major complication occurred. The present results can assist with risk stratification in patients undergoing oncologic esophagectomy.

Objective: To assess the effect of preoperative prophylactic corticosteroid use on short-term outcomes after oncologic esophagectomy. Background: Previous studies have shown that prophylactic corticosteroid use may decrease the risk of respiratory failure following esophagectomy by attenuating the perioperative systemic inflammation response. However, its effectiveness has been controversial, and its impact on mortality remains unknown. Methods: Data of patients who underwent oncologic esophagectomy between July 2010 and March 2019 were extracted from a Japanese nationwide inpatient database. Stabilized inverse probability of treatment weighting, propensity score matching, and instrumental variable analyses were performed to investigate the associations between prophylactic corticosteroid use and short-term outcomes, such as in-hospital mortality and respiratory failure, adjusting for potential confounders. Results: Among 35,501 eligible patients, prophylactic corticosteroids were used in 22,620 (63.7%) patients. In-hospital mortality, respiratory failure, and severe respiratory failure occurred in 924 (2.6%), 5440 (15.3%), and 2861 (8.1%) patients, respectively. In stabilized inverse probability of treatment weighting analyses, corticosteroids were significantly associated with decreased in-hospital mortality [odds ratio (OR)=0.80; 95% confidence interval (CI): 0.69-0.93], respiratory failure (OR=0.84; 95% CI: 0.79-0.90), and severe respiratory failure (OR=0.87; 95% CI: 0.80-0.95). Corticosteroids were also associated with decreased postoperative length of stay and total hospitalization costs. The proportion of anastomotic leakage did not differ with the use of Propensity score matching and instrumental variable analysis demonstrated similar results. Conclusions: Prophylactic corticosteroid use in oncologic esophagectomy was associated with lower in-hospital mortality as well as decreased respiratory failure and severe respiratory failure, suggesting a potential benefit for preoperative corticosteroid use in esophagectomy.

Objective: This study aimed to evaluate the impact of drain placement on the incidence of postoperative complications in patients undergoing gastrectomy. Background: The effectiveness of prophylactic abdominal drain placement in gastrectomy remains unclear. Nevertheless, they are still commonly used following gastrectomy. Methods: We conducted a retrospective cohort study using a nationwide inpatient database in Japan. Patients who underwent gastrectomy for gastric cancer between January 2014 and March 2022 were included. We applied overlap weighting based on propensity scores to adjust for baseline characteristics. The primary outcome was the incidence of intra-abdominal infections. Secondary outcomes included postoperative percutaneous drainage, in-hospital death, length of hospital stay, and total hospitalization costs. Results: A total of 217,750 patients met the inclusion criteria, and 196,660 (90.3%) received prophylactic abdominal drains. After overlap weighting, the drain group had a significantly lower incidence of intra-abdominal infections compared to the no-drain group (6.3% vs. 7.6%; 95% confidence interval [CI] − 1.7 to − 1.0). The prophylactic drains were also associated with reduced in-hospital postoperative mortality (0.6% vs. 0.8%; 95% CI − 0.3 to − 0.1). No significant differences were observed between the two groups in postoperative percutaneous drainage or hospital stay duration. Conclusion: This study suggests that prophylactic abdominal drainage was associated with a reduced incidence of intra-abdominal infections after gastrectomy without increasing hospitalization duration or medical costs.

Purpose: Systematic inflammation has been reported to contribute to cancer progression through various mechanisms; however, the exact mechanism is still the subject of research. In this study, we evaluated the influence of systematic inflammation on lung metastasis, using a murine abdominal sepsis model, and assessed its relationship with pneumonia after curative esophagectomy in patients with esophageal cancer. Methods: We used a murine abdominal sepsis model given highly metastatic osteosarcoma, to reveal the mechanism of systematic inflammation and its potential for lung metastasis. The therapeutic effect of aspirin (ASA) in preventing distant metastasis was also investigated. Subsequently, we analyzed, retrospectively, the relationship between pneumonia and lung metastasis after esophagectomy in patients who underwent esophagectomy at Keio University between January, 2007 and October, 2020. Results: Abdominal sepsis provoked lung injury in the acute phase. ASA inhibited the recruitment of neutrophils triggered by the lung injury, and it also suppressed lung metastasis. Our retrospective study revealed that lung metastasis was more frequent in patients with postoperative pneumonia. Conclusions: Postoperative acute lung injury is associated with a higher risk of lung metastasis. ASA may be a potential preoperative treatment for inhibiting lung metastasis by preventing the recruitment of neutrophils.

Background: Although combinations of immune-checkpoint inhibitors (ICI) with chemotherapy have been approved for esophageal squamous cell carcinoma (ESCC), it remains unclear whether immunochemotherapy (ICT) offers advantages over the simple addition of individual monotherapies. This study aimed to investigate whether ICT exhibits a synergistic effect in patients with advanced ESCC. Methods: Reconstructed individual patient data of 3330 patients were electronically extracted from the Kaplan–Meier (KM) curves of eight randomized-controlled trials (ATTRACTION-3, CheckMate648, KEYNOTE-181, KEYNOTE-590, RATIONALE-302, RATIONALE-306, ESCORT, and ESCORT-1st). The observed progression-free survival (PFS) curve of each constituent monotherapies was used to estimate simulated PFS curves expected under a model of independent drug action. If the observed curve demonstrated significantly better PFS than the simulated curve, the combination of ICI and chemotherapy may have a synergistic effect, implying a superior outcome compared to simply adding the component monotherapy. Results: The 1-year, 2-year, and median PFS of the observed and simulated KM curves were 26.3% vs. 24.8%, 14.6% vs. 12.0%, and 6.9 vs. 6.4 months, respectively. The one-sample log-rank test showed no significant differences between the observed and simulated KM curves (p = 0.073). Conclusions: The observed PFS with ICT was comparable to the simulated PFS estimated from the data for each monotherapy. Although it is unclear whether potential synergies exist for ICT, these findings suggest that the benefits of ICI and chemotherapy do not interfere with each other, thereby providing theoretical support for the efficacy of ICT.

Purpose: Although immune checkpoint inhibitors (ICIs) and chemotherapy combinations have been approved for the treatment of gastric and gastroesophageal junction cancer (GC/ GEJC), whether immunochemotherapy (ICT) offers advantages over the simple addition of individual monotherapies remains unclear. This study aimed to investigate whether ICT has a synergistic effect in patients with advanced GC/GEJC. Materials and Methods: Reconstructed individual patient data were electronically extracted from the Kaplan-Meier curves of 3 randomized controlled trials comparing pembrolizumab (KEYNOTE-061, KEYNOTE-062, and KEYNOTE-859). The observed progression-free survival (PFS) curve for each monotherapy was used to estimate the simulated PFS curve expected under an independent drug action model. If the observed curve demonstrated significantly better PFS than the simulated curve, combined ICI and chemotherapy was determined to have a synergistic effect, implying a superior outcome compared to adding-component monotherapy. Results: In patients with programmed cell death ligand 1 combined positive scores of ≥1 (n=2,194), the 1-year and median PFS of the observed and simulated curves were 28.0% vs. 27.9% and 6.89 months vs. 6.88 months, respectively. The one-sample log-rank test revealed no significant differences between the observed and simulated curves (P=0.107). Conclusions: The observed PFS with ICT was comparable to the predicted PFS based on the data for each monotherapy. Our findings do not provide direct evidence of synergistic effects, but they suggest that combining ICI and chemotherapy does not compromise efficacy. These results may support the continued clinical use of ICT in patients with advanced GC/GEJC.

Esophageal cancer (EC) is one of the leading causes of cancer-related deaths globally. Surgery is the standard treatment for resectable EC after preoperative chemoradiotherapy or chemotherapy, followed by postoperative adjuvant chemotherapy in certain cases. Upper gastrointestinal endoscopy and computed tomography (CT) are predominantly performed to evaluate the efficacy of these treatments, but their sensitivity and accuracy for evaluating minimal residual disease remain unsatisfactory, thereby requiring the development of alternative methods. In recent years, interest has been increasing in using liquid biopsy to assess treatment responses. Liquid biopsy is a noninvasive technology for detecting cell components in the blood and other body fluids. It involves collecting a small sample of body fluid, which is then analyzed for the presence of components, including circulating tumor DNA (ctDNA), microRNA (miRNA), or circulating tumor cells (CTCs). Further, ctDNA and miRNA are analyzed with various techniques, including digital polymerase chain reaction (dPCR) and next-generation sequencing (NGS). CTCs are isolated by determining surface antigens using immunomagnetic techniques or by filtering the blood according to cell size and rigidity. Several studies indicate that investigating these materials helps predict EC prognosis and recurrence and possibly stratifies high-risk groups. Liquid biopsy may also apply to the selection of cases that have achieved a complete response through preoperative treatment to prevent surgery and preserve the esophagus, as well as identifying the suitability of postoperative chemotherapy and the timing of conversion surgery for unresectable EC. The potential of liquid biopsy to enhance treatment decisions will further advance EC treatment.

Changes in muscle mass may be an objective approach toward measuring the quality of life after surgery, but long-term changes due to surgery without the effect of cachexia remain unclear. Patients with esophageal cancer who underwent esophagectomy and did not experience cancer recurrence for 3 years were analyzed. The psoas muscle mass index (PMI) was assessed before surgery and 7 days, 1 year, and 3 years after surgery. Patients with no change or increased PMI within 7 days after surgery were categorized into the Nondecreasing-PMI group, whereas those with decreased PMI were categorized into the Decreasing-PMI group. Eighty-four and 51 patients were categorized into the Nondecreasing- and Decreasing-PMI groups, respectively. The Decreasing-PMI group had a higher incidence rate of anastomotic leakage than the Nondecreasing-PMI group (25% vs. 12%, respectively; P = 0.042). Moreover, the Decreasing-PMI group showed a significantly greater decrease in the PMI 1 year after surgery than the Nondecreasing-PMI group (−9.2% vs. −4.0%, respectively; P = 0.048). However, although the Decreasing-PMI group had a greater decrease in the PMI than the Nondecreasing-PMI group, no significant difference was observed 3 years after surgery (−9.8% vs. −5.3%, respectively; P = 0.115). A decrease in PMI in the acute phase after esophagectomy may contribute to a long-term decrease in the PMI. Intensive interventions may be beneficial for these patients to improve their long-term quality of life.

Abundant lymphatic flow and the anatomical location of the esophagus can result in the widespread distribution of lymph node metastasis of esophageal cancer from the cervical to the abdominal field. Historically, the Japan Esophageal Society and American Joint Committee on Cancer offer two different classifications of lymph node group location surrounding the esophagus. The location of sentinel lymph nodes in midthoracic esophageal cancer reflects the variety of lymphatic drainage routes. In fact, in cT1N0 esophageal cancer, pathological lymph node metastasis has been observed from the cervical to the abdominal field, and the locations were shown to be closely linked to the primary tumor location in advanced stages. While the impact of histology on the distribution of LN metastasis has been extensively debated, a recent prospective study on esophagogastric junction cancer found that metastatic patterns did not differ by histology. Thoracic duct lymph nodes were defined as one of the regional lymph node stations in the mediastinum. Although lymph node metastasis around the thoracic duct has occasionally been observed, the oncologic impact of thoracic duct lymph node dissection has not been fully elucidated. To eradicate tumors locoregionally, three-field lymph node dissection, a strategy for extended lymph node clearance, has been established. In esophagectomy, three-field lymph node dissection is defined as a procedure for complete regional cervico-thoraco-abdominal lymph node dissection. However, its therapeutic efficacy must be evaluated based on the balance between oncological outcomes and possible added surgical risk. To further improve survival, multidisciplinary treatment consisting of surgery, chemotherapy, and radiotherapy has been established worldwide as a standard treatment for esophageal cancer. Now that neoadjuvant therapy followed by esophagectomy is the standard, adding adjuvant therapy including immunotherapy could be a promising treatment option. The ideal combination of various multidisciplinary treatment approaches and extensive LN dissection need to be established to improve the oncological outcomes for EC patients.

Background: Esophageal cancer has a poor prognosis because of its rapid progression and early and extensive lymph node metastasis. Simple, objective indicators for predicting long-term outcomes are needed to select optimal perioperative treatment and appropriate follow-up for patients with esophageal cancer. The aim of this study is to investigate the relationship between the lymphocyte-to-C-reactive protein ratio (LCR) and the survival of patients with esophageal cancer, by performing time-dependent receiver operating characteristic (ROC) curve analysis. The results were compared to those of traditional inflammation-based markers. Methods: This study enrolled 495 patients who underwent thoracic esophagectomy for esophageal cancer as the primary treatment between 2000 and 2019 in our department. We investigated the predictability of the LCR for oncological outcomes compared to that of other traditional inflammatory markers. Results: The 3-year overall survival (OS) and recurrence-free survival (RFS) were 72.6% and 57.5%, respectively. Low LCR was significantly associated with higher cancer stage, included depth of invasion (p < 0.001), lymph node metastasis (p < 0.001) and cStage (p < 0.001). The LCR had the highest AUC value (0.675) for predicting OS compared to the other examined inflammatory markers. In multivariate analysis, the LCR (optimal cutoff threshold = 19,000) was identified as a significant predictor of death (hazard ratio, 2.24; 95% confidence interval [CI], 1.61–3.12; p < 0.001) and recurrence (hazard ratio, 1.97; 95%CI, 1.48–2.63; p < 0.001). Conclusion: The LCR is novel indicator for oncological outcomes for patients with esophageal cancer and may assist to facilitate personalized multidisciplinary treatments.

Objective: This study aimed to validate the prognostic significance of stratification using pathological stage and response to neoadjuvant chemotherapy with a nationwide database from an authorized institute by the Japan Esophageal Society. Background: We proposed the combined criteria using pStage and pathological response. Conducting a validation study using an expanded cohort in the clinical setting would be valuable since it was developed using retrospective data collection. Methods: Patients with esophageal squamous cell carcinoma who underwent subtotal esophagectomy at 85 authorized institutes were retrospectively reviewed for esophageal cancer between 2010 and 2015. The prognostic value of the pathological response was evaluated within the same pStage. Moreover, risk stratification was developed to predict cancer-specific survival (CSS). Results: The pathological response showed significant stratification of CSS in 3761 patients included in this analysis. We classified the patients into 7 groups as survival was significantly different between responders and nonresponders under the stratification with pStage, excluding pStage I comprising pStage 0-I/II responder/II nonresponder/III responder/III nonresponder/IV responder/IV nonresponder with the 5-year CSS of 83.7%/75.8%/68.9%/59.8%/44.4%/40.7%/23.1%, respectively. Furthermore, the area under the curve was significantly higher under the new classification than in the pStage alone (P<0.001). Conclusions: The prognostic value of classification using pStage and the pathological response was successfully validated using real-world data in Japan. This result would guide appropriate treatment for patients with esophageal squamous cell carcinoma who received neoadjuvant chemotherapy followed by esophagectomy.

Background: Although neoadjuvant treatment has become the standard of care for patients with locally advanced esophageal cancer, previous studies comparing neoadjuvant chemotherapy (NAC) and neoadjuvant chemoradiotherapy (NACRT) have demonstrated inconclusive results. Methods: Our study cohort included 3978 patients from 85 institutions. Those who underwent NAC or NACRT followed by surgery for esophageal squamous cell carcinoma (ESCC) were eligible for inclusion. We used the inverse probability of treatment weighting (IPTW) method to compare the outcomes between NAC and NACRT. Results: Among the 3978 patients, 3777 (94.9%) received NAC and 201 (5.1%) received NACRT. After IPTW adjustment, the NACRT group had more patients with pathologically downstaged diseases and significantly better pathological response compared with the NAC group (p < 0.001); however, 5-year overall survival (OS), recurrence-free survival (RFS), and regional recurrence-specific survival (RRSS) were comparable between the groups. Subgroup analysis stratifying patients according to cT category showed that among cT1-2 patients, those in the NACRT group had significantly longer 5-year OS, RFS, and RRSS than those in the NAC group (P = 0.024, < 0.001, and 0.020, respectively). In contrast, no significant differences were observed among cT3-4a patients. The competing risks regression model showed comparable subdistribution hazard ratios for 10-year cancerous and noncancerous deaths between the NAC and NACRT groups. Conclusions: Compared with NAC, NACRT for ESCC did not promote better survival despite better therapeutic effects and did not increase noncancerous deaths.

Background: Evaluating tumor response to neoadjuvant chemotherapy (NAC) is important to predict survival and to select the optimal strategy for patients with esophageal cancer. The aim of this study is to investigate the relation between neutrophil-to-lymphocyte ratio (NLR) change after NAC and histological response and oncological outcomes in patients with esophageal cancer. Methods: This study enrolled 209 patients who underwent NAC and thoracic esophagectomy for esophageal cancer as the primary treatment between 2000 and 2019 in our department. Several predictors of survival including NLR change, which was calculated as post-NAC NLR/pre-NAC NLR, were investigated. We used classification and regression tree (CART) analysis to determine the optimal cutoff values of NLR change for the prediction of histological response. Results: The best cutoff value of NLR change was 0.55 using the CART analysis. Then we divided all patients into two groups; the patients with NLR change below the cutoff were allocated to the NLR reduction group (n = 53), whereas the patients with NLR change above the cutoff were allocated to the no-NLR reduction group (n = 156). NLR change was identified as a significant predictor for histological responder (odds ratio 3.80; 95% confidence interval (CI) 1.69–8.58; p = 0.001) and recurrence-free survival (hazard ratio 0.55; 95% CI 0.33–0.89; p = 0.015) in multivariable analysis. Conclusion: The present study demonstrated that NLR change is associated with both histological response to and oncological outcomes of NAC for patients with esophageal cancer. NLR change can help not only to predict survival, but also to facilitate personalized multidisciplinary treatment.

Introduction: There remains a lack of evidence regarding the optimal abdominal approach, including laparoscopy, hand-assisted, and open laparotomy for minimally invasive thoracoscopic esophagectomy. We aimed to compare the incidence of postoperative complications, particularly pulmonary complications, between laparoscopy and open laparotomy for minimally invasive thoracoscopic esophagectomy using nationwide Japanese databases. Methods: Data from patients in the National Clinical Database (NCD) who underwent thoracoscopic esophagectomy for esophageal cancer were analyzed. The incidence of pulmonary complications was compared between abdominal laparoscopy and laparotomy after matching the propensity scores (PS) from preoperative factors to account for confounding bias. Laparoscopic-assisted surgery (LAS) was also compared to hand-assisted laparoscopic surgery (HALS). Results: Of the 24,790 patients who underwent esophagectomy between 2018 and 2021, data from 12,633 underwent thoracoscopic procedure. The proportion of patients who experienced pulmonary complications did not significantly differ between the laparoscopy group and the laparotomy group after matching (664/3195 patients, 20.8% versus 702/3195 patients, 22.0%; P = 0.25). No difference in the incidence of pulmonary complications was observed among patients treated using the laparoscopic approach (508/2439 patients, 20.8% in the LAS group versus 498/2439 patients, 20.4% in the HALS group; P = 0.72). Conclusions: We observed no significant difference in the incidence of postoperative pulmonary complications between laparoscopy and laparotomy for thoracoscopic esophagectomy. Short-term outcomes were similar between the laparoscopic-assisted approach and the hand-assisted approach. This study provides valuable insights into the optimal abdominal approach for thoracoscopic esophagectomy using data from a nationwide database that reflect real-world clinical practice.

Background: The prognostic impact of docetaxel, cisplatin, and 5-FU (DCF) reported in JCOG1109 was successfully validated using real-world data in patients < 75 years old. However, DCF was not reported to be beneficial in elderly patients with a relatively higher postoperative complication incidence. This study aimed to clarify the impact of postoperative complications on the prognosis of ESCC and the difference in the magnitude of the impact by age and regimen. Methods: Patients with esophageal squamous cell carcinoma (ESCC) who underwent subtotal esophagectomy at 85 authorized institutes were retrospectively reviewed from 2010 to 2015. The prognostic impact of postoperative anastomotic leakage (AL) and pneumonia on survival was evaluated. The prognostic value of the postoperative complications was assessed by stratifying patients according to age and neoadjuvant chemotherapy regimen. Results: Patients with AL, pneumonia, and infectious complications (ICs: a combination of pneumonia and AL) showed significantly worse overall survival (OS). IC served as a negative prognostic factor of OS and recurrence-free survival, and its negative prognostic impact was more evident in patients aged > 75 years. When the patients were further stratified by chemotherapeutic regimens, using the CF/IC(−) group as a reference, the DCF/IC (+) group showed significantly shorter OS in patients aged > 75 years with a hazard ratio (HR) of 2.551. The HR of the CF/IC (+) group was 1.503. Conclusions: The negative impact of postoperative complications on survival was confirmed in this nationwide study. Furthermore, its magnitude was higher in elderly patients who received triplet chemotherapy.

Despite advances in multidisciplinary treatment, esophagectomy remains the main curative treatment for esophageal cancer. The advantages and disadvantages of thoracic duct (TD) resection have been controversial for decades. We have herein reviewed relevant published literature regarding 'thoracic duct,' 'esophageal cancer,' and 'esophagectomy' describing the anatomy and function of the TD, and incidence of thoracic duct lymph nodes (TDLN) and TDLN metastases, as well as the oncological and physiological effects of TD resection. The presence of lymph nodes around the TD, referred to as TDLN, has been reported previously. The delineation of TDLNs is clearly defined by a thin fascial structure covering the TD and the surrounding adipose tissue. Previous studies have examined the number of TDLNs and the percentage of patients with TDLN metastasis and revealed that each patient had approximately two TDLNs. The percentage of patients with TDLN metastasis was reported to be 6-15%. Several studies have been conducted to compare the survival after TD resection with that after TD preservation. However, no consensus has been reached because all studies were retrospective, precluding firm conclusions. Although the issue of whether the risk of postoperative complications is affected by TD resection is still unclear, resecting the TD has been shown to have a long-term impact on nutritional status after surgery. In summary, TDLNs are quite common and present in most patients, while metastasis in the TDLNs occurs in a minority. However, the oncological value of TD resection in esophageal cancer surgery remains controversial due to varying findings and methodological limitations of previous comparative studies. Considering the potential but unproven oncological benefits and possible physiological drawbacks of TD resection, including postoperative fluid retention and disadvantages in the long-term nutritional outcome, clinical stage, and nutritional status should be considered before deciding whether to perform TD resection or not.

Background: The optimal timing of surgery following neoadjuvant therapy in esophageal squamous cell carcinoma (ESCC) remains uncertain. This exploratory analysis aims to assess the impact of time to surgery (TTS) on perioperative and survival outcomes in patients with advanced ESCC enrolled in the phase III trial JCOG1109. Methods: Patients who underwent esophagectomy following neoadjuvant chemotherapy or chemoradiotherapy were included. Within each treatment arm, patients were categorized into four TTS subgroups according to cohort quartiles. Perioperative complications, overall survival (OS), and progression-free survival (PFS) were evaluated. Results: The median TTS was 35 (range, 16–81), 38 (17–109), and 41 (14–98) days for the cisplatin plus fluorouracil (CF), docetaxel, cisplatin plus fluorouracil, and CF with radiotherapy (CF-RT) arms, respectively. Baseline characteristics were comparable across the TTS subgroups. Operative time and overall complication rates showed no significant differences. In the CF-RT arm, a longer TTS was associated with increased blood loss (200, 210, 300, and 370 mL) and a trend toward a higher anastomotic leakage (6%, 7%, 14%, and 18%), as well as a trend toward poorer PFS and OS, particularly at more prolonged intervals. However, across all treatment arms, OS and PFS did not differ among the TTS subgroups, with multivariable analysis revealing no consistent associations between TTS and survival. Conclusions: Time to surgery following neoadjuvant therapy did not significantly influence prognosis in advanced ESCC. Nonetheless, prolonged intervals after chemoradiotherapy may increase surgical complexity and leakage risk, in addition to elevating the potential for adverse prognostic effects associated with excessive delays.

Background: Minimal data was reported regarding the characteristics, risks of lymph node metastasis, and prognostic factors in esophageal cancer patients who achieved remarkable response in the primary lesion to neoadjuvant treatment (NAT). Methods: This study evaluated the nationwide data of esophageal squamous cell carcinoma (ESCC) patients who underwent surgery following NAT in Japan. Of 4484 patients, 300 (6.7%) had ypT0 following NAT and curative esophagectomy. Factors associated with lymph node metastasis and prognosis were analyzed. Results: Neoadjuvant chemotherapy (NAC) and neoadjuvant chemoradiotherapy (NACRT) were administered in 260 (86.2%) and 40 (13.8%) patients, respectively. Pathologically, 72 (24.0%) had lymph node metastasis (residual nodal disease; RND), and pretherapeutic lymph node metastasis was the independent risk factor for RND (odd ratio [OR]: 3.21; 95% confidence interval [CI]: 1.44–8.20; P = 0.008). The 5-year overall and relapse-free survivals were significantly longer in patients with pathological complete response (pCR) than in those with RND (both P < 0.001). Pretherapeutic cT3 or T4a tumors (hazard ratio [HR]: 1.71; 95% CI: 1.02–2.88; P = 0.043), RND (HR: 3.30; 95% CI: 1.98–5.50; P < 0.001), and operative blood loss (Liter, HR: 1.53; 95% CI: 1.07–2.19; P = 0.021) were independent risk factors affecting relapse-free survival in multivariable analysis. Conclusions: Of patients with ypT0 after NAT, 24.0% had RND, and pretherapeutic lymph node metastasis was the risk factor. In addition, pretherapeutic cT3, or T4a tumors, RND, and operative blood loss were the poor prognosticators in patients with ypT0 after NAT.