Principles of esophageal cancer surgery, including surgical approaches and optimal node dissection (2- vs. 3-field)

Application of overlap anastomosis in digestive tract reconstruction during minimally invasive Ivor-Lewis esophagectomy

This study aims to assess the feasibility of the Overlap anastomosis technique in minimally invasive Ivor-Lewis esophagectomy. An accompanying video presentation elucidates our surgical procedures. A retrospective review of 46 patients diagnosed with middle and lower esophageal cancer was conducted. These patients underwent minimally invasive Ivor-Lewis esophagectomy with Overlap anastomosis between January 2019 and December 2020. A consistent team of surgeons performed all procedures. The initial phase involved laparoscopic stomach mobilization, intra-abdominal lymphadenectomies, and preparation of the tubular stomach. Subsequently, with the patient in the left decubitus position, thoracoscopy was used to dissect the esophagus, excise the diseased segment, and conduct mediastinal lymph node dissection. The final stage encompassed the intrathoracic gastroesophageal anastomosis using the Overlap method. All surgeries were completed without converting to an open approach, achieving complete resection. There were no operative fatalities, with an average surgery duration of 259.4 min. Average statistics included intraoperative blood loss of 92.3 ml, 16.2 lymph nodes dissected, and a postoperative hospital stay of 10.3 days. Postoperative complications comprised three instances of hoarseness due to recurrent laryngeal nerve palsy, two cases of aspiration pneumonia, one occurrence of chylothorax, and one gastric emptying disorder. Anastomotic technique-related complications were minimal, with only one patient experiencing an anastomotic leak that resolved spontaneously and two patients facing anastomotic stenosis, which was subsequently alleviated. Our findings posit that the Overlap anastomosis method is safe and efficient for minimally invasive Ivor-Lewis esophagectomy, marked by a notably low rate of anastomosis-related complications. Further evaluation of its long-term implications remains necessary.

Clinical Outcomes of Preserving Bronchial Arteries During Radical Esophagectomy: A Propensity-Score Matched Analysis

BACKGROUND

Postoperative pneumonia is a common and major cause of mortality after radical esophagectomy. Intraoperative preservation of the bronchial arteries is often aimed at avoiding tracheobronchial ischemia; however, it is unknown whether this contributes to a reduction in postoperative pneumonia.

PATIENTS AND METHODS

We enrolled 348 consecutive patients who underwent radical esophagectomy for esophageal cancer at Toranomon Hospital from January 2011 to July 2018. We classified patients into a bronchial artery-resected (BA-R) group (n = 93) and a bronchial artery-preserved (BA-P) group (n = 255) and compared the incidence of postoperative pneumonia between the two groups. A propensity score-matching analysis for bronchial artery preservation versus resection was performed.

RESULTS

Overall, 182 patients were matched. Univariate analysis of the propensity score-matched groups showed that Brinkman index ≥ 400, vital capacity (%VC) < 80%, and bronchial artery resection were associated with the development of postoperative pneumonia. Multivariate analysis revealed three significant factors associated with postoperative pneumonia: Brinkman index ≥ 400 [p = 0.006, odds ratio (HR) 3.302, 95% confidence interval (95% CI) 1.399-7.790], %VC < 80% (p = 0.034, HR 6.365, 95% CI 1.151-35.205), and bronchial artery resection (p = 0.034, HR 2.131, 95% CI 1.060-4.282). The incidence of postoperative complications (CD grade III) was higher in the BA-R group (BA-R 42.8% versus BA-P 27.5%, p = 0.030). There was no significant difference in overall survival between the two groups at 5 years (BA-R 63.1% versus BA-P 72.1%, p = 0.130).

CONCLUSION

Preserving the bronchial artery is associated with a decreased incidence of postoperative pneumonia.

Primary Surgery Not Inferior to Neoadjuvant Chemoradiotherapy for Esophageal Adenocarcinoma

BACKGROUND

The current gold standard for treatment of locally advanced esophageal adenocarcinoma is neoadjuvant chemotherapy or chemoradiotherapy followed by surgery. The shift toward neoadjuvant chemoradiotherapy (nCRT) was driven by the Chemoradiotherapy for Oesophageal Cancer Followed by Surgery Study (CROSS) trial. This study reassessed, in daily practice, the presumed advantage of nCRT followed by surgery on long-term survival compared with primary surgery, in a group of all adenocarcinomas treated through a transthoracic approach with extensive 2-field lymphadenectomy.

METHODS

This retrospective cohort study with propensity score-matched analysis included all surgically treated patients between 2000 and 2018 with locally advanced adenocarcinoma (cT1/2 N+ or cT3/4 N0/+). For appropriate comparison, exclusion criteria of the CROSS trial were applied. Patients were matched on age, Charlson comorbidity score, clinical tumor length, and lymph node status. The primary end point was 5-year overall survival.

RESULTS

There were 473 eligible patients who underwent primary surgery (225 patients) or nCRT + surgery (248 patients). After propensity score-matched analysis, 149 matched cases were defined in each group for analysis. There was no significant difference after 5 years between the matched groups in median overall survival (32.5 and 35.0 months, P = .41) and median disease-free survival (14.3 and 13.5 months, P = .16). nCRT was associated with significantly more postoperative complications (mean Comprehensive Complication Index score: 21.0 vs 30.5, P < .0001) and longer mean stay in the hospital (14.0 vs 18.2 days, P = .05) and intensive care unit (11.7 vs 37.7 days, P = .05).

CONCLUSIONS

Our propensity score-matched results indicate that primary surgery, performed through transthoracic approach with extensive 2-field lymphadenectomy, can offer a comparable overall and disease-free survival after 5 years, with potentially fewer postoperative complications and shorter hospital and intensive care unit stay compared with nCRT followed by surgery.

Surgical Approach to Esophagectomy Post CheckMate 577

Following the results of the CheckMate 577 trial, the Food and Drug Administration approved adjuvant immune checkpoint inhibitor therapy for patients with locally advanced esophageal cancer without a pathologic complete response following neoadjuvant chemoradiotherapy and esophagectomy. This innovation in systemic therapy has rekindled the debate around the clinical value of an extended lymphadenectomy at the time of esophagectomy. In this article, we provide a review of the oncologic principles and potential risks and benefits of extended lymphadenectomy at the time of esophagectomy with acknowledgments to current and forthcoming innovations in thoracic surgery.

Machine learning models predict lymph node metastasis in patients with stage T1-T2 esophageal squamous cell carcinoma

Background

For patients with stage T1-T2 esophageal squamous cell carcinoma (ESCC), accurately predicting lymph node metastasis (LNM) remains challenging. We aimed to investigate the performance of machine learning (ML) models for predicting LNM in patients with stage T1-T2 ESCC.

Methods

Patients with T1-T2 ESCC at three centers between January 2014 and December 2019 were included in this retrospective study and divided into training and external test sets. All patients underwent esophagectomy and were pathologically examined to determine the LNM status. Thirty-six ML models were developed using six modeling algorithms and six feature selection techniques. The optimal model was determined by the bootstrap method. An external test set was used to further assess the model’s generalizability and effectiveness. To evaluate prediction performance, the area under the receiver operating characteristic curve (AUC) was applied.

Results

Of the 1097 included patients, 294 (26.8%) had LNM. The ML models based on clinical features showed good predictive performance for LNM status, with a median bootstrapped AUC of 0.659 (range: 0.592, 0.715). The optimal model using the naive Bayes algorithm with feature selection by determination coefficient had the highest AUC of 0.715 (95% CI: 0.671, 0.763). In the external test set, the optimal ML model achieved an AUC of 0.752 (95% CI: 0.674, 0.829), which was superior to that of T stage (0.624, 95% CI: 0.547, 0.701).

Conclusions

ML models provide good LNM prediction value for stage T1-T2 ESCC patients, and the naive Bayes algorithm with feature selection by determination coefficient performed best.

Feasibility study of adjuvant chemotherapy with S-1 after curative esophagectomy following neoadjuvant chemotherapy for esophageal cancer

BACKGROUND

Despite advances in surgical techniques, long-term survival after esophagectomy for esophageal cancer remains unacceptably low, and more effective perioperative chemotherapy is expected. However, an important concern regarding the application of postoperative adjuvant chemotherapy is treatment toxicity. We aimed to evaluate the feasibility of adjuvant chemotherapy with S-1 in patients after esophagectomy.

METHODS

We investigated the tolerability of a 2-week administration followed by 1-week rest regimen of S1 as postoperative adjuvant therapy in 20 patients with esophageal squamous cell carcinoma who received neoadjuvant chemotherapy (NAC) and 22 patients who did not receive NAC during 2011-2020.

RESULTS

In the non-NAC group, the mean and median relative dose intensity (RDI) were 78.7% and 99.4%, respectively, and 11 patients (50%) had altered treatment schedules. The corresponding rates in the NAC group were 77.9% and 100%, respectively, and nine patients (45%) had altered treatment schedules, with no significant difference among the groups. Moreover, 17 patients (77.2%) in the non-NAC group and 16 patients (80.0%) in the NAC group continued S-1 treatment as planned for one year postoperatively, with no significant difference in the S-1 continuation rate (p = 0.500). Seventeen of 22 patients (77.3%) and 15 of 20 patients (75.0%) experienced several adverse events in the non-NAC and NAC groups, respectively. The frequency, severity, and type of adverse events were consistent among patients with and without NAC.

CONCLUSIONS

S-1 could be safely and continuously administered as adjuvant chemotherapy for patients with esophageal cancer regardless of NAC. Long-term prognosis should be evaluated for S-1 to become the standard treatment after esophagectomy.

Protocadherin B9 Is Associated with Human Esophageal Squamous Cell Carcinoma Progression

INTRODUCTION

Esophageal cancer is the sixth leading cause of cancer-related death worldwide. However, molecular targeted therapy and novel therapeutic targets are needed for esophageal squamous cell cancer (ESCC). In a previous study, we reported that protocadherin (PCDH) B9 plays an important role in several cancers. Therefore, in this study, we examined the clinical significance of PCDHB9 expression in ESCC.

METHODS

PCDHB9 expression was examined using immunohistochemistry in 128 cases and using quantitative reverse transcription-polymerase chain reaction in 16 cases of ESCC. PCDHB9 function in ESCC cells was examined using RNA interference.

RESULTS

High PCDHB9 expression was identified in 5 of 16 (31.3%). In total, 51 (40%) ESCC cases showed strong PCDHB9 expression, whereas nonneoplastic mucosa rarely showed its expression. High PCDHB9 expression was significantly associated with T classification, N grade, and stage in ESCC. In ESCC cell lines, PCDHB9 knockdown affected cell growth, migration, and adhesion. Further, the expression of integrin (ITG) A3, ITGA4, ITGA5, ITGB1, ITGB6, vimentin, snail family transcriptional repressor 1, and cadherin 2 (NCAD) was significantly reduced and cadherin 1 was significantly increased in PCDHB9 knockdown ESCC cells.

CONCLUSION

These results suggest that PCDHB9 plays a tumor-promoting role and is a potential biomarker and therapeutic target in ESCC.

Impact of the introduction of an enhanced recovery pathway in esophageal cancer surgery: a cohort study and propensity score matching analysis

Enhanced recovery pathways (ERP) have the potential to improve clinical outcomes. Aim of this study was to determine the impact of ERP on perioperative results as compared with traditional care (TC) after esophagectomy. In this study, two cohorts were compared. Cohort 1 represented 296 patients to whom TC was provided. Cohort 2 consisted of 200 unselected ERP patients. Primary endpoints were postoperative complications. Secondary endpoints were the length of stay and 30-day readmission rates. To confirm the possible impact of ERP, a propensity matched analysis (1:1) was conducted. A significant decrease in complications was found in ERP patients, especially for pneumonia and respiratory failure requiring reintubation (39% in TC and 14% in ERP; P<0.0001 and 17% vs. 12%; P<0.0001, respectively) and postoperative blood transfusion (26.7%-11%; P<0.0001). Furthermore, median length of stay was also significantly shorter: 13 days (interquartile range [IQR] 10-23) in TC compared with 10 days (IQR 8-14) in ERP patients (P<0.0001). The 30-day readmission rate (5.4% in TC and 9% in ERP; P=0.121) and in-hospital mortality rate (4.4% in TC and 2.5% in ERP; P=0.270) were not significantly affected. A propensity score matching confirmed a significant impact on pneumonia (P=0.0001), anastomotic leak (P=0.047), several infectious complications (P=0.01-0.034), blood transfusion (P=0.001), Comprehensive Complications Index (P=0.01), and length of stay (P=0.0001). We conclude that ERP for esophagectomy is associated with significantly fewer postoperative complications and blood transfusions, which results in a significant decrease of length of stay without affecting readmission and mortality rates.

Prognostic features of the tumour microenvironment in oesophageal adenocarcinoma

Oesophageal adenocarcinoma (OAC) is a disease with an incredibly poor survival rate and a complex makeup. The growth and spread of OAC tumours are profoundly influenced by their surrounding microenvironment and the properties of the tumour itself. Constant crosstalk between the tumour and its microenvironment is key to the survival of the tumour and ultimately the death of the patient. The tumour microenvironment (TME) is composed of a complex milieu of cell types including cancer associated fibroblasts (CAFs) which make up the tumour stroma, endothelial cells which line blood and lymphatic vessels and infiltrating immune cell populations. These various cell types and the tumour constantly communicate through environmental cues including fluctuations in pH, hypoxia and the release of mitogens such as cytokines, chemokines and growth factors, many of which help promote malignant progression. Eventually clusters of tumour cells such as tumour buds break away and spread through the lymphatic system to nearby lymph nodes or enter the circulation forming secondary metastasis. Collectively, these factors need to be considered when assessing and treating patients clinically. This review aims to summarise the ways in which these various factors are currently assessed and how they relate to patient treatment and outcome at an individual level.

Importance of Lymph Node Response After Neoadjuvant Chemoradiotherapy for Esophageal Adenocarcinoma

BACKGROUND

Tumor response and lymph node involvement are the most important prognosticators in resected patients with esophageal adenocarcinoma after neoadjuvant chemoradiotherapy (nCRT). We hypothesize that lymph node response (LNR) is also a valuable prognosticator in these patients, potentially revealing the added effect of nCRT.

METHODS

Hematoxylin and eosin slides of 193 esophageal adenocarcinoma patients with clinical suspicion of lymph node involvement (cN+) and treated with nCRT between 2008 and 2015 were assessed. Lymph nodes containing viable tumor cells were considered ypN+, and those negative for viable tumor were ypN0. LNR was also described according to an earlier defined method. Three groups were obtained: ypN0/LNR-, ypN0/LNR+, and ypN+. They were compared with 188 cN+ patients being pN0 (n = 45) or pN+ (n = 143) after upfront esophageal resection.

RESULTS

Forty-four patients were ypN0/LNR-, 55 were ypN0/LNR+, and 94 were ypN+. Median overall survival was 96.4, 31.2, and 20.6 months, respectively, and was significantly different between ypN0/LNR- and ypN0/LNR+ groups (P = .020). Survival was comparable between ypN0/LNR- and pN0 (104.2 months) groups (P = .519) and between ypN+ and pN+ (21.6 months) groups (P = .966). In ypN0 patients, risk of death in LNR+ patients was tripled compared with LNR- patients.

CONCLUSIONS

In cN+ esophageal adenocarcinoma patients treated with nCRT with postoperative final pathology being ypN0, median overall survival is tripled when no signs of LNR were found and comparable to cN+/pN0 upfront esophagectomy patients, suggesting that 23% of patients treated with nCRT were in fact true N0 and overtreated by nCRT. ypN+ patients have no survival benefit compared with pN+ patients.

Differences in Esophageal Cancer Surgery in Terms of Surgical Approach and Extent of Lymphadenectomy: Findings of an International Survey

INTRODUCTION

Esophagectomy and lymphadenectomy are essential parts of the multimodal treatment of esophageal carcinoma with curative intent. Treatment regimens vary globally and are subject to debate. A global survey was designed to gain insight into current practice.

METHODS

Fifty-seven international expert upper gastrointestinal surgeons received a personal invitation to participate in the survey, which focused on demographics and experience; extent of lymphadenectomy in adeno and squamous cell carcinoma; use of classification systems; neoadjuvant therapy; surgical approach; and specimen handling.

RESULTS

The response rate was 88% (50/57 surgeons), with a mean age of 51.6 years and a median number of 15 years of experience in esophageal surgery. The variety in the extent of lymphadenectomy in proximal, middle and distal squamous cell carcinoma, and Siewert I, II and III adenocarcinoma, was considerable. The number of different combinations of lymph node (LN) stations that were resected in the same tumor was high, while the number of surgeons who removed the exact same combination of LN stations was low. Illustrative is Siewert I adenocarcinoma, in which 27 unique combinations of LN stations were resected, with a maximum of two surgeons performing the exact same dissection. Use of neoadjuvant therapy, surgical approach, and specimen handling also show great variety among participants.

CONCLUSION

There is no uniform, worldwide strategy for surgical treatment of esophageal cancer. The extent of lymphadenectomy shows great variation for both histologic types. An international observational study is needed to provide evidence on the distribution pattern of lymph node metastases in esophageal cancer and the necessary extent of lymphadenectomy.

ANXA10 induction by interaction with tumor-associated macrophages promotes the growth of esophageal squamous cell carcinoma

Tumor‐associated macrophages (TAMs) have important roles in the growth, angiogenesis and progression of various tumors. Although we have demonstrated the association of an increased number of infiltrating CD204⁺ TAMs with poor prognosis in esophageal squamous cell carcinomas (ESCCs), the roles of TAMs in ESCC remain unclear. Here, to study the effects of TAMs on the tumor microenvironment of ESCCs, we established a co‐culture assay using a human ESCC cell line and TAM‐like peripheral blood monocyte‐derived macrophages and performed a cDNA microarray analysis between monocultured and co‐cultured ESCC cell lines. Our qRT‐PCR confirmed that in the co‐cultured ESCC cell lines, CYP1A1, DHRS3, ANXA10, KLK6 and CYP1B1 mRNA were highly up‐regulated; AMTN and IGFL1 mRNA were down‐regulated. We observed that the high expression of a calcium‐dependent phospholipid‐binding protein ANXA10 was closely associated with the depth of invasion and high numbers of infiltrating CD68⁺ and CD204⁺ TAMs and poor disease‐free survival (P = 0.0216). We also found ANXA10 promoted the cell growth of ESCC cell lines via the phosphorylation of Akt and Erk1/2 pathways in vitro. These results suggest that ANXA10 induced by the interaction with TAMs in the tumor microenvironment is associated with cell growth and poor prognosis in human ESCC tissues.

Does the Approach Matter? Comparing Survival in Robotic, Minimally Invasive, and Open Esophagectomies

BACKGROUND

Our objective was to determine how surgical approach impacts overall survival and postoperative outcomes when comparing robotic-assisted minimally invasive esophagectomy (RAMIE), minimally invasive esophagectomy (MIE), and open esophagectomy (OE).

METHODS

The National Cancer Database was queried for patients diagnosed with pathologic Stage 0 to III esophageal cancer from 2010 to 2015. Primary outcome measures evaluated were length of stay, 30-day unplanned readmissions, mortality rates at 30 and 90 days, and overall survival rates. The surgical cohorts underwent 1:1 propensity score matching, and Kaplan-Meier survival estimates were compared by surgical approach. Cox proportional hazards regression was utilized to estimate factors associated with overall survival.

RESULTS

Of 5,553 patients that met criteria, 28.4% were MIE, 7.8% RAMIE, and 63.8% OE. From 2010 to 2015, an increasing trend was seen for both minimally invasive approaches, with MIE surpassing the number of OEs. Unplanned 30-day readmissions and 30-day and 90-day mortality rates were not significantly different between the different groups. Median length of stay was significantly shorter in MIE (9 [interquartile range (IQR), 8 to 14] days) and RAMIE (9 [IQR, 7 to 14] days), compared with OE (10 [IQR, 8 to 15] days; p < 0.001). MIE and RAMIE had comparable survival rates compared with OE, with no significant differences in median overall survival estimates after propensity score matching (log-rank p = 0.603), with a trend for increased survival in MIE (adjusted hazard ratio, 0.97; 95% confidence interval, 0.89 to 1.06; p = 0.530) and RAMIE (hazard ratio, 0.81; 95% confidence interval, 0.69 to 0.95; p = 0.012). Both minimally invasive approaches had a significantly higher median lymph node counts (MIE: 15 [IQR, 9 to 22]; RAMIE: 17 [IQR, 11 to 24]; OE: 13 [IQR, 8 to 20]), which may highlight important differences in postoperative upstaging.

CONCLUSIONS

Trends in MIE use is surpassing the open approach. Minimally invasive approaches are becoming the preferred approach, with noninferior long-term results compared with OEs. A significantly higher lymph node yield was seen for RAMIE and MIE.

Palliative esophagectomy in unexpected metastatic disease: sense or nonsense?

Background Despite integrated positron emission tomography and computed tomography screening before and after neoadjuvant treatment in patients with locally advanced esophageal cancer, unexpected metastatic disease is still found in some patients during surgery. Should then esophagectomy be aborted or is there a place for palliative resection? Methods Between 2002 and 2015, 681 patients with potentially resectable esophageal cancer were sheduled for neoadjuvant therapy and subsequent esophagectomy. In 552 patients, a potentially curative esophagectomy was performed. In 12 patients, unexpected disease was discovered during surgery but esophagectomy was performed with synchronous resection of metastases; 10 of them had oligometastatic disease (≤4 single-organ metastases). Esophagectomy was not performed in 117 patients (because of disease progression in 50); 14 were also single-organ oligometastatic. Data of 10 single-organ oligometastatic patients who underwent esophageal resection (group 1) were compared those of 10 non-resected but treated counterparts (group 2) and with 228 patients who underwent potentially curative esophagectomy with persistent pathological lymph nodes (group 3). Results Five oligometastatic esophagectomy patients had lung metastases: 1 peritoneal, 2 adrenal, 1 pleural, and 1 pancreatic. Two oligometastatic non-resected patients had lung, 5 liver, and 3 brain metastases. Median overall survival was 21.4, 12.1, and 20.2 months in the respective groups (group 1 vs. group 2  p = 0.042; group 2 vs. group 3  p = 0.002; group 1 vs. group 3  p = 0.88). Conclusions Survival is longer in patients undergoing palliative esophagectomy with unexpected single-organ oligometastatic disease and comparable to survival in patients with persistent pathological lymph nodes. Palliative resection in these patients seems to be justified.

ypT0N+: the unusual patient with pathological complete tumor response but with residual lymph node disease after neoadjuvant chemoradiation for esophageal cancer, what's up?

Background

Little is known about the prognostic significance of residual nodal disease in otherwise complete pathologic responders (ypT0N+) after neoadjuvant chemoradiation (nCRT) for esophageal cancer (EC). The purpose is to analyze the long-term outcomes of EC patients with ypT0N+ following nCRT and esophagectomy.

Methods

From a single institution database, 466 consecutive EC patients undergoing esophagectomy after nCRT were collected (1996-2016). ypT0N+ responders were compared to pathological complete responders (ypT0N0) and to pathological non-complete responders (ypT+N0 and ypT+N+).

Results

There were 149 ypT0N0, 31 ypT0N+, 141 ypT+N0 and 145 ypT+N+. Median overall survival (OS) was worse in ypT0N+ (21.7 months) and ypT+N+ (16.8 months) compared to ypT0N0 (55.2 months) and ypT+N0 (42.0 months). Stratification by histology revealed a significant difference in prevalence of ypT0: 62.5% in 184 squamous cell carcinomas (SCC) compared to 23.0% in 282 adenocarcinomas (ADC) (P<0.0001) but not in ypT0N+ (15% vs. 22% respectively, P=0.25). In ADC, locoregional recurrence in ypT0N+ (43%) was comparable to ypT+N+ (31%) and more common compared to ypT0N0 (7%) and ypT+N0 (10%), reflected in median OS rates of 20.6, 17.5, 53.0 and 36.6 months respectively. Median OS in ADC is significantly determined by number of positive lymph nodes, being 21.7 months for pN1 and 2.7 months for pN2/3 (P=0.005) in ypT0N+ and 33.7 months for pN1 and 16.2 months for pN2/3 (P=0.031) in ypT+N+. In SCC, locoregional recurrences were found in 17% of ypT0N+, 33% of ypT+N+, 11% of ypT0N0 and 22% in ypT+N0 and median OS was 26.6, 15.6, 55.2 and 43.8 months respectively. In SCC ypN+ number of affected lymph nodes showed no difference on OS.

Conclusions

ypT0N+ in EC patients following nCRT has a poor prognosis and behaves similar to ypT+N+. However, stratification by histology shows that this is especially true in ADC but seems determined by the number of involved lymph nodes.

Effect of perioperative oral care on prevention of postoperative pneumonia associated with esophageal cancer surgery: A multicenter case-control study with propensity score matching analysis

The aim of this study was to investigate the effectiveness of oral care in prevention of postoperative pneumonia associated with esophageal cancer surgery.Postoperative pneumonia is a severe adverse event associated with esophageal cancer surgery. It is thought to be caused by aspiration of oropharyngeal fluid containing pathogens. However, the relationship between oral health status and postoperative pneumonia has not been well investigated.This study included 539 patients with esophageal cancer undergoing surgery at 1 of 7 university hospitals. While 306 patients received perioperative oral care, 233 did not. Various clinical factors as well as occurrence of postoperative pneumonia were retrospectively evaluated. Propensity-score matching was performed to minimize selection biases associated with comparison of retrospective data between the oral care and control groups. Factors related to postoperative pneumonia were analyzed by logistic regression analysis.Of the original 539 patients, 103 (19.1%) experienced postoperative pneumonia. The results of multivariate analysis of the 420 propensity score-matched patients revealed longer operation time, postoperative dysphagia, and lack of oral care intervention to be significantly correlated with postoperative pneumonia.The present findings demonstrate that perioperative oral care can reduce the risk of postoperative pneumonia in patients undergoing esophageal cancer surgery.