Blood flow assessment of gastric tube with indocyanine green fluorescence angiography and postoperative endoscopy during esophagectomy: indocyanine green enhancement time indicated congestion.

BACKGROUND: During esophagectomy, evaluation of blood supply to the gastric tube is critically important to estimate and avoid anastomotic complications. This retrospective study investigated the relationship between indocyanine green (ICG) fluorescence angiography during esophagectomy and postoperative endoscopy findings, especially mucosal color change. METHODS: This study retrospectively collected data from 86 patients who underwent subtotal esophagectomy and reconstruction using a gastric tube for esophageal cancer at the Tokyo Medical and Dental University between 2017 and 2020. The flow speed of ICG fluorescence in the gastric tube was evaluated during the operation. Additionally, the main root of ICG enhancement and pattern of ICG distribution in the gastric tube were evaluated. On postoperative day 1 (POD1), the change in the mucosal color to white, thought to reflect ischemia, or black, thought to reflect congestion of the proximal gastric tube, was evaluated. The correlations between these factors, clinical parameters, and surgical outcomes were evaluated. Univariate and multivariate analyses used logistic regression to identify the risk factors affecting mucosal color change. RESULTS: Multivariate analyses revealed that the only independent significant predictor of mucosal congestion on POD1 was the ICG enhancement time of the right gastric tube tip (odds ratio, 14.49; 95% confidential interval, 2.41-87.24; P = 0.004). CONCLUSIONS: This study indicated that the ICG enhancement time is related to venous malperfusion and congestion rather than arterial malperfusion and ischemia.

Intraoperative Recurrent Laryngeal Nerve Monitoring for Esophagectomy: A National Cohort Study.

BACKGROUND: Lymphadenectomy around the recurrent laryngeal nerve (RLN) is an essential part of curative surgery for esophageal cancer. Although several single-center studies have shown that intraoperative nerve monitoring (IONM) can avoid RLN palsy, this has not been confirmed in a large-scale multicenter study. This study used a national database to evaluate whether IONM can reduce postoperative RLN palsy during minimally invasive esophagectomy (MIE) for esophageal cancer. METHODS: We retrieved data of patients with esophageal cancer who underwent 3-field thoracoscopic or robotic MIE with cervical anastomosis with IONM(+) (502 patients) and without IONM(-) (4353 patients) from April 2020 to March 2022 from the Diagnosis Procedure Combination database in Japan. We used propensity score-matching analysis to compare the frequency of postoperative RLN palsy and respiratory complications between the IONM(+) group and IONM(-) group. RESULTS: The postoperative RLN palsy rate was significantly lower in the IONM(+) than IONM(-) group (odds ratio, 0.24; 95% CI, 0.13-0.46). The respiratory complication rate was also significantly lower in the IONM(+) than in the IONM(-) group (odds ratio, 0.66; 95% CI, 0.45-0.97). The anesthesia time was significantly longer in the IONM(+) group (regression coefficient, 60.1 minutes; 95% CI, 44.2-76.9 minutes). The length of postoperative hospitalization tended to be shorter in the IONM(+) than in the IONM(-) group (regression coefficient, -1.39 days; 95% CI, -3.91 to 1.14). CONCLUSIONS: This national cohort study showed that IONM during 3-field MIE for esophageal cancer was associated with a reduction of postoperative RLN palsy and respiratory complications.

Technical feasibility and oncological outcomes of robotic esophagectomy compared with conventional thoracoscopic esophagectomy for clinical T3 or T4 locally advanced esophageal cancer: a propensity-matched analysis.

BACKGROUND: Minimally invasive esophagectomy is the first-line approach for esophageal cancer; however, there has recently been a paradigm shift toward robotic esophagectomy (RE). We investigated the clinical outcomes of patients who underwent RE compared with those of patients who underwent conventional minimally invasive thoracoscopic esophagectomy (TE) for locally advanced cT3 or cT4 esophageal cancer using a propensity-matched analysis. METHODS: Overall, 342 patients with locally advanced cT3 or cT4 esophageal cancer underwent transthoracic esophagectomy with total mediastinal lymph node dissection between 2018 and 2022. The propensity-matched analysis was performed to assign the patients to either RE or TE by covariates of histological type, tumor location, and clinical N factor. RESULTS: Overall, 87 patients were recruited in each of the RE and TE groups according to the propensity-matched analysis. The total complication rate and the rates of the three major complications (recurrent laryngeal nerve paralysis, anastomotic leakage, and pneumonia) were not significantly different between the RE and TE groups. However, the peak C-reactive protein concentration on postoperative day 3, rate of surgical site infection, and intensive care unit length of stay after surgery were significantly shorter in the RE group than in the TE group. No significant differences were observed in the harvested total and mediastinal lymph nodes. The total operation time was significantly longer in the RE group, while the thoracic operation time was shorter in the RE group than in the TE group. There was no significant difference between the two groups in the recurrence rate of oncological outcomes after surgery. CONCLUSION: RE may facilitate early recovery after esophagectomy with total mediastinal lymph node dissection and has the same technical feasibility and oncological outcomes as TE.

Novel reconstruction using pedicled ileocolic interposition with intrathoracic esophago-ileal anastomosis after distal esophagectomy for esophagogastric junction cancer: A report of two cases.

There is no optimal reconstruction after radical distal esophagectomy for cancers of the esophagogastric junction. We designed a novel reconstruction technique using pedicled ileocolic interposition with intrathoracic anastomosis between the esophagus and the elevated ileum. Two patients underwent the surgery. Case 1 was a 70-year-old man with esophagogastric junction adenocarcinoma with 3 cm of esophageal invasion. Case 2 was a 70-year-old man with squamous cell carcinoma of the esophagogastric junction; the epicenter of which was located just at the junction. These two patients underwent radical distal esophagectomy and pedicled ileocolic interposition with intrathoracic anastomosis. They were discharged on postoperative days 17 and 14, respectively, with no major complication. Pedicled ileocolic interposition is characterized by sufficient elevation and perfusion of the ileum, which is fed by the ileocolic artery and vein. As a result, we can generally adapt this reconstruction method to most curable esophagogastric junction cancers.

Prognosis of patients with residual pathological disease after neoadjuvant docetaxel, cisplatin, and 5-fluorouracil therapy and surgery for esophageal squamous cell carcinoma: a retrospective cohort study.

Background: Docetaxel, cisplatin, and 5-fluorouracil (DCF) combination chemotherapy has been established as one of the standard neoadjuvant therapies for locally advanced esophageal squamous cell carcinoma (ESCC). However, little is known about prognostic factors in patients with residual pathological disease after neoadjuvant DCF followed by surgery for locally advanced ESCC who are candidates for adjuvant nivolumab. Objectives: This study aimed to investigate prognostic factors in patients with residual pathological disease after neoadjuvant DCF chemotherapy followed by surgery for locally advanced ESCC. Design: This was a retrospective cohort study. Methods: This retrospective cohort study included patients who received neoadjuvant DCF followed by surgery for locally advanced ESCC between June 2014 and January 2020 at the National Cancer Center Hospital East. Results: Among a total of 210 patients, 45 patients (21.4%) achieved a pathological complete response. The 3-year disease-free survival (DFS) rate was significantly lower in patients with residual pathological disease than in those with a pathological complete response [53.5% versus 74.5%; hazard ratio (HR): 2.09, 95% confidence interval (CI): 1.16-3.77, p = 0.01]. In patients with residual pathological disease (n = 165), multivariate analysis revealed that pathological node positivity (HR: 3.59, 95% CI: 1.92-6.71, p < 0.01), supraclavicular lymph node metastasis (HR: 2.15, 95% CI: 1.19-3.90, p = 0.01), and lymphovascular invasion (HR: 1.90, 95% CI: 1.14-3.17, p = 0.02) were significantly associated with poor DFS. Conclusion: In this largest-to-date cohort study, patients with residual pathological disease after neoadjuvant DCF followed by surgery for locally advanced ESCC had a poor prognosis. In these patients, pathological node positivity, including supraclavicular lymph node metastasis, and lymphovascular invasion were considered significant prognostic factors.

Histological study of the structural layers around the esophagus in the lower mediastinum.

BACKGROUND: In Japan, the transhiatal approach, including lower mediastinal lymph node dissection, is widely performed for Siewert type II esophagogastric junction adenocarcinoma. This procedure is generally performed in a magnified view using laparoscopy or a robotic system, therefore, the microanatomy of the lower mediastinum is important. However, mediastinal microanatomy is still unclear and classification of lower mediastinal lymph nodes is not currently based on fascia or other microanatomical structures. AIM: To clarify the fascia and layer structures of the lower mediastinum and classify the lower mediastinal tissue. METHODS: We dissected the esophagus and surrounding organs en-bloc from seven cadavers fixed in 10% formalin. Organs and tissues were then cut at the level of the lower thoracic esophagus, embedded in paraffin, and serially sectioned. Tissue sections were stained with Hematoxylin-Eosin (all cadavers) and immunostained for the lymphatic endothelial marker D2-40 (three cadavers). We observed the periesophageal fasciae and layers, and defined lymph node boundaries based on the fasciae. Lymphatic vessels around the esophagus were observed on immunostained tissue sections. RESULTS: We identified two fasciae, A and B. We then classified lower mediastinal tissue into three areas, paraesophageal, paraaortic, and intermediate, using these fasciae as boundaries. Lymph nodes were found to be present and were counted in each area. The dorsal part of the intermediate area was thicker on the caudal side than on the cranial side in all cadavers. On the dorsal side, no blood vessels penetrated the fasciae in six of the seven cadavers, whereas the proper esophageal artery penetrated fascia B in one cadaver. D2-40 immunostaining showed lymphatic vessel connections between the paraesophageal and intermediate areas on the lateral and ventral sides of the esophagus, but no lymphatic connection between areas on the dorsal side of the esophagus. CONCLUSION: Histological studies identified two fasciae surrounding the esophagus in the lower mediastinum and the layers separated by these fasciae were used to classify the lower mediastinal tissues.

Combination of four bacterial strains isolated from Yamahai-shubo in traditional Japanese sake brewing.

This study investigated the interactions of four bacteria strains isolated from Yamahai-shubo, the source of yeast used to produce a Japanese traditional rice wine, Yamahai-shikomi sake. The bacterial strains were nitrate-reducing Pseudomonas sp. 61-02, Leuconostoc mesenteroides LM-1, Lactiplantibacillus plantarum LP-2, and Latilactobacillus sakei LS-4. We examined fermentation factors for Yamahai-shubo and Yamahai-shikomi sake samples to compare the suitability of their bacterial combination (16 variations). As a result of principal component analysis, we found that two major groups were formed; one containing strain LP-2 and the other containing strain LS-4, and that strains LP-2 and LS-4 were important in the Yamahai-shikomi sake in the presence of strains 61-02 and LM-1. Then, we investigated the effects of strains LP-2 and LS-4 on the concentration of organic acids (pyruvic acid, citric acid, succinic acid, malic acid, and lactic acid) in Yamahai-shikomi sake. Only in lactic acid, a tendency to decrease with a smaller proportion of LS-4 strains in Yamahai-shubo was observed. Subsequently, their effect on the concentration of diacetyl, crucial for aroma, was investigated between the LP-2 and LS-4 strains. The sample prepared in the absence of strain LS-4 exhibited the lowest concentration of diacetyl. This result was supported by the statistical analysis for the sensory scores performed for aroma of each Yamahai-shikomi sake sample. In conclusion, strain LP-2 plays a more significant role in improving Yamahai-shikomi sake quality with strains LM-1 and 61-02 rather than strain LS-4 in Yamahai-shubo preparation and Yamahai-shikomi sake brewing.

Optimal placement of self-fixating mesh in the rectus abdominis muscle for ventral hernia repair when using the enhanced-view totally extraperitoneal Rives-Stoppa technique.

INTRODUCTION: Laparoscopic retro-muscular Rives-Stoppa (RS) ventral hernia repair using the enhanced-view totally extraperitoneal (eTEP) technique (eTEP-RS) is becoming common. Although self-fixating mesh is useful with good fixation, some surgeons think the fixating surface must be oriented towards the rectus abdominis muscle for safety reasons in eTEP-RS. Attaching the self-fixating mesh to the rectus abdominis, the ceiling of the operative field, is challenging and time-consuming. MATERIAL AND SURGICAL TECHNIQUE: First, the self-fixating mesh is folded in half with the fixation surface facing outwards. Second, we create a partition sheet and insert the sheet between the two arms of the folded mesh. The folded mesh is then inserted intracorporeally. We can unfold the mesh easily from one-quarter width to half width on the rectus abdominis muscle because of the insertion of the partition sheet. Finally, the mesh is unfolded to full width, and the mesh placement is completed. DISCUSSION: The eTEP-RS is still a new procedure and has not yet been standardized. However, our technique will increase the use of self-fixating mesh and improve the outcomes of eTEP-RS.

Complete response to definitive chemoradiotherapy in unresectable locally advanced esophageal squamous cell carcinoma.

BACKGROUND: Although definitive chemoradiotherapy (CRT) is the standard therapy for patients with unresectable locally advanced esophageal squamous cell carcinoma (ESCC), poor survival has been reported. Although the complete response (CR) rate is strongly correlated with good prognosis, the predictive factors for CR have not been elucidated. METHODS: This registry study aimed to identify predictors of CR to definitive CRT in patients with unresectable locally advanced ESCC. "Unresectable" was defined as the primary lesion invading unresectable adjacent structures such as the aorta, vertebral body, and trachea (T4b), or the regional and/or supraclavicular lymph nodes invading unresectable adjacent structures (LNT4b). RESULTS: Overall, 175 patients who started definitive CRT between January 2013 and March 2020 were included. The confirmed CR (cCR) rate was 24% (42/175). The 2-year progression-free survival (PFS) and overall survival (OS) rates of cCR cases vs. non-cCR cases were 59% vs. 2% (log-rank p < 0.001) and 90% vs. 31% (log-rank p < 0.001), with a median follow-up period of 18.5 and 40.5 months, respectively. Multivariate analysis of clinicopathological factors revealed that tumor length ≥ 6 cm [odds ratio (OR) 0.446; 95% CI 0.220-0.905; p = 0.025] was a predictor of cCR. CONCLUSIONS: Favorable PFS and OS rates were observed in patients with cCR. Tumor length was a predictive factor for cCR.

Impact of pre-diabetes, well-controlled diabetes, and poorly controlled diabetes on anastomotic leakage after esophagectomy for esophageal cancer: a two-center retrospective cohort study of 1901 patients.

BACKGROUND: Diabetes is known to be associated with anastomotic leakage (AL) after esophagectomy. However, it is unknown whether well-controlled diabetes is also associated with AL. METHODS: We conducted a two-center retrospective cohort database study of patients who underwent oncological esophagectomy (2011-2019). Patients were divided into four groups: normoglycemia, pre-diabetes, well-controlled diabetes (hemoglobin A1c [HbA1c] < 7.0%), and poorly controlled diabetes (HbA1c ≥ 7.0%). The occurrence of AL and length of stay were compared between groups using multivariable analyses. The relationship between categorical HbA1c levels and AL was also investigated in patients stratified by diabetes medication before admission. RESULTS: Among 1901 patients, 1114 (58.6%) had normoglycemia, 480 (25.2%) had pre-diabetes, 180 (9.5%) had well-controlled diabetes, and 127 (6.7%) had poorly controlled diabetes. AL occurred in 279 (14.7%) patients. Compared with normoglycemia, AL was significantly associated with both well-controlled diabetes (odds ratio 1.83, 95% confidence interval [CI] 1.22-2.74) and poorly controlled diabetes (odds ratio 1.95, 95% CI 1.23-3.09), but not with pre-diabetes. Preoperative HbA1c levels showed a J-shaped association with AL in patients without diabetes medication, but no association in patients with diabetes medication. Compared with normoglycemia, only poorly controlled diabetes was significantly associated with longer hospital stay after surgery, especially in patients with operative morbidity (unstandardized coefficient 14.9 days, 95% CI 5.6-24.1). CONCLUSIONS: Diabetes was associated with AL after esophagectomy even in well-controlled patients, but pre-diabetes was not associated with AL. Operative morbidity, including AL, in poorly controlled diabetes resulted in prolonged hospital stays compared with normoglycemia.

Impact of early postoperative factors on changes in skeletal muscle mass after esophagectomy in older patients with esophageal cancer.

BACKGROUND: Loss of skeletal muscle mass, measured by the skeletal muscle mass index (SMI), after esophagectomy negatively impacts prognosis. However, the information to develop novel supportive care options for preventing loss of skeletal muscle mass is limited. The purpose of this retrospective cohort study was to investigate the impact of early postoperative factors on change in SMI 4 months after curative esophagectomy in older patients with esophageal cancer. METHODS: This study included 113 subjects who underwent esophagectomy between 2015 and 2020. Preoperative and postoperative SMI (cm2/m2) were calculated from computed tomography images. The percentage change in SMI 4 months after surgery (SMI%) was calculated as follows: ([postoperative SMI - preoperative SMI] ÷ preoperative SMI) × 100. Potential factors affecting percentage change of SMI after surgery were analyzed by multiple regression. RESULTS: The mean SMI% was - 5.6%. The percentage change (per 1%) in quadriceps muscle strength in the first month after surgery (standardized ß = 0.190, p = 0.048) impacted the SMI%, which was independent of age, sex, preoperative SMI, comorbidity, pathological stage, and neoadjuvant chemotherapy. CONCLUSION: Quadriceps muscle weakness in the first month after esophagectomy impacted the SMI% in a dose-dependent relationship.

Prognostic Impact of the Loss of Skeletal Muscle Mass During Neoadjuvant Chemotherapy on Older Patients with Esophageal Cancer.

BACKGROUND: In older adults, skeletal muscle mass is an important factor for health and prognosis. The loss of SMM during neoadjuvant therapy affects the prognosis of patients with locally advanced esophageal cancer. However, information is limited regarding this possibility in older patients. This study aimed to establish the prognostic impact of SMM loss during neoadjuvant chemotherapy on older patients with locally advanced esophageal cancer. METHODS: This was a single-center retrospective cohort study. Patients age 65 years or older had undergone R0 curative esophagectomy after NAC. The skeletal muscle mass index before and after NAC was calculated from computed tomography images. The percentage change in the SMI during NAC (SMI%) was calculated from the SMI before and after NAC. RESULTS: The study analyzed 150 patients with a mean age of 71.1 ± 3.7 years. The mean value of the SMI was 42.7 ± 7.2 cm2/m2 before NAC, and the SMI% was - 6.4% ± 5.9%. The cutoff of SMI% for overall survival was defined by the log-rank test as - 12%. The Cox proportional hazard model showed that major loss of the SMI (≥ 12%) significantly influenced OS (hazard ratio, 2.490; 95% confidence interval, 1.121-5.529; p = 0.025) independently of age, sex, pathologic T and N factors, or treatment regimen. CONCLUSIONS: Major SMI loss has an impact on OS after R0 curative esophagectomy for older patients with locally advanced esophageal cancer.

Definitive chemoradiotherapy has comparable survival outcomes to esophagectomy in patients with clinical T1N0M0 esophageal squamous cell carcinoma: real-world data.

BACKGROUND: Recently, the JCOG0502 has shown a comparable efficacy of chemoradiotherapy and esophagectomy in patients with clinical T1N0M0 esophageal squamous cell carcinoma. However, few studies have compared the clinical outcomes of these treatments in esophageal squamous cell carcinoma patients (including elderly patients) based on real-world data. METHODS: This retrospective study determined real-world outcomes in patients who underwent chemoradiotherapy or esophagectomy, including those with clinical T1N0M0 esophageal squamous cell carcinoma, between 2009 and 2017 at the National Cancer Center Hospital East. RESULTS: Among a total of 156 patients, 120 and 36 patients underwent esophagectomy and chemoradiotherapy, respectively; 138, 12 and 6 patients had Eastern Cooperative Oncology Group performance status 0, 1, and 2, respectively; and 33 and 123 patients had clinical tumor depth MM-SM1 and SM2-SM3, respectively. In a median follow-up of 72 months, 5-year progression-free survival and overall survival were respectively 77.0% and 81.5% in the esophagectomy group and 74.4% and 82.6% in the chemoradiotherapy group (P = 0.48 and, P = 0.89). Moreover, no treatment-related death was detected in both groups. In elderly patients (75 years or older), 5-year progression-free survival and overall survival were not significantly different between esophagectomy and chemoradiotherapy groups (5-year progression-free survival: 72.3% vs. 81.8%, P = 0.38; 5-year overall survival: 76.9% vs. 81.8%, P = 0.59). CONCLUSIONS: This real-world study confirms the results of a previous clinical trial, and the present findings support chemoradiotherapy as one of the standard treatment options in patients of all ages with clinical T1N0M0 esophageal squamous cell carcinoma.

Tumor response and survival outcomes of salvage concurrent chemoradiotherapy with three-dimensional conformal radiotherapy and 5-fluorouracil/platinum-based chemotherapy for postoperative locoregional recurrence of esophageal squamous cell carcinoma.

BACKGROUND: Salvage concurrent chemoradiotherapy is effective against locoregional recurrence after curative resection of esophageal squamous cell carcinoma. However, there is no consensus on its application. We investigated the outcomes of salvage concurrent chemoradiotherapy (60 Gy in 30 fractions) with three-dimensional conformal radiotherapy and 5-fluorouracil/platinum-based chemotherapy. METHODS: We retrospectively investigated the outcomes and prognostic factors in 51 patients with esophageal squamous cell carcinoma treated with salvage concurrent chemoradiotherapy. RESULTS: The median follow-up was 17.5 (range, 2.8-116.1) months. The overall response, complete response, and partial response rates were 74.5%, 49.0%, and 25.5%, respectively. The median progression-free survival was 8.2 months; the 3-year progression-free survival rate was 22.9%. The median overall survival was 23.1 months; the 3-year overall survival rate was 40.7%. Overall survival was significantly longer in patients with a complete response than in those without (median overall survival: not reached vs. 15.3 months); 3-year overall survival rate: 62.5% vs. 20.3% (hazard ratio: 0.222; P < 0.001). Multivariate analysis showed that the independent prognostic factor for overall survival was < 25 mm longest diameter of metastatic lymph nodes (hazard ratio: 3.71). CONCLUSIONS: Salvage concurrent chemoradiotherapy (60 Gy in 30 fractions) with three-dimensional conformal radiotherapy and 5-fluorouracil/platinum-based chemotherapy was an effective and safe treatment for locoregional recurrence after curative resection of esophageal squamous cell carcinoma, especially in those approaching a complete response. Additionally, a shorter longest diameter of metastatic lymph nodes may be associated with better long-term survival.

Propensity-Matched Analysis of the Short-Term Outcome of Robot-Assisted Minimally Invasive Esophagectomy Versus Conventional Thoracoscopic Esophagectomy in Thoracic Esophageal Cancer.

BACKGROUND: In this matched-cohort study, we investigated the short-term outcome of robot-assisted minimally invasive esophagectomy (RAMIE) compared with conventional minimally invasive thoracoscopic esophagectomy (MIE) in esophageal cancer patients. METHODS: One hundred eighty-nine patients with thoracic esophageal cancer scheduled to undergo thoracic esophagectomy between 2020 and 2021 were assigned to either RAMIE or MIE. Then, we retrospectively evaluated the postoperative surgical complications between two groups in a propensity-matched analyzation. RESULTS: Based on the propensity-matched score, 50 patients who underwent RAMIE or MIE were selected. Thoracic surgery time in RAMIE/MIE group were 233.1/173.3 min (p < 0.01), respectively. No significant intergroup differences were observed regarding incisional anastomotic leakage (RAMIE group 4.0% vs. MIE group 6.0%) and pneumonia (RAMIE group 8.0% vs. MIE group 12.0%; p = 0.68). The respective incidences of recurrent laryngeal nerve paralysis were 34.0 and 8.0% in the MIE and RAMIE groups, respectively (p < 0.01). In the matched cohort, no differences were observed between the groups in the success accomplishment of the clinical management pathway (RAMIE group 94.0% vs. MIE group 88.0%). CONCLUSIONS: Although patients who underwent RAMIE had longer operation times, the incidence of recurrent laryngeal nerve paralysis was lower than with MIE. Further study in a prospective multi-institutional setting are required to confirm the superiority of RAMIE compared with MIE.

Prognostic Impact of Postoperative Loss of Skeletal Muscle Mass in Patients Aged 70 Years or Older with Esophageal Cancer.

BACKGROUND: The number of patients with esophageal cancer aged ≥ 70 years with a poor prognosis is increasing. In general patients with esophageal cancer, postoperative loss of skeletal muscle mass (SMM) is a prognostic factor. This study was designed to investigate the prognostic impact of postoperative loss of SMM in patients aged ≥ 70 years with esophageal cancer. METHODS: This study was a single-center, retrospective cohort study. Patients with esophageal cancer who underwent R0 esophagectomy between 2016 and 2020 were included. The percentage postoperative loss of skeletal muscle mass index (SMI%) was calculated using computed tomography images before and at 4 ± 2 months after surgery. RESULTS: The number of subjects in the ≥ 70-year and < 70-year age groups was 166 and 218, respectively. The median SMI% was 5% in all patients; thus, 5% was defined as the cutoff point to define major loss of SMI. Major loss of SMI impacted 3-year overall survival (OS) in the ≥ 70-year age group, independent of age, sex, clinical stage, pathological T and N factors, Charlson comorbidity index, and length of hospital stay (adjusted hazard ratio [HR]: 4.400; 95% confidence interval: 1.202-16.105; P = 0.025). The adjusted HR of major loss of SMI in the ≥ 70-year age group was higher than in the < 70-year age group (adjusted HR: 4.400 vs. 2.388, respectively). CONCLUSIONS: Postoperative loss of SMI in patients with esophageal cancer aged ≥ 70 years more strongly impacted 3-year OS than in patients aged < 70 years.

Real-time detection of the recurrent laryngeal nerve in thoracoscopic esophagectomy using artificial intelligence.

BACKGROUND: Artificial intelligence (AI) has been largely investigated in the field of surgery, particularly in quality assurance. However, AI-guided navigation during surgery has not yet been put into practice because a sufficient level of performance has not been reached. We aimed to develop deep learning-based AI image processing software to identify the location of the recurrent laryngeal nerve during thoracoscopic esophagectomy and determine whether the incidence of recurrent laryngeal nerve paralysis is reduced using this software. METHODS: More than 3000 images extracted from 20 thoracoscopic esophagectomy videos and 40 images extracted from 8 thoracoscopic esophagectomy videos were annotated for identification of the recurrent laryngeal nerve. The Dice coefficient was used to assess the detection performance of the model and that of surgeons (specialized esophageal surgeons and certified general gastrointestinal surgeons). The performance was compared using a test set. RESULTS: The average Dice coefficient of the AI model was 0.58. This was not significantly different from the Dice coefficient of the group of specialized esophageal surgeons (P = 0.26); however, it was significantly higher than that of the group of certified general gastrointestinal surgeons (P = 0.019). CONCLUSIONS: Our software's performance in identification of the recurrent laryngeal nerve was superior to that of general surgeons and almost reached that of specialized surgeons. Our software provides real-time identification and will be useful for thoracoscopic esophagectomy after further developments.