Esophageal cancer is one of the most aggressive gastrointestinal malignancies (1), with an overall 5-year survival rate between 15% and 25% worldwide, and is the sixth leading cause of cancer-related deaths worldwide (2). In the era of multimodality treatment, esophagectomy remains the primary treatment for the patients with resectable esophageal cancer. Since the first report by Lewis-sanby (3) in 1946, the Ivor-Lewis procedure of esophageal cancer has progressively become the standard surgical approach for treating esophageal cancer in Europe and the United States owing to the fact that it agrees with the principles of surgical treatment of malignant tumors by removing the esophageal tumor and surrounding tissues in a whole block. However, the wide resection area of the Ivor-Lewis procedure requires whole resection of the esophageal tumor and its surrounding mediastinal tissues, including the esophagus and surrounding lymphatic fatty tissues, bilateral mediastinal pleura, and part of the pericardium; and also requires resection of the posterior esophagus, azygous vein, thoracic duct, and surrounding tissues, it is highly traumatic and has more postoperative complications, and is slowly carried out in China (4, 5). In recent years, with the extensive application of thoracoscopic techniques, the combined thoracolaparoscopic esophagectomy has become the mainstream surgical treatment of esophageal cancer in China (6, 7). In thoracoscopic esophageal cancer resection, the azygous vein, thoracic duct and surrounding tissues are preserved, and it remains unclear whether the reduction of surgical extent will increase the risk of postoperative recurrence and decrease the long-term outcome. Therefore, the purpose of present study was to compare the clinical results of the modified Ivor-Lewis procedure, which preserves the azygous vein, thoracic duct and surrounding tissues, with the classical Ivor-Lewis procedure, which removes these tissues, for the treatment of esophageal squamous cell carcinoma, in order to provide more options for the improvement of the esophageal cancer procedure.

This study has been reviewed by the Ethics Committee of Gansu Provincial People’s Hospital, approval number: 2022-350. All patients signed the informed consent form for surgery before surgery.

With the gradual promotion of minimally invasive surgery and standardized treatment for esophageal cancer, transrectal thoracic surgery for esophageal cancer has been recognized by Chinese thoracic surgeons (9). The thoracoscopic approach through the right chest fully exposes the anatomical structure and tissue adjacent to the esophagus, making it easy to dissect and resect the esophageal tumor, and clear the lymph nodes more thoroughly, with good clinical efficacy (10, 11). However, whole thoracoscopic resection of the azygous vein, thoracic duct and surrounding tissues is difficult and does not easily meet the Ivor-Lewis resection criteria. Therefore, in clinical application, a modified Ivor-Lewis surgical protocol was used to reduce the extent of resection and preserve the azygous vein, thoracic duct, and surrounding tissues; this strategy reduces the difficulty of surgery, while its influence on the long-term outcome is worthy of in-depth investigation.

Our present results showed that the modified group was superior than the traditional group in terms of operative time(p=0.007), intraoperative bleeding(p=0.003), and postoperative 3 days chest drainage(p=0.001) in both two groups, with statistically significant differences. There was no significant difference between the two groups in the aspects of pulmonary infection(p=0.732), anastomotic fistula(p=0.560), and perioperative mortality, and further, our reported results agree well with previously published results (12). Our results disclosed that both surgical resection or preservation of the azygous vein, thoracic duct and surrounding tissues for esophageal cancer have the same safety, but the preservation of the thoracic duct and azygous vein reduces surgical trauma, saves surgical time, facilitates postoperative recovery, and accords well with the trend of minimally invasive treatment.

Pasquali et al. (13) reported that the metastasis rate of parathoracic duct lymph nodes was 6.6%, and metastasis was related to the depth of tumor infiltration, and the metastasis rate of parathoracic duct lymph nodes was 2.2% for T1b to T2 and 10% for T3 to T4. The preservation of the azygous vein and thoracic duct may not reveal adequately and affect the complete clearance of parathoracic duct lymph nodes. In this study, lymph node metastasis was detected in 2 patients in the traditional group, with a metastasis rate of 2.3%, which is lower than previous value of 6.6%, as reported by Pasquali et al. (13). In these 2 patients, the absence of resection means that the tumor remains and a recent local recurrence of the tumor may occur. Compared with the modified Ivor-Lewis procedure, the traditional Ivor-Lewis procedure has some obvious advantages of thoroughly removing the thoracic duct, the azygous vein, and surrounding tissue, and thus, theoretically reducing the potential for local recurrence in this area. However, the differences in 3-year postoperative survival rates, tumor recurrence types and local recurrence rates among the two groups were not statistically significant based on long-term follow-up results. Therefore, our results showed that few cases of local recurrence are directly related to the surgical modification. Furthermore, Schröder et al. (14) also pointed out that the preservation of the thoracic duct and the azygous vein hasn’t increased local recurrence. It makes clear that the same long-term clinical outcome can be obtained by preserving the thoracic duct, the azygous vein and the surrounding tissue. The effectiveness of preoperative neoadjuvant therapy for esophageal cancer has been proven, and neoadjuvant radiotherapy combined with surgery can prolong patient survival (15, 16). Chinese clinical guidelines also recommend preoperative neoadjuvant radiotherapy for progressive esophageal cancer, and the intervention of preoperative radiotherapy may compensate for the potential risk of residual tumor due to the preservation of the thoracic duct, azygous vein, and surrounding tissue.

Our present study is of some limitations and shortcomings: (i) possible bias in the results due to the single-center data source of the included studies; (ii) despite PSM has been applied to control confounding factors among groups, the potential selection bias has not been eliminated completely. (iii) although the 3-year OS results of the two methods in this study are similar, the long-term oncology effect still needs more research to explore. In addition, a few patients did not undergo positron emission tomography (PET)/CT due to poor economic conditions. Despite these limitations, our study provides insight into the improvement of thoracolaparoscopic Ivor-Lewis esophageal cancer resection.

The modified way of preserving the thoracic duct and the azygous vein in esophageal surgery reduces the scope of surgery and surgical trauma compared with the classical Ivor-Lewis resection, which is in line with the trend of minimally invasive treatment and does not affect the long-term outcome. Our findings suggest that the thoracic duct, azygous vein and surrounding tissues may not be removed when the tumor does not invade the tissue during the surgery of esophageal cancer. We look forward to large sample randomized controlled trials to verify these results in the future.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The studies involving human participants were reviewed and approved by the Ethics Committee of Gansu Provincial People’s Hospital. The patients/participants provided their written informed consent to participate in this study. Written informed consent was obtained from the individual(s) for the publication of any potentially identifiable images or data included in this article.

Study design: ZH, YG and XB. Data collection: WG and YS. Data analysis: YL, BC and DJ. Drafting the manuscript: ZH and XW. Project supervision: ZH and YG. All authors contributed to the article and approved the submitted version.