The Study On Surgical Treatment Strategy For Adenocarcinoma Of Esophagogastric Junction

Background and aims: Adenocarcinoma of esophagogastric junction(AEG)is one of the most common malignancies,with morbidity and mortality rates increasing rapidly in recent decades.A combination of surgery and perioperative radiotherapy and chemotherapy remains the mainstay of treatment for AEG,but the prognosis for patients is poor.The treatment of AEG remains controversial due to its unique anatomical location and different biological behaviour from that of oesophageal and gastric cancers.Therefore,it would be beneficial to discuss the controversies and issues that remain to be explored in the clinical management of AEG,especially in relation to the surgical approach in line with the Siewert staging,the minimum length of the proximal margin,neoadjuvant radiotherapy and other treatment modalities.In this study,we explore the controversial issues related to AEG and adopt the approach of "clinical diagnosis and treatment process-controversial issues and issues to be explored-clinical case study-systematic review-database case analysis" to further explore AEG and provide theoretical basis for clinical work.Methods: According to this study proposal,the safety and tumour prognosis of two surgical routes,thoracoabdominal oesophagectomy and trans-fissure dilated gastrectomy,were compared by collecting data from patients with Siewert II AEG in our hospital in recent years,and then systematic reviewing and analysing a large database study on controversial hotspot issues of AEG surgical treatment strategies based on clinical research and practice.Through a comprehensive search of database systems with a search deadline of September 2020,statistical analyses were conducted using software such as Rev Man to summarise and comprehensively evaluate the current literature data on AEG-related surgical routes,minimum length of proximal margins,neoadjuvant radiotherapy,etc.Based on the available evidence,a systematic review approach was applied to study and analyse them.The SEER database was searched to select patients eligible for this study,and the patient data were summarised to analyse the results related to the prognosis of neoadjuvant radiotherapy and adjuvant radiotherapy for Siewert II AEG.Results: By searching,analyzing and summarizing the research on the problems faced in the clinical process and the current hotspots of clinical controversies related to the surgical treatment of AEG,this study is divided into 5 chapters,including 1original clinical case study: "safety and prognosis analysis of transthoracoabdominal esophagectomy and trans-fissure dilated gastrectomy for Siewert II adenocarcinoma of the esophagogastric junction"(Part I);3 systematic reviews: " systematic review of the thoracoabdominal surgical approach versus the transhiatal surgical approach for adenocarcinoma of the esophagogastric junction"(Part II)," systematic review of the minimum length of the proximal resection margin for adenocarcinoma of the esophagogastric junction"(Part III),and " systematic review of neoadjuvant radiotherapy or chemotherapy for adenocarcinoma of the oesophagogastric junction"(Part IV);1 database case study: "Prognosis-related outcome analysis of neoadjuvant radiotherapy and adjuvant radiotherapy for Siewert II-type adenocarcinoma of the oesophagogastric junction based on the SEER database "(Part V).A total of 249 patients were included in Part I.The study found that patients with locally advanced AEG type II tumours may be more suitable for TAE treatment compared to THG.A total of 8 relevant studies were included in Part II and the results illustrated that postoperative morbidity was significantly lower with a trans-lateral extension approach in terms of similar tumours,surgical outcomes and short-term postoperative mortality,while data from a small subgroup of patients with AEG type II suggested a higher survival rate after thoracoabdominal resection in the presence of similar perioperative outcomes.A total of 13 relevant studies were included in Part III,and the results illustrate that there is very little evidence on the impact of PM length on survival,and that the available data on the treatment of PM,and in particular the relationship between PM and patient survival,are very limited.A total of 22 relevant studies were included in Part IV.The results illustrate that preoperative radiotherapy and preoperative chemotherapy have similar survival rates,and although preoperative radiotherapy showed higher p CR rates and better local control compared to preoperative chemotherapy alone,it was not associated with improved prognosis or reduced risk of distant metastases.A total of 1497 patients from the SEER database were included in Part V.The results demonstrate the benefit of adjuvant radiotherapy in the treatment of Siewert II AEG,with a lower risk of death and a lower risk of disease-specific death with adjuvant radiotherapy than with neoadjuvant radiotherapy,after controlling for other risk factors.Conclusions:(1)Patients with locally advanced AEG type II tumours may be more suitable for TAE treatment compared to THG;(2)Recurrence rates after TAE are significantly higher with similar surgical outcomes for both TAE and TEG surgical routes;(3)Considering the available data and shrinkage phenomenon,a PM >2 cm may be necessary to obtain adequate PM;(4)The combined approach has a higher p CR rate and lower risk of local recurrence,but no difference in median OS,further studies are needed;(5)For patients with Siewert II AEG,adjuvant radiotherapy is associated with a survival benefit compared to neoadjuvant radiotherapy.