OBJECTIVE: To investigate the relationship between the clinicopathological features of cardia cancer and the metastasis of paraesophageal lymph nodes, and to provide a basis for selecting a reasonable surgical incision. METHODS: The clinical data of 448 patients with pancreatic cancer who were treated surgically through thoracic or combined thoracoabdominal incisions were retrospectively analyzed. RESULTS: The overall metastasis rate of lower thoracic segment paraoesophageal lymph nodes was 10.94% (49/448). The metastasis rate was 10.23% in male patients and 13.54% in female patients (P>0.05). The metastasis rates were 17.83% for low- and undifferentiated adenocarcinoma and 1.58% for high- and moderately differentiated adenocarcinoma (P<0.001); 25.16% for tumor diameter ≥4 cm and 3.11% for tumor diameter <4 cm (P<0.001); 22.09% for tumor invasion to the plasma layer of the stomach and 3.99% for tumor non-invasion to the plasma layer (P <0.001); the metastasis rate of Borrmann's type III and IV was 19.90%, and the metastasis rate of Borrmann's type I and II was 3.31% (<0.001); the metastasis rate of tumor invasion to esophageal length ≥2 cm was 29.41%, and the metastasis rate of <2 cm was 4.26% (P<0.001). CONCLUSION: There was a significant relationship between tumor pathological type, diameter, depth of invasion, Borrmann staging, and length of esophageal invasion and metastasis to paraesophageal lymph nodes. The choice of a transabdominal surgical incision is feasible in cases with a low likelihood of paraoesophageal lymph node metastasis. Choosing a reasonable surgical incision is an important guarantee for radical resection of cardia cancer. It is generally accepted that the combined thoracoabdominal incision is the most favorable incision for radical pancreatic cancer surgery because it can easily clear the lower thoracic paraesophageal lymph nodes compared with the transabdominal incision alone [1]. However, the metastasis rate of paraesophageal lymph nodes in cardia cancer is only about 10% [2], while the complication rate after combined thoracoabdominal surgery is high [3], which is often difficult to be tolerated by elderly and patients with cardiopulmonary insufficiency. If the pattern between the clinicopathological features of cardia cancer and the occurrence of paraesophageal lymph node metastasis can be revealed, it will help surgeons to choose the surgical incision for cardia cancer more reasonably and reduce unnecessary surgical trauma. In this study, we retrospectively analyzed the metastasis of lower thoracic paraesophageal lymph nodes in 448 patients with pancreatic cancer treated by transthoracic or combined thoracoabdominal incision, and investigated the relationship between them and the patients’ gender as well as the pathological type, diameter, depth of infiltration, Borrmann staging and length of esophageal invasion. 1. Clinical data (1) General data The clinical data of 448 patients with pancreatic cancer treated by transthoracic (362 cases) or combined thoracoabdominal incision (86 cases) in our hospital from 1993 to 2001 were collected. There were 352 male cases and 96 female cases, age ranged from 36 to 80 years, with a median age of 64 years. There were 190 cases of highly and moderately differentiated adenocarcinoma and 258 cases of poorly differentiated adenocarcinoma (including indolent cell carcinoma and adenosquamous carcinoma). The tumor diameter was <4 cm in 289 cases, and the diameter was ≥4 cm in 159 cases. The tumors did not infiltrate into the plasma layer of the stomach in 276 cases and infiltrated into the plasma layer in 172 cases. 242 cases of Borrmann's type I and II and 206 cases of type III and IV were classified. The invasion of esophagus was <2 cm in 329 cases and ≥2 cm in 119 cases. The pathological type of tumor was based on the preoperative gastroscopy results; the tumor diameter, infiltration depth and esophageal invasion length were based on the surgical records (i.e., the results of intraoperative exploration); Borrmann typing was combined with the preoperative gastroscopy results and intraoperative exploration. (2) Statistical methods: SPSS11.0 software was applied, and χ2 test was performed for statistical processing. 2. Results The overall metastasis rate of paraoesophageal lymph nodes in the lower thoracic segment of pancreatic cancer patients in this group was 10.94% (49/448). The gender of the patients and the biological behavior of the tumor were compared with the metastasis of the paraesophageal lymph nodes. (38/172) and 3.99% (11/276) without invasion to the plasma layer, (χ2=35.67, P<0.001). 0.001); (6) the metastasis rate of tumor invasion of esophagus length ≥2 cm was 29.41% (35/119), and the metastasis rate of <2 cm was 4.26% (14/329), (χ2=66.82, P<0.001). 3, Discussion Surgery is currently the main treatment method for cardia cancer. In the surgical treatment of this disease, the selection of the surgical approach is very important. Cardia cancer is different from both gastric cancer and esophageal cancer, and its lymph node metastasis has two ways: to the abdomen and to the chest, and the metastasis to the abdomen is the main one. Due to the special characteristics of its location, there is no uniform standard for the selection of surgical approach. The commonly used transabdominal, transthoracic and combined thoracoabdominal incisions all have their corresponding adaptations and limitations, and no single incision is suitable for all patients with cardia cancer. General surgeons are accustomed to the transabdominal surgical approach. With the wide application of gastrointestinal anastomosis in clinical practice and the improvement of surgical techniques in recent years, the length of transabdominal esophageal resection can reach about 5-6 cm, which can basically meet the requirements of radical pancreatic cancer surgery. However, the clearance of the lower thoracic paraesophageal lymph nodes has always been a problem that cannot be solved by the transthoracic approach. The transthoracic approach is conducive to clearing the lower thoracic paraesophageal lymph nodes and fully resecting the lower esophagus, but not conducive to total gastrectomy, intra-abdominal lymph node clearance and combined organ resection. The combined thoracoabdominal incision with adequate exposure can take into account the thoracoabdominal cavity and is currently recognized as the most favorable incision for radical surgery for cardia cancer. However, due to its large trauma, many postoperative complications and high morbidity and mortality rate, it is especially not suitable for the elderly and frail patients. The selection of a reasonable surgical approach should take into account not only the thoroughness of surgery but also the patient’s ability to tolerate it. As patients with cardia cancer have more or less difficulty in eating and malnutrition, their ability to tolerate surgery is reduced; meanwhile, patients are older, and the median age of this group is 64 years old, that is, half of them are older patients over 64 years old. Most of the patients in this part have diabetes or cardiopulmonary insufficiency, and tolerate surgical trauma less well. Lu Shijie [4] et al. found that cardiopulmonary complications were three times more frequent in patients over 60 years of age than in those under 60 years of age after cardia cancer surgery. Zhang Yajun [5] et al. found that postoperative cardiopulmonary complications in pancreatic cancer have become a major cause of surgical death. Therefore, it is extremely important to reduce the trauma of surgery, reduce surgical complications and morbidity and mortality rates, and improve patients’ postoperative quality of life while ensuring the efficacy of surgery as much as possible. The overall metastasis rate of lower thoracic paraesophageal lymph nodes in 448 patients with cardia cancer in our group was 10.94%, which was similar to the literature. In other words, nearly 90% of the patients did not have metastasis in the lower thoracic paraesophageal lymph nodes and therefore did not need to undergo the trauma caused by open chest. Therefore, how to determine whether there is metastasis in the lower thoracic paraesophageal lymph nodes by preoperative examination data and intraoperative exploration becomes the key to decide whether a combined thoracoabdominal incision is necessary. The metastasis rate of paraesophageal lymph nodes was less than 5.00% for those with tumor diameter <4 cm, tumor not invading the plasma layer, Borrmann type I and II, and tumor invading the esophagus <2 cm, which is a small probability event. Therefore, for this group of patients, especially the elderly and those with reduced tolerance to surgical trauma due to other reasons, choosing a transabdominal approach to reduce surgical trauma is a wise choice. In cases where it is not clear that the surgical outcome can be improved, blindly using a combined thoracoabdominal incision and emphasizing the thoroughness of lymph node dissection will not only be futile to a large extent, but will also bring unnecessary trauma to the patient and will only increase the complications and morbidity and mortality rate of the operation, which may not be worth the loss.