Patient characteristics
After the study was approved by the Ethics Committee of Çukurova University Faculty of Medicine (IRB no Date:03.12.2021 and No: 117/14), patients who had curative surgical resection and transcrural lymphadenectomy for proximal gastric tumor between January 2012 and January 2020 were included in the study. Transcrural lymphadenectomy was performed on all patients.
The patients were divided into Group 1 (Negative) and Group 2 (Positive) according to the positivity of mediastinal lymph nodes. These groups were compared for demographic data, body mass index, ASA score, comorbidities, neoadjuvant therapy status, preoperative laboratory parameters [(tumor markers (CEA, Ca19,9), C-Reactive protein (CRP), lymphocyte count, platelet count, albumin, and hemoglobin], length of surgery, type of surgery, intraoperative complications, pathological data (tumor grade, mucinous histology, signet-ring cell component, tumor size, tumor localization, number of total and metastatic lymph nodes dissected, the P, T, PN, and PTNM stages, and lymphovascular and perineural invasion), postoperative complications, postoperative respiratory complications, anastomotic leaks, length of postoperative hospital stay, postoperative reoperation and 90-day unplanned hospital admission, survival, and composite indices [the neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, CRP-to-albumin ratio, and HALP score). The ratio of the composite indices to predict positive lymph nodes were calculated separately.
Definitions
The study patients received proximal gastrectomy with distal esophagectomy and proximal gastrectomy or radical total gastrectomy plus D2 lymph node dissection according to the criteria defined in the Japanese Classification of Gastric Cancer by the Japanese Gastric Cancer Association.15 Stations No. 110, 111, 112, 19, and 20 (as defined in the Japanese Classification) were dissected by transcrural lymphadenectomy.The pathological stage of the disease was determined according to the 7th or 8th TNM Classification.13, 14 The tumor localization was identified using the Siewert classification.
Patients with non-adenocarcinoma tumor histology, and patients who had endoscopic submucosal dissection before surgery were excluded from the study. Patients with distant metastases, positive intraoperative cytology, or who had palliative surgery were also excluded.
The HALP score was calculated by the following formula: hemoglobin (g/L) × albumin (g/L) × lymphocytes (/L) / platelets (/L). Blood samples for laboratory examination were collected at the admission of the patient for the surgery.
Statistical Assessment
Statistical analysis of the data was performed using SPSS v23.0. Categorical measurements were summarized using number and percentage, and continuous measurements using mean, standard deviation, and minimum-maximum. The normality of the data was analyzed by the Shapiro-Wilk test. Categorical variables were compared using the Chi-square and Fisher’s tests. Independent Samples (Student's) t-test was used for the normally distributed groups and Mann-Whitney U test for non-normally distributed groups. The sensitivity and specificity of the NLR, PLR, CRP/Albumin, and HALP were calculated based on the lymph node positivity of the study patients and cut-off points were established by examining the area under the ROC curve. The Cox regression analysis was used for multivariate evaluations. The Kaplan-Meier analysis and Log-Rank tests were used for survival analysis. The statistical significance level was set at 0.05 for all tests.