Impact of postoperative TNM stages after neoadjuvant therapy on prognosis of adenocarcinoma of the gastro-oesophageal junction tumours

AIM: To compare prognostic relevance of postoperative tumour/node/metastasis (TMN) stages between patients with and without neoadjuvant treatment. METHODS: Data from patients with adenocarcinoma of the gastro-oesophageal junction (AEG) who had undergone surgical resection at a single German university centre were retrospectively analysed. Patients with or without neoadjuvant preoperative treatment were selected by exact matching based on preoperative staging. Standard assessment of preoperative (c)TNM stage was based on endoscopic ultrasound and computed tomography of the thorax and abdomen, according to the American Joint Committee on Cancer/Union for International Cancer Control classification system. Patients with cT1cN0cM0 and cT2cN0cM0 stages were excluded from the study, as these patients are generally not recommended for pretreatment. Long-term survival among the various postoperative TNM stages was compared between the groups of patients with or without neoadjuvant treatment. For statistical assessments, a P-value of ≤ 0.05 was considered significant. RESULTS: The study included a total of 174 patients. The group of patients who had received preoperative neoadjuvant treatment included more cases of AEG (Siewert) type 1 carcinoma (P < 0.001), and consequently oesophagectomy was performed more frequently among these patients (P < 0.001). The two groups (with or without preoperative neoadjuvant treatment) had comparable preoperative T stages, but the group of patients with preoperative neoadjuvant treatment presented a higher rate of preoperative N-positive disease (P = 0.020). Overall long-term survival was not different between the two groups of patients according to tumours of different AEG classifications, receipt of oesophagectomy or gastrectomy, nor between patients with similar postoperative TNM stage, resection margin and grading. However, an improvement of long-term survival was found for patients with nodal down-staging after neoadjuvant therapy (P = 0.053). CONCLUSION: The prognostic relevance of postoperative TNM stages is similar for AEG in patients with or without neoadjuvant preoperative treatment, but treatment-related nodal down-staging prognosticates longer-term survival.