Perioperative systemic therapy as a part of comprehensive multimodal treatment in esophageal and gastric cancer - new treatment guidelines.

Esophageal and gastric cancer are diseases with a serious prognosis. While the incidence of gastric cancer is decreasing, the incidence of the gastroesophageal junction and esophageal cancer is increasing. Men are affected more often than women. Despite some progress in the last 10 years, cancer-specific mortality is very high, reaching 70%. The prognosis is mainly determined by the stage, histology, general condition and comorbidities. The treatment approach is curative for early and localized stages, requir-ing comprehensive care already during neoadjuvant therapy. Nutritional support is an essential part of preoperative preparation, and centres specializing in esophagogastric surgery are increasingly adopting the concept of prehabilitation. The main treatment modalities are endoscopy, surgery, systemic therapy and radiotherapy. In locally ad-vanced squamous cell carcinoma, neoadjuvant chemoradiotherapy followed by post-operative immunotherapy is the standard of care, if pathological complete remission has not been achieved. Definitive chemoradiotherapy is an alternative in patients with comorbidities. For adenocarcinoma, perioperative FLOT chemotherapy is the first choice and has shown better results than chemoradiotherapy. Chemoradiotherapy has its place in patients who would not tolerate FLOT or when trying to achieve a higher response rate. According to phase II studies, patients with MSI-high tumours could be treated with neoadjuvant immunotherapy, alone or in combination with chemotherapy; this approach has led to a pathological complete remission rate of approximately 60% and is a promising organ-preserving approach. For HER2-positive tumours, preoperative systemic therapy with trastuzumab may be considered as it demonstrates a significantly higher number of pathological complete remissions and offers the possibility of achiev-ing a higher R0 resection rate. In oligometastatic disease, surgical management of the primary tumour and metastases may be considered in individual cases in patients who respond to systemic therapy. However, an impact on overall survival has only been documented in patients with retroperitoneal involvement and no peritoneal metastases.