This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

The primary objective of the present systematic review is to assess if perioperative chemotherapy for patients with locoregionally advanced resectable adenocarcinoma of the stomach, gastroesophageal junction and lower esophagus leads to a longer overall survival as compared to surgery without prior tumor‐specific therapy. Secondary objectives are to compare disease‐free survival, resectability, tumor stage upon resection, perioperative morbidity and mortality between patients with and without perioperative chemotherapy and to assess its safety and toxicity as well as reasons for possible non‐administration of the postoperatively planned cycles of chemotherapy where foreseen in the study protocol.