Stomach cancer is the fifth most common digestive cancer and third main cause of death from cancer in the world. Modern management of Gastric cancer involves a multi-disciplinary approach involving surgical oncologists, medical oncologists, gastroenterologists and oncological radiologists. The most common clinical approach to Gastric adenocarcinoma is to begin with staging, which usually involves CT scan/ MRI combined with endoscopic US for more accurate T, N staging. Once the patient is deemed to have locally advanced gastric cancer (T3/T4,N0/+), a staging laparoscopy is recommended to rule out obvious or microscopic peritoneal metastatic disease. Additionally, neoadjuvant chemotherapy is initiated and followed by surgery +/- adjuvant radiation and chemotherapy.This protocol involves the addition of neoadjuvant HIPEC at the time of diagnostic laparoscopy as well as neoadjuvant radiation therapy for improved local and systemic control. The goal of this phase II clinical trial is to evaluate the efficacy of a multi-modality approach to treating patients with locally advanced Gastric cancer by incorporating diagnostic laparoscopy with HIPEC, neo-adjuvant chemo-radiotherapy, followed by surgical resection and adjuvant chemotherapy. The trial aims to assess this multi-modality approach in inducing pathological complete response; decreased rates of disease progression during neoadjuvant therapy; and increased overall, disease-free, and peritoneal disease-free survival.