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.

Inclusion Criteria:

• Clinical diagnosis of gastric cancer post endoscopic ultrasound (EUS), staging must be T3/T4
• N0/+, M0. EUS must have been done within 8 weeks of the protocol start.
• Patient must plan to undergo surgical treatment.
• ECOG Scale of Performance Status of 0-2
• Adequate organ and marrow function (leukocytes ≥ 3000/mcl, absolute neutrophil count ≥ 1500, platelets ≥ 100,000/mcl, total bilirubin ≥ 1.5mg/dl (Gilbert's syndrome, then <3.0), AST(SGOT)/ALT(SPGT) ≤ 2.5 X institutional upper limit of normal, creatinine within normal institutional limits)
• Women of child-bearing potential and men must agree to use adequate contraception prior to study entry, for the duration of study participation, and for 90 days following completion of therapy. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately.
• Ability to understand and the willingness to sign a written informed consent.

Exclusion Criteria:

• Subjects who have any previous treatment for their cancer.
• Patients with known metastatic disease; this includes patients with clinically apparent or suspected metastasis to sites other than lymph nodes or peritoneal surfaces.
• Subjects with early stage gastric cancer (Stage T1/T2 N0)
• History of allergic reactions attributed to compounds of similar chemical or biological composition to any of the agents being used in this study, including but not limited to: Carboplatin, Taxol, 5-FU, Leucovorin, Mitomycin C.
• Subjects who have received prior radiation to any portion of the abdominal cavity or pelvis are excluded.
• Subjects who have had prior malignancies, except for cured non-melanoma skin cancer, or curatively treated in situ carcinoma of the cervix, or adequately treated malignancies for which there has been no evidence of activity for more than three years.
• Patients must not be pregnant or nursing due to the potential for congenital abnormalities and the potential of this regimen to harm nursing infants.
• Subjects with a condition that may interfere with the subjects' ability to understand the requirements of the study.
• Known HIV, Hepatitis B, or Hepatitis C positive patients.
• Patients with active coronary artery disease (defined as unstable angina or a positive cardiac stress test) will be excluded. Subjects with a history of coronary artery disease may be included if they have had a normal stress test within 30 days of enrollment.
• Patients with restrictive or obstructive pulmonary disease that would limit study compliance or place the patient at unacceptable risk for participation in the study will be excluded.
• Patients with a history of cerebrovascular disease that would limit study compliance or place the patient at unacceptable risk for participation in the study will be excluded.
• Subjects with other concurrent severe medical problems unrelated to the malignancy that would significantly limit full compliance with the study, or places them at an unacceptable risk for participation in the study, will also be excluded.
• Evidence of extensive intraperitoneal adhesions at the time of surgery which prohibits intraperitoneal therapy, as determined by the operating surgeon.
• Patients with any condition that would precluded the ability to deliver appropriate IP therapy.
• Patients with a life expectancy of less than 12 weeks will be excluded from this study.