Heated Intraperitoneal Chemotherapy and Gastrectomy for Gastric Cancer With Positive Peritoneal Cytology

* INCLUSION CRITERIA:
* Patients must have histologically or cytologically confirmed gastric adenocarcinoma or gastroesophageal junction (Siewert I-III) adenocarcinoma confirmed by the Laboratory of Pathology, national Cancer Institute (NCI).
* Must have received systemic chemotherapy, minimum 3 months or maximum 6 months, prior to enrollment
* Systemic therapy should consist of at least fluoropyrimidine-based and/or platinum-based chemotherapy
* Trastuzumab may be added for human epidermal growth factor receptor 2 (HER2)-neu over-expressing cancers as clinically indicated
* Last dose of chemotherapy within 8 weeks of enrollment with recovery to Grade 1 from chemotherapy-related toxicities
* Documentation of chemotherapy administration must be obtained
* Subradiographic and/or cytopathologic evidence of peritoneal carcinomatosis found at staging laparoscopy.
* Documentation of cytopathologic diagnosis of malignant peritoneal cytology in the absence of disseminated peritoneal disease must be obtained. If cytologic analysis reveals atypical cells of undetermined significance, a repeat lavage with cytopathologic analysis will be performed and must demonstrate evidence of malignancy.
* Limited peritoneal involvement found at staging laparoscopy or on final pathology that is deemed completely resectable is permitted
* Age \>18 years.
* Eastern Cooperative Oncology Group (ECOG) performance status \<2
* Patients must have normal organ and marrow function as defined below:
* hemoglobin \> 8.0 g/dL
* absolute neutrophil count greater than or equal to 1,000/mcL
* platelets greater than or equal to100,000/mcL
* total bilirubin within normal institutional limits
* Aspartate aminotransferase (AST)Serum glutamic-oxaloacetic transaminase (SGOT)/Alanine aminotransferase (ALT)Serum glutamic-pyruvic transaminase (SGPT) less than or equal to 2.5 X institutional upper limit of normal
* creatinine \< 1.5 mg/dl
* estimated glomerular filtration rate (GFR) (creatinine clearance) greater than or equal to 60 mL/min/1.73 m\^2.
* Physiologically able to undergo heated intraperitoneal chemotherapy (HIPEC) and gastrectomy
* No history of malignancy within 2 years of enrollment except for basal cell carcinoma of the skin, squamous cell skin cancer or carcinoma in situ of the cervix.
* Ability of subject to understand and the willingness to sign a written informed consent document
* Previous exploratory laparotomy or laparoscopy with tissue biopsy or peritoneal lavage is permitted.
* Women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while she or her partner is participating in this study, she should inform her treating physician immediately
* Subjects must agree to co-enrollment on the tissue collection protocol 13C0176, Tumor, Normal Tissue and Specimens from Patients Undergoing Evaluation or Surgical Resection of Solid Tumors.

EXCLUSION CRITERIA:

* Patients who are receiving any investigational agents
* Disseminated extra-peritoneal or solid organ metastases
* Includes carcinomatosis associated with clinically or radiographically evident ascites (greater than 500cc)

  --Excludes greater omentum and ovarian metastases
* Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.
* Pregnant women are excluded from this study because HIPEC and gastrectomy have not been studied in pregnant women and has the potential for teratogenic or abortifacient effects. Because there is an unknown but potential risk for adverse events in nursing infant's secondary to treatment of the mother with HIPEC and gastrectomy, breastfeeding should be discontinued if the mother is treated on this study.
* Human immunodeficiency virus (HIV)-positive patients may be considered for this study only after consultation with a National Institute of Allergy and Infectious Diseases (NIAID) physician.