Pembrolizumab and Palliative Radiation Therapy in Treating Patients With Metastatic Esophagus, Stomach, or Gastroesophageal Junction Cancer

Exclusion Criteria

• •Anti-PD-1, anti-PD-L1, or anti-PD-L2 agents
• •Prior radiation therapy within the field of the target lesion that in the opinion of the treating radiation oncologist would preclude further palliative radiation to a dose of 30 gray (Gy)
• •Anti-cancer monoclonal antibody (mAb) within 4 weeks prior to study day 1 or who has not recovered (i.e., =\< grade 1 or at baseline) from adverse events due to agents administered more than 4 weeks earlier
• •Chemotherapy, targeted small molecule therapy, or radiation therapy within 2 weeks prior to study day 1 or who has not recovered (i.e., =\< grade 1 or at baseline) from adverse events due to a previously administered agent
• •* Note: Subjects with =\< grade 2 neuropathy are an exception to this criterion and may qualify for the study
• •* Note: If subject received major surgery, they must have recovered adequately from the toxicity and/or complications from the intervention prior to starting therapy
• •Live vaccine within 30 days of planned start of study therapy
• •* Note: Seasonal influenza vaccines for injection are generally inactivated flu vaccines and are allowed; however intranasal influenza vaccines (e.g., Flu-Mist) are live attenuated vaccines, and are not allowed
• •Immunosuppressive therapy within 7 days prior to the first dose of trial treatment
• •Investigational device within 4 weeks of the first dose of treatment
• •Currently receiving an investigational agent
• •About to undergo palliative radiation for a symptomatic central nervous system (CNS) metastasis
• •Systemic steroid therapy
• •Hypersensitivity to pembrolizumab or any of its excipients
• •Diagnosis of immunodeficiency
• •Active autoimmune disease that has required systemic treatment in the past 2 years (i.e., with use of disease modifying agents, corticosteroids or immunosuppressive drugs)
• •* Replacement therapy (e.g., thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency, etc.) is not considered a form of systemic treatment
• •Known history of, or any evidence of active, non-infectious pneumonitis
• •Current active infection requiring systemic therapy
• •Known history of active tuberculosis (TB), human immunodeficiency virus (HIV) 1/2, hepatitis B or hepatitis C
• •Known additional malignancy that is progressing or requires active treatment
• •* Exceptions include basal cell carcinoma of the skin or squamous cell carcinoma of the skin that has undergone potentially curative therapy or in situ cervical cancer
• •Known active central nervous system (CNS) metastases and/or carcinomatous meningitis
• •* Subjects with previously treated brain metastases may participate provided they are stable, have no evidence of new or enlarging brain metastases, and are not using steroids for at least 7 days prior to trial treatment; this exception does not include carcinomatous meningitis which is excluded regardless of clinical stability
• •History or current evidence of any condition, therapy, or laboratory abnormality that might confound the results of the trial, interfere with the subject's participation for the full duration of the trial, or is not in the best interest of the subject to participate, in the opinion of the treating investigator
• •Known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial
• •Pregnant or breastfeeding (female only)