Testing the Addition of Sunitinib Malate to Lutetium Lu 177 Dotatate (Lutathera) in Pancreatic Neuroendocrine Tumors

Inclusion Criteria: * Patients must have histologically or cytologically confirmed metastatic or unresectable well- or moderately-differentiated pancreatic neuroendocrine tumors (PNETs) of all grades (Grade 1, grade 2 and grade 3) * Patients with measurable disease per RECIST 1.1 appropriate for lutetium Lu 177 dotatate treatment, as determined by positive screening with SSR PET/CT and appropriate theranostics consultation (nuclear medicine or radiation oncology consultation) * Patients may be treatment naïve or have disease progression on or intolerance of up to one line of systemic therapy other than somatostatin analog therapy (somatostatin analog therapy is not considered a line of systemic therapy). Systemic therapy is considered therapy for unresectable or metastatic disease. Any prior adjuvant therapy with curative intent will not be considered a line unless relapse occurs within 6 months. Prior and/or concurrent use of somatostatin analogs are allowed * Patients who have have received a prior line of therapy must have documented disease progression per RECIST 1.1 within 12 months of initiation of the study protocol * Age \>= 18 years. Because no dosing or adverse event data are currently available on the use of sunitinib malate in combination with lutetium Lu 177 dotatate in patients \< 18 years of age, children are excluded from this study * Eastern Cooperative Oncology Group (ECOG) performance status =\< 2 (Karnofsky \>= 60%) * Absolute neutrophil count \>= 1,000/m…