This phase II trial compares the effect of retreatment with 177Lu-DOTATATE peptide receptor radionuclide therapy (PRRT) to the usual approach of treatment with everolimus in patients who have previously received 177Lu-DOTATATE for midgut neuroendocrine tumor (NET) that has spread from where it first started (primary site) to other places in the body (metastatic) and that cannot be removed by surge...