Rechallenge with Additional Doses of ¹⁷⁷Lu-DOTATOC after Failure of Maintenance Therapy with Cold Somatostatin Analogs

Here, we report a case of a 52-year-old woman with a well-differentiated, metastasized neuroendocrine tumor (NET G1) of the duodenum. Initial imaging with 68Ga-DOTATOC revealed multiple sites of disease with intense uptake. Peptide receptor radionuclide therapy (PRRT) with 177Lu-DOTATOC induced partial remission. Treatment was then switched to cold somatostatin analog as a maintenance therapy. After 2 years of follow-up, progressive disease with multiple lesions in the skeleton was noted. Given the initial response to PRRT, a rechallenge with another 2 cycles of PRRT were given, and the patient had an excellent response to treatment, in particular in the skeleton.