Tandem peptide receptor radionuclide therapy using 90Y/177Lu-DOTATATE for neuroendocrine tumors efficacy and side-effects - polish multicenter experience.

INTRODUCTION: One of the concepts of theranostics in nuclear medicine is peptide receptor radionuclide therapy (PRRT), whereby labeled somatostatin analogs are used for imaging and treating inoperable or disseminated neuroendocrine tumors (NET). AIM: The aim of the study was to determine the therapeutic efficacy and toxicity of tandem 90Y /177Lu-DOTATATE in patients with disseminated NET in a multicenter trial. MATERIALS AND METHODS: 103 patients with NET G1/G2 treated with 90Y/177Lu-DOTATATE (1:1) with amino-acid infusion for nephroprotection were included in the study. RESULTS: Overall survival from the disease diagnosis (OS-D) was 127.4 months and from the time of PRRT (OS-T) was 89.5 months. Progression-free survival (PFS) was 29.9 months. An analysis based on the proliferation index revealed a statistically significant impact on PFS and OS-T (PFS G1 vs G2, 59.3 vs 24.3 months; OS-T G1 vs G2, not reached vs 79.9 months). The effect of the primary disease site was also analyzed. For pancreatic vs small bowel vs large bowel, the PFS was 30.8 vs 30.3 vs 40.6 months, the OS-T was 94 vs 61.9 vs 131.2 months and OS-D was 130.4 vs 89.2 vs not reached months, respectively. The 2-year risk of progression was 42%. The probability of 2-year and 5-year overall survival was 89% and 62%, respectively. PRRT was well tolerated by all patients. One patient (1%) developed myelodysplastic syndrome. No other grade 3 and 4 hematological or renal toxicity was observed. CONCLUSIONS: This multicenter trial showed that tandem 90Y/177Lu-DOTATATE is highly effective and safe therapy for patients with disseminated NET.