Efficacy of lutetium-peptide receptor radionuclide therapy in inducing prolonged tumour regression in small-bowel veuroendocrine tumours. A case of favourable response to retreatment after Initial objective response

Introduction: The efficacy of 177Lu-Dotatate was shown in the NETTER-1 trial, an international, open-label, multicentre phase III clinical trial that evaluated the safety and efficacy of 177Lu-Dotatate in patients with well-differentiated, advanced midgut neuroendocrine tumours (NETs) with evidence of disease progression. Recently, retreatment with peptide receptor radionuclide therapy (PRRT) has been proposed as a valid therapeutic option in patients without other effective options who had responded to initial PRRT; however, data on this therapeutic option are still inadequate. Case Report: In this report, we present the case of a patient who achieved a delayed complete radiological response after initial 177Lu-Dotatate treatment and who had a complete tumour response with PRRT retreatment 5 years later. Conclusions: This case report shows that, although rare, a complete, prolonged tumour response may occur in patients with advanced small-bowel NETs receiving PRRT. Retreatment with PRRT may be a valid option in cases of subsequent disease recurrence.