A Peptide Meets a Radionuclide to Combat a Rare Tumor.

Neuroendocrine carcinomas (NECs) are rare malignancies with limited treatment options beyond surgery. Peptide receptor radionuclide therapy (PRRT) is a process by which a somatostatin analog (octreotate) is combined with a chelator (DOTA) and a radionuclide (lutetium-177 [Lu-dotatate]). This therapy targets receptors on neuroendocrine cells, causing internalization of the radionuclide by the tumor cell, which results in cellular damage and apoptosis. We describe the clinical and therapeutic course of a 69-year-old male with a metastatic rectal NEC in whom progressive disease was noted after multiple therapies were attempted. After PRRT with Lu-dotatate, the patient was asymptomatic and demonstrated a near-complete radiologic response. This case illustrates that treatment with PRRT may improve the outcome of patients with metastatic rectal NEC. Our case highlights the importance of further research into the use of PRRT in patients with a Ki-67 <55% and uptake on somatostatin receptor imaging.