Radiomolecular Therapy of Neuroendocrine Character, Positive for sst2 Receptor Hepatocellular Malignancies

In 1996, Krenning et al. injected the radiopeptide for the first time intravenously.111In-Octreotide as a new treatment approach, today, worldwide known as Peptide Receptor Radionuclide Therapy (PRRT) to confront unresectable neuroendocrine tumors. We started treating this rare category of neoplasms in our Institution in 1997, exclusively injecting intra-arterially, initially 111In Octreotide, in high doses, focused our interest on multiple liver metastases (particularly, less than 20 mm, in diameter) after catheterization of the hepatic artery [“Aretaieion Protocol”]. The radiopeptide was infused in repeated high activity, ranging per session from 4.070 GBq (110 mCi) to 5.920 GBq (160 mCi) with a time interval between sessions of 6-8 weeks, seeking to achieve a tumor absorbed dose according to the dosimetry followed, over 70 Gy (tumor mass 10 gr). When 90Y DOTA-TOC was used (3 folds in total, in bi-monthly intervals between sessions), the infused activity was 4.1± 0.2 GBq per patient, per session, whereas when n.c.a. 177Lu-TOTA-TOC was injected (6 folds in total, in bimonthly intervals between sessions), the activity was 7.0 ± 0.4 GBq per patient, per session. Follow-up at tri-monthly intervals was performed by means of ultrasonography (US) and every six months, by contrast, material-enhanced computed tomography (CT) and / or magnetic resonance tomography (MRI). This therapeutic procedure is described in detail, based on the experience in more than 800 hundred catheterizations, analyzing its advantages and limitations as a first-line treatment scheme for the management of this rare category of tumors.