Yttrium-labelled peptides for therapy of NET

Abstract

Peptide receptor radionuclide therapy (PRRT) consists in the systemic administration of a synthetic peptide, labelled with a suitable beta-emitting radionuclide, able to irradiate tumours and their metastases via the internalization through a specific receptor, overexpressed on the cell membrane. After 15 years of experience, we can state that PRRT with (90)Y-labelled peptides is generally well tolerated. Acute side effects are usually mild, some of which are related to the co-administration of amino acids, such as nausea. Others are related to the radiopeptide, such as fatigue or the exacerbation of an endocrine syndrome, which rarely occurs in functioning tumours. Chronic and permanent effects on target organs, particularly the kidneys and the bone marrow, are generally mild if the necessary precautions are taken. Currently, the potential risk to kidney and red marrow limits the amount of radioactivity that may be administered. However, when tumour masses are irradiated with adequate doses, volume reduction may be observed. (90)Y-octreotide has been the most widely used radiopeptide in the first 8-10 years of experience. Unfortunately, all of the published results derive from different and inhomogeneous phase I/II studies. Hence, a direct comparison is virtually impossible to date. Nevertheless, even with these limitations, objective responses are registered in 10-34% of patients. The optimal timing of (90)Y-DOTATOC in the management of somatostatin receptor (SSTR)-positive tumours and the way in which it should be integrated with other treatments have yet to be defined, and prospective phase II/III trials comparing the efficacy and toxicity of different schemes of (90)Y-DOTATOC administration are still warranted.

Radiation Dosimetry for177Lu-PSMA I&T in Metastatic Castration-Resistant Prostate Cancer: Absorbed Dose in Normal Organs and Tumor Lesions

“…In several radio-receptor therapies, the kidney is regarded as the dose-limiting organ (21). Our results for kidneys (mean, 0.72 Gy/GBq) are well comparable to a recent publication using the same radiopharmaceutical (kidney: median, 0.8 Gy/GBq) (7).…”

90Y Radioembolization After Radiation Exposure from Peptide Receptor Radionuclide Therapy

“…Hepatic radiation exposure in PRRT has generally not been seen as a concern for liver function (1,31,32). Reported absorbed doses of healthy liver tissue were mainly in the range of 0.1-0.3 Gy/GBq for 177 Lu-based PRRT (33-35) and 0.5-1.0 Gy/GBq for 90 Y-based PRRT (36)(37)(38).…”

Assessment of predictors of response and long-term survival of patients with neuroendocrine tumour treated with peptide receptor chemoradionuclide therapy (PRCRT)

“…90 Y emits the most energetic beta particles and is associated with favourable responses but moderate toxicity, particularly including renal impairment [3, 4]. 111 In emits the least energetic particles but, although associated with minimal significant side effects, is associated with low response rates [5, 6].…”