Endocrine Abstracts

Peptide receptor radionuclide therapy (PRRT) is a targeted therapy using synthetic somatostatin analogues attached to a radionuclide, which binds to tumours expressing somatostatin receptors. The aim was to review the role of PRRT in a tertiary referral centre. We retrospectively reviewed a cohort of 25 patients (eight males, 17 females), with a median age of 65, who received Yttrium-90 DOTATATE or Lutetium-177 DOTATATE at Addenbrookes Hospital. The location of the primary tumour varied; small bowel (52%); pancreatic (16%), appendix (8%); paraganglioma (4%); other (12%). All patients had metastases, the liver (96%) and peritoneum (56%) were the most common sites of metastatic spread. 32% had other tumour manifestations pre-PRRT, including: pleural effusion (16%); SMV obstruction (12%); ascites (12%); hydronephrosis (4%) and varices (4%). Side effects from PRRT occurred in 76% and GI side effects were the most common occurring in 80%. Thromobocytopenia was the most common haematological side effect occurring in 32%. 36% of patients stopped PRRT before the four full cycles, 24% due to disease progression and 12% due to intolerance of treatment. Gut hormone hypersecretion was noted in 56% (n=14). Relief of symptoms caused by gut peptide hypersecretion was achieved in 79% (n=11) post PRRT. Disease stabilisation was analysed post PRRT initiation. 19 (76%) had tumour stabilisation and 6 (24%) had tumour progression. In conclusion, PRRT is an effective treatment option for clinical symptom relief, biochemical and tumour burden stabilisation. However, progression of other tumoral manifestations can occur, particularly ascites as seen in 8% of patients in this study, hence PRRT is not appropriate for patients with pre-existing ascites or signs of abdominal venous occlusion. Finally, PRRT is often a later treatment option for neuroendocrine tumour (NET), but our review highlights PRRT as an effective and well tolerated adjunctive treatment and patients may benefit from starting PRRT earlier in the treatment regime.