Lessons on Tumour Response: Imaging during Therapy with 177Lu-DOTA-octreotate. A Case Report on a Patient with a Large Volume of Poorly Differentiated Neuroendocrine Carcinoma

Favourable outcomes of peptide receptor radiotherapy (PRRT) of neuroendocrine tumours have been reported during the last years. Still, there are uncertainties on the radionuclides to be used, the treatment planning, and the indication in patients with a high proliferation rate

Whole-body MRI including diffusion-weighted MRI compared with 5-HTP PET/CT in the detection of neuroendocrine tumors

Aim: We wanted to explore if whole-body magnetic resonance imaging (MRI) including diffusion-weighted (DW) and liver-specific contrast agent-enhanced imaging could be valuable in lesion detection of neuroendocrine tumors (NET). [11C]-5-Hydroxytryptophan positron emission tomography/computed tomography (5-HTP PET/CT) was used for comparison. Materials and methods: Twenty-one patients with NET were investigated with whole-body MRI, including DW imaging (DWI) and contrast-enhanced imaging of the liver, and whole-body 5-HTP PET/CT. Seven additional patients underwent upper abdomen MRI including DWI, liver-specific contrast agent-enhanced imaging, and 5-HTP PET/CT. Results: There was a patient-based concordance of 61% and a lesion-based concordance of 53% between the modalities. MRI showed good concordance with PET in detecting bone metastases but was less sensitive in detecting metastases in mediastinal lymph nodes. MRI detected more liver metastases than 5-HTP PET/CT. Conclusion: Whole-body MRI with DWI did not detect all NET lesions found with whole-body 5-HTP PET/CT. Our findings indicate that MRI of the liver including liver-specific contrast agent-enhanced imaging and DWI could be a useful complement to whole-body 5-HTP PET/CT

177Lu-DOTATATE Therapy of Advanced Pancreatic Neuroendocrine Tumors Heavily Pretreated With Chemotherapy : Analysis of Outcome, Safety and Their Determinants

Objective: To retrospectively analyze toxicity, progression-free survival (PFS), overall survival (OS) and their determinants in patients with advanced pancreatic neuroendocrine tumors (panNETs), previously pretreated with chemotherapy, undergoing peptide receptor radionuclide therapy (PRRT) with 177Lu-DOTATATE. Methods: In total, 102 patients with advanced panNETs, previously pretreated with one (67%) or several (33%) lines of chemotherapy were included, of whom 90 % had progressive disease and the majority (74.5%) with grade 2 tumors. 177Lu-DOTATATE, 7.4 GBq per cycle, was administered with 6 to 8 weeks interval, in 88 % of patients utilizing a dosimetry-guided protocol, until an absorbed dose of 23 Gy to the kidneys was reached. Results: Mean 32±10.9 GBq per patient was administered in 1-10 cycles starting median 36 months after panNET diagnosis. Median follow-up was 34 months. Median PFS was 24 months and median OS was 42 months from start of PRRT. Independent risk factors for both progression and death were liver tumor burden >50%, more than one line of previous chemotherapy and elevated alkaline phosphatase (ALP). Resection of the primary tumor was linked to longer survival. Bone marrow toxicity grade 3-4 occurred in 10.8%. One patient (1.0 %) developed acute myeloid leukemia. Bone marrow toxicity was unrelated to type and length of previous chemotherapy, amount of administered activity and absorbed dose to the bone marrow. Conclusion: 177Lu-DOTATATE therapy was feasible, highly effective and safe in patients with advanced panNETs heavily pretreated with chemotherapy. More than one line of chemotherapy was a therapy related independent risk factor for shorter PFS and OS

Prospective observational study of 177Lu-DOTA-octreotate therapy in 200 patients with advanced metastasized neuroendocrine tumours (NETs) : feasibility and impact of a dosimetry-guided study protocol on outcome and toxicity

PURPOSE: Peptide receptor radionuclide therapy in patients with neuroendocrine tumours has yielded promising results. This prospective study investigated the feasibility of dosimetry of the kidneys and bone marrow during therapy and its impact on efficacy and outcome. METHODS: Lu-DOTA-octreotate with co-infusion of a mixed amino acid solution, and cycles were repeated until the absorbed dose to the kidneys reached 23 Gy or there were other reasons for stopping therapy. The Ki-67 index was ≤2% in 47 patients (23.5%), 3-20% in 121 (60.5%) and >20% in 16 (8%). RESULTS: In 123 patients (61.5%) the absorbed dose to the kidneys reached 23 Gy with three to nine cycles during first-line therapy; in no patient was a dose to the bone marrow of 2 Gy reached. The best responses (according to RECIST 1.1) were a complete response (CR) in 1 patient (0.5%), a partial response (PR) in 47 (23.5%), stable disease (SD) in 135 (67.5%) and progressive disease (PD) in 7 (3.5%). Median progression-free survival was 27 months (95% CI 22-30 months) in all patients, 33 months in those in whom the absorbed dose to the kidneys reached 23 Gy and 15 months in those in whom it did not. Median overall survival (OS) was 43 months (95% CI 39-53 months) in all patients, 54 months in those in whom the absorbed dose to the kidneys reached 23 Gy and 25 months in those in whom it did not. Median OS was 60 months in patients with a best response of PR or CR, 42 months in those with SD and 16 months in those with PD. Three patients (1.5%) developed acute leukaemia, 1 patient (0.5%) chronic leukaemia (unconfirmed) and 30 patients (15%) grade 3 or 4 bone marrow toxicity. Eight patients (4%) developed grade 2 kidney toxicity and one patient (0.5%) grade 4 kidney toxicity. CONCLUSIONS: Lu-DOTA-octreotate is feasible. Patients in whom the absorbed dose to the kidneys reached 23 Gy had a longer OS than those in whom it did not. Patients with CR/PR had a longer OS than those with SD. Bone marrow dosimetry did not predict toxicity