Background: Lutetium-177-DOTA-octreotate ( 177 Lu-DOTATATE) significantly increases survival and response rates in patients with grade I and grade II neuroendocrine tumors (NETs). However, survival and response rates are significantly lower in patients with bulky liver metastases. Increasing the tumor-absorbed dose in liver metastases may improve response to 177 Lu-DOTATATE. The LUTIA (Lutetium Intra-Arterial) study aims to increase the tumor-absorbed dose in liver metastases by intra-arterial (IA) administration of 177 Lu-DOTATATE, compared to conventional intravenous (IV) administration.Methods: A multicenter, within-patient randomized controlled trial (RCT) in 26 patients with progressive, liverdominant, unresectable grade I or grade II NET will be conducted. Patients with bilobar bulky disease will be randomly allocated to receive IA treatment into either the left or the right hepatic artery. Using this approach, one liver lobe will be treated intra-arterially (first-pass effect), while the contralateral lobe will receive an intravenous treatment as a second-pass effect. The primary endpoint of this study is the difference in tumor-to-non-tumor ratio of 177 Lu-DOTATATE uptake between the two liver lobes on post-treatment SPECT/CT (IA versus IV). Secondary endpoints include absorbed dose in both liver lobes, tumor response, dose-response relationship, toxicity, uptake in extrahepatic lesions, and renal uptake. Discussion: This multicenter, within-patient RCT will investigate whether IA administration of 177 Lu-DOTATATE results in a higher activity concentration in liver metastases compared to IV administration. Trial registration: ClinicalTrials.gov, NCT03590119. Registered on 17 July 2018.

Purpose Currently, peptide receptor radionuclide therapy (PRRT) with lutetium-177 (177Lu)-DOTATATE is used in patients with progressive neuroendocrine neoplasms (NEN) as salvage therapy. The standard treatment schedule consists of multiple cycles of intravenous (IV) administration. However, patients with liver metastases suffer from reduced tumor targeting and worse response and survival. This review provides an overview of the available evidence on the intra-arterial (IA) administration of radionuclide-labeled somatostatin analogues. Methods Databases of PubMed and Embase were searched systematically in May 2018 for studies that addressed IA PRRT. Included studies were original research publications focusing on absorbed tumor dose or tumor response after IA administration of PRRT for NEN. Publications on combined PRRT with other therapies or treatment of nonhepatic sites were excluded. Included publications were critically appraised on quality and their results reported accordingly. Results Seven publications were included in this review, including a total of 114 patients treated IA with different types of radiopeptides. Objective response was seen in 13 to 69% of the patients and disease stabilization in 18 to 52%. Disease progression occurred in 0 to 29% of the patients. IA administration resulted in a 1.06 to 9.2-fold increase in tumor-to-nontumor dose ratios in liver tumors, while normal liver and kidney doses remained within expected ranges. The incidence of adverse events was comparable to IV administration. Conclusion There is limited evidence that IA application of PRRT results in higher tumor-to-non-tumor dose ratios compared with IV infusion. IA administration of 177Lu-DOTATATE seems to be a promising new improvement in current clinical practice, achieving a higher absorbed tumor dose in patients with hepatic metastases of NEN.

Earlier studies have mostly identified pre-therapeutic clinical and laboratory parameters for the prediction of treatment response to [177Lu]Lu-PSMA-617 in metastatic castration resistant prostate cancer patients (mCRPC). The current study investigated whether imaging-derived factors on baseline [68Ga]Ga-PSMA-11 PET/CT can potentially predict the response after two cycles of [177Lu]Lu-PSMA-617 treatment, in a lesion- and patient-based analysis in men with mCRPC. Included patients had histologically proven mCRPC and a [68Ga]Ga-PSMA-11 PET/CT before and after two cycles of [177Lu]Lu-PSMA-617 treatment. The imaging-based response was evaluated on lesion-level (standardized uptake value (SUV) reduction) and patient-level (total lesion PSMA (TL-PSMA) reduction). In the lesion-level analysis, a clear relationship was found between SUVpeak/max and the imaging-based response to [68Ga]Ga-PSMA-11 PET/CT (most avid lesion SUVpeak/max ≥30% reduction) (p < 0.001), with no significant difference in cut-off values between different sites of metastases (i.e., lymph node, bone or visceral metastasis). In patient-level analysis, baseline PSA and SUVpeak values of most avid metastasis were significantly associated with imaging-based response (TL-PSMA ≥30% reduction) (p = 0.019 and p = 0.015). In pre-treatment with [68Ga]Ga-PSMA-11 PET/CT, a clear accumulation-response relationship in lesion-level was found for SUVpeak/max in men with mCRPC receiving two cycles of [177Lu]Lu-PSMA-617 treatment. The SUVpeak of the most avid lesion was the only image-derived factor predictive of the imaging-based response at the patient-level.

Purpose In patients with neuroendocrine tumor liver metastases, additional tumor reduction can be achieved by sequential treatment with [166Ho]-radioembolization after peptide receptor radionuclide therapy (PRRT). The aim of this study was to analyze hematotoxicity profiles, (i.e. lymphocyte and neutrophile toxicity) and the prognostic value of neutrophil-to-lymphocyte ratio (NLR) and thrombocyte-to-lymphocyte ratio (TLR). Methods All patients included in the prospective HEPAR PLuS study were included in this study. Blood testing was performed at baseline (before radioembolization) and at regular intervals during 1-year follow-up. Radiological response was assessed at 3, 6, 9, and 12 months according to RECIST 1.1. Logistic regression was used to analyze the prognostic value of NLR and TLR on response. Results Thirty-one patients were included in the toxicity analysis; thirty were included in the response analysis. Three weeks after radioembolization, a significant decrease in lymphocyte count (mean change − 0.26 × 109/L) was observed. Ten patients (32.2%) experienced grade 3–4 lymphocyte toxicity. This normalized at 6 weeks and 3 months after treatment, while after 6 months a significant increase in lymphocyte count was observed. An increase in NLR and TLR at 3 weeks, compared to baseline, significantly predicted response at 3 months (AUC = 0.841 and AUC = 0.839, respectively) and at 6 months (AUC = 0.779 and AUC = 0.765). No significant relation with survival was found. Conclusions Toxicity after sequential treatment with PRRT and [166Ho]-radioembolization is limited and temporary, while significant additional benefit can be expected. Change in NLR and TLR at 3-weeks follow-up may be valuable early predictors of response. Trial registration ClinicalTrials.gov, NCT02067988. Registered 20 February 2014, https://clinicaltrials.gov/ct2/show/record/NCT02067988.

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