Table 1 Detailed inclusion and exclusion criteria

Patients must have given written informed consent

Any previous radioembolization, chemoembolization, bland embolization, or external beam radiation therapy to the liver, at any time, or surgery or radiofrequency ablation (or other ablative therapies) within 12 weeks prior to randomization in the study

Male or female aged 18 years or older

Interferons, everolimus (mTOR-inhibitors), or other systemic therapies within 4 weeks prior to randomization in the study

Inoperable histologically proven neuroendocrine tumor with an indication for ¹⁷⁷Lu-DOTATATE

Use of octreotide or octreotide LAR, if it cannot be interrupted for 24 h or 4 weeks before therapy, respectively, unless tumor uptake on somatostatin receptor imaging is higher than normal liver uptake

Ki-67 index ≤ 20% and a mitotic count of ≤ 20

Unresolved toxicity from previous anti-cancer therapy greater than grade 2

Confirmed presence of somatostatin receptors on target lesions

Serum bilirubin > upper limit of normal (ULN), serum albumin < 3.0 g/dL

Life expectancy of 6 months or longer

Glomerular filtration rate < 50 ml/min

Eastern Cooperative Oncology Group (ECOG) performance score 0–1

Hb < 5.5 mmol/L; leucocytes < 3.0 × 10⁹/L; platelets < 100 × 10⁹/L (at baseline; 75 × 10⁹/L is sufficient for cycles 2–4)

At least one lesion ≥ 3 cm on cross-sectional imaging in both the right and left liver lobes

Uncontrolled congestive heart failure or diabetes mellitus

Presence of excessive liver metastases, defined as > 25% tumor burden

Patients suffering from diseases with an increased chance of liver toxicity

Patients must have clinical or radiological progressive disease

Patients declared incompetent or suffering from psychic disorders making comprehensive judgement impossible

Negative pregnancy test for women of childbearing potential

Previous enrollment in the present study or previous treatment with ¹⁷⁷Lu-DOTATATE

Female patients who are not using an acceptable method of contraception, OR are less than 1 year postmenopausal or surgically sterile

Male patients who are not surgically sterile or do not use an acceptable method of contraception

Body weight more than 150 kg

Current spontaneous urinary incontinence

Severe allergy for intravenous contrast