Tailored timing of radioactive therapy may boost tumor control in NETs

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Age ≥18 years * Written informed consent * Eastern Cooperative Oncology Group (ECOG) 0-1 * Presence of histologically confirmed, advanced, well-differentiated, inoperable neuroendocrine tumors (NET) of any primary tumor origin and any grade, except for pheochromocytoma and paraganglioma. * Somatostatine receptor (SSTR)-expression in tumor lesions \> basal liver uptake on 68Ga-DOTA-PET * Radiologically progressive disease within the last 1-24 months according to common clinical criteria and confirmed by the institutional multidisciplinary conference for the treatment of NETs. The CT/MRI that shows tumor progression compared to screening/baseline must have been performed 1-24 months earlier. * All previous anti-tumor treatment except SSA must be terminated at least 4 weeks before start of treatment within the trial. * Measurable disease according to RECIST v 1.1 * Given the available, approved anti-tumor treatments and the specific characteristics of the patient and the tumor, the investigator judges peptide receptor radionuclide therapy (PRRT) to be the treatment of choice * GFR \> 50 ml/min/1.73 m2 as determined by iohexol- or 51Cr-EDTA clearance, calculated according to a combination of LMR18 and CAPA formulas, or equally accurate method * Hemoglobin \> 90 g/L, platelets \>100 x109/L, leukocytes \> 3.0x109/L, neutrophils \> 1.5 x109/L, aspartate transaminase (ASAT)/alanine aminotransferase (ALAT) \< 3 x ULN, bilirubin \< 2 x upper limit of normal (ULN), albumin \> 25 g/L * For women of child-bearing potential, highly effective contraception should be used from the time of inclusion up to at least six months after the end of treatment (EOT) visit. Exclusion Criteria: * Pregnancy or lactation * Previous treatment with PRRT * Concomitant systemic anti-tumor therapy other than somatostatin analogue (SSA) * Contraindications for treatment with capecitabine according to the approved label. * Discordance between CT/MRI/18F-FDG-PET and 68Ga-DOTA-PET, with evidence of tumor lesions without uptake on 68Ga-DOTATOC. * Any other serious, uncontrolled medical or psychiatric condition that, in the opinion of the investigator, precludes the patient from participation in the trial * Unwillingness, or inability, to participate in any part of the trial procedures or treatments.