Inflammation-Based Index and 68Ga-DOTATOC PET–Derived Uptake and Volumetric Parameters Predict Outcome in Neuroendocrine Tumor Patients Treated with 90Y-DOTATOC

Elin Pauwels, Sofie Van Binnebeek, Vincent Vandecaveye, Kristof Baete, Hubert Vanbilloen, Michel Koole, Felix M. Mottaghy, Karin Haustermans, Paul M. Clement, Kristiaan Nackaerts, Eric Van Cutsem, Chris Verslype, Christophe M. Deroose*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


We performed post hoc analyses on the utility of pretherapeutic and early interim Ga-68-DOTATOC PET tumor uptake and volumetric parameters and a recently proposed biomarker, the inflammation-based index (IBI), for peptide receptor radionuclide therapy (PRRT) in neuroendocrine tumor (NET) patients treated with Y-30-DOTATOC in the setting of a prospective phase II trial. Methods: Forty-three NET patients received up to 4 cycles of Y-90-DOTATOC at 1.85 GBq/m(2)/cycle with a maximal kidney biologic effective dose of 37 Gy. All patients underwent Ga-68-DOTATOC PET/CT at baseline and 7 wk after the first PRRT cycle. Ga-68-DOTATOC-avid tumor lesions were semiautomatically delineated using a customized SUV threshold- based approach. PRRT response was assessed on CT using RECIST 1.1. Results: Median progression-free survival and overall survival (OS) were 13.9 and 22.3 mo, respectively. An SUVmean higher than 13.7 (75th percentile) was associated with better survival (hazard ratio [HR], 0.45; P = 0.024), whereas a Ga-68-DOTATOC- avid tumor volume higher than 578 cm(3) (75th percentile) was associated with worse OS (HR, 2.18; P = 0.037). Elevated baseline IBI was associated with worse OS (HR, 3.90; P = 0.001). Multivariate analysis corroborated independent associations between OS and SUVmean = 0.016) and IBI (P = 0.015). No significant correlations with progression-free survival were found. A composite score based on SUVmean and IBI allowed us to further stratify patients into 3 categories with significantly different survival. On early interim PET, a decrease in SUV mean of more than 17% (75th percentile) was associated with worse survival (HR, 2.29; P = 0.024). Conclusion: Normal baseline IBI and high Ga-68-DOTATOC tumor uptake predict better outcome in NET patients treated with Y-30-DOTATOC. This method can be used for treatment personalization. Interim Ga-68-DOTATOC PET does not provide information for treatment personalization.

Original languageEnglish
Pages (from-to)1014-1020
Number of pages7
JournalJournal of Nuclear Medicine
Issue number7
Publication statusPublished - 1 Jul 2020


  • PRRT
  • Ga-68-DOTATOC
  • Y-90-DOTATOC
  • neuroendocrine tumors
  • PET
  • SUV

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