Ziel/Aim Patient selection in the NETTER-1 trial was based on the degree of somatostatin receptor (SSTR) expression in the highest uptake lesion as assessed by planar 111Indium-Pentetreotid. A recent head-to-head comparative study has shown that 111Indium-Pentetreotid considerably underestimates the expression levels in lesions 111Indium-Pentetreotid cannot be directly translated to SSTR-PET. We retrospectively investigate pre-PRRT SSTR-PET parameters for prognostication and therapy selection.
Methodik/Methods All patients who received at least two cycles of PRRT in the department of nuclear medicine Essen between 2008 and 2019 were included in this retrospective analysis. All tumor lesions were manually segmented and SUVmax and MTV noted. MTV was quantified using 50 % of the local SUVmax as threshold. Mean SUVmax was calculated on a per-patient basis by averaging the SUVmax of all segmented metastases. Additionally, primary NET location, tumor grade, Chromogranin levels, age, metastatic pattern, alkaline phosphatase, and lactate dehydrogenase levels were tested to establish a prediction nomogram. Natural logarithm of continuous parameters was used for cox regression.
Ergebnisse/Results 209 patients were eligible. The mean SUVmax of all lesions was a statistically significant positive prognosticator in multivariate cox regression (HR = 0.61, p = 0.0046). The baseline whole-body tumor volume was a statistically independent negative prognosticator of overall (HR= 1.53, p < 0.001) and progression-free survival in a multivariate cox regression (HR= 1.18, p = 0.02). Moreover, baseline whole-body tumor volume was significantly associated with response in a multivariate logistic regression (p = 0.019).
Schlussfolgerungen/Conclusions Baseline tumor volume and mean uptake were significant prognosticators of overall and progression-free survival. These findings might lead to the identification of patients that might profit from combinational therapy or alpha emitting PRRT strategies.
