Modified TGR: A new strong radiological marker to accurately predict early response to PRRT in GEP-NETs

#3531

Introduction: .

Aim(s): To evaluate the added value of modified TGR (tumor growth rate) as radiological predictor of early response to PRRT, in GEP-NET patients.

Materials and methods: Progressive metastatic G1-G2 GEP-NETs treated with PRRT (177Lu-Oxodotreotide, 4 administrations, 7.4GBq/each) at our centre from 04/2019 to 10/2020 were considered. Inclusion criteria were 3 CT per patient: 1 performed within 3 months before PRRT, 1 after 2 PRRT and 1 within 4 months after the end of PRRT to assess early response, according to RECIST1.1. TGR was calculated in 2 ways: assuming the volume the lesions can be calculated applying the volume of a sphere formula or the volume of an elliptical cylinder. In both cases, baseline versus interim evaluations were compared. Patients were subdivided as responders and non-responders (PD), lines of therapies were calculated as possible confounders. Logistic regression was performed to determine predictability of TGR models and clinical features for PD. ROC analysis was applied to assess model performance and evaluate optimal TGR cut-off.

Conference:

Presenting Author:

Authors: Scalorbi F, Calareso G, Garanzini E, Argiroffi G, Fuoco V,

Keywords: gep-net, prrt, tgr, progression, predictive model,