GEP-NET and early progression after RLT – Application of a modified TGR to increase the accuracy of prediction

#3671

Introduction: Tumor Growth Rate (TGR) allows for early SSA and RLT response assessment in NET.

Aim(s): To evaluate the added value of modified TGR to correctly identify the early progression after RLT, in case of no spherical lesions.

Materials and methods: Progressive metastatic G1-G2 GEP-NETs treated with RLT (177Lu-DOTATATE, 7.4 GBq X 4) at our centre from 2019 to 2021 were considered. Inclusion criteria were 3 CT per patient: One within 3 months before RLT, one after 2 RLT and one within 4 months after RLT, to assess the early progression (according to RECIST 1.1). TGR, obtained comparing baseline and interim CT, was calculated in 2ways: By approximating lesion volume to (i) a sphere (the classical-TGR) or (ii) an elliptical cylinder (modified TGR). Multivariate analysis was performed to determine predictability of the 2 TGR models and clinical features in the evaluation of PD. ROC curves were calculated for the 2 models. A sub-analysis was run only considering non-spherical lesions, to compare the two models in this particular setting. Stata software was applied for statistical analysis. P value <0.05 was considered statistically significant.

Conference:

Presenting Author: Scalorbi F

Authors: Scalorbi F, Calareso G, Garanzini E, Prinzi N, Pusceddu S,

Keywords: TGR, RLT, NET,