Towards new response criteria in neuroendocrine tumors: which changes in MRI parameters are associated with longer progression-free survival after radioembolization of liver metastases?
OBJECTIVE
To evaluate the association of therapy-related changes in imaging parameters with progression-free survival (PFS) of patients with unresectable liver metastases from neuroendocrine tumors (NETLMs).


METHODS
Forty-five radioembolized patients (median age: 62 years; range: 43-75) received a pre- and 3 months posttherapeutic magnetic resonance imaging (MRI) examination. The latter were evaluated for tumor size, arterial enhancement, and necrosis pattern. Influences of therapy-related changes on PFS were analyzed. Statistical analysis included Student's t-test, Wilcoxon test, Cox regression analysis, and Kaplan-Meier curves.


RESULTS
The median percentage decrease in sum of diameters was 9.7% (range: 43.9% decrease to 15.4% increase). Twenty-one patients (47%) showed increased necrosis. Three parameters were associated with significantly longer PFS: a decrease of diameter (hazard ratio [HR]: 0.206; 95% confidence interval [CI]: 0.058-0.725; P = 0.0139), a decrease in tumor arterial enhancement (HR: 0.143; 95% CI: 0.029-0.696; P = 0.0160), and an increase in necrosis after 3 months (HR: 0.321; 95% CI: 0.104-0.990; P = 0.0480). Multivariate analysis revealed that changes in diameter and arterial enhancement have complementary information and are associated independently with long PFS.


CONCLUSIONS
A decrease both in sum of diameters and arterial enhancement of metastases, as well as an increase in necrosis, are associated with significantly longer PFS after radioembolization.
Department of Clinical Radiology, University Hospitals-Grosshadern, Ludwig-Maximilians University, Munich, Germany; Interdisciplinary Center of Neuroendocrine Tumours of the GastroEnteroPancreatic System (GEPNET-KUM), University Hospitals-Grosshadern, Ludwig-Maximilians University, Munich, Germany.
Felix
F
Ceelen
Daniel
D
Theisen
Xabier García
XG
de Albéniz
Christoph J
CJ
Auernhammer
Alexander R
AR
Haug
Melvin
M
D'Anastasi
Philipp M
PM
Paprottka
Carsten
C
Rist
Maximilian F
MF
Reiser
Wieland H
WH
Sommer
D000328:Adult; D000368:Aged; D003287:Contrast Media; D018572:Disease-Free Survival; D004621:Embolization, Therapeutic / Q000379:methods*; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008113:Liver Neoplasms / Q000556:secondary* / Q000628:therapy*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008863:Microspheres; D008875:Middle Aged; D060787:Neoplasm Grading; D018358:Neuroendocrine Tumors / Q000473:pathology*; D012189:Retrospective Studies; D016896:Treatment Outcome; D015021:Yttrium Radioisotopes / Q000627:therapeutic use
D003287:Contrast Media; D015021:Yttrium Radioisotopes; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA
liver metastases; neuroendocrine tumors; progression free survival; radioembolization