Osseous metastases of gastro-enteropancreatic neuroendocrine tumours. Diagnostic value of intra-therapeutic 177Lu-octreotate imaging in comparison with bone scintigraphy

Riferimento: 
Nuklearmedizin. 2012;51(3):95-100.
Autori: 
Sabet A, Ezziddin S, Heinemann F, Guhlke S, Muckle M, Willinek W, Biersack HJ, Ahmadzadehfar H.
Fonte: 
Nuklearmedizin. 2012;51(3):95-100.
Anno: 
2012
Azione: 
Il valore diagnostico delle immagini intra-terapeutiche con 177Lu-octreotide è superiore rispetto alla scintigrafia ossea per il rilevamento delle metastasi ossee nei tumori neuroendocrini gastro-entero-pancreatici (GEP NET).
Target: 
177Lu-octreotide/tumori neuroendocrini gastro-entero-pancreatici.

ABSTRACT
AIM:
Peptide receptor radionuclide therapy with 177Lu-octreotate is an effective treatment option for metastati gastroenteropancreatic neuroendocrine tumors (GEP NET) and allows intratherapeutic imaging through a 177Lu-octreotate scan (LuS). The diagnostic value of this treatment scan is not yet established. This study aims to compare the sensitivity of LuS and bone scintigraphy (BS) regarding bone metastases and investigate potential implications of functional imaging results.
PATIENTS, METHODS:
We retrospectively analyzed 29 consecutive GEP NET patients with bone metastases and baseline BS treated with 177Lu-octreotate. A semi-quantitative scoring system was used for the comparative evaluation. Treatment outcome (time-to-progression of bone metastases) was correlated with the intra-individual imaging discrepancy (Kaplan-Meyer curves, log-rank test, p < 0.05).
RESULTS:
In 19 of 29 patients (65.5%) LuS was superior (LuS > BS), whereas in 10 patients (34.5%) both modalities were comparable. BS showed no additional (LuS-negative) metastatic bone lesions in our cohort. None of the investigated baseline characteristics was associated with imaging
discrepancy. On the other hand, functional imaging discrepancy had no impact on treatment response (p = 0.43) or time-to-progression (p = 0.92).
CONCLUSIONS:
Intra-therapeutic 177Lu-octreotate imaging is superior over bone scintigraphy for detection of bone metastases in GEP NET. BS may help to distinguish osseous from non-osseous localization. The presence of an osteoblastic correlate in BS seems to have no impact on therapeutic outcome.