Prognostic Value of Volume-Based Metabolic Parameters Measured by 18F-FDG PET/CT of Pancreatic Neuroendocrine Tumors

Abstract

Purpose To date, the prognostic value of 18 F-FDG PET/CT for patients with pancreatic neuroendocrine tumors (PNETs) has not been well characterized. We investigated the prognostic value of volumetric parameters using 18 F-FDG PET/CT in this patient population. Methods We retrospectively reviewed 20 cases of pathologically proven PNET in patients who had undergone pretherapeutic 18 F-FDG PET/CT. PET parameters including maximum and average standardized uptake values (SUV max , SUV ave ), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of the primary tumor were measured using a threshold SUV to determine the boundaries of the tumors. Univariate and multivariate survival analyses were performed with adjustments for PET parameters and other clinical values.Results The median clinical follow-up was 22.3 (range, 1.2-95.4) months. Cancer-related death occurred in 5 of 20 patients (25 %). Patients had clinical or pathological stages of I in seven patients, II in six patients, III in three patient, and IV in four patients. According to the WHO histological classification of subtypes, 3 patients exhibited well-differentiated PNETs, 13 patients had well-differentiated endocrine carcinomas, and 4 had poorly differentiatedendocrine carcinomas. Univariate analysis showed that tumor size (p=0.028), AJCC stage (p=0.009), T stage (p=0.028), M stage (p=0.029), treatment modality (p=0.045), MTV (p=0.003) and TLG (p=0.027) were significant predictors of overall survival. On multivariate analysis, MTV (HR=10.859, p=0.031) was a significant independent predictor of overall survival along with the AJCC stage (HR=11.556, p=0.027).

18F-FDG Uptake in Well-Differentiated Neuroendocrine Tumors Correlates with Both Ki-67 and VHL Pathway Inactivation

“…Our relatively high number of 18 F-FDG-PET-positive tumors could be explained by the fact that we included a large proportion of patients with well-differentiated grade 2 (40%) and grade 3 (29%) tumors (Ki-67 index >10% accounted for 50% of our cases). We observed a significant correlation between SUV max , proliferation index, and tumor size, confirming the recently published data [11,19] and strengthening the use of these parameters in clinical practice to adapt the treatment and follow-up strategies.…”

“…HIF1 controls the expression of several endogenous hypoxia-and glycolysis-related transporters and enzymes, such as glucose transporter 1 (GLUT1), responsible for cellular glucose uptake, and carbonic anhydrase 9 (CA9), which regulates intracellular pH and prevents intracellular acidification. Both GLUT1 and CA9 are markers of aggressiveness in different tumor types, since they are upregulated in tumors with poor prognosis [8,11]. This is also true in NEN, where expression of CA9 has been demonstrated to be linked with poor prognosis, especially in poorly differentiated carcinomas [12].…”

Prognostic Value of 68Ga-DOTANOC PET/CT SUVmax in Patients with Neuroendocrine Tumors of the Pancreas

“…Several reports indicated that when positive, 18 F-FDG is associated with a worse prognosis, although to our knowledge most studies investigated the impact on PFS of 18 F-FDG positivity and not the role of SUV max specifically (27,28). Recently, in a population of 20 pNET patients undergoing pretreatment evaluation with 18 F-FDG PET/CT, Kim et al (29) reported the potential utility of the metabolic tumor volume of the primary tumor, along with American Joint Committee on Cancer stage, as an independent prognostic factor for overall survival.…”

Metabolic tumor burden is associated with major oncogenomic alterations and serum tumor markers in patients with resected pancreatic cancer

“…The prognositic value of positron emission tomography-computed tomography (PET/CT) has been demonstrated in various types of solid tumors [3][4][5][6]. Recent reports have demonstrated the feasibility of measuring metabolic tumor burden using 18 F-fludrodeoxyglucose ( 18 F-FDG) PET/CT in patients with prostate [7], esophageal [8] and non-small-cell lung cancers and multiple sites of disease [9].…”