Prognostic implication of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography in patients with recurrent papillary thyroid cancer.

BACKGROUND: Fluorine-18 fluorodeoxyglucose positron emission tomography/CT (18 F-FDG PET/CT) has been widely accepted as an effective method for detecting recurrent papillary thyroid cancer (PTC) in patients with increased serum thyroglobulin (Tg) or Tg antibody (TgAb) levels and negative whole-body scintigraphy (WBS) results. The role of WBS as a diagnostic tool in detecting recurrence has relatively decreased recently. However, only a few studies have examined the usefulness of 18 F-FDG PET/CT for evaluating patients with recurrent PTC, regardless of the WBS results. The purpose of this analysis was to evaluate the diagnostic value and prognostic role of 18 F-FDG PET/CT for patients with recurrent PTC, irrespective of their WBS results. METHODS: Sixty-six patients with locoregional recurrent PTC who underwent 18 F-FDG PET/CT and neck CT within 6 months before surgical treatment were included in this retrospective analysis. Imaging findings were compared with postoperative histopathologic results. The diagnostic values of 18 F-FDG PET/CT and neck CT were compared according to the serum Tg and TgAb levels and cervical levels. Each patient's status at the last follow-up was also reviewed, and survival probabilities were estimated using the Kaplan-Meier plot. RESULTS: The sensitivity, specificity, and diagnostic accuracy of 18 F-FDG PET/CT for the entire patient group were 38.5%, 90.2%, and 58.3%, respectively. The corresponding neck CT values were 55.0%, 85.7%, and 66.7%, respectively. According to the serum Tg and TgAb levels, except for the specificity, most diagnostic values of 18 F-FDG PET/CT were worse than those of the neck CTs, with or without statistical significance. For the high maximum standardized uptake value (SUVmax) group (SUVmax >10) and the low SUVmax group, the median locoregional disease-free survival times were 33.3 months and 81.8 months, respectively (P < .001). CONCLUSION: The diagnostic value of 18 F-FDG PET/CT for localizing recurrent lesions was worse than that of the neck CT, irrespective of the WBS results. However, patients with a higher SUVmax showed a significantly worse prognosis than did those with a lower SUVmax. Therefore, we suggest that, in patients with recurrent PTC, 18 F-FDG PET/CT should be considered for prognostication rather than diagnosis.

Differential Prognostic Value of Metabolic Heterogeneity of Primary Tumor and Metastatic Lymph Nodes in Patients with Pharyngeal Cancer.

BACKGROUND/AIM: We aimed to explore the prognostic value of metabolic heterogeneity of 18F-FDG uptake in chemoradiotherapy-treated pharyngeal cancer patients. PATIENTS AND METHODS: This study included 52 consecutive patients with pharyngeal cancer who underwent 18F-FDG PET/CT before definitive chemoradiotherapy. The heterogeneity factor (HF) was defined as the derivative (dV/dT) of a volume-threshold function for primary tumors and metastatic lymph nodes. The relationships between clinical parameters and HFs of primary tumors (pHF) and metastatic lymph nodes (nHF) were analyzed. RESULTS: The pHF (range=∓1.367 - -0.027; median=-0.152) was significantly correlated with the maximum standardized uptake value, metabolic tumor volume, and total lesion glycolysis. Induction chemotherapy response was not correlated with HF, whereas response to radiotherapy was significantly better in patients with high pHF (low heterogeneity). Consistently, the 2-year locoregional recurrence-free survival was significantly better in patients with high pHF (82.9% for pHF>-0.152 vs. 30.5% for pHF<-0.152, log-rank p=0.009). The nHF (range=-1.067 - -0.039; median=-0.160) was not correlated with response to radiotherapy and locoregional recurrences. CONCLUSION: pHF, but not nHF, was a significant predictor of response to radiotherapy and locoregional recurrence in pharyngeal cancer. Thus, HF use can prevent unnecessary treatment and surgical delays.

High total metabolic tumor volume in PET/CT predicts worse prognosis in diffuse large B cell lymphoma patients with bone marrow involvement in rituximab era.

Bone marrow involvement (BMI) in diffuse large B cell lymphoma (DLBCL) was naively regarded as an adverse clinical factor. However, it has been unknown which factor would separate clinical outcomes in DLBCL patients with BMI. Recently, metabolic tumor volume (MTV) on positron emission tomography/computed tomography (PET/CT) was suggested to predict prognosis in several lymphoma types. Therefore, we investigated whether MTV would separate the outcomes in DLBCL patients with BMI. MTV on PET/CT was defined as an initial tumor burden as target lesion ≥ standard uptake value, 2.5 in 107 patients with BMI. Intramedullary (IM) MTV was defined as extent of BMI and total MTV was as whole tumor burden. 260.5 cm(3) and 601.2 cm(3) were ideal cut-off values for dividing high and low MTV status in the IM and total lymphoma lesions in Receiver Operating Curve analysis. High risk NCCN-IPI (p<0.001, p<0.001), bulky disease (p=0.011, p=0.005), concordant subtype (p=0.025, p=0.029), high IM MTV status (p<0.001, p<0.001), high total MTV status (p<0.001, p<0.001), and ≥ 2CAs in BM (p=0.037, p=0.033) were significantly associated with progression-free survival (PFS) and overall survival (OS) than other groups. In multivariate analysis, high risk NCCN-IPI (PFS, p=0.006; OS, p=0.013), concordant subtype (PFS, p=0.005; OS, p=0.007), and high total MTV status (PFS, p<0.001; OS, p<0.001) had independent clinical impacts. MTV had prognostic significances for survivals in DLBCL with BMI.

The Prognostic Value of the Metabolic Tumor Volume in FIGO stage IA to IIB Cervical Cancer for Tumor Recurrence: Measured by F-18 FDG PET/CT.

PURPOSE: The purpose of this study was to evaluate the prognostic value of the metabolic tumor volume (MTV), in FIGO stage IA-IIB cervical cancer patients, measured by F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) imaging. METHODS: Forty-five patients with invasive cervical cancer who underwent FDG-PET imaging were recruited. Metabolically active tumor regions were delineated on the pretreatment FDG-PET scans by encompassing regions equal to or greater than an standardized uptake value (SUV) of 40% of the peak tumor intensity. The relationship of the metabolic tumor volume (MTV) to the disease-free survival was analyzed. The MTV of the cervical cancer was compared with pathological and clinical prognostic factors, including lymph node metastasis, parametrial invasion, the depth of invasion, resection margins, tumor differentiation and FIGO stages. RESULTS: Cox proportional hazard regression analysis showed that the MTV was a significant independent predictor of recurrence of cervical cancer (p = 0.027). Patients with an MTV of >20 cm(3) had a significantly reduced disease-free survival compared with patients with an MTV ≤ 20 cm(3) (p = 0.029). The correlation of the MTV with traditional prognostic factors showed significantly higher values in patients that were lymph node (LN) metastasis positive (p = 0.028) and parametrial invasion positive (p = 0.022). The MTV significantly differed among the groups according to tumor differentiation (p = 0.0319) and FIGO stage (p = 0.001). CONCLUSION: The MTV measured by FDG-PET was an independent prognostic factor for tumor recurrence in patients with stage IA-IIB cervical cancer. These findings must be confirmed by large population based prospective studies.