BACKGROUND: The objective of the current study was to determine the accuracy of magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT) for detecting lymph node metastases in patients with uterine cervical carcinoma compared with thin‐section histopathologic results from systemic lymphadenectomy.METHODS: Twenty‐two patients with International Federation of Obstetrics and Gynecology (FIGO) Stage IB–IVA cervical carcinoma who underwent both MRI and PET/CT before lymphadenectomy were included in this study. Lymphadenectomy involved removing all visible lymph nodes in the surgical fields. To enable region‐specific comparisons, paraaortic and pelvic lymph nodes were divided into seven regions: the paraaortic area, both common iliac areas, both external iliac areas, and both internal iliac/obturator areas. Histopathologic evaluation of lymph nodes was the diagnostic standard. Chi‐square analysis was used to compare the accuracy of MRI and PET/CT for the detection of metastatic lymph nodes. A P value ≤ 0.05 was considered statistically significant.RESULTS: With MRI, the sensitivity, specificity, and accuracy rates for detecting metastatic lymph nodes in each lymph node group were 30.3% (10 of 33 lymph node groups), 92.6% (112 of 121 lymph node groups), and 72.7% (122 of 154 lymph node groups), respectively; with PET/CT, those rates were 57.6% (19 of 33 lymph node groups), 92.6% (112 of 121 lymph node groups), and 85.1% (131 of 154 lymph node groups), respectively. Statistical analysis showed that PET/CT was more sensitive than MRI (P = 0.026) but that there were no statistical differences noted with regard to specificity (P = 1.000) or accuracy (P = 0.180). Power analysis demonstrated that a sample size of 685 lymph node groups (98 patients) would be necessary to demonstrate that PET/CT was more accurate than MRI (α = 0.05; β = 0.80).CONCLUSIONS: PET/CT was more sensitive than MRI for detecting lymph node metastases in patients with uterine cervical carcinoma. Cancer 2006. © 2006 American Cancer Society.

We conducted a comprehensive systematic review of the literature on volumetric parameters and a meta-analysis of the prognostic value of metabolic tumor volume (MTV) and total lesion glycolysis (TLG) in patients with head and neck cancer (HNC). Methods: A systematic search of MEDLINE and EMBASE was performed using the key words PET, head and neck, and volume. Inclusion criteria were ¹⁸F-FDG PET used as an initial imaging tool; studies limited to HNC; patients who had not undergone surgery, chemotherapy, or radiotherapy before PET scans; and studies reporting survival data. Event-free survival and overall survival were considered markers of outcome. The impact of MTV or TLG on survival was measured by the effect size hazard ratio (HR). Data from each study were analyzed using Review Manager. Results: Thirteen studies comprising 1,180 patients were included in this study. The combined HR for adverse events was 3.06 (2.33–4.01, P < 0.00001) with MTV and 3.10 (2.27–4.24, P < 0.00001) with TLG, meaning that tumors with high volumetric parameters were associated with progression or recurrence. Regarding overall survival, the pooled HR was 3.51 (2.62–4.72, P < 0.00001) with MTV and 3.14 (2.24–4.40, P < 0.00001) with TLG. There was no evidence of significant statistical heterogeneity at an I² of 0%. Conclusion: MTV and TLG are prognostic predictors of outcome in patients with HNC. Despite clinically heterogeneous HNC and the various methods adopted between studies, we can confirm that patients with a high MTV or TLG have a higher risk of adverse events or death.

Because ¹⁸F-FDG PET has insufficient sensitivity for the detection of hepatocellular carcinoma (HCC), ¹¹C-acetate PET has been proposed as another technique for this use. We prospectively evaluated the value of PET/CT using these 2 tracers for the detection of primary and metastatic HCC. Methods: One hundred twelve patients (99 with HCC, 13 with cholangiocellular carcinoma) underwent biopsy and ¹⁸F-FDG and ¹¹C-acetate PET/CT. Results: The overall sensitivities of ¹⁸F-FDG, ¹¹C-acetate, and dual-tracer PET/CT in the detection of 110 lesions in 90 patients with primary HCC were 60.9%, 75.4%, and 82.7%, respectively. Elevated serum α-fetoprotein levels, an advanced tumor stage, portal vein tumor thrombosis, large tumors, and multiple tumors were significantly associated with positive ¹⁸F-FDG PET/CT results. Uptake of ¹¹C-acetate was associated with large and multiple tumors. For ¹⁸F-FDG, the sensitivities according to tumor size (1–2, 2–5, and ≥5 cm) were 27.2%, 47.8%, and 92.8%, respectively; for ¹¹C-acetate, these respective values were 31.8%, 78.2%, and 95.2%. ¹⁸F-FDG was more sensitive in the detection of poorly differentiated HCC. Overall survival was lower in patients with ¹⁸F-FDG PET/CT positive for all indexed lesions than in those with FDG negative or partially positive through the entire follow-up period. In analysis based on biopsied lesions, the sensitivity of ¹⁸F-FDG PET/CT was 64.4% for primary HCC and 84.4% for ¹¹C-acetate PET/CT. The overall sensitivities of ¹⁸F-FDG, ¹¹C-acetate, and dual-tracer PET/CT for 35 metastatic HCCs were 85.7%, 77.0%, and 85.7%, respectively. There was no significant difference in the sensitivity of tracers according to metastatic tumor size, location, or differentiation. Conclusion: The addition of ¹¹C-acetate to ¹⁸F-FDG PET/CT increases the overall sensitivity for the detection of primary HCC but not for the detection of extrahepatic metastases. ¹⁸F-FDG, ¹¹C-acetate, and dual-tracer PET/CT have a low sensitivity for the detection of small primary HCC, but ¹⁸F-FDG PET/CT has a relatively high sensitivity for the detection of extrahepatic metastases of HCC.

We performed a retrospective review of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) examination to determine the prevalence of thyroid FDG-PET incidentaloma in a patient group evaluated for metastasis of cancer and in a group of healthy subjects who underwent voluntary cancer screening. We also evaluated the risk of malignancy in focal thyroid FDG-PET incidentaloma and its association with standard uptake values (SUVs) (maximum and greater than 0.75 threshold). A total of 1330 subjects underwent FDG-PET for metastasis evaluation (n = 999) and cancer screening (n = 331). Twenty-nine of 1330 subjects (2.2%) showed focal (n = 21) or diffuse (n = 8) thyroid FDG-PET incidentaloma. There was no significant difference in the prevalence of thyroid FDG-PET incidentaloma between the two groups (19 of 999 vs. 10 of 331; P > 0.05). Four of 15 focal incidentalomas (26.7%) whose histological diagnoses were available showed papillary thyroid cancer. The maximum SUV (16.5 +/- 4.70) and greater than 0.75 threshold SUV (14.2 +/- 5.3) of malignant lesions were significantly higher than those of benign tumors (6.5 +/- 3.8 and 4.9 +/- 3.0; P < 0.05). In conclusion, thyroid FDG-PET incidentaloma has prevalence of 2.2%, and its prevalence was not different according to the purpose of the FDG-PET. The focal thyroid FDG-PET incidentaloma carries a high risk of malignancy, especially in cases with high SUVs. Therefore, focal thyroid FDG-PET incidentaloma with high SUVs warrants a pathological diagnostic procedure if it changes a patient's treatment plan or prognosis.

Prostate-specific membrane antigen (PSMA) is overexpressed in most prostate adenocarcinoma (AdPC) cells and acts as a target for molecular imaging. However, some case reports indicate that PSMA-targeted imaging could be ineffectual for delineation of neuroendocrine (NE) prostate cancer (NEPC) lesions due to the suppression of the PSMA gene (FOLH1). These same reports suggest that targeting somatostatin receptor type 2 (SSTR2) could be an alternative diagnostic target for NEPC patients. This study evaluates the correlation between expression ofFOLH1, NEPC marker genes andSSTR2. We evaluated the transcript abundance forFOLH1andSSTR2genes as well as NE markers across 909 tumors. A significant suppression ofFOLH1in NEPC patient samples and AdPC samples with high expression of NE marker genes was observed. We also investigated protein alterations of PSMA and SSTR2 in an NE-induced cell line derived by hormone depletion and lineage plasticity by loss of p53. PSMA is suppressed following NE induction and cellular plasticity in p53-deficient NEPC model. The PSMA-suppressed cells have more colony formation ability and resistance to enzalutamide treatment. Conversely, SSTR2 was only elevated following hormone depletion. In 18 NEPC patient-derived xenograft (PDX) models we find a significant suppression ofFOLH1and amplification ofSSTR2expression. Due to the observedFOLH1-supressed signature of NEPC, this study cautions on the reliability of using PMSA as a target for molecular imaging of NEPC. The observed elevation ofSSTR2in NEPC supports the possible ability of SSTR2-targeted imaging for follow-up imaging of low PSMA patients and monitoring for NEPC development.