Tc-99m depreotide imaging of I-131-negative recurrent metastatic papillary thyroid carcinoma

The detection of radioiodine (I-131)-negative metastases of differentiated thyroid carcinoma (DTC) has been hitherto successfully tried by the well-known synthetic somatostatin analogue indium-111-labeled DTPA-octreotide (In-111 pentetreotide). The objective of this study was to evaluate the usefulness of scintiscan with the newer synthetic somatostatin analogue Tc-99m depreotide, in the restaging of papillary thyroid carcinoma (PTC) with detectable serum thyroglobulin (Tg) levels and negative I-131 whole-body scan (WBS). Whole-body planar and cervico-thoracic tomographic scintigraphy (single-photon emission tomography-SPET) with Tc-99m depreotide was performed in a 68-year-old male patient suffering from PTC stage III, with a mild increase in serum Tg levels coupled with a recent negative I-131 WBS. The findings were compared with those of neck ultrasonography (US) and computerized tomography (CT). Nodal neck dissection and histopathology provided the definitive diagnosis. Tc-99m depreotide scanning revealed foci of cervical lymph node metastases, which did not accumulate I-131. The findings were in accordance with neck US and CT. Histopathology established the diagnosis of metastatic cervical lymph node PTC. Lymph node immunoreactivity was positive for the somatostatin receptor subtypes 2, 5 and 3. Scintigraphy with Tc-99m depreotide could prove a useful adjunct to the armamentarium for the follow-up of PTC, especially in the setting of detectable serum Tg and negative I-131 WBS.     

The usefulness of MRI and PET imaging for the detection of parametrial involvement and lymph node metastasis in patients with cervical cancer

OBJECTIVE: The purpose of this study is to elucidate the usefulness of magnetic resonance imaging (MRI) and positron emission tomography (PET) for the detection of parametrial involvement and lymph node metastasis in patients with cervical cancer. METHODS: Thirty-six patients with cervical cancer were retrospectively enrolled. MRI and PET scans were performed for all patients within a week before radical surgery. The criterion for malignancy on MRI was >1 cm short axis diameter of the suspected lymph node. On PET, only fluorodeoxyglucose (FDG) uptake was significantly higher than the background and, if this FDG uptake showed on at least two consecutive axial slices, then the lesion was considered as a malignancy. We compared the extent of tumor on the surgical findings with the FIGO staging, MRI and PET scans. RESULTS: The accuracy of FIGO and MRI staging was 67 and 84.4%, respectively. The accuracy for detecting pelvic lymph node metastasis was better for PET than for MRI (78 versus 67%, respectively). All FDG uptake lymph nodes were confirmed as metastatic lymph nodes by pathological evaluation; this included five lymph nodes <1 cm in diameter. CONCLUSION: MRI provides an improved evaluation of local tumor extension, but PET is more useful for the evaluation of pelvic lymph nodes than MRI; however, PET still misses microscopic disease. Further studies are necessary to evaluate the usefulness of PET/computed tomography (CT) for the accuracy of the disease extension and the cost-effectiveness of MRI, PET or PET/CT in patients with cervical cancer.     

Utility of 18F-fluorodeoxyglucose positron emission tomography in the preoperative staging of squamous cell carcinoma of the oropharynx.

BACKGROUND: 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has been reported to be superior to computed tomography (CT)/magnetic resonance imaging (MRI) in the evaluation of head and neck cancers, but little is known about its usefulness in oropharyngeal squamous cell carcinoma (SCC). We therefore compared FDG PET and CT/MRI in the preoperative staging of previously untreated oropharyngeal SCC. METHODS: Thirty-two consecutive patients with oropharyngeal SCC underwent FDG PET and CT/MRI before surgery. Each method was interpreted separately to assess primary tumor and cervical node status. Their sensitivity and specificity were compared relative to histopathologic analysis. RESULTS: Histopathology revealed metastases in 29 of 39 dissected neck sides and in 47 of 163 dissected cervical levels. FDG PET had higher sensitivities than CT/MRI for primary tumor detection (25/32 vs. 30/32, P=0.063) and for identification of cervical metastases on neck side (22/29 vs. 28/29, P<0.05) and level-by-level (37/47 vs. 45/47, P<0.05) bases. In contrast, the specificity of the two methods did not differ significantly (P>0.5). FDG PET correctly interpreted the false-negative results of CT/MRI in 6 of 7 primary tumors and 8 of 10 cervical levels. CONCLUSIONS: The improved preoperative staging of FDG PET may help in planning treatment, but its accuracy is insufficient to replace pathologic staging based on neck dissection.     

Comparison of the accuracy of magnetic resonance imaging and positron emission tomography/computed tomography in the presurgical detection of lymph node metastases in patients with uterine cervical carcinoma: a prospective study

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 < or = 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 (alpha = 0.05; beta = 0.80). CONCLUSIONS: PET/CT was more sensitive than MRI for detecting lymph node metastases in patients with uterine cervical carcinoma.     

An Introduction to Managing Medullary Thyroid Cancer

MTC is a rare neuroendocrine thyroid tumour accounting for 3% to 10% of all thyroid malignancies. It can occur in a sporadic and a hereditary clinical setting. Hereditary MTC may either occur alone (familial MTC, FMTC) or as part of multiple endocrine neoplasia (MEN) type 2A, or MEN 2B. These disorders are due to germline mutations in the RET (REarranged during Transfection) gene. In carriers of MEN 2B-associated RET mutations, prophylactic thyroidectomy is indicated before the first year of life. In the case of MEN 2A-associated germline RET mutations with a high-risk profile, total thyroidectomy is warranted before the age of 2 years and certainly before the age of 4 years. At that age the risk of invasive MTC and metastases is acceptably low. Depending on the type of RET mutation, thyroidectomy can take place at an older age in patients with a lower risk profile. In case of elevated basal or stimulated serum calcitonin, preventive surgery including total thyroidectomy and central compartment dissection should be performed regardless of age. When MTC presents as a palpable tumour, total thyroidectomy should be combined with extensive lymph node dissection of levels II-V on both sides and level VI to prevent locoregional recurrences.     

Diagnostic accuracy of <Superscript>18</Superscript>F–FDG PET/CT and MR imaging in patients with adenoid cystic carcinoma

Background

The aim of this study was to evaluate the value of 18F–FDG PET/CT (PET/CT) and MRI for local and/or whole-body restaging of adenoid cystic carcinoma of the head and neck (ACC).

Methods

Thirty-six patients with ACC underwent conventional MRI of the head and neck and a whole-body PET/CT and were analysed with regards to detection of a local tumor recurrence, lymph node or distant metastases. A consensus interpretation of all available imaging data was used as reference standard. Sensitivity, specificity, diagnostic accuracy, positive and negative predictive values were calculated for MRI and PET/CT.

Results

The sensitivity of PET/CT and MRI was 96% (89%), specificity 89% (89%), PPV 96% (96%), NPV 89% (73%) and accuracy 94% (89%) for detection of local tumors. Additionally, PET/CT revealed lymph node metastases in one patient and distant metastases in 9/36 patients. In three patients secondary primaries were found.

Conclusions

Whole-body PET/CT in addition to MRI of the head and neck improves detection of local tumour and metastastic spread in ACC.

     

Combination of FDG PET/CT and Contrast-Enhanced MSCT in Detecting Lymph Node Metastasis of Esophageal Cancer

Background: Lymph node metastasis is believed to be a dependent negative prognostic factor of esophagealcancer. To explore detection methods with high sensitivity and accuracy for metastases to regional and distantlymph nodes in the clinic is of great significance. This study focused on clinical application of FDG PET/CT andcontrast-enhanced multiple-slice helical computed tomography (MSCT) in lymph node staging of esophagealcancer. Materials and Methods: One hundred and fifteen cases were examined with enhanced 64-slice-MSCTscan, and FDG PET/CT imaging was conducted for neck, chest and upper abdomen within one week. Theprimary lesion, location and numbers of metastatic lymph nodes were observed. Surgery was performed withinone week after FDG PET/CT detection. All resected lesions were confirmed histopathologically as the goldstandard. Comparative analysis of the sensitivity, specificity, and accuracy based on FDG PET/CT and MSCTwas conducted. Results: There were 946 lymph node groups resected during surgery from 115 patients, and221 were confirmed to have metastasis pathologically. The sensitivity, specificity, accuracy of FDG PET/CT indetecting lymph node metastasis were 74.7%, 97.2% and 92.0%, while with MSCT they were 64.7%, 96.4%, and89.0%, respectively. A significance difference was observed in sensitivity (p=0.030), but not the others (p>0.05).The accuracy of FDG PET/CT in detecting regional lymph node with or without metastasis were 91.9%, ascompared to 89.4% for MSCT, while FDG PET/CT and MSCT values for detecting distant lymph node with orwithout metastasis were 94.4% and 94.7%. No significant difference was observed for either regional or distantlymph node metastasis. Additionally, for detecting para-esophageal lymph nodes metastasis, the sensitivity ofFDG PET/CT was 72%, compared with 54.7% for MSCT (p=0.029). Conclusions: FDG PET/CT is more sensitivethan MSCT in detecting lymph node metastasis, especially for para-esophageal lymph nodes in esophagealcancer cases, although no significant difference was observed between FDG PET/CT and MSCT in detectingboth regional and distant lymph node metastasis. However, enhanced MSCT was found to be of great value indistinguishing false negative metastatic lymph nodes from FDG PET/CT. The combination of FDG PET/CTwith MSCT should improve the accuracy in lymph node metastasis staging of esophageal cancer.     

Familial medullary thyroid cancer: clinical aspects and prognosis.

OBJECTIVE: To assess clinical features and long-term results of treatment of familial medullary thyroid carcinoma (FMTC). DESIGN: Retrospective analysis of all patients with familial forms of MTC diagnosed between 1949-2000 and treated in our unit. RESULTS: Fifty five patients (25 males, 30 females) were identified with at least two first-degree relatives affected by medullary thyroid cancer; 26 were classified as MEN 2A, 1 as MEN 2B and 28 as FMTC. Median age at diagnosis was 35 years (MEN 2A), 25 (MEN 2B) and 47.5 (FMTC). Median follow-up was 9 years (range: 4-24). Total or near-total thyroidectomy was performed in all patients and 11 received adjuvant external beam radiotherapy. Cause specific survival was 89% at 10 years and 77% at 20 years for MEN patients, 51% and 32% for those with sporadic MTC, and 46% and 26% for those with FMTC. In multivariate analysis, factors predicting survival were presence of metastases, nodal status and age at diagnosis. CONCLUSIONS: Improved survival rates associated with familial types of MTC can be accounted for by the earlier stage at which disease is detected and the younger age at presentation. These observations emphasize the need for early detection in those at risk.     

Diagnostic significance of characteristic findings on ultrasonography for the stitch abscess after surgery in patients with oral squamous cell carcinoma

To elucidate the clinical significance of imaging modalities for detection of stitch abscess after surgery in patients with oral squamous cell carcinoma (SCC). In 137 patients with oral SCC suspected of having lymph node metastases, local recurrence of tumor, or stitch abscess after surgery, the characteristic imaging findings related to lymph node metastases, local recurrence of tumor, and stitch abscess on ultrasonography (US), computed tomography (CT), magnetic resonance (MR), and (18)fluorodeoxyglucose (18FDG)-positron emission tomography (PET) images were identified and analyzed. In all six patients with stitch abscess, characteristic findings were demonstrated on US, different from those of metastatic lymph nodes and local recurrence on CT, MRI, and 18FDG-PET images. Our results suggest that ultrasonography may be a very useful tool for diagnosis of postoperative stitch abscess and may help improve the quality of life of oral SCC patients.     

Value of fused positron emission tomography CT in detecting primaries in patients with primary unknown cervical lymph node metastasis

Objective: Identification of the primary tumour can prolong the life expectancy of patients with primary unknown cervical lymph node metastasis (PUCLNM) through targeted therapy. This study investigated the value of 18F‐fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET‐CT) at identifying primaries in patients with PUCLNM. Methods: Twenty‐seven patients (21 males and 6 females, median age 48.2 ± 16.3, age range 30–73) with PUCLNM underwent FDG PET‐CT to search for the primary tumour, which could not be detected by conventional diagnostic modalities. The results were analysed and correlated with either pathological findings or clinical follow up. Results: Pathological FDG uptake suspicious for the primary was detected in 13 cases, while the primary tumour remained occult in 14 cases. Eleven of 13 patients with suspected primaries were confirmed by histological findings. One with a coexisting second tumour and three with unexpected distant metastases were found in patients with confirmed primaries. The most common primary location in patients with PUCLNM found in our study was nasopharynx. In those 14 patients with negative FDG PET‐CT results, only one patient had a primary malignancy that was proven histologically after endoscopy with biopsy during a period of clinical follow up. The sensitivity, specificity, accuracy and positive predictive values of FDG PET‐CT were 91.7, 86.7, 88.9 and 84.6%, respectively. Conclusion: FDG PET‐CT is a useful tool to help search for unknown primaries in patients with cervical lymph node metastasis and has an acceptable diagnostic yield for the detection of distant malignancies.     

Current status of inherited medullary thyroid carcinoma in Japan

We conducted a large-scale nationwide questionnaire survey to characterize the clinical course of inherited medullary thyroid carcinoma (MTC). Out of a total of 634 MTC patients (M:F ratio 1:2.5), 175 patients had multiple endocrine neoplasia (MEN) 2A, 49 had familial non-MEN medullary thyroid carcinoma (FMTC), 20 had MEN 2B, and 390 had sporadic MTC. Median age at the time of diagnosis was 40.3, 43.0, 26.5 and 48.5 years, respectively. Total thyroidectomy plus modified neck dissection (MND) was the most common operation. The 5-year survival rates were 96.9% in MEN 2A, 100% in FMTC, 73.8% in MEN 2B, 90.8% in sporadic MTC. The outcome in order from best to worst was: FMTC, MEN 2A, sporadic MTC, and MEN 2B, with MEN 2B considered the most aggressive type.     

COVID-19 vaccine related hypermetabolic lymph nodes on PET/CT: Implications of inflammatory findings in cancer imaging

We observed several patients presenting 2-[¹⁸F]FDG uptake in the reactive axillary lymph node at PET/CT imaging, ipsilateral to the site of the COVID-19 vaccine injection. Analog finding was documented at [¹⁸F]Choline PET/CT. The aim of our study was to describe this source of false positive cases. All patients examined by PET/CT were included in the study. Data concerning patient anamnesis, laterality, and time interval from recent COVID-19 vaccination were recorded. SUVmax was measured in all lymph nodes expressing tracer uptake after vaccination. Among 712 PET/CT scans with 2-[¹⁸F]FDG, 104 were submitted to vaccination; 89/104 patients (85%) presented axillary and/or deltoid tracer uptake, related to recent COVID-19 vaccine administration (median from injection: 11 days). The mean SUVmax of these findings was 2.1 (range 1.6–3.3). Among 89 patients with false positive axillary uptake, 36 subjects had received chemotherapy due to lymph node metastases from somatic cancer or lymphomas, prior to the scan: 6/36 patients with lymph node metastases showed no response to therapy or progression disease. The mean SUVmax value of lymph nodal localizations of somatic cancers/lymphomas after chemotherapy was 7.8. Only 1/31 prostate cancer patients examined by [¹⁸F]Choline PET/CT showed post-vaccine axillary lymph node uptake. These findings were not recorded at PET/CT scans with [¹⁸F]-6-FDOPA, [⁶⁸Ga]Ga-DOTATOC, and [¹⁸F]-fluoride. Following COVID-19 mass vaccination, a significant percentage of patients examined by 2-[¹⁸F]FDG PET/CT presents axillary, reactive lymph node uptake. Anamnesis, low-dose CT, and ultrasonography facilitated correct diagnosis. Semi-quantitative assessment supported the visual analysis of PET/CT data; SUVmax values of metastatic lymph nodes were considerably higher than post-vaccine lymph nodes. [¹⁸F]Choline uptake in reactive lymph node after vaccination was confirmed. After the COVID-19 pandemic, nuclear physicians need to take these potential false positive cases into account in daily clinical practice.     

Role of FDG PET-CT in evaluation of locoregional nodal disease for initial staging of breast cancer

Fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) is not indicated or recommended in the initial staging of early breast cancer. Although it is valuable for detecting distant metastasis, providing prognostic information, identifying recurrence and evaluating response to chemotherapy, the role of FDG PET/CT in evaluating locoregional nodal status for initial staging of breast cancer has not yet been well-defined in clinical practice. FDG PET/CT has high specificity but compromised sensitivity for identifying axillary nodal disease in breast cancer. Positive axillary FDG PET/CT is a good predictor of axillary disease and correlates well with sentinel lymph node biopsy (SLNB). FDG PET/CT may help to identify patients with high axillary lymph node burden who could then move directly to axillary lymph node dissection (ALND) and would not require the additional step of SLNB. However, FDG PET/CT cannot replace SLNB or ALND due to unsatisfactory sensitivity. The spatial resolution of PET instruments precludes the detection of small nodal metastases. Although there is still disagreement regarding the management of internal mammary node (IMN) disease in breast cancer, it is known that IMN involvement is of prognostic significance, and IMN metastasis has been associated with higher rates of distant metastasis and lower overall survival rates. Limited clinical observations suggested that FDG PET/CT has advantages over conventional modalities in detecting and uncovering occult extra-axillary especially IMN lesions with upstaging the disease and an impact on the adjuvant management.     

Detection of hematogenous bone metastasis in cervical cancer

BACKGROUND:

In this large‐scale, retrospective study, the authors evaluated the diagnostic performances of computed tomography (CT), magnetic resonance (MR) imaging, and ¹⁸F‐fluorodeoxyglucose‐positron emission tomography (¹⁸F‐FDG–PET) in detecting hematogenous bone metastasis in patients with cervical cancer. The associated risk factors also were analyzed.

METHODS:

Patients with invasive cervical cancer who had both ¹⁸F‐FDG–PET studies and CT or MR imaging studies were selected. Patients who had either International Federation of Gynecology and Obstetrics (FIGO) stage III/IV disease or positive lymph node metastasis at the time of primary staging and patients who had suspected recurrent disease were included in the analyses. The diagnostic performances of PET was compared with the performance of CT and MR imaging by using the area under the receiver‐operating‐characteristic curve (AUC). Both univariate and multivariate analyses were applied to assess the risk factors for hematogenous bone metastasis at primary staging.

RESULTS:

PET was more sensitive than CT (P = .004) and was more specific than MR imaging (P = .04). The diagnostic performance of PET was significantly superior to the performance CT (AUC, 0.964 vs 0.662; P < .001) and MR (AUC, 0.966 vs 0.833; P = .033). Both FIGO stage and the extent of lymph node metastases were associated with hematogenous bone metastasis in univariate analysis. However, the extent of lymph node metastases was the only significant risk factor in multivariate analysis (P = .025).

CONCLUSIONS:

The current study demonstrated the superiority of ¹⁸F‐FDG–PET over CT and MR imaging for detecting hematogenous bone metastasis in patients with advanced cervical cancer. Hematogenous bone metastasis in cervical cancer was associated with the extent of lymph node metastases rather than with FIGO stage. Cancer 2009. © 2009 American Cancer Society.     

FDG-PET in thyroid cancer

The most widely used diagnostic nuclear medicine technique in well-differentiated thyroid cancer (DTC) is radioiodine scintigraphy, either diagnostic or post-therapeutic, together with serum thyroglobulin (Tg) measurement; this combination is usually able to determine the presence or absence of cancer. FDG-PET has shown less sensitivity in DTC that retains the ability to trap 131I. Several alternative procedures with single photon emitting radiopharmaceuticals have been evaluated including whole body scan with 201Tl, 99mTc-sestamibi or tetrofosmin scan, with different sensitivity and specificity. The main advantage of these tests is that their results are not influenced by the levels of TSH, therefore they do not require a hypothyroid state in the patient. Recently positron emission tomography (PET) with FDG has been demonstrated to be highly useful in thyroid cancer patients with a negative 131I whole body scan but measurable Tg. According to reports in the literature FDG-PET in the follow-up of operated patients has a sensitivity ranging from 70% to 90% in identifying the source of Tg. The demonstration of lesions can lead to a change in treatment including surgery or external radiation instead of radioiodine treatment. In Europe, medullary thyroid cancer (MTC) is currently visualized by 99mTc pentavalent dimercaptosuccinic acid (DMSA) and 99mTc-sestamibi or tetrofosmin. Metaiodobenzylguanidine (MIBG) radiolabeled with 123I or 131I is another reliable radiopharmaceutical for medullary tumors. (111)In-pentetreotide scan is positive in a high percentage of patients because MTC expresses somatostatin receptors. FDG-PET has an interesting role to play in calcitonin-positive patients, where PET has been shown to correctly identify lesions in cervical and mediastinal lymph nodes as well as at distant sites. Furthermore, calcitonin-guided PET has been found to be superior to CT and MRI in many patients. Recent reports indicated that 18F-DOPA scan in MTC seems to be more accurate than FDG-PET.     

Utility of 2-[18F] fluoro-2-deoxy-D-glucose positron emission tomography and positron emission tomography/computed tomography imaging in the preoperative staging of head and neck squamous cell carcinoma

The combination of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and computed tomography (CT) has been reported to be more accurate than CT or PET alone in a preoperative setting. We compared the diagnostic utility of preoperative PET/CT, PET and CT/MRI in 167 patients with newly diagnosed head and neck squamous cell carcinoma (HNSCC), of whom 104 underwent FDG PET and 63 underwent combined PET/CT with all receiving CT/MRI. These preoperative PET, PET/CT, and CT/MRI results were reviewed and their accuracies were compared in patients in whom diagnosis was confirmed histopathologically. Age, sex, primary sites and stage, and nodal involvement were comparable between two groups. The accuracy of PET and PET/CT for detecting primary tumors and cervical metastases was comparable, but significantly higher than that of CT/MRI (98%-97% vs. 86-88% for primary; 92%-93% vs. 85%-86% for neck on a level-by-level basis; P<.05). PET and PET/CT gave false negative results: in 2 (2%) and 2 (3%) patients for primary tumors; in 6 (6%) and 3 (5%) patients for neck metastases, respectively. PET and PET/CT also gave false-positive results for cervical metastases in 5 (5%) and 4 (6%) patients, respectively. Compared with PET alone, preoperative FDG PET/CT may not yield significantly improved diagnostic accuracy in patients with HNSCC. Moreover, despite their high accuracy, PET and PET/CT may not abrogate the need for conventional imaging and pathologic staging based on primary resection and neck dissection.     

The incremental effect of positron emission tomography on diagnostic accuracy in the initial staging of esophageal carcinoma

BACKGROUND: The purpose of the current study was to assess whether [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) provides incremental value (e.g., additional information on lymph node involvement or the presence of distant metastases) compared with computed tomography (CT) in patients with esophageal carcinoma. METHODS: The authors examined 149 consecutive patients with thoracic esophageal carcinoma. Eighty-one patients underwent radical esophagectomy without pretreatment, 17 received chemoradiotherapy followed by surgery, 3 underwent endoscopic mucosal resection, and the remaining 48 patients received definitive radiotherapy and chemotherapy. The diagnostic accuracy of FDG-PET and CT was evaluated at the time of diagnosis. RESULTS: The primary tumor was visualized using FDG-PET in 119 (80%) of 149 patients. Regarding lymph node metastases, FDG-PET had 32% sensitivity, 99% specificity, and 93% accuracy for individual lymph node group evaluation and 55% sensitivity, 90% specificity, and 72% accuracy for lymph node staging evaluation. PET exhibited incremental value over CT with regard to lymph node status in 14 of 98 patients who received surgery: 6 patients with negative CT findings were eventually shown to have lymph node metastases (i.e., they had positive PET findings and a positive reference standard [RS]); 6 patients with positive CT findings were shown not to have lymph node metastases (i.e., they had negative PET findings and a negative RS); and 2 patients were shown to have cervical lymph node metastases in addition to mediastinal or abdominal lymph node metastases. Among the remaining patients, PET showed incremental value over CT with regard to distant organ metastases in six patients. The overall incremental value of PET compared with CT with regard to staging accuracy was 14% (20 of 149 patients). CONCLUSIONS: FDG-PET provided incremental value over CT in the initial staging of esophageal carcinoma. At present, combined PET-CT may be the most effective method available for the preoperative staging of esophageal tumors.     

Diagnostic value of fluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography for the detection of metastases in non–small‐cell lung cancer patients

In the recent years, fluorine 18 fluorodeoxyglucose (¹⁸F‐FDG) positron emission tomography (PET)/computed tomography (CT) has emerged as a new modality for staging non–small‐cell lung cancer (NSCLC) patients. The aim of this meta‐analysis was to assess the diagnostic value of ¹⁸F‐FDG PET/CT in detecting metastatic lesions in NSCLC patients. Meta‐analysis methods were used to pool sensitivity, specificity, positive and negative likehood ratios, diagnostic odd ratios and to construct a summary receiver‐operating characteristic curve. Data from included studies were pooled to compare the diagnostic accuracy between PET/CT and PET or CT alone in nodal staging. Totally, 56 studies involving 8,699 patients met the inclusion criteria. The pooled sensitivities and specificities of ¹⁸F‐FDG PET/CT were 0.72 [95% confidence interval (CI): 0.65–0.78] and 0.91 (95% CI: 0.86–0.94) in determining mediastinal nodal staging; 0.71 (95% CI: 0.60–0.80) and 0.83 (95% CI: 0.77–0.88) in intrathoracic staging; 0.78 (95% CI: 0.64–0.87) and 0.90 (95% CI: 0.84–0.94) in intrathoracic staging on a per‐node basis. For detecting extrathoracic metastases, the pooled sensitivities and specificities of ¹⁸F‐FDG PET/CT were 0.77 (95% CI: 0.47–0.93) and 0.95 (95% CI: 0.92–0.97) for all extrathoracic metastases; 0.91 (95% CI: 0.80–0.97) and 0.98 (95% CI: 0.94–0.99) for bone metastases. ¹⁸F‐FDG PET/CT is beneficial in detecting lymph node metastases and extrathoracic metastases although PET/CT showed low sensitivity in detecting brain metastases. ¹⁸F‐FDG PET/CT confers significantly higher sensitivity and specificity than contrast‐enhanced CT (both p < 0.01) and higher sensitivity than ¹⁸F‐FDG PET in staging NSCLC (p < 0.05).     

Clinicopathologic Significance of False-Positive Lymph Node Status on FDG-PET in Lung Cancer

Introduction2-[¹⁸F] Fluoro-d-deoxyglucose (FDG) positron emission tomography (PET) is a relevant diagnostic procedure for staging lung cancer. However, accurate evaluation of lymph node metastases by PET is controversial because of false-positive FDG uptake.Patients and MethodsA total of 245 patients with lung cancer were retrospectively analyzed. Standardized maximum uptake values (SUV_max) of the primary tumor and lymph nodes were compared to pathologic lymph node metastases to correlate PET findings with clinicopathologic variables and patient outcomes.ResultsThe SUV_max values of metastatic lymph nodes were significantly higher than those of lymph nodes without metastases (P = .0036). When SUV_max ≥ 4 was defined as PET positive for metastasis, the sensitivity, specificity, and accuracy were 48.1%, 79.8%, and 73.1%, respectively. Multivariate logistic regression analysis showed that age > 75 years, bilateral hilar FDG uptake, and no lymph node swelling were significant factors related to false-positive lymph node metastases. Smoking status, FDG uptake in the primary tumor, and concurrent lung diseases were not significant factors.ConclusionMetastatic lymph nodes show higher FDG uptake than false-positive lymph nodes, and older patient age, bilateral hilar FDG uptake, and no swollen nodes are associated with no metastases. Patients with lymph node metastases have worse survival than those with false-positive FDG-PET findings. However, abnormal FDG uptake in the lymph node is an important prognostic factor.     

Clinical evaluation of whole-body 18F-fluorodeoxyglucose positron emission tomography in the detection of liver metastases

Background: Assessment of metastatic involvement of the liver remains a diagnostic challenge. The objective of this study was to evaluate the potential role of FDG PET in the detection of liver metastases.Patients and methods: Sixty-four patients with malignancy and possible liver involvement were included. Liver metastases were present in 31 cases, demonstrated by histopathological analysis in 15 cases and by follow-up in 16 cases. The negative cases were confirmed by pathology in four cases, peroperative ultrasonography in 12 cases, and follow-up in 17 cases. Whole-body FDG PET was compared to CT (n = 53) and US (n = 43).Results: PET demonstrated a 97% sensitivity, an 88% specificity and a 92% accuracy, compared to 93%, 75% and 85%, respectively, for CT (P = NS). Concordant results were obtained in 44 of 64 patients (69%; 19 TP, 25 TN). PET provided new and accurate information in 15 of 64 patients (23.4%). PET demonstrated liver metastases in 11 patients in whom conventional methods yielded negative (two cases) or doubtful (nine cases) results. Four patients free of liver involvement were correctly staged with PET, while CT/US were equivocal. PET was erroneous in five of 64 cases (7.8%, four FP, one FN).Conclusions: FDG PET allows an accurate screening of liver involvement in patients with malignancy. Combined with CT, it provides additional diagnostic information that could directly affect the management of these patients.