Integrated FDG-PET/CT does not make invasive staging of the intrathoracic lymph nodes in non-small cell lung cancer redundant: a prospective study

BACKGROUND: Staging of non-small cell lung cancer (NSCLC) is important for determining choice of treatment and prognosis. The accuracy of FDG-PET scans for staging of lymph nodes is too low to replace invasive nodal staging. It is unknown whether the accuracy of integrated FDG-PET/CT scanning makes invasive staging redundant. METHODS: In a prospective study, the mediastinal and/or hilar lymph nodes in patients with proven NSCLC were investigated with integrated FDG-PET/CT scanning. Pathological confirmation of all suspect lymph nodes was obtained to calculate the accuracy of the fusion images. In addition, the use of the standardised uptake value (SUV) in the staging of intrathoracic lymph nodes was analysed. RESULTS: 105 intrathoracic lymph node stations from 52 patients with NSCLC were characterised. The prevalence of malignancy in the lymph nodes was 36%. The sensitivity of the integrated FDG-PET/CT scan to detect malignant lymph nodes was 84% and its specificity was 85% (positive likelihood ratio 5.64, negative likelihood ratio 0.19). SUV(max), SUV(mean) and the SUV(max)/SUV(liver) ratio were all significantly higher in malignant than in benign lymph nodes. The area under the receiver operating curve did not differ between these three quantitative variables, but the highest accuracy was found with the SUV(max)/SUV(liver) ratio. At a cut-off value of 1.5 for the SUV(max)/SUV(liver )ratio, the sensitivity and specificity to detect malignant lymph node invasion were 82% and 93%, respectively. CONCLUSION: The accuracy of integrated FDG-PET/CT scanning is too low to replace invasive intrathoracic lymph node staging in patients with NSCLC. The visual interpretation of the fusion images of the integrated FDG-PET/CT scan can be replaced by the quantitative variable SUV(max)/SUV(liver) without loss of accuracy for intrathoracic lymph node staging.     

^18FDG—PET在肺癌诊断中的价值

目的研究氟脱氯葡萄糖F18-正电子发射计算机电子扫描(18FDG-PET)在鉴别肺部肿块性质和肺癌术前纵隔淋巴结转移分期中的应用价值.方法对34例肺部肿块患者进行18FDG-PET和CT检查,PET资料分别采用目测法和计算标准化摄取值(SUV)的半定量法进行分析,并同病理结果对照.结果目测法18FDG-PET诊断肺部肿块性质的敏感度、准确度分别是93%、85%;CT分别为63%、53%,2种方法差异有显著性意义(P＜0.05);半定量法准确度为74%,与CT相比,差异也有显著性意义(P＜0.05).肺部恶性肿块的SUV是4.4±1.9,良性为2.2±1.7,2者差异有显著性意义(P＜0.05).18FDG-PET和CT2种检查方法术前对纵隔淋巴结转移的分期与病理结果符合率分别为100%和78%,2者差异有显著性意义(P＜0.05).结论同CT相比,18FDG-PET能更准确地鉴别肺部肿块性质及确定纵隔淋巴结转移分期,是一种较好的无创性肺癌诊断技术.     

~(18)FDG-PET在肺癌诊断中的价值

目的　研究氟脱氯葡萄糖F18 正电子发射计算机电子扫描 (1 8FDG PET)在鉴别肺部肿块性质和肺癌术前纵隔淋巴结转移分期中的应用价值。　方法　对 34例肺部肿块患者进行1 8FDG PET和CT检查 ,PET资料分别采用目测法和计算标准化摄取值 (SUV)的半定量法进行分析 ,并同病理结果对照。　结果　目测法1 8FDG PET诊断肺部肿块性质的敏感度、准确度分别是 93%、85 % ;CT分别为 6 3%、5 3% ,2种方法差异有显著性意义 (P <0 0 5 ) ;半定量法准确度为 74% ,与CT相比 ,差异也有显著性意义 (P <0 0 5 )。肺部恶性肿块的SUV是 4 4± 1 9,良性为 2 2± 1 7,2者差异有显著性意义 (P <0 0 5 )。1 8FDG PET和CT 2种检查方法术前对纵隔淋巴结转移的分期与病理结果符合率分别为10 0 %和 78% ,2者差异有显著性意义 (P <0 0 5 )。　结论　同CT相比 ,1 8FDG PET能更准确地鉴别肺部肿块性质及确定纵隔淋巴结转移分期 ,是一种较好的无创性肺癌诊断技术。     

Role of the standardized uptake value of 18-fluorodeoxyglucose positron emission tomography–computed tomography in detecting the primary tumor and lymph node metastasis in colorectal cancers

Purpose

To assess the role of positron emission tomography–computed tomography (PET–CT) and multidetector-row CT (MD-CT) in detecting the primary lesion and lymph node metastasis in patients with colorectal cancers.

Methods

A collective total of 80 lesions resected from 77 patients were examined pathologically. We analyzed the significance of the standardized uptake value (SUV) and its relationship with the clinicopathologic findings of primary lesions and lymph node metastasis. The detectability of primary lesions and lymph node metastases on PET–CT images was compared with that on MD-CT images.

Results

The detectability of primary lesions was better on PET–CT images than on MD-CT images (p = 0.0023). We observed no significant differences in the SUV with respect to staging, tumor grade, lymphatic or vessel invasion, and macroscopic type; however, primary tumor size analysis revealed that tumors larger than 3 cm had a higher SUV than those smaller than 3 cm. The sensitivity of PET–CT for detecting lymph node metastasis was lower than that of MD-CT, but the specificity of PET–CT was higher than that of MD-CT.

Conclusions

The SUV of primary cancers tends to increase in proportion to tumor size. Although the value of PET–CT in detecting lymph node metastasis is limited, PET -positive lymph nodes can be considered metastatic.     

超声内镜与CT对胰腺及壶腹部周围肿瘤的术前诊断价值

目的评估超声内镜(endoscopic ultrasonography,EUS)和CT对胰腺及壶腹部周围肿瘤的术前诊断价值。方法回顾性分析33例胰腺及壶腹部肿瘤患者术前EUS、CT资料,与手术探查及术后病理结果对照,从肿瘤大小、部位等角度筛选出影响EUS准确性的因素。结果 EUS在判断胰周脂肪浸润、胆管扩张、胰周脏器侵犯、血管侵犯等方面敏感性、特异性与CT的差异无统计学意义(P>0．05);EUS在胰管扩张及淋巴结转移方面的诊断价值优于CT(P=0．039和P=0．004); EUS判断胰周脂肪浸润和胰周脏器侵及的准确性与肿瘤大小有关(P=0．015和P=0．022),判断胰管扩张的准确性与肿瘤部位有关(P<0．001)。结论 EUS对胰腺及壶腹部周围肿瘤诊断的临床价值很高,结合CT检查有助于加强对患者术前评价的认识。     

Clinical utility of positron emission tomography in the diagnosis and management of periampullary neoplasms

Background This study examined the effect that 18-fluorodeoxyglucose positron emission tomography (¹⁸FDG-PET) imaging had on the clinical management of patients with suspected periampullary malignancy. Methods Fifty-four patients with suspected pancreatic neoplasms underwent both whole-body¹⁸FDG-PET and abdominal computed tomography (CT). Malignant or benign disease was confirmed pathologically in 47 patients. Results Of the 41 patients with malignancy,¹⁸FDG-PET failed to identify the primary tumor in 5 patients.¹⁸FDG-PET demonstrated increased uptake suggesting primary malignancy in 37 patients. Malignant pathology was confirmed in 36 cases.¹⁸FDG-PET identified malignant locoregional lymph node metastases in six of ten patients. All nodes identified before surgery by¹⁸FDG-PET were also seen on preoperative CT. Six patients who were thought to have resectable disease by CT were found to have distant metastasis at laparotomy.¹⁸FDG-PET did not detect metastasis in any of these cases. Before surgery,¹⁸FDG-PET identified distant metastases that were not detected by CT in one patient. Conclusions Despite high sensitivity and specificity in diagnosing periampullary malignancy,¹⁸FDG-PET did not change clinical management in the vast majority of patients previously evaluated by CT. In addition,¹⁸FDG-PET missed>10% of periampullary malignancies and did not provide the anatomical detail necessary to define unresectability.     

PET/CT诊断乳腺癌及腋窝淋巴结状态的作用评价

目的：评价PET／CT诊断乳腺癌和腋窝淋巴结转移的临床价值。方法：对33例疑似乳腺癌病人进行PET／CT检查，定性分析肿瘤病灶、淋巴结摄取氟脱氧葡萄糖（FDG）的程度，半定量测量标准摄取值（SUV），根据乳腺和淋巴结的FDG摄取强度诊断乳腺癌和淋巴结转移，检验SUV与乳腺癌分化程度、有丝分裂计数的关联性。结果：PET／CT诊断乳腺癌和腋窝淋巴结转移的敏感度、特异度和精确度分别为92．6％、100％、93．9％和82．3％、90％、85．2％；SUV与乳腺癌分化程度、有丝分裂计数显著相关（P〈0．05）；诊断乳腺癌的Kappa指数=0．835，μ=8．48，（P〈0．01）。结论：PET／CT诊断乳腺癌和腋窝淋巴结转移的敏感度、特异度较高，作为一种非侵袭性检查方法，可提供乳腺癌在活体内的多方面生物学信息，为选择合理的手术方式及新辅助化疗提供参考，弥补传统检查方法的不足。     

Prediction of true-negative lymph node metastasis in clinical IA non-small cell lung cancer by measuring standardized uptake values on positron emission tomography

Purpose

We developed a method for predicting true-negative lymph node metastases in clinical IA non-small lung cancer (NSCLC) by the combined evaluation of computed tomography (CT), 2-[18F]-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) findings and the maximum standardized uptake value (SUVmax) of primary tumors.

Methods

The subjects of this study were 94 patients with clinical stage IA NSCLC who underwent both preoperative CT and FDG-PET. We analyzed the relationship between the SUVmax of primary tumors and various clinicopathological factors to find the best method available for assessing true-negative lymph node metastasis.

Results

The pathological stages were IA (n = 80), IB (n = 4), IIA (n = 5), IIIA (n = 4), and IV (n = 1). Pathologic lymph node metastasis was recognized in nine patients and the SUVmax of these tumors ranged from 3.3 to 20.3. A SUVmax of 3.0 was defined as the cut-off point and patients were dichotomized according to this point. Tumors with SUVmax of 3.0 or less were associated with a significantly lower incidence of pleural and vascular invasion and were characterized by the degree of differentiation.

Conclusion

The SUVmax of primary tumors reflects the grade of malignancy; therefore, the combined evaluation of FDG-PET/CT findings with the SUVmax of primary tumors may help predict lymph node metastasis negativity.     

Evaluation of 18F-2-deoxy-2-fluoro-<Emphasis Type="SmallCaps">d</Emphasis>-glucose Positron Emission Tomography for Gastric Cancer

Positron emission tomography (PET) with ¹⁸F-2-deoxy-2-fluoro-d-glucose (FDG) has been investigated as a means of detecting certain primary tumors and their metastatic disease in recent years. The aim of this study was to compare the performance of FDG-PET and operative assessment with formal pathologic staging. Altogether, 85 patients had undergone surgical treatment for gastric cancer with curative intent, with FDG-PET preoperatively. The results using FDG-PET were compared with those using computed tomography (CT); they were also correlated with the pathologic findings. For quantitative analysis, the regional tumor uptake was measured by the standard uptake value (SUV) using a region of interest technique. Using FDG-PET, the primary tumor was visualized in 75.2% of patients. A comparison of the FDG uptake and the clinicopathologic findings showed that there was a significant association between FDG uptake and the depth of invasion, the size of the tumor, and lymph node metastasis. FDG-PET scans had less accuracy for diagnosing locoregional lymph nodes than CT because of a significant lack of sensitivity (23.3% vs. 65.0%). The survival rate for patients with high FDG uptake (SUV > 4) was significantly lower than that for those with low FDG uptake (SUV < 4) (p < 0.05). FDG-PET was successful in detecting the primary gastric cancer lesion but not for finding early-stage gastric cancers. Detection of nodal metastasis also was not possible by FDG-PET. However, FDG-PET appears to provide important additional information concerning the aggressiveness of the tumor and the prognosis in patients with gastric cancer.     

Preoperative FDG-PET for axillary metastases in patients with breast cancer

HYPOTHESIS: Fludeoxyglucose F 18 (FDG) positron emission tomography (PET) can be used to predict axillary node metastases. DESIGN: Case series. SETTING: Comprehensive breast care center. PATIENTS: Fifty-one women with 54 biopsy-proven invasive breast cancers. INTERVENTION: Whole-body FDG-PET performed before axillary surgery and interpreted blindly. MAIN OUTCOME MEASURES: Axillary FDG activity, quantified by standardized uptake value (SUV); axillary metastases, quantified histologically; and tumor characteristics. RESULTS: There was PET activity in 32 axillae (59%). The SUVs ranged from 0.7 to 11.0. Twenty tumors had an SUV of 2.3 or greater, and 34 had an SUV of less than 2.3. There were no significant differences between these 2 groups except in axillary metastasis size (SUV /=2.3): mean age, 53 vs 58 years (P = .90); mean modified Bloom-Richardson score, 7.7 vs 7.6 (P = .20); lymphovascular invasion present, 25% vs 36% (P = .40); mean Ki-67 level, 25% vs 32% (P = .20); mean tumor size, 2.9 vs 3.2 cm (P = .05); and axillary metastasis size, 0.9 vs 1.7 (P = .001). By adopting an SUV threshold of 2.3, FDG-PET had a sensitivity of 60%, a specificity of 100%, and a positive predictive value of 100%. CONCLUSIONS: Patients with an SUV greater than 2.3 had axillary metastases. This finding obviates the need for sentinel lymph node biopsy or needle biopsy to diagnose axillary involvement. Surgeons can proceed to axillary node dissection to assess the number of nodes involved, eliminate axillary disease, or perhaps provide a survival benefit if preoperative FDG-PET has an SUV greater than 2.3.     

FDG-PET/CT in the staging of local/regional metastases in breast cancer

Breast cancer is the commonest female malignancy in the Western world and the most reliable predictor for survival is axillary lymph node metastases. Conventional staging techniques employed in breast cancer include mammography, ultrasonography, isotope bone scanning, sentinel lymph node biopsy, axillary lymph node dissection and magnetic resonance imaging. More recently FDG-PET and FDG-PET/CT have been used to complement the above methods. This review assesses the role of FDG-PET/CT in axillary staging in patients with primary breast cancer.A PubMed search was conducted and all articles containing relevant or new information were included. Relevant studies examined identified that FDG-PET/CT has a sensitivity of 60% and a specificity of 97% in detecting lymphatic metastasis.Although positive axillary FDG-PET/CT is a good predictor of axillary disease and correlates well with SLNB, the relatively poor sensitivity (60%) must be considered for treatment planning.     

Indications for pancreatoduodenectomy in patients undergoing lymphadenectomy for advanced gallbladder carcinoma

Background/Purpose Carcinoma of the gallbladder shows diverse patterns of spread. The most appropriate surgical procedures according to the depth and extent of the spread of the tumor are still controversial.Methods We investigated this surgical problem clinicopathologically, especially regarding the indications for pancreatoduodenectomy (PD), by retrospectively reviewing the clinical records of 216 patients who were surgically treated for advanced gallbladder carcinoma. Detailed studies of resected specimens, in our department, showed that preservation of the pancreas head carried an increased risk of residual microscopic metastases in small peripancreatic lymphatic nodes and ducts. Some patients with curative operations had shown recurrence in lymph nodes around the head of the pancreas within a few years after PD. Therefore, we performed hepatopancreatoduodenectomy (HPD) in 93 patients, some of whom underwent the HPD as a prophylactic dissection of peripancreatic lymph nodes and some of whom underwent the HPD as a curative resection due to invasion to the peripancreatic lymph nodes, duodenum, and pancreas, observed macroscopically. The surgical outcome after PD was compared with that obtained after other curative resections (non-HPD).Results In patients with microscopically negative lymph node metastasis without hepatoduodenal ligament invasion, PD was not necessary for a complete resection of lymphatic metastases around the pancreas head. The 5-year survival rate of these patients who had HPD was not significantly higher than that for non-HPD resections with curative intent (73% vs 63%), and lymphatic recurrence was not marked. On the other hand, in patients with positive lymph node metastases without hepatoduodenal ligament invasion, PD was necessary for a complete resection. The 5-year survival rate after HPD in these patients was significantly improved compared to that after non-HPD resections with curative intent (87% vs 17%), because lymphatic recurrence was reduced (0% vs 80%).Conclusions In advanced carcinomas with positive hepatoduodenal ligament invasion, although the basic operative strategy, which inevitably includes right lobectomy, should be curative, PD should not be performed for prophylactic lymphatic resection, because local recurrence in the hepatoduodenal ligament cannot be controlled by PD, and the 5-year survival rate of curative HPD was only 4% (non-HPD resection with curative intent, 18%); moreover, frequent, lethal, major postoperative complications (hepatic failure) occurred after combined right lobectomy.     

Positron emission tomography for detection of lymph node metastases in lung cancer

Although radiography, computed tomography (CT), and magnetic resonance imaging are still the methods of choice for the study of lung cancer, they have certain limitations in the evaluation of mediastinal lymph node metastases. Positron emission tomography (PET) with 18F-fluoro-2-deoxy-D-glucose (FDG) has recently emerged as a practical and useful imaging modality in patients with lung cancer. We evaluated the usefulness of FDG-PET in the detection of mediastinal lymph node metastases and then compared the findings with the results of CT by region based on the histological diagnosis. For FDG-PET, the sensitivity, specificity and accuracy were 93%, 76%, and 98%, respectively, whereas, for CT, this was 65%, 87%, and 82%, which showed significant differences. FDG-PET is significantly more accurate than CT in lymph node staging of lung cancer, and also can improve the diagnostic accuracy in distant metastases.     

18F-fluorodeoxyglucose positron emission tomography (FDG-PET) negative poorly differentiated adenocarcinoma of lung with mediastinal lymph node metastases

A 58-year-old woman was referred to our hospital for further medical examination of bilateral lung nodules on the chest computed tomography. Standardized uptake valve (SUV) max of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) were negative value at both lung nodules, but positive value (3.4) at a pretracheal lymph node. The size of the small lung nodule of the left lower lobe (S9) was unchanged, but the lung nodule of the right upper lobe (S1) was gradually enlarged. By the biopsy of the right lung nodule, the poorly differentiated adenocarcinoma was diagnosed pathologically. The right upper lobectomy with mediastinal lymph node dissection was performed. The metastasis was pathologically determined for FDG-PET positive lymph node. The most important reason for negative FDG-PET at primary lesion was considered that the expression of glucose transporter 1 (GLUT-1) was very few. FDG-PET has become a useful tool in the diagnosis of the pulmonary cancer, but we should understand its limitation and diagnose carefully.     

Is there any maximum standardized uptake value variation among positron emission tomography scanners for mediastinal staging in non-small cell lung cancer?

The maximum standardized uptake value (SUV(max)) varies among positron emission tomography-integrated computed tomography (PET/CT) centers in the staging of non-small cell lung cancer. We evaluated the ratio of the optimum SUV(max) cut-off for the lymph nodes to the median SUV(max) of the primary tumor (ratioSUV(max)) to determine SUV(max) variations between PET/CT scanners. The previously described PET predictive ratio (PPR) was also evaluated. PET/CT and mediastinoscopy and/or thoracotomy were performed on 337 consecutive patients between September 2005 and March 2009. Thirty-six patients were excluded from the study. The pathological results were correlated with the PET/CT findings. Histopathological examination was performed on 1136 N2 lymph nodes using 10 different PET/CT centers. The majority of patients (group A: 240) used the same PET/CT scanner at four different centers. Others patients were categorized as group B. The ratioSUV(max) for groups A and B was 0.18 and 0.22, respectively. The same ratio for centers 1, 2, 3 and 4 was 0.2, 0.21, 0.21, and 0.23, respectively. The optimal cut-off value of the PPR to predict mediastinal lymph node pathology for malignancy was 0.49 (likelihood ratio +2.02; sensitivity 70%, specificity 65%). We conclude that the ratioSUV(max) was similar for different scanners. Thus, SUV(max) is a valuable cut-off for comparing-centers.     

CT检查淋巴结短径评估胸段食管鳞癌左侧喉返神经旁淋巴结转移的应用价值

目的探讨CT检查淋巴结短径评估胸段食管鳞癌左侧喉返神经旁淋巴结转移的应用价值。方法采用回顾性描述性研究方法。收集2009年10月至2016年12月2家医疗中心收治的628例(中山大学肿瘤防治中心236例、郑州大学附属肿瘤医院392例)胸段食管鳞癌病人的临床病理资料;男462例,女166例;中位年龄为62岁,年龄范围为38~85岁。观察指标:(1)手术情况和左侧喉返神经旁淋巴结清扫及转移情况。(2)CT检查左侧喉返神经旁淋巴结短径评估术后左侧喉返神经旁淋巴结转移效能。(3)最佳截断值确定。(4)不同诊断标准的检测情况。偏态分布的计量资料以M(范围)表示。计数资料以绝对数或百分比表示。以受试者工作特征曲线(ROC)的曲线下面积(AUC)评估检测方法的效能。约登指数最大值对应最佳截断点。结果(1)手术情况和左侧喉返神经旁淋巴结清扫及转移情况:628例病人中,572例行二野淋巴结清扫,56例行三野淋巴结清扫;408例行微创手术,220例行开放手术。628例病人中,60例发生左侧喉返神经旁淋巴结转移。628例病人共清扫左侧喉返神经旁淋巴结1666枚,其中左侧喉返神经旁淋巴结转移75枚,转移率为4.502%(75/1666)。(2)CT检查左侧喉返神经旁淋巴结短径评估术后左侧喉返神经旁淋巴结转移效能:CT检查左侧喉返神经旁淋巴结短径预测左侧喉返神经旁淋巴结转移的AUC为0.854(95%可信区间为0.792~0.916,P<0.05)。(3)最佳截断值的确定:分别以CT检查左侧喉返神经旁淋巴结短径为5、6、7、8、9、10 mm作为最佳截断值,其对应的约登指数分别为0.556、0.384、0.258、0.063、0.003。确定CT检查左侧喉返神经旁淋巴结短径5 mm为最佳截断值。(4)不同诊断标准的检测情况:分别以CT检查左侧喉返神经旁淋巴结短径≥5 mm和≥10 mm作为胸段食管鳞癌左侧喉返神经旁淋巴结转移的诊断标准,两者灵敏度、特异度、准确度、阳性预测值、阴性预测值、漏诊情况分别为66.3%和5.0%、92.3%和99.8%、89.5%和90.7%、46.3%和75.0%、96.0%和90.9%、20和57例。结论CT检查淋巴结短径可用于评估胸段食管鳞癌左侧喉返神经旁淋巴结转移。以淋巴结短径≥5 mm作为胸段食管鳞癌左侧喉返神经旁淋巴结转移标准时,灵敏度、特异度和准确度较好。     

Preoperative evaluation of patients with primary head and neck cancer using dual-head 18fluorodeoxyglucose positron emission tomography

OBJECTIVE: To evaluate the value of 18fluorodeoxyglucose (FDG) positron emission tomography (PET) in primary head and neck cancer. BACKGROUND DATA: Head and neck carcinomas tend to metastasize to regional lymph nodes rather than to spread hematogenously. With nodal metastases, cure rates decrease by approximately 50%. Moreover, in approximately 3% of the patients, a second primary tumor is found at initial presentation. METHODS: Fifty-four consecutive patients (31 men and 23 women; mean age 60 years, range 34-81 years) with previously untreated squamous cell carcinomas of the oral cavity or oropharynx were studied. Before surgery and within a period of 3 weeks, clinical examination, chest x-ray, computed tomography (CT), ultrasonography with fine-needle aspiration cytology (US/ FNAC), and FDG-PET were performed. All study results were scored per neck side and were also classified as 0 (no metastases), 1 (single metastasis), or 2 (multiple metastases). RESULTS: The sensitivity for the detection of lymph node metastases per neck side was 96%, 85%, and 64% for FDG-PET, CT, and US/FNAC, respectively. The specificity was 90%, 86%, and 100% for FDG-PET, CT, and US/FNAC, respectively. In terms of the classification, FDG-PET showed the best correlation with the histologic data. Finally, in nine patients (17%), a second primary tumor was detected by FDG-PET and confirmed by histologic evaluation. CONCLUSION: Because of the high prevalence of second primary tumors detected by FDG-PET and the decreased error rate in the assessment of lymph node involvement compared with CT and US, FDG-PET should be routinely performed in patients with primary head and neck cancer.     

Diagnosis of esophageal cancer using positron emission tomography

Fluorodeoxyglucose positron emission tomography (FDG-PET) is more accurate than computed tomography (CT) for evaluating lymph node metastases and for N staging, but less accurate than combined CT and endoscopic ultrasonography (EUS). Lymph nodes located adjacent to the primary lesion tend to be false negatives. We consider that combined FDG-PET and EUS is the most accurate for the detection of lymph node metastasis in esophageal cancer. FDG-PET is also more accurate than CT for detecting distant metastases and improves the detection of stage IV disease compared with the conventional staging modalities. For the diagnosis of recurrence except for perianastomotic recurrence, FDG-PET provides additional information and is more sensitive than conventional work-ups. FDGPET is a valuable tool for the noninvasive assessment of tumor response after neoadjuvant therapy. 11C-methionine (MET) is another tracer for PET that can be used to assess the metabolism of amino acids, since MET accumulates in esophageal malignant tumors. Choline-PET is more accurate than FDG-PET for the detection of mediastinal lymph node metastases.     

Defining a role for endoscopic ultrasound in staging periampullary tumors

BACKGROUND: The goal of the preoperative workup in patients with suspected periampullary carcinoma is to establish the diagnosis with a high degree of certainty. In this study we compared endoscopic ultrasonography (EUS) and computed tomography (CT) scans for the detection of tumor, lymph node metastasis, and vascular invasion in patients with suspected periampullary carcinoma in order to define a role for EUS in the preoperative staging of these patients. METHODS: Thirty-seven consecutive patients received EUS and CT scanning followed by operation for presumed periampullary carcinoma during a 30-month period. Both imaging modalities were reviewed in a blinded fashion and the results compared with pathology and operative reports on all patients. RESULTS: Sensitivity, specificity, positive predictive value, and negative predictive value for tumor detection by EUS were 97%, 33%, 94%, and 50%, respectively, compared with 82%, 66%, 97%, and 25% for CT scan. For lymph nodes the values were 21%, 80%, 57%, and 44%, respectively, for EUS compared with 42%, 73%, 67%, and 50% for CT. For vascular invasion, the values were 20%, 100%, 100%, and 89%, respectively, for EUS, compared with 80%, 87%, 44%, and 96% for CT. CONCLUSIONS: CT is the initial study of choice in patients with suspected periampullary tumors. EUS is superior for detecting tumor and for predicting vascular invasion. Therefore, EUS should be used for patients in whom CT does not detect a mass and for those with an identifiable mass on CT in whom vascular invasion cannot be ruled out.     

Incidental Thyroid Carcinoma by FDG-PET/CT: A Study of Clinicopathological Characteristics

Background

The rising incidence of incidental thyroid carcinoma (ITC) detected during fluoro-2-deoxy-d-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) scanning poses a challenge to clinicians. The present study aims to critically evaluate the clinicopathological characteristics of ITC detected by FDG-PET/CT.

Methods

Among the 557 patients managed at our institution, 40 (7.2%) patients were identified as having ITC. Of these, 22 patients had their tumor detected by FDG-PET/CT (PET group) and 11 by ultrasonography (USG group). Additional bedside ultrasonography ± fine-needle aspiration (FNA) was done in all patients at their clinic visit. The clinicopathological characteristics were compared between the PET and USG groups.

Results

The PET group had significantly more patients with history of nonthyroidal malignancy (P < 0.001). Papillary carcinoma was the most common histological type in both groups. Despite having similar histological and prognostic features including tumor size, tumor multifocality, capsular invasion, extrathyroidal extension, and lymph node metastases, tumor bilaterality (or presence of contralateral tumor focus) was significantly more frequent in the PET than the USG group (P = 0.04). The tumors were also more advanced by the tumor–node–metastasis (TNM) staging system in the PET group (P = 0.021). None of the contralateral tumor foci were evident preoperatively. One patient in the USG group developed metastatic thyroid carcinoma in neck lymph nodes 28 months after thyroid resection.

Conclusion

ITC by FDG-PET/CT had higher incidence of tumor bilaterality than those detected by ultrasonography. Total thyroidectomy should be considered for ITC detected by FDG-PET/CT even for tumor size <10 mm.