Combining independent studies of diagnostic fluorodeoxyglucose positron-emission tomography and computed tomography in mediastinal lymph node staging for non-small cell lung cancer

AIMS AND BACKGROUND: A meta-analysis of diagnostic test performance was conducted to compare the results of relevant studies reporting diagnostic accuracy values for mediastinal staging in patients with non-small cell lung cancer (NSCLC). This paper deals with the two most accurate imaging techniques currently in use: positron emission tomography (PET) with FDG and computed tomography (CT). A statistical pooling method was used to perform a quantitative meta-analysis aimed at demonstrating the potential advantage of one of these two methods. METHODS: Studies in all languages published between 1998 and 2005 that examined the use of FDG-PET and CT for mediastinal staging in NSCLC patients, enrolled at least 18 participants, and provided enough data to allow calculation of sensitivity and specificity rates were considered eligible for the quantitative meta-analysis. Statistical methods to pool the overall estimates of sensitivity and specificity and to compare the discriminant power of PET and CT were discussed and used. RESULTS: Of the 13 studies included in the analysis, 12 reported greater accuracy of FDG-PET than CT in detecting mediastinal lymph node metastases. The sensitivity of FDG-PET ranged from 50% to 100%. The estimate of the overall sensitivity was 0.83% with 95% CI (0.749-0.913). Specificity ranged from 79% to 100%, with an overall estimated specificity of 0.87% with 95% CI (0.80-0.95). For CT, the sensitivity and specificity ranged from 50% to 97% and 58% to 94%, respectively; the overall estimate was 0.68% with 95% CI (0.582-0.788) and 0.76% with 95% CI (0.668-0.859). The summary receiver operating characteristic (SROC) approach was used to assess the superior diagnostic accuracy of one of the two methods. The areas under the two SROC curves were AUC(PET) = 0.909 vs. AUC(CT) = 0.794. CONCLUSIONS: Numerical and visual results of the meta-analysis of recent relevant reports agreed that FDG-PET is more accurate than CT in identifying mediastinal lymph node metastases in non-small cell lung cancer.     

FDG-PET in staging lung cancer: how does it change the algorithm?

BACKGROUND: In patients with lung cancer, positron emission tomography (PET) using fluor-18-fluorodesoxyglucose (FDG) may be used both to detect extrathoracic metastases (ETM) and for mediastinal lymph node staging (MLS), potentially reducing the need for mediastinoscopy. We assessed the added value of FDG-PET in detecting ETM and focused on the reliability of FDG-PET and mediastinoscopy for MLS. PATIENTS AND METHODS: In 72 consecutive patients with non-small cell lung cancer, the impact of adding FDG-PET to full conventional clinical staging was prospectively analyzed. The predictive value of FDG-PET findings and tumor location for pathologic mediastinal lymph node status were assessed in a logistic regression analysis. RESULTS: Unexpected extrathoracic metastases were detected by FDG-PET in 15% of patients. In MLS overall negative and positive predictive values were 71 and 83% for FDG-PET, and 92 and 100% for mediastinoscopy. However, the negative predictive value of FDG-PET was only 17% in case of FDG-PET positive N1 nodes and/or a centrally located primary tumor, whereas it was 96% in case of FDG-PET negative N1 nodes and a non-centrally located primary tumor. CONCLUSION: By incorporating FDG-PET in clinical staging, 15% of patients with lung cancer are upstaged due to unexpected extrathoracic metastases. In case of a negative mediastinal FDG-PET, mediastinoscopy can only be omitted in the presence of a non-centrally located primary tumor and without FDG-PET positive N1 nodes.     

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).     

The role of positron emission tomography in evaluating mediastinal lymph node metastases in non-small-cell lung cancer

Positron emission tomography (PET) is a modality that differentiates malignant from benign processes based upon metabolism rather than anatomy. A number of studies have confirmed improved accuracy of PET over computed tomography (CT), but until a few recent studies, most had failed to include satisfactory histologic confirmation. The objective of this study was to compare PET and CT to histologic staging of the mediastinum in patients with non-small-cell lung cancer (NSCLC). Histologic examination of mediastinal lymph nodes (MLNs) was performed on 40 patients with NSCLC at mediastinoscopy and/or at surgical resection. PET scans were interpreted by one of two nuclear medicine physicians, blinded to histology, using CT scans for anatomic localization. CT scans were independently evaluated for mediastinal lymphadenopathy. The overall accuracy, sensitivity, and specificity of PET were 78% (31 of 40), 67% (four of six), and 79% (27 of 34), respectively. The overall accuracy, sensitivity, and specificity of CT were 68% (27 of 40), 50% (three of six), and 71% (24 of 34), respectively. PET was superior to CT at correctly identifying mediastinal nodal metastases; however, both modalities were inferior to the gold standard of surgical staging. PET is more accurate than CT in staging the mediastinum of patients with NSCLC. PET failed to identify lymph node metastasis in 33% of patients with histologically proven MLN involvement, and false positives were present in 15%. At present, mediastinoscopy should remain the standard of care for preoperative mediastinal staging for NSCLC.     

Accuracy of positron emission tomography in mediastinal node assessment in coal workers with lung cancer

The purpose of this study was to explore the accuracy of ¹⁸F-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) in the assessment of mediastinal lymph node in coal workers who had non-small cell lung cancer. We retrospectively reviewed 42 retired coal workers who had lung cancer without distant metastasis, between May 2007 and May 2010. Regarding the mediastinal lymph nodes, when the standard uptake value was greater than 2.5, it was considered “malignancy positive.” After histological examination of the mediastinal lymph nodes, anthracotic and metastatic ones were detected. The results of PET/CT were analyzed to determine its accuracy. Of these 42 patients, PET/CT detected 47 positive mediastinal lymph nodes in 24 patients with a mean SUV maximum of 6.2 (2.6–13.8). One hundred and thirty-one mediastinal lymph node foci were dissected. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of FDG-PET/CT in detecting nodal metastases were 84% (16/19), 65% (15/23), 66% (16/24), 83% (15/18), and 74% (31/42) on a per-patient basis, respectively. Mediastinal node staging with FDG-PET/CT in coal workers is insufficient due to the high false-positive rates due to the presence of pneumoconiosis. In these patients, an invasive technique such as mediastinoscopy seems mandatory for confirmation of ipsilateral or contralateral mediastinal lymph node metastasis.     

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.     

Towards a minimally invasive staging strategy in NSCLC: analysis of PET positive mediastinal lesions by EUS-FNA

STUDY OBJECTIVE: To asses the value of endoscopic ultrasound guided fine needle aspiration (EUS-FNA) in the nodal staging of patients with (suspected) non-small cell lung cancer (NSCLC) and a (18)FDG positron emission tomography (PET) scan suspect for N2/N3 mediastinal lymph node (MLN) metastases. BACKGROUND: Due to the imperfect specificity of positron emission tomography, PET positive MLN should be biopsied in order to confirm or rule out metastasis. Currently, invasive surgical diagnostic techniques such as mediastinoscopy/-tomy are standard procedures to obtain MLN tissue. The minimally invasive technique of EUS-FNA has a high diagnostic accuracy (90-94%) for the analysis of MLN in patients with enlarged MLN on computed tomography of the chest (CT). DESIGN AND PATIENTS: Thirty-six patients with proven n=26 or suspected n=10 non-small cell lung cancer and a PET scan suspect for N2/N3 lymph node metastases underwent EUS-FNA. When EUS-FNA did not confirm metastasis and the PET lesion was within reach of mediastinoscopy, a mediastinoscopy was performed. EUS-FNA negative patients with PET lesions beyond the reach of mediastinoscopy or those with a negative mediastinoscopy were referred for surgical resection of the tumour and MLN sampling or dissection. RESULTS: EUS-FNA confirmed N2/N3 disease in 25 of the 36 patients (69%) and was highly suspicious in one. In the remaining 10 patients, one PET positive and one PET negative N2 metastasis was detected at thoracotomy. The PPV, NPV, sensitivity, specificity and accuracy of EUS-FNA in analysing PET positive MLN were 100%, 80%, 93%, 100% and 94%, respectively. No complications of EUS-FNA were recorded. CONCLUSIONS AND SIGNIFICANCE: EUS-FNA yields minimally invasive confirmation of MLN metastases in 69% of the patients with potential mediastinal involvement at FDG PET. The combination of PET and EUS-FNA might qualify as a minimally invasive staging strategy for NSCLC.     

Inefficacy of F-18 fluorodeoxy-D-glucose-positron emission tomography scans for initial evaluation in early-stage cutaneous melanoma

BACKGROUND: The purpose of the current study was to determine the sensitivity and specificity of initial F-18 fluorodeoxy-D-glucose-positron emission tomography (FDG-PET) scanning for detection of occult lymph node and distant metastases in patients with early-stage cutaneous melanoma. METHODS: The authors conducted a prospective nonrandomized clinical trial. Inclusion criteria were patients with cutaneous melanoma tumors > 1.0 mm Breslow thickness, local disease recurrence, or solitary intransit metastases without regional lymph or distant metastases by standard clinical evaluation. All patients underwent whole-body FDG-PET scanning before surgical therapy. Abnormal PET findings were studied by targeted conventional imaging and/or biopsy. FDG-PET scans were interpreted in a blinded fashion. Regional lymph node basins were staged by sentinel lymph node biopsy (SLNB). PET scan findings in regional lymph nodes were compared with histology of SLNB specimens. Abnormal distant PET scan findings were studied with repeat conventional scan imaging at 3-6 months and were correlated with the first site(s) of clinical disease recurrence. Blinded PET scan findings were correlated with all information to determine sensitivity and specificity. RESULTS: There were 144 assessable patients with a mean tumor depth of 2.8 mm. The median follow-up for these patients was 41.4 months. Blinded interpretations of FDG-PET scan images showed that 31 patients (21%) had signs of metastatic disease, 13 patients had probable regional lymph node metastases, and 18 patients had 23 sites of possible distant metastases. SLNB and/or follow-up demonstrated regional lymph node metastases in 43 of 184 lymph node basins in 40 patients (27.8%). Compared with all clinical information, FDG-PET scan sensitivity for detection of regional lymph node metastases was 0.21 (95% confidence [CI], 0.10-0.36) and specificity was 0.97 (95% CI, 0.93-0.99). No distant sites were confirmed to be true positive by targeted conventional imaging/biopsy at the time of presentation. Thirty-four patients (23.6%) presented with 54 foci of metastatic disease at initial disease recurrence. FDG-PET scan sensitivity for prediction of the first site(s) of clinical disease recurrence was 0.11 (95% CI, 0.04-0.23). Excluding patients with brain metastases, FDG-PET scan sensitivity for detection of occult Stage IV disease in patients was 0.04 (95% CI, 0.001-0.20) and specificity was 0.86 (95% CI, 0.79-0.92). CONCLUSIONS: FDG-PET scanning did not impact the care of patients with early-stage melanoma already staged by standard techniques. Routine FDG-PET scanning was not recommended for the initial staging evaluation in this population.     

Value of positron emission tomography for lung cancer staging.

OBJECTIVE: The therapeutic strategy in non-small-cell lung cancer (NSCLC) requires exact staging of tumour invasion (T) as well as differentiation between ipsi- and contralateral lymph node invasion (N1/2 vs N3). [18F]FDG-positron emission tomography (FDG-PET) has been shown to detect invaded N with high accuracy while correct determination of T appears to be unclear. The purpose of this prospective study was to evaluate benefit and necessity of 18FDG-PET as an additive to conventional staging modalities. METHODS: Forty patients with suspected non-small-cell lung cancer (NSCLC) were staged by means of computed tomography (CT), bronchoscopy, mediastinoscopy and bone scintigraphy. Additionally, attenuation corrected FDG-PET of the thorax was performed pre-operatively for analysis of T and N topography. After surgical resection with radical lymphadenectomy T and N staging results of CT and PET were compared with the pathological diagnoses. Specificity, sensitivity, positive predictive value and accuracy of CT and PET were calculated. RESULTS: Twenty three squamous cell carcinomas, 14 adenocarcinomas, and three non-malignant tumours were found. Accuracy of CT-T was 0.75 and of PET-T 0.78; accuracy of CT-N was 0.78 and of PET-N 0.80. By combination of CT-T and PET-T accuracy was 0.88. Combination of CT-N and PET-N yielded an accuracy of 0.90. In two out of three cases, PET correctly determined T0. In two cases non-malignant inflammatory lymph nodes were falsely staged as malignant by PET. CONCLUSIONS: Adequate pre-operative T- and N-staging is possible with both CT and FDG-PET. Accuracy can be improved by combination of CT and FDG-PET. FDG-PET is superior to CT in order to differentiate between malignant and benign tumours. However, acute inflammation can mimic malignant lymph node invasion. FDG-PET is justified as a supporting staging measure in cases presenting unclear differentiation between N2 and N3 after conventional staging and is helpful in cases with unclear cell type of the primary tumour.     

非小细胞肺癌纵隔淋巴结分期诊断研究进展

目的 肺癌是全球死亡率最高的恶性肿瘤之一,其中80％是非小细胞肺癌(non-small cell lung cancer,NSCLC).本研究回顾总结国内外NSCLC纵隔淋巴结分期诊断的研究进展,为临床采取合适的检查方法及治疗方案提供一定指导.方法 应用PubMed、中国知网、万方数据库、维普中文期刊服务平台等检索系统,以“NSCLC、术前、纵隔淋巴结分期、电子发射计算机体层显像-X线计算机体层(integrated positron emission tomography-computed tomography,PET-CT)、计算机断层成像(computed tomography,CT)、磁共振成像(magnetic resonance imaging,MRI)、纵隔镜、针吸活检术”为关键词,检索2000-07-27-2016-03-05相关文献,纳入标准:(1) NSCLC纵隔淋巴结的有创性外科检查方法;(2) NSCLC纵膈淋巴结的无创性影像学检查方法.结果 根据纳入标准纳入分析40篇相关文献.总结出无创性影像学分期、有创性外科分期各检查的优缺点、灵敏度、特异度、准确度、假阳性率、假阴性率及临床应用情况.NSCLC纵隔淋巴结检查方法中,CT对纵隔淋巴结分期的灵敏度(61.1％)及特异性(71.1％)均较低;脱氧葡萄糖(fluorodeox-yglucose,FDG)PET-CT灵敏度和特异度分别是64％和83.3％,但其价格昂贵;磁共振扩散加权成像诊断NSCLC纵隔淋巴结转移的效能优于FDG PET-CT;纵隔镜灵敏度和特异度分别是78％和100％,存在一定的并发症(2％)和死亡率(0.08％);支气管内镜超声引导针吸活检操作方便,其灵敏度和特异度分别是92％和100％,不能取检主动脉旁及下纵隔淋巴结.结论 CT已作为评估NSCLC纵隔淋巴结分期的常规检查;FDG PET-CT是最准确的无创性检查方法;纵隔镜是目前诊断纵隔淋巴结分期的金标准,未来的趋势是各技术整合、优势互补以达到更准确的NSCLC纵隔分期.     

Axillary lymph node staging in breast cancer by 2-fluoro-2-deoxy-D-glucose-positron emission tomography: clinical evaluation and alternative management

BACKGROUND: Surgical removal of axillary lymph node and histologic examination for metastases are used to determine whether adjuvant treatment is necessary for patients with breast cancer. Axillary lymph node dissection (ALND) is a costly procedure associated with various side effects, and 80% or more of patients with tumors of 20 mm or less are lymph node negative and might avoid ALND. In this study, we evaluated whether an alternative, noninvasive method--i.e., positron emission tomography (PET) with 2-[(18)F]fluoro-2-deoxy-D-glucose (FDG)-- could be used to determine axillary lymph node status in patients with breast cancer. METHODS: One hundred sixty-seven consecutive patients with breast cancers of 50 mm or less (range = 5-50 mm; mean = 21 mm) scheduled for complete ALND were studied preoperatively with FDG-PET, and then PET and pathology results from ALND were compared. All statistical tests were two-sided. RESULTS: The overall sensitivity, specificity, and accuracy of lymph node staging with PET were 94.4% (PET detected 68 of 72 patients with axillary involvement; 95% confidence interval [CI] = 86.0% to 98.2%), 86.3% (82 of 95 patients without axillary involvement; 95% CI = 77.8% to 91.9%), and 89.8% (150 of 167 patients with breast cancer; 95% CI = 84.2% to 93.6%), respectively. Positive- and negative-predictive values were 84.0% (68 patients with histologically positive lymph nodes of 81 patients with positive FDG-PET scan; 95% CI = 74.2% to 90.5%) and 95.3% (82 patients with histologically negative lymph nodes of 86 patients with negative FDG-PET scan; 95% CI = 88.2% to 98.5%), respectively. When PET results for axillary metastasis were analyzed by tumor size, the diagnostic accuracy was similar for all groups (86.0%-94.2%), with higher sensitivity for tumors of 21-50 mm (98.0%) and higher specificity for tumors of 10 mm or less (87.8%), and the range was 93.5%-97.3% for negative-predictive values and 54.5%-94.1% for positive-predictive values. Among the 72 patients with axillary involvement, PET detected three or fewer metastatic lymph nodes in 27 (37.5%) patients, about 80% of whom had no clinically palpable axillary lymph nodes. CONCLUSIONS: Noninvasive FDG-PET appears to be an accurate technique to predict axillary status in patients with breast cancer and thus to identify patients who might avoid ALND. These results should be confirmed in large multicenter studies.     

Endobronchial ultrasound and value of PET for prediction of pathological results of mediastinal hot spots in lung cancer patients

SUMMARY: In the staging of lung cancer with positron emission tomography (PET) positive mediastinal lymph nodes, tissue sampling is required. The performance of transbronchial needle aspiration (TBNA) using linear endobronchial ultrasound (real-time EBUS-TBNA) under local anaesthesia and the value of PET for prediction of pathological results were assessed in that setting. The number of eluded surgical procedures was evaluated. All consecutive patients with suspected/proven lung cancers and FDG-PET positive mediastinal adenopathy were included. If no diagnosis was reached, further surgical sampling was required. Lymph node SUVmax (maximum standardized uptake value) was assessed in patients whose PET was performed in the leading centre. One hundred and six patients were included. The average number of TBNA samples per patient was 4.9+/-1.1. The prevalence of lymph node metastasis was 58%. Sensitivity, accuracy and negative predictive value of EBUS-TBNA in the staging of mediastinal hot spots were 95, 97 and 91%. Patients without malignant lymph node involvement showed lower SUVmax (respective median values of 3.7 and 10.0; p<0.0001). Surgical procedures were eluded in 56% of the patients. Real-time EBUS-TBNA should be preferred over mediastinoscopy as the first step procedure in the staging of PET mediastinal hot spots in lung cancer patients. In case of negative EBUS, surgical staging procedure should be undertaken. The addition of SUVmax cut-off may allow further refinement but needs validation.     

Mediastinal lymph node staging by means of positron emission tomography is less sensitive in elderly patients with non-small-cell lung cancer

PURPOSE: We sought to identify the impact of age on the sensitivity and specificity of integrated positron emission tomography/computed tomography (PET-CT; CT) on mediastinal lymph node staging of patients with non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: We conducted a retrospective review of 206 consecutive patients with histologically proven NSCLC who underwent resection and/or mediastinoscopy in our center between September 2004 and January 2007. All of these patients had preoperative staging with integrated PET-CT as an adjunct to chest CT before resection and/or mediastinoscopy. Diabetic patients and patients who received neoadjuvant chemotherapy were excluded. The pathologic results of all of these cases were reviewed and correlated with those on CT and integrated PET-CT. RESULTS: The sensitivity and positive predictive values (PPV) of PET-CT in mediastinal nodal staging were significantly lower in elderly patients (age>or=65 years; sensitivity, 42%; PPV, 66%) than in younger patients (age<65 years; sensitivity, 52%; PPV, 74%). Specificity and negative predictive values were similar in both groups. CONCLUSION: PET-CT staging of the mediastinum is less sensitive in elderly patients with NSCLC who have a lower PPV. Positive mediastinal uptake on PET-CT should be verified by mediastinoscopy, irrespective of age. Elderly patients with positive mediastinal uptake should not be refuted a curative intent surgical resection on the basis of positive mediastinal uptake alone.     

Improvement in preoperative staging of gastric adenocarcinoma with positron emission tomography

BACKGROUND: Positron emission tomography (PET) with 18- fluorodeoxyglucose (FDG) has been used to both detect and stage a variety of malignancies. The current study examined the value of PET for preoperative staging of gastric adenocarcinoma. METHODS: Sixty-eight patients (49 males and 19 females) with gastric adenocarcinoma, who were referred for preoperative FDG-PET scans, were enrolled in this study. The patients underwent spiral-computed tomography (CT) within 1 week of referral. The final diagnosis in all patients was made by histologic and surgical findings. For quantitative PET analysis, the regional tumor FDG uptake was measured by the standardized uptake value (SUV). RESULTS: For the primary tumor of a gastric adenocarcinoma, PET demonstrated an increased uptake in 64 of 68 patients (sensitivity, 94%), with a mean SUV of 7.0 (range, 0.9-27.7). A comparison of FDG uptake and clinicopathologic features showed significant association between FDG uptake and macroscopic type, tumor size, lymph node metastasis, histologic type, and TNM stage. The PET scan had a similar accuracy with that of CT for diagnosing local and distant lymph node metastases as well as peritoneal status. In assessing local lymph node status, however, PET had a higher specificity than CT (92% vs. 62%, P = 0.000). Moreover, PET had additional diagnostic value in 10 (15%) of 68 patients by upstaging 4 (6%) and downstaging 6 (9%) patients. PET combined with CT was more accurate for preoperative staging than either modality alone (66% vs. 51%, 66% vs. 47%, respectively; P = 0.002). CONCLUSIONS: FDG-PET improves the preoperative TNM staging of gastric adenocarcinoma. Based on its superior specificity, FDG-PET can facilitate the selection of patients for a curative resection by confirming a nodal status identified by CT.     

非小细胞肺癌纵隔淋巴结转移危险因素分析及术前纵隔镜检查的应用策略

目的 探讨纵隔镜技术评估非小细胞肺癌(NSCLC)术前纵隔淋巴结状态(是否存在转移)的临床应用策略.方法 2000年10月至2007年6月,对临床连续收治的经病理确诊的临床分期为Ⅰ～Ⅲ期的NSCLC患者152例,分别采用CT和纵隔镜技术评估纵隔淋巴结状态.根据纵隔淋巴结最终病理结果,计算CT下纵隔肺门淋巴结阴性NSCLC的纵隔镜检查阳性率和实际纵隔淋巴结转移发生率.以患者性别、年龄、肿瘤部位、病理类型、肿瘤T分期、肿瘤类型(中央型或外周型)、CT下纵隔淋巴结大小和血清癌胚抗原(CEA)水平等作为预测因子,进行纵隔淋巴结转移危险因素的单因素和多因素分析.结果 69例CT下纵隔肺门淋巴结阴性NSCLC,纵隔镜检查阳性8例,阳性率为11.6%;实际纵隔淋巴结转移14例,发生率为20.1%.62例临床Ⅰ期(cT1～2NOMO)NSCLC,纵隔镜检查阳性7例,阳性率为11.3%;实际纵隔淋巴结转移12例,发生率为19.4%.对全部152例NSCLC患者纵隔淋巴结转移危险因素的分析结果显示,病理类型和CT下纵隔淋巴结大小是纵隔淋巴结转移的独立危险因素.对69例CT下纵隔肺门淋巴结阴性NSCLC患者纵隔淋巴结转移危险因素的分析结果显示,病理类型是纵隔淋巴结转移的独立危险因素.结论 对于CT下纵隔淋巴结短径≥1 cm的NSCLC患者,术前必须进行纵隔镜检查;对于腺癌患者,即使是CT下纵隔肺门淋巴结短径<1 cm,术前也应该进行纵隔镜检查.     

Negative predictive value of positron emission tomography and computed tomography for stage T1-2N0 non-small-cell lung cancer: a meta-analysis

BackgroundNodal staging of non–small-cell lung cancer (NSCLC) is crucial in evaluation of prognosis and determination of therapeutic strategy. This study aimed to determine the negative predictive value (NPV) of combined positron emission tomography and computed tomography (PET-CT) in patients with stage I (T1-2N0) NSCLC and to investigate the possible risk factors for occult nodal disease.MethodsStudies investigating the performance of PET in conjunction with CT in the nodal staging of stage I NSCLC were identified in the MEDLINE database. The initiative of standards for reporting of diagnostic accuracy (STARD) was used to ensure study quality. Pathologic assessments through mediastinoscopy or thoracotomy were required as the reference standard for evaluation of PET-CT accuracy. Stata-based meta-analysis was applied to calculate the individual and pooled NPVs.ResultsTen studies with a total of 1122 patients with stage I (T1-2N0) NSCLC were eligible for analysis. The NPVs of combined PET and CT for mediastinal metastases were 0.94 in T1 disease and 0.89 in T2 disease. Including both T1 disease and T2 disease, the NPVs were 0.93 for mediastinal metastases and 0.87 for overall nodal metastases. Adenocarcinoma histology type (risk ratio [RR], 2.72) and high fluorine-18 (¹⁸F) fluorodeoxyglucose (FDG) uptake in the primary lesion were associated with greater risk of occult nodal metastases.ConclusionsAlthough overall occult nodal metastases in clinical stage T1-2N0 NSCLC is not infrequent, combined PET and CT provide a favorable NPV for mediastinal metastases in T1N0 NSCLC, suggesting a low yield from routine invasive staging procedures for this subgroup of patients.     

非小细胞肺癌纵隔淋巴结分期:螺旋CT和病理检查对照

背景与目的:非小细胞肺癌纵隔淋巴结分期对肿瘤的规范化治疗方案的选择和预后判断具有极其重要的意义。本研究旨在通过比较螺旋CT和病理检查对非小细胞肺癌纵隔淋巴结分期的结果,评价螺旋CT检查对纵隔淋巴结分期的临床参考价值。方法:对89例病理确诊的非小细胞肺癌患者同时进行螺旋CT检查和纵隔镜检查,将CT对纵隔淋巴结分期结果与淋巴结最后病理分期做一一对照,对比分析螺旋CT检查诊断纵隔淋巴结转移的敏感性、特异性和准确率。结果:与纵隔淋巴结最后病理分期一一对照,螺旋CT检查诊断纵隔淋巴结转移的敏感性为58.9%,特异性为70.0%,阳性预测值60.5%,阴性预测值68.6%,总的准确率为65.2%。螺旋CT检查诊断4R、5、6、7组淋巴结转移的准确率和特异性偏低,诊断4R组和7组淋巴结转移的假阳性和假阴性较高。结论:螺旋CT检查对非小细胞肺癌纵隔淋巴结临床分期有一定的临床参考价值,但存在一定的假阳性和假阴性,应结合其他检查手段,比如纵隔镜,以进行更精确的分期。     

Mediastinal staging (take home messages)

Mediastinal lymph-node involvement is still the major prognostic factor in NSCLC. Currently, cervical mediastinoscopy is the gold standard of mediastinal lymph-node staging. However, less invasive methods such as transbronchial or transoesophageal FNA are becoming more popular and might replace or adjunct mediastinoscopy under certain circumstances. It has been clearly shown that FDG PET is more accurate than CT for the detection of mediastinal lymph-node metastases. However, a positive finding on the PET scan implies that these lymph nodes have to be examined by invasive methods (e.g. mediastinoscopy). It has been demonstrated that PET might be useful in order to detect non-symptomatic distant metastases. The method of pathological analysis of the lymph nodes is critical for the correct determination of the N stage.     

Prospective study of fluorodeoxyglucose-positron emission tomography imaging of lymph node basins in melanoma patients undergoing sentinel node biopsy.

PURPOSE: To prospectively compare positron emission tomography (PET) imaging of regional lymph node basins to sentinel node biopsy (SNB) in patients with American Joint Committee on Cancer (AJCC) stage I, II, and III melanoma localized to the skin. METHODS: Patients with cutaneous melanoma with Breslow's depth greater than 1 mm (AJCC T2-4N0M0) or localized regional cutaneous recurrence (TxN2bM0) underwent whole-body imaging of glucose metabolism with fluorodeoxyglucose (FDG) PET followed by SNB. PET scans were interpreted in a blinded fashion and compared with histologic analyses of SNB specimens and clinical follow-up examination. Nodal tumor volumes were estimated. RESULTS: Eighty-nine lymph node basins were evaluated by FDG-PET and SNB in 70 assessable patients. Eighteen patients (25.7%) had lymph node metastases at the time of FDG-PET imaging: 17 proved by SNB (24.3%) and one by follow-up examination (1.4%). Median tumor volume in positive sentinel node basins was 4.3 mm3 (range, 0.07 to 523 mm3). Sensitivity of SNB for detection of occult regional lymph node metastases was 94.4%, specificity was 100%, positive predictive value (PPV) was 100%, and negative predictive value (NPV) was 98.6%. Sensitivity of FDG-PET was 16.7%, specificity was 95.8%, PPV was 50%, and NPV was 81.9%. At a median follow-up duration of 16.6 months, seven patients (10%) developed recurrent disease. PET predicted one recurrence (14.3%) in a node basin missed by SNB. CONCLUSION: FDG-PET is an insensitive indicator of occult regional lymph node metastases in patients with melanoma because of the minute tumor volumes in this population. FDG-PET does not have a primary role for staging regional nodes in patients with clinically localized melanoma.     

Selective mediastinal node irradiation based on FDG-PET scan data in patients with non-small-cell lung cancer: a prospective clinical study

PURPOSE: To evaluate the patterns of recurrence when selective mediastinal node irradiation based on FDG-PET scan data is used in patients with non-small-cell lung cancer (NSCLC). METHODS AND MATERIALS: A prospective Phase I/II study was undertaken on 44 patients with NSCLC without detectable distant metastases on CT and FDG-PET scan, delivering either 61.2 Gy in 34 fractions over 23 days or 64.8 Gy in 36 fractions over 24 days (1.8 Gy b.i.d. with 8-h interval). Only the primary tumor and the positive mediastinal areas on the pretreatment FDG-PET scan were irradiated. Isolated nodal failure was defined as recurrence in the regional nodes outside of the clinical target volume, in the absence of in-field failure. RESULTS: The CT and FDG-PET stage distribution was as follows: Stage I: 8 patients (18%) and 13 patients (29%); Stage II: 6 patients (14%) and 10 patients (23%); Stage IIIA: 15 patients (34%) and 7 patients (16%); Stage IIIB: 15 patients (34%) and 14 patients (32%), respectively. After a median follow-up time of 16 months (95% confidence interval [CI], 11-21 months) postradiotherapy, 11 patients (25%) developed a local recurrence. Only 1 patient (crude rate, 2.3%; upper bound of 95% CI, 10.3%), with a Stage II tumor on both CT and PET, developed an isolated nodal failure. The median actuarial overall survival was 21 months (95% CI, 14-28 months), and the median actuarial progression-free survival was 18 months (95% CI, 12-24 months). CONCLUSIONS: Selective mediastinal node irradiation based on FDG-PET scan data in patients with NSCLC results in low isolated nodal failure rates. In the Phase I component of this trial, radiation dose escalation up to 64.8 Gy in 36 fractions over 24 days is feasible.