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.     

食管癌IMRT前FDG PET-CT显像对治疗决策的影响

目的 探讨食管癌初治患者IMRT前PET-CT显像对其治疗方案的影响。方法 回顾分析60例经食管镜检证实的食管癌患者,患者均为初次治疗,经常规影像检查后拟行IMRT。放疗前行PET-CT显像,观察是否有分期和治疗方案改变。结果 与常规影像比,PET-CT显像使12例患者分期发生改变(2例T期上调、6例N期上调、2例N期下调、2例M期上调)。3例患者由于新发现较多的远处转移,治疗方案由放疗改为化疗。PET-CT检查导致20例患者靶区改变,其中16例因发现更多转移淋巴结使靶体积增大,4例则排除了淋巴结转移使靶区缩小。结论 PET-CT对食管癌区域淋巴结和远处转移诊断有一定优势,有助提高分期准确性,改变了部分患者治疗决策方案。     

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.     

Lymph node staging by positron emission tomography in patients with carcinoma of the cervix.

PURPOSE: The aim of this study was to compare the results of computed tomography (CT) and positron emission tomography (PET) with [18F]-fluoro-2-deoxy-D-glucose (FDG) for lymph node staging in patients with carcinoma of the cervix and to evaluate the relationship of the imaging findings to prognosis. PATIENTS AND METHODS: We retrospectively compared the results of CT lymph node staging and whole-body FDG-PET in 101 consecutive patients with carcinoma of the cervix. Patients were treated with standard irradiation and chemotherapy (as clinically indicated) and observed at 3-month intervals for a median of 15.4 months (range, 2.5 to 30 months). Progression-free survival was evaluated by the Kaplan-Meier method. RESULTS: CT demonstrated abnormally enlarged pelvic lymph nodes in 20 (20%) and para-aortic lymph nodes in seven (7%) of the 101 patients. PET demonstrated abnormal FDG uptake in pelvic lymph nodes in 67 (67%), in para-aortic lymph nodes in 21 (21%), and in supraclavicular lymph node in eight (8%). The 2-year progression-free survival, based solely on para-aortic lymph node status, was 64% in CT-negative and PET-negative patients, 18% in CT-negative and PET-positive patients, and 14% in CT-positive and PET-positive patients (P <.0001). A multivariate analysis demonstrated that the most significant prognostic factor for progression-free survival was the presence of positive para-aortic lymph nodes as detected by PET imaging (P =.025). CONCLUSION: This study demonstrates that FDG-PET detects abnormal lymph node regions more often than does CT and that the findings on PET are a better predictor of survival than those of CT in patients with carcinoma of the cervix.     

The additional value of integrated PET/CT over PET in initial lymph node staging of esophageal cancer

The purpose of the present study was to assess the contribution of simultaneous functional/anatomical imaging using integrated 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT), compared with PET alone for the evaluation of initial lymph node staging in esophageal cancer. We studied 167 consecutive patients with thoracic esophageal squamous cell carcinoma (SCC) who had radical esophagectomy performed between January 1999 and April 2007. For individual nodal group evaluation, PET/CT showed 46.0% sensitivity (p<0.05 vs. PET), 99.4% specificity, 95.1% accuracy (p<0.05 vs. PET), 87.0% positive and 95.5% negative predictive values. PET showed 32.9% sensitivity, 98.9% specificity, 93.1% accuracy, 74.7% positive predictive value and 93.9% negative predictive value. Thus, the sensitivity and accuracy of PET/CT were significantly higher than those of PET. Comparisons between CT, PET and PET/CT in detecting lymph node metastasis by each region showed that PET/CT had a higher sensitivity in lower thoracic regions than PET and CT (p<0.05 vs. CT and PET). Lymph node staging (N0 vs. N1) was not significantly different, but staging per lymph nodal group was significantly better with PET/CT. Integrated PET/CT imaging with co-registration of anatomic and functional imaging data is useful in the initial lymph node staging of patients with operable esophageal cancer compared with PET alone.     

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.     

Added value of para-aortic surgical staging compared to 18F-FDG PET/CT on the external beam radiation field for patients with locally advanced cervical cancer: An ONCO-GF study

ObjectiveExtended field chemoradiation is recommended for patients with locally advanced cervical cancer (LACC) and para-aortic lymph node (PALN) metastases. The radiation planning may be based on PET/CT while others recommend to rely on surgical staging. We report the rate of patients for whom the radiation field defined on PET/CT was modified by the histological PALN status.MethodsBetween March 2010 and December 2016, 168 consecutive patients with LACC underwent a pre-therapeutic PET/CT and PALN dissection. The data were reviewed retrospectively. The diagnostic performance of the PET/CT for definition of PALN status was calculated. We determined the percentage of patients for whom PALN dissection altered the external beam radiotherapy (EBRT) field defined on the PET/CT basis.ResultsOf 151 patients with negative PALNs on PET/CT, 26 had histological PALN metastases. Of 17 patients with positive PALNs on PET/CT, 9 were negative on histology of which 7 were located in the common iliac region. Sensitivity, specificity, positive and negative predictive value of PET/CT were 23.5, 93.3, 47.1 and 82.8% respectively. In total, 35 out of 168 patients underwent EBRT - field adaptation (pelvic vs extended field). The rate of radiation field modification (27,7%) was particularly high in the subgroup of patients with metastatic pelvic lymph nodes (PLNs) on PET/CT.ConclusionPara-aortic surgical staging contributes significantly to individualize the radiation treatment of patients with LACC, particularly for those with positive PLNs at PET/CT. Indication of surgical staging deserves particular attention when the PET/CT suggests positive LNs in the common iliac region.     

A comparative study on the value of FDG-PET and sentinel node biopsy to identify occult axillary metastases.

BACKGROUND: Sentinel node biopsy (SNB) has become a standard treatment in staging axillary lymph nodes in early breast cancer. SNB, however, is an invasive procedure and is time-consuming when the sentinel node is analysed intra-operatively. Breast cancer is frequently characterised by increased 2-fluoro-2-deoxy-D-glucose uptake and many studies have shown encouraging results in detecting axillary lymph node metastases. The aim of this study was to compare SNB and -positron emission tomography (-PET) imaging, to assess their values in detecting occult axillary metastases. PATIENTS AND METHODS: In all, 236 patients with breast cancer and clinically negative axilla were enrolled in the study. 18-FDG-PET was carried out before surgery, using a positron emission tomography (PET)/computed tomography scanner. In all patients, SNB was carried out after identification through lymphoscintigraphy. Patients underwent axillary lymph nodes dissection (ALND) in cases of positive FDG-PET or positive SNB. The results of PET scan were compared with histopathology of SNB and ALND. RESULTS: In all, 103 out of the 236 patients (44%) had metastases in axillary nodes. Sensitivity of FDG-PET scan for detection of axillary lymph node metastases in this series was low (37%); however, specificity and positive predictive values were acceptable (96% and 88%, respectively). CONCLUSIONS: The high specificity of PET imaging indicates that patients who have a PET-positive axilla should have an ALND rather than an SNB for axillary staging. In contrast, FDG-PET showed poor sensitivity in the detection of axillary metastases, confirming the need for SNB in cases where PET is negative in the axilla.     

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.     

Maximum standardized uptake value on PET/CT in preoperative assessment of lymph node metastasis from thoracic esophageal squamous cell carcinoma

The presence of lymph node metastasis is an important prognostic factor for patients with esophageal cancer. Accurate assessment of lymph nodes in thoracic esophageal carcinoma is essential for selecting appropriate treatment and forecasting disease progression. Positron emission tomography combined with computed tomography （PET/CT） is becoming an important tool in the workup of esophageal carcinoma. Here, we evaluated the effectiveness of the maximum standardized uptake value （SUVmax） in assessing lymph node metastasis in esophageal squamous cell carcinoma （ESCC） prior to surgery. Fifty-nine surgical patients with pathologically confirmed thoracic ESCC were retrospectively studied. These patients underwent radical esophagectomy with pathologic evaluation of lymph nodes. They all had 18F-FDG PET/CT scans in their preoperative staging procedures. None had a prior history of cancer. The pathologic status and PET/CT SUVmax of lymph nodes were collected to calculate the receiver operating characteristic （ROC） curve and to determine the best cutoff value of the PET/CT SUVmax to distinguish benign from malignant lymph nodes. Lymph node data from 27 others were used for the validation. A total of 323 lymph nodes including 39 metastatic lymph nodes were evaluated in the training cohort, and 117 lymph nodes including 32 metastatic lymph nodes were evaluated in the validation cohort. The cutoff point of the SUVmax for lymph nodes was 4.1, as calculated by ROC curve （sensitivity, 80%; specificity, 92%; accuracy, 90%）. When this cutoff value was applied to the validation cohort, a sensitivity, a specificity, and an accuracy of 81%, 88%, and 86%, respectively, were obtained. These results suggest that the SUVmax of lymph nodes predicts malignancy. Indeed, when an SUVmax of 4.1 was used instead of 2.5, FDG-PET/ CT was more accurate in assessing nodal metastasis.     

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.     

Is there a role for FGD-PET in radiotherapy planning in esophageal carcinoma?

BACKGROUND AND PURPOSE: To determine the additional value of FDG-positron emission tomography (PET) to optimize delineation of the clinical target volume (CTV) in patients with advanced esophageal carcinoma. METHODS AND MATERIALS: The imaging and radiotherapy data from 30 patients with an advanced esophageal carcinoma were analysed. The lymph node classification for esophageal cancer was modified and translated into anatomical volumes on computed tomography (CT). The so defined 14 different regions were scored individually for lymph node involvement on CT, endoscopic ultrasound (EUS) and FDG-PET. The influence of discordant findings between conventional and functional imaging on the decision as to what should be irradiated was assessed. RESULTS: In 14 of the 30 patients (47%) discordances were found in detection of the pathological lymph nodes between CT/EUS and FDG-PET. In 8 patients, 9 lymph node regions were found with pathologic nodes on conventional imaging only. In three of these patients the influence of FDG-PET findings would have led to a decrease of the irradiated volume. In 6 patients, 8 lymph node regions were found with a normal CT/EUS and pathologic nodes on FDG-PET. In three of these patients (10%) the influence of the FDG-PET would have led to enlargement of the irradiated volume. CONCLUSIONS: The chance of a false negative result on FGD-PET is not negligible; therefore, the irradiated volume should not be reduced based on a negative FDG-PET in a region with suspect nodes on other investigations. However, due to the high specificity of FDG-PET enlarging the irradiated volume based on a positive FDG-PET in a region without suspected lymph nodes on CT and/or EUS should be considered. This indicates a role for FDG-PET in radiotherapy planning for esophageal cancer.     

Usefulness of (18)F-FDG positron emission tomography/computed tomography for the diagnosis of pyothorax-associated lymphoma: A report of three cases

Pyothorax-associated lymphoma (PAL) is a unique and rare non-Hodgkin's lymphoma developing in the pleural cavity following a long-standing history of chronic pyothorax (CP). The development of F-18 2'-deoxy-2fluoro-D-glucose (FDG) positron emission tomography combined with computed tomography (PET/CT) has contributed to the evaluation of lymphoma staging. However, only a few studies describing FDG-PET/CT findings in PAL have been published. This study reported three cases of PAL; all 3 patients had previously undergone artificial collapse therapy for pulmonary tuberculosis. Both the first case (an 84-year-old male) and second case (an 83-year-old male) complained of abdominal pain. An ultrasound scan revealed a mass shadow in the left chest wall without abnormal findings in the abdomen, and the CT and magnetic resonance imaging scans suggested malignant lymphoma of the left chest. FDG-PET/CT imaging showed extremely intense FDG uptake only in the left pleura and chest wall. Diagnosis was CP in the two patients, showing a high maximum standardized uptake value (SUVmax: early, 14.8 and delayed, 19.4 in the first case; early, 20.8 and delayed, 27.3 in the second case, respectively). Histopathological analysis of the specimens obtained by biopsy of the PET/CT-positive pleural mass showed non-Hodgkin's, diffuse large B cell lymphoma in the two cases. The third case was a 79-year-old male with relapse after right pleuropneumonectomy for PAL (diffuse large B cell lymphoma) 4 years earlier. PET/CT showed intense FDG uptake (SUVmax: early, 19.9 and delayed, 35.7) in the right pleura and chest wall. Diagnosis was CP, suggesting the recurrence of PAL. Furthermore, abnormal intense FDG uptake was noted in the hilar, mediastinal and supraclavicular lymph nodes, as well as in the spleen. In conclusion, FDG-PET/CT imaging is useful in the evaluation of the area of invasion in PAL.     

Potential impact of 18F-FDG PET/CT on patients selection for neoadjuvant chemotherapy before radical cystectomy

BackgroundThe detection of lymph node metastases in bladder cancer has a major impact on treatment decisions and patients prognosis. Due to limited value of conventional imaging, the place of molecular and functional imaging needs to be precised, particularly in the neoadjuvant setting.MethodsFrom June 2011 to June 2013, 102 patients with clinically localized BCa were simultaneously staged with ¹⁸F-FDG PET/CT before RC. This study assessed the diagnostic accuracy of ¹⁸F-FDG PET/CT for the detection of metastases in normal-sized lymph nodes using extended pelvic lymph node dissection and histopathology as the reference standard.ResultsA total of 1211 LNs were examined histopathologically. Sixty-seven (5.5%) metastatic nodes were found in 26/102 patients (25.5%). Lymph node density was 22%. On patient-based analysis, sensitivity, specificity, predictive positive value (PPV), negative positive value (NPV) and accuracy for ¹⁸F-FDG PET/CT were calculated as 50%, 96.2%, 80%, 86.2% and 85.3% respectively. On a field-based analysis, sensitivity, specificity, PPV, NPV and accuracy for ¹⁸F-FDG PET/CT were calculated as 50.0%, 99.0%, 71.9%, 97.4%, and 96.5% respectively. The majority of missed metastases were micrometastasis <5 mm in long axis diameter.Conclusions¹⁸F-FDG PET/CT improves diagnostic efficacy for lymph node staging in patients staged N0 with conventional cross-sectional imaging. ¹⁸F-FDG PET/CT could be used as a surrogate marker for detection of metastases in non-enlarged pelvic lymph nodes and enhances management strategy guiding patients selection for neoadjuvant chemotherapy.     

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.     

18FDG-PET对大肠癌分期、再分期诊断的价值

目的:评价18FDG-PET(18氟标记脱氧葡萄糖-正电子发射断层扫描)对大肠癌分期及术后再分期的价值。方法:对24例经肠镜检查初步诊断为直肠、结肠癌的患者行全身18FDG-PET检查,并在1～2W内完成手术及病理诊断。大肠癌术后18FDG-PET随访56例。结果:24例病理证实为大肠癌,23例局部18FDG摄取增高,SUVmax=7.09±3.26,2.98～12.2(SUV,Standarduptakevalue)。18FDG-PET对于肿瘤原发病灶诊断准确率为95%(23/24)。假阴性1例。单纯局部(主要为第1站)淋巴结转移8例(灵敏度8/16,50%),远处转移8例。改变33%(8/24)的患者治疗方案。56例随访病例中30例PET显示阴性,其中5例随访2年后复发,准确率83.4%。26例发现局部和/或多发转移,其中颈部淋巴结转移8例;肺及纵隔转移4例;肝转移7例;腹腔淋巴结转移11例;吻合口局部复发12例,骨转移11例。结论:18FDG-PET对大肠癌的分期和术后的再分期诊断有较高价值。     

Diagnosis efficacy of structural (CT) and functional (FDG-PET) imaging methods in the thoracic and extrathoracic staging of non-small cell lung cancer

Purpose. To evaluate the efficacy of FDG-PET in the definition of tumour lung node lesions and to compare the diagnostic validity of CT and FDGPET in the staging of patients with non-small cell lung cancer (NSCLC). Material and methods. Patients with clinical suspicion of potentially resectable NSCLC (n = 108) were studied by standard procedures in our setting, including fibrobronchoscopy, transthoracic fine-needle aspiration, thoracoabdominal CT and FDG-PET. PET images were analysed by researchers blinded to results of other imaging modalities. Definitive tumour diagnosis was by histopathological study in patients who underwent surgery and by specific imaging methods and biopsy, when available, in patients who did not. Diagnostic accuracy was evaluated by comparing CT/PET results with the definitive diagnosis. Results. In 13% of patients, no FDG-PET findings were observed and the histological study was negative for tumour. In 22% of patients, FDG-PET detected metastatic disease (M0 by CT). For mediastinal involvement, global diagnostic accuracy was 0.90 with FDG-PET and 0.59 with CT. False positive FDG-PET findings were produced by inflammatory conditions and false negative findings by the small size or proximity of lymph nodes to primary tumour. Mediastinal staging by CT and FDG-PET was correct in 56% and 87% of patients, respectively. CT indicated mediastinal invasion in 17% of patients with no FDG-PET finding of mediastinal involvement. Conversely, mediastinal spread was undetected by CT in 14% of patients with FDG-PET findings of mediastinal involvement. Conclusions. Although complementary, the functional method (FDG-PET) is significantly superior to the structural method (CT) for detection of mediastinal tumour disease.     

The roles of PET and PET/CT in the diagnosis and management of prostate cancer

2-(18)F-fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET) imaging in prostate cancer is challenging because glucose utilization in well-differentiated prostate cancer is often lower than in other tumor types. Nonetheless, FDG-PET has a high positive predictive value for untreated metastases in viscera, but not lymph nodes. A positive FDG-PET can provide useful information to aid the clinician's decision on future management in selected patients who have low prostate-specific antigen levels and visceral changes as a result of metastases. On the other hand, FDG-PET is limited in the identification of prostate tumors, as normal urinary excretion of radioisotope can mask pathological uptake. Moreover, there is an overlap in the degree of uptake between prostate cancer, benign prostatic hyperplasia and inflammation. The tracer choice is also important. (11)C-choline has the advantage of reduced urinary excretion, and thus (11)C-choline PET may provide more accurate information on the localization of main primary prostate cancer lesions than MRI or MR spectroscopy. (11)C-choline PET is sensitive and accurate in the preoperative staging of pelvic lymph nodes in prostate cancer. A few studies are available but there were no PET or PET/CT studies with a large number of patients for tissue confirmation of prostate cancer; further investigations are required.     

2-(fluorine-18)fluoro-2-deoxy-D-glucose positron emission tomography in the detection and staging of malignant lymphoma. A bicenter trial

BACKGROUND: The authors undertook a prospective evaluation of the clinical value of 2-fluoro [18-]-2-deoxyglucose positron emission tomography (FDG-PET) in the detection and staging of malignant lymphoma compared with computed tomography (CT) and bone marrow biopsy (BMB). METHODS: Fifty-two consecutive patients with untreated malignant lymphoma were evaluated prospectively in a bicenter study. FDG-PET, CT, and BMB were performed for investigating lymph node/extranodal manifestations and bone marrow infiltration. Thirty-three percnt of the discrepant results were verified by biopsy, magnetic resonance imaging, or clinical follow-up (range, 4-24 month). RESULTS: Altogether, 1297 anatomic regions (lymph nodes, organs, and bone marrow) were evaluated. FDG-PET and CT scans were compared by receiver operating characteristic (ROC) curve analysis. The area under the ROC curve were as follows: lymph nodes, 0.996 (PET) and 0.916 (CT); extranodal, 0.999 (PET) and 0.916 (CT); supradiaphragmatic, 0.996 (PET) and 0.905 (CT); and infradiaphragmatic, 0.999 (PET) and 0.952 (CT). In these analyses, FDG-PET was significantly superior to CT (P < 0.05), except in infradiaphragmatic regions, in which the two methods produced equivalent results. In detecting bone marrow infiltration, FDG-PET was superior to CT and was equivalent to BMB. In 4 of 52 patients (8%), FDG-PET led to an upstaging and a change of therapy. CONCLUSIONS: Noninvasive FDG-PET is very accurate in the staging of malignant lymphoma. Compared with standard staging modalities (CT and BMB), PET was significantly superior and led to changes in the therapy regimen for 8% of patients.     

Prognostic effect of incongruous lymph node status in early-stage non-small cell lung cancer

IntroductionTumor recurrence is an important issue for patients with stage I non-small cell lung cancer (NSCLC) and adjuvant therapy is considered of no benefit to a tumor less than 4 cm. The purpose of this study was to evaluate the impact of positron emission tomography/computed tomography (PET/CT) on tumor recurrence in patients with a completely resected pN0 NSCLC less than 4 cm.MethodsBetween January 2011 and December 2016, 211 consecutive patients with diagnoses of stage I NSCLC less than 4 cm after complete resection were included. The maximum of standard uptake value (SUVmax) of primary tumor and the presence of positive lymph nodes on PET/CT scans were documented. Disease-free survival was evaluated by the Kaplan-Meier method and recurrence risk factors were identified by univariable and multivariable analyses.ResultsPatients with positive lymph nodes on PET/CT had a lower 5-year disease-free survival (37.6% vs 72.7%, p < 0.001). Multivariable analysis demonstrated that the tumor SUVmax >2.93, the presence of positive lymph nodes on PET/CT, and poor differentiation were significant factors for tumor recurrence. Patients with the tumor SUVmax >2.93 and positive lymph nodes on PET/CT simultaneously had 5.33-fold increase in the risk of recurrence (p < 0.001).ConclusionThe presence of positive lymph nodes on PET/CT scans can be a good indicator in predicting patients with high risk of developing recurrence in pN0 NSCLC less than 4 cm. This result helps identify patients likely to benefit from adjuvant therapy.