Positron emission tomography in nonsmall cell lung cancer

PURPOSE OF REVIEW: Positron emission tomography (PET) has become a major adjunct to structural imaging for nonsmall cell lung cancer. Established indications are the differential diagnosis of lung nodules, as well as mediastinal lymph node and extrathoracic staging. RECENT FINDINGS: More details for small or faint pulmonary nodules became available--information of interest in the era of lung cancer screening trials, in which PET might help to reduce unwanted invasive procedures for benign findings. The strength of PET in mediastinal staging (its high negative predictive value) was confirmed in a randomized study, in which PET reduced the number of invasive procedures without loss of accuracy in staging. Isolated positive lesions that are decisive for radical compared with palliative treatment should be confirmed by other tests, as they may be benign or due to second primary cancer. PET with integrated computed tomography (CT) may guide modern radiotherapy, by improving radiation fields. Integrated PET-CT is a promising tool in the indication for surgery in stage IIIA-N2 patients after induction treatment. Predictive values for lymph node downstaging become in acceptable ranges and PET response in the primary tumor could be clearly linked to pathologic response and survival. SUMMARY: In recent years, PET has seen further refinements in established indications and definition of new indications.     

Positron emission tomography using 18F-fluorodeoxyglucose for the evaluation of residual Hodgkin's disease mediastinal masses

Given its obvious prognostic implications, the correct interpretation of the significance of any residual mediastinal mass following Hodgkin's disease (HD) treatment keeps maintaining its paramount importance. In this respect, 18F-fluorodeoxyglucose positron emission tomography (PET) is proving very effective for both active disease detection and relapse prediction. Twenty-nine consecutive HD patients, in whom computed tomography (CT) scan performed after therapy completion had documented a residual mediatinal mass of at least 2 cm, prospectively entered the study and underwent PET within 1 week from CT scan. With a median follow-up of 28 months from PET execution, no relapse was recorded among the 17 patients presenting with a negative PET. On the contrary, 9 of the 12 patients presenting with a positive PET relapsed/progressed within one year from PET execution. PET's negative and positive predictive values at 1 year were 100% and 75%, respectively. A negative PET seems to possibly exclude relapse in HD patient with a residual mediastinal mass. On the contrary, a positive PET result indicates a significantly higher risk of relapse. However, due to possible false positive results, a closer follow-up for all and a pathologic study in few selected patients is warranted.     

Positron emission tomography in the management of non-small cell lung cancer

In the past 10 years, FDG-PET has become an important imaging modality in NSCLC. Its indication in the assessment of lung nodules and staging is based on large prospective experience, further supported by some meta-analyses. This evidence has important consequences for patient management, which recently was proved in a randomized trial that showed a reduction in the number of futile thoracotomies by preoperative PET. The use of FDG-PET could become more widespread when commercial isotope distributors are able to deliver FDG so that an on-site cyclotron is no longer a prerequisite. FDG has a half-life of 110 minutes, so a practical distribution radius of 200 km should be feasible. Current indications for PET in the staging of newly diagnosed NSCLC are mainly the patients who are considered to be candidates for radical treatment. The technique does not have a clinical indication in other patients--for example, when metastatic lymph nodes are detected at clinical examination, when a simple ultrasound study already points to diffuse hepatic metastases, or in cases of poor performance status. PET also has prognostic value; it can be used for the evaluation of response or restaging after radiotherapy or chemotherapy and for early detection of relapse. The combination of CT and PET improves radiotherapy planning and it is to be expected that combined CT-PET-guided planning devices will further refine three-dimensional conformal radiotherapy. Finally, a whole new field of application of PET in molecular biology using new radiopharmaceutics is in development. FDG, with its possibility to study tumor glucose metabolism, has paved the way for PET in clinical oncology. It is hoped that PET examinations with new molecular tracers will allow ever better specificity and become sufficiently reliable and manageable to evaluate receptors, transport proteins, and intracellular enzymes so that very early response monitoring during chemotherapy or radiotherapy, evaluation of novel molecular-targeted lung cancer therapies, or even gene therapy becomes possible. New tracers that have showed their promise in early clinical studies include 18F-fluorothymidine (a proliferation marker that might give better specificity in the assessment of solitary pulmonary nodules or better accuracy in the evaluation of early response), (99m)Tc-Annexin V (Apomate; an apoptosis-imaging agent that could be correlated with overall and progression-free survival in phase I data), or 18F-fluoromisonidazole (which can be used to quantify regional hypoxia in human tumors with PET).     

Positron emission tomography imaging in lung cancer

Over the past several years, positron emission tomography (PET) has become a clinically useful, noninvasive study which complements conventional imaging (chest radiographs, computed tomography [CT], and magnetic resonance imaging [MRI]) in the evaluation of patients with lung cancer. PET imaging of lung cancer is typically performed with the radiopharmaceutical 18F-2-deoxy-D-glucose (FDG), a d-glucose analog. Increased glucose metabolism by malignant cells results in increased uptake and accumulation of FDG, which serves as the basis for tumor detection. This review will focus on the current applications of FDG-PET in lung cancer patients including evaluation of focal pulmonary abnormalities, staging lung cancer, determining tumor recurrence, and in assessing prognosis.     

Positron emission tomography in the management of lymphomas

Positron emission tomography is a functional imaging modality that capitalizes on biochemical changes within tumour cells to localize these changes within the body. As a functional imaging tool, unlike an anatomical imaging tool such as CT, it does not require enlargement of lymph nodes affected by disease but does require sufficient numbers of tumour cells to be present with altered biochemical function to visualize these disease sites. These changes are most commonly monitored using a glucose mimic fluorodeoxyglucose which is not only taken up into tumour cells but is trapped within these cells owing to alterations of the hexokinase and dephosphorylase enzymes. This review examines the current role of FDG PET imaging in patients with Hodgkins and Non-Hodgkins lymphoma and also speculates on future roles for this imaging modality.     

Positron emission tomography scanning for the diagnosis and management of lung cancer

Opinion statement The dissemination of positron emission tomography (PET) technology has enabled a functional approach to the evaluation of lung cancer that complements the anatomic assessment provided by chest radiography, computed tomography (CT) scanning, and magnetic resonance imaging. PET has excellent sensitivity and good specificity for the determination of malignancy in the solitary pulmonary nodule, but these data must be weighed against the evidence of instances of false-positive results because of inflammatory lesions and false-negative results in small-or low-metabolism neoplasms. Therefore, PET may not be advisable when these scenarios apply. Furthermore, in a patient with a very high pretest likelihood of lung cancer (eg, a new or enlarging spiculated nodule in a long-time smoker), the value of PET is less certain because a negative result may be discounted. PET has altered the approach to the staging of lung cancer. It adds value to the evaluation of the mediastinum and extrathoracic structures compared to conventional methods by upstaging or downstaging a substantial proportion of patients. If the staging assessment is negative on PET, the use of mediastinoscopy may be obviated in selected cases. Histologic confirmation of positive PET findings should be obtained before excluding patients from curative resection. PET provides incremental information to CT in the evaluation of persistent and recurrent disease, and response measured on PET appears more accurate as a predictor of ultimate survival. The more recent development of PET-CT permits fusion of anatomic and functional information. Early investigations suggest that this strategy provides superior results compared to either technique alone.     

Prognostic significance of 18F-fluorodeoxyglucose positron emission tomography in lymphoma

Today, many patients with lymphoma are cured by polychemotherapy and irradiation. However, residual masses are frequently observed after treatment and discrimination between vital tumor and inactive fibrotic tissue by computed tomography or magnetic resonance tomography is often not possible. 18 F-Fluorodeoxyglucose (FDG) positron emission tomography (PET) is a metabolic imaging modality that is able to detect active lymphoma lesions. The application of PET may play a crucial role in identifying patients with residual disease and contribute valuable prognostic information. To assess the prognostic implications of PET in the post-therapeutic setting, we performed a MedLine Search and reviewed the current available studies on this important issue together with our own data.     

Positron emission tomography in bronchioloalveolar carcinoma of the lung

Objectives

This study assessed the maximum standard uptake value of positron emission tomography–computed tomography in patients of pulmonary adenocarcinoma with bronchioloalveolar carcinoma features and whether SUVmax correlates with pathological status, lymph node metastasis, and prognosis.

Methods

We retrospectively reviewed 674 patients diagnosed with non-small-cell lung cancer between January 2002 and June 2009. Patients with clinical stage I–II disease underwent a preoperative PET–CT scan followed by anatomic resection. We reviewed the clinical features of 209 patients with an average follow-up of 87 months.

Results

We analyzed clinical variables for 40 patients with BAC features and 169 patients without BAC features. Age, sex, location, and number of dissected lymph nodes, carcinoembryonic antigen level, and lymphovascular invasion had no difference between the two groups. Compared with non-BAC patients, patients with BAC features had a lower SUVmax (2.51 ± 2.02 vs 4.98 ± 4.03, p < 0.001), lower ratio of SUVmax (1.10 ± 0.34 vs 1.22 ± 0.27, p = 0.014), better tumor differentiation (p < 0.001), and smaller tumor size (2.30 ± 1.41 vs 2.97 ± 1.71, p < 0.03). The negative prediction rate was 87.08% for N2 and 80.80% for N1 disease. All patients in the BAC group were alive after the operation. The five-year survival rate of patients without BAC features was 71.2%.

Conclusions

Preoperative SUVmax of PET–CT was more accurate at predicting negative N2 than N1 disease. BAC is associated with markedly better prognosis compared with invasive adenocarcinoma and may be cured with surgical resection Aggressive surgical resection is recommended even for patients with false-negative N2 disease.     

Evolving role of (18)F-fluorodeoxyglucose positron emission tomography in the management of esophageal carcinoma

Positron emission tomography (PTE) and PET/CT imaging with (18)F-fluorodeoxyglucose are metabolic imaging modalities that depict tissues based on their level of glucose uptake. PET provides useful information in the primary staging of disease. PET performance in detecting locoregional nodal metastases is limited; however, it is the most accurate single noninvasive modality for detecting distant metastases. It is the imaging modality of choice for whole-body scanning in high-risk patients or patients who have clinically suspected recurrence, and is particularly helpful in determining which patients are the best candidates for surgical cure.     

Positron emission tomography imaging in nonsmall-cell lung cancer

Positron emission tomography (PET) using 18F-2-deoxy-D-glucose, a D-glucose analog labeled with fluorine-18, complements conventional radiologic assessment in the evaluation of patients with nonsmall-cell lung cancer (NSCLC). PET is being routinely used to improve the detection of nodal and extrathoracic metastases. PET is also currently being evaluated in the assessment of prognosis and therapeutic response and by potentially allowing an earlier assessment of response may prove invaluable in the oncologic management of patients. The article discusses the diagnosis, staging, and assessment of treatment response and prognosis with an emphasis on the appropriate clinical use of PET in management.     

PET-CT在霍奇金淋巴瘤治疗中的作用

 　准确的影像学检查对淋巴瘤的优化治疗至关重要。通过提供解剖学和功能学信息,PET-CT从根本上改变了包括霍奇金淋巴瘤在内的淋巴瘤分期、疗效监测与评估以及治疗方法的选择。与标准检查方法联合应用,PET-CT可以提高病变部位检测的敏感性,监测治疗期间疾病的缓解程度,区分纤维坏死性瘢痕组织和有活性的肿瘤组织,提供预后信息。PET-CT已成为现代淋巴瘤治疗不可或缺的一部分,但是作为相对较新的诊断技术,其全部优点和缺点没有完全研究清楚。根据临床试验的最新结果和单中心应用PET-CT的经验,从临床角度探讨PET-CT的优点和缺点。     

The role of 18F-fluorodeoxyglucose positron emission tomography in thyroid neoplasms

(18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has established itself as an important imaging modality in many oncological and nononcological specialties and, as a consequence, it is increasingly being used in clinical practice. Since the first report of FDG being taken up by metastatic differentiated thyroid carcinoma (DTC) cells >20 years ago, various groups of investigators have explored the potential role of FDG-PET scanning in patients with benign and malignant thyroid neoplasms. With the increasing demand for FDG-PET scanning, clinicians are faced with the challenge of managing an increasing number of FDG-PET-detected thyroid incidentalomas because their significance remains unclear. The aims of this review are to address some of these issues, specifically, the clinical significance of FDG-PET-detected thyroid incidentalomas, the ability of FDG-PET to characterize thyroid nodules, especially those with indeterminate fine needle aspiration cytology results, and the role of FDG-PET in patients with confirmed primary DTC and with suspected recurrent DTC, by reviewing the current literature.     

Assessment of 18F-fluorodeoxyglucose positron emission tomography combined with computed tomography in the preoperative management of patients with gastric cancer

Background

The significance of ¹⁸F-2-deoxy-2-fluoro-glucose positron emission tomography combined with computed tomography imaging (FDG-PET/CT) in the diagnosis of gastric cancer remains controversial. This study aimed to evaluate the efficacy of preoperative FDG-PET/CT in staging of gastric cancer.

Methods

FDG-PET/CT results for 90 patients with gastric cancer were retrospectively examined. For quantitative PET analysis, FDG uptake was assessed based on the maximum standardized uptake values (SUV_max).

Results

FDG-PET/CT detected the primary gastric cancer in 71 of the 90 patients (sensitivity 78.9 %). The median SUV_max was significantly higher in patients with T3/T4 disease than in those with T1/T2 (9.0 vs. 3.8; P < 0.001), in patients with distant metastasis than in those with no metastasis (9.5 vs. 7.7; P = 0.018), and with stage III/IV tumors than in those with stage I/II (9.0 vs. 4.7; P = 0.017). The SUV_max of the primary tumor was significantly correlated with tumor size (r = 0.461, P < 0.001). The sensitivity, specificity, and accuracy of FDG-PET/CT in assessing metastasis to regional lymph nodes were 64.5, 85.7, and 71.1 %, respectively.

Conclusions

FDG-PET/CT results are significantly associated with tumor progression in gastric cancer, and such findings can reliably identify cancer cell populations.     

Positron emission tomography (PET) with 18F-fluorodeoxyglucose (18F-FDG) for the staging of low-grade non-Hodgkin's lymphoma (NHL).

Background:Although PET has been shown to be highlysensitive in the primary staging of lymphoma, previous studies withsmall numbers of patients indicated that low-grade NHL may not always beadequately detected by PET. We undertook this study to determine factorsinfluencing the detection of lesions by PET in low-grade NHL and toevaluate the utility of PET in this indication. Patients and methods:Forty-two patients underwentconventional staging procedures (clinical examination,oto-rhino-laryngologic examination, computed tomography of the chest,abdomen and pelvis, gastroscopy and bone marrow biopsy as well aswhole-body non-attenuation corrected ¹⁸F-FDG-PET. Results:PET detected 40% more abnormal lymph nodeareas than conventional staging in follicular lymphoma but wasinappropriate for the staging of small lymphocytic lymphoma where itdetected less than 58% of abnormal lymph node areas. PET showedmore lesions than conventional staging for peripheral (34% morelymph node areas detected) and thoracic lymph node (39% more)areas but not for abdominal or pelvic lymph nodes (26% fewerareas detected). The sensitivity to detect bone marrow infiltration wasunacceptably low for PET. In contrast, PET was as effective as standardprocedures for the detection of other extranodal localizations, althougha few localizations were detected only by PET and a few others only byconventional procedures. Conclusions:PET may contribute to the management ofpatients with low-grade follicular NHL. For the other low-grade lymphomasubtypes, the role of PET is less evident. Further studies using PET toevaluate the results of treatment or to diagnose disease recurrence arewarranted in low-grade follicular NHL.     

Clinical influence of 18F-fluorodeoxyglucose positron emission tomography on the management of primary tumours of the thymus

The objective of the current study was to evaluate the effect of PET on the management of primary tumours of the thymus. Patients with a primary tumour of the thymus who underwent PET were identified from a prospective database. Forty-three PET scans were carried out on 26 patients with primary thymic tumours. Sensitivity, specificity and accuracy were 79, 100 and 85%, respectively. Conventional imaging and PET findings were discordant in 10 cases (23%). PET appropriately changed patient management in three (7.0%) cases based on accurate results that differed from pre-PET imaging. Most PET scans carried out (88%) did not influence clinical management. Patient comorbidities, limited treatment options and already planned surgery are factors that may hinder the effect of PET in the setting of thymic tumours. The potential for false-negative results, probably because of a combination of low-fluorodeoxyglucose avidity and small volume residual disease, needs to be considered in management planning. However, the positive predictive value of PET is high and enables appropriate modification of management in a small, but potentially important subset of patients.