PET scanning in lung cancer: current status and future directions.
ABSTRACT Positron emission tomography (PET) represents a dramatic advance in the imaging of lung cancer. It is valuable for the diagnosis, staging, prognosis, and restaging of disease, and is most useful in patients considered for potentially curative therapy for non-small-cell lung cancer (NSCLC). In this work the current status and potential future applications of PET scanning in lung cancer are discussed. The relevant literature is also discussed, with an emphasis on studies with clinical applicability. Most of these studies involved the use of 18F-fluorodeoxyglucose (FDG). Numerous studies of the use of PET to assess undiagnosed pulmonary nodules have reported significant improvements in accurate diagnosis or exclusion of malignancy compared to conventional structural imaging alone. All of these studies, including metaanalysis, have shown that PET is more accurate than CT-based structural imaging in staging the mediastinum in surgical candidates. PET may have value in radiotherapy planning, and PET-based staging more accurately predicts survival in radiotherapy-treated patients than conventional staging. The rate of unsuspected distant metastasis detection in stage III disease exceeds 20%. PET also facilitates an accurate assessment of response in patients treated with radical chemoradiation or neoadjuvant therapy prior to surgery. PET has rapidly become an indispensable part of the evaluation of patients with potentially curable lung cancer; however, more work is required to define its role.
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ABSTRACT: Cancer cells show increased metabolism of both glucose and amino acids, which can be monitored with 18F-2-deoxy-2-fluoro-D-glucose (FDG), a glucose analogue, and 11C-L-methionine (Met), respectively. FDG uptake is higher in fast-growing than in slow-growing tumors. FDG uptake is considered to be a good marker of the grade of malignancy. Several studies have indicated that the degree of FDG uptake in primary lung cancer can be used as a prognostic indicator. Differential diagnosis of lung tumors has been studied extensively with both computed tomography (CT) and positron emission tomography (PET). It has been established that FDG-PET is clinically very useful and that its diagnostic accuracy is higher than that of CT. Detection of lymph node or distant metastases in known cancer patients using a whole-body imaging technique with FDG-PET has become a good indication for PET. FDG uptake may be seen in a variety of tissues due to physiological glucose consumption. Also FDG uptake is not specific for cancer. Various types of active inflammation showed FDG uptake to a certain high level. Understanding of the physiological and benign causes of FDG uptake is important for accurate interpretation of FDG-PET. In monitoring radio/chemotherapy, changes in FDG uptake correlate with the number of viable cancer cells, whereas Met is a marker of proliferation. Reduction of FDG uptake is a sensitive marker of viable tissue, preceding necrotic extension and volumetric shrinkage. FDG-PET is useful for the detection of recurrence and for monitoring the therapeutic response of tumor tissues in various cancers, including those of the lung, colon, and head and neck. Thus, PET, particularly with FDG, is effective in monitoring cancer cell viability, and is clinically very useful for the diagnosis and detection of recurrence of lung and other cancers.Annals of Nuclear Medicine 01/2002; 15(6):471-86. · 1.41 Impact Factor
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ABSTRACT: To meta-analytically compare 2-[fluorine 18]fluoro-2-deoxy-D-glucose positron emission tomography (PET) and computed tomography (CT) for the demonstration of mediastinal nodal metastases in patients with non-small cell lung cancer. English-language reports on the diagnostic performance of PET (14 studies, 514 patients) and/or CT (29 studies, 2,226 patients) for demonstration of mediastinal nodal metastases from NSCLC were selected by using the MEDLINE database. In eligible studies, an objective diagnostic standard was used, data were presented to allow recalculation of contingency tables, and established diagnostic criteria were used for abnormal test results. Summary receiver operating characteristic (ROC) curves were calculated. Pooled point estimates of diagnostic performance and summary ROC curves indicated that PET was significantly more accurate than CT for demonstration of nodal metastases (P < .001). Mean sensitivity and specificity (+/- 95% CI) were 0.79 +/- 0.03 and 0.91 +/- 0.02, respectively, for PET and 0.60 +/- 0.02 and 0.77 +/- 0.02, respectively, for CT. The log odds ratios were 1.79 (95% CI: 1.49, 2.09) for CT and 3.77 (95% CI: 2.77, 4.77) for PET (P < .001). Subgroup analyses did not alter findings. PET is superior to CT for mediastinal staging of non-small cell lung cancer, independent of performance index or clinical context of PET imaging.Radiology 11/1999; 213(2):530-6. · 6.34 Impact Factor
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ABSTRACT: The goals of this study were to survey and summarize the advances in imaging that have potential applications in radiation oncology, and to explore the concept of integrating physical and biological conformality in multidimensional conformal radiotherapy (MD-CRT). The advances in three-dimensional conformal radiotherapy (3D-CRT) have greatly improved the physical conformality of treatment planning and delivery. The development of intensity-modulated radiotherapy (IMRT) has provided the "dose painting" or "dose sculpting" ability to further customize the delivered dose distribution. The improved capabilities of nuclear magnetic resonance imaging and spectroscopy, and of positron emission tomography, are beginning to provide physiological and functional information about the tumor and its surroundings. In addition, molecular imaging promises to reveal tumor biology at the genotype and phenotype level. These developments converge to provide significant opportunities for enhancing the success of radiotherapy. The ability of IMRT to deliver nonuniform dose patterns by design brings to fore the question of how to "dose paint" and "dose sculpt", leading to the suggestion that "biological" images may be of assistance. In contrast to the conventional radiological images that primarily provide anatomical information, biological images reveal metabolic, functional, physiological, genotypic, and phenotypic data. Important for radiotherapy, the new and noninvasive imaging methods may yield three-dimensional radiobiological information. Studies are urgently needed to identify genotypes and phenotypes that affect radiosensitivity, and to devise methods to image them noninvasively. Incremental to the concept of gross, clinical, and planning target volumes (GTV, CTV, and PTV), we propose the concept of "biological target volume" (BTV) and hypothesize that BTV can be derived from biological images and that their use may incrementally improve target delineation and dose delivery. We emphasize, however, that much basic research and clinical studies are needed before this potential can be realized. Whereas IMRT may have initiated the beginning of the end relative to physical conformality in radiotherapy, biological imaging may launch the beginning of a new era of biological conformality. In combination, these approaches constitute MD-CRT that may further improve the efficacy of cancer radiotherapy in the new millennium.International Journal of Radiation OncologyBiologyPhysics 07/2000; 47(3):551-60. · 4.52 Impact Factor