PET imaging in oncology.

Bar-Shalom R, Valdivia AY, Blaufox MD.   Semin Nucl Med 2000 Jul;30(3):150-85

Department of Nuclear Medicine, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, USA.

Perhaps the most striking development is the use of PET in oncology. PET imaging is approved in the United States for lung, lymphoma, colon, and melanoma cancer imaging. Data are accumulating rapidly to attest the efficacy of Fluorine-18 fluorodeoxyglucose (FDG) imaging in a wide variety of malignant tumors with sensitivities and specificities often in the high 90s. FDG uptake has been shown in tumors of the head and neck, ovary, breast, musculoskeletal system, and neuroendocrine system as well. The major role of PET has emerged as a reliable method for evaluating and staging recurrent disease. But it also has an important role in differentiating benign and malignant primary tumors. This has been shown particularly well in the differential diagnosis of solitary lung nodules. Although FDG has emerged as the dominant radiopharmaceutical for PET imaging in oncology, numerous other compounds are being evaluated. It is likely that more specific and efficacious compounds will be introduced during the next decade. F-18, because of its highly favorable physical characteristics, is likely to become the technetium of PET imaging. The next decade will witness an explosive growth of PET technology in oncologic imaging.

Clinical role of positron emission tomography in oncology.

Bomanji JB, Costa DC, Ell PJ.     Lancet Oncol 2001 Mar;2(3):157-64

Institute of Nuclear Medicine, Middlesex Hospital, University College London, UK.

Positron emission tomography (PET) is now in routine use in oncology, through the success of metabolic imaging, mainly with fluorodeoxyglucose (FDG). Clear benefit is obtained with FDG PET in the assessment of patients with recurrent or residual disease, especially colorectal cancer and lymphoma. Preoperative staging of non-small-cell lung cancer with FDG PET is of proven benefit. Staging and restaging of patients with melanoma of stage II or greater is useful, and FDG PET has also been successfully used to investigate single pulmonary nodules. Tumour grading has been assessed, especially in the brain, but an important and emerging indication is the evaluation of tumour response with PET. Rapid decline of FDG uptake has been observed in responsive cancers. Further advances are being made with other fluorine-18-labelled and generator-based PET tracers, the only ones that can be used in units without dedicated cyclotrons.

Strahlenther Onkol 1999 Aug;175(8):356-73

Relevance of positron emission tomography (PET) in oncology.

Numerous studies have documented the high diagnostic accuracy of PET studies using the glucose analogue F-18-fluordeoxyglucose (FDG-PET) for detection and staging of malignant tumors. In this field, FDG-PET has been particularly successful in lung cancer, colorectal cancer, malignant lymphoma and melanoma. Furthermore, FDG-PET has often proven to be superior to morphological imaging techniques for differentiation of tumor recurrence from scar tissue. Due to the high glucose utilization of normal gray matter radiolabeled amino-acids like C-11-methionine are superior to FDG for detection and delineation of brain tumors by PET.

Curr Opin Oncol 2000 Mar;12(2):132-7

Positron emission tomography in initial staging and diagnosis of persistent or recurrent disease.

Positron emission tomography (PET) constitutes a major advance in the diagnosis, staging, prognostic assessment, and follow-up of lung cancer. However, it is not a magic bullet that can solve all of the uncertainties that beguile the imaging of this disease. Small lesions, particularly those in the brain, may often be missed with PET, and three-dimensional localization of suspected sites may also be unreliable. We are still learning how best to apply this new technology in an environment that demands the efficient use of medical resources. PET will probably be used most enthusiastically in the prethoracotomy staging of patients who are considered operable or probably operable on the basis of computed tomography and in the assessment of treatment response and disease recurrence when clinical management will be determined by prompt recognition of these events.

World J Surg 1999 Sep;23(9):882-7

Diagnosis and staging of pancreatic cancer by positron emission tomography.

The detection of pancreatic cancer or the discrimination between pancreatic cancer and chronic pancreatitis remains an important diagnostic problem. Several imaging modalities are now used to diagnose pancreatic cancer, including transabdominal ultrasonography (US), contrast-enhanced computed tomography (CT), magnetic resonance imaging (MRI), endoscopic retrograde cholangiopancreatography (ERCP), endoscopic ultrasonography, and selective angiography. None of these six methods is perfect: Each has advantages and disadvantages, and their sensitivity and specificity are in a high range. In 1990 positron emission tomography (PET) was first applied to diagnose pancreatic cancer. This new diagnostic modality is based on functional changes in the pancreatic cancer cells caused by enhanced glucose metabolism. Increased glucose utilization is one of the characteristics of malignantly transformed cells, independent of their origin. The technical development of PET has allowed this new procedure to be used for clinical evaluation. Using 2-((18)F)-fluoro-2-deoxy-d-glucose, PET can identify pancreatic cancer and differentiate pancreatic cancer from chronic pancreatitis with a sensitivity of 85% to 98% and a specificity of 53% to 93%. However, high sensitivity and high specificity are strongly dependent on the tumor stage. At present PET is still experimental and is available only in specialized centers. It may represent a new and noninvasive diagnostic procedure for the detection and the staging of pancreatic cancer. Further clinical studies, especially including patients with early tumor stages (small tumor size), are needed. This review discusses the possibilities and limits of PET and evaluates its importance in the future.

J Nucl Med 1999 May;40(5):814-20

PET in lung cancer.

Fluorodeoxyglucose (FDG) PET imaging provides physiologic and metabolic information that characterizes lesions that are indeterminate by CT, accurately stages the distribution of lung cancer and provides prognostic information. FDG PET imaging takes advantage of the increased accumulation of FDG in transformed cells and is sensitive (approximately 95%) to the detection of cancer in patients who have indeterminate lesions on CT. The specificity (approximately 85%) of PET imaging is slightly less than its sensitivity because some inflammatory processes, such as active granulomatous infections, avidly accumulate FDG. The high negative predictive value of PET suggests that lesions considered negative on the study are benign, biopsy is not needed and radiographic follow-up is recommended. Several studies have documented the increased accuracy of PET compared with CT in the evaluation of the hilar and mediastinal lymph-node status in patients with lung cancer. Whole-body PET studies detect metastatic disease that is unsuspected by conventional imaging and demonstrate some of the anatomic abnormalities detected by CT to be benign lesions. Management changes have been reported in up to 41% of patients on the basis of the results of whole-body studies.

J Nucl Med 1999 Apr;40(4):591-603

Oncological applications of FDG PET imaging: brain tumors, colorectal cancer, lymphoma and melanoma.

This article will focus primarily on body oncology diagnosis, staging and therapy monitoring using fluorodeoxyglucose (FDG) PET imaging. Common pitfalls and artifacts in body FDG imaging will be covered. Examples of diagnosis, staging and therapy monitoring of brain tumor, colorectal cancer, lymphoma and melanoma will be given. Importance of correlation with anatomic imaging and practical use of FDG imaging in patient management will be stressed.

Nucl Med Biol 1994 Jul;21(5):739-47

PET FDG studies in oncology.

Positron emission tomography (PET) studies of cancer with the glucose analog 2-[F-18]fluoro-2-deoxy-D-glucose (FDG) have emerged as both a useful research and clinical method for detecting (diagnosing), staging, and monitoring treatment responses in a variety of neoplasms, including tumors of the brain, head and neck, lung, breast, gastrointestinal and genitourinary systems, lymphatic system, musculoskeletal system, and other organ systems. In addition to FDG, many other positron emitting radiopharmaceuticals are under investigation and development in oncology, but the largest set of clinically relevant results to date has been acquired with FDG. Because most aggressive neoplasms have high glycolytic rates, neoplasms throughout the body may potentially be visualized with PET, using both standard transaxial imaging methods and techniques such as whole body PET imaging for surveying the entire body.

Predictive features of positron emission tomography after two cycles of induction therapy in malignant lymphoma

Slaby J, Belohlavek O, Taborska K, Prochazka M, Trneny M, Klener P.   Cas Lek Cesk 2002 May 24;141(10):312-5

BACKGROUND: Positron emission tomography (PET) is a modern functional imaging method, recently introduced to clinical oncology. The aim of our study was the evaluation of prognostic value of PET performed in malignant lymphoma patients after two cycles of chemotherapy. METHODS AND RESULTS: From 9/99 to 11/00 PET was performed in 37 patients with malignant lymphoma (9x m. Hodgkin, 21x HG + IG-NHL, 7x LG-NHL; 26x new diagnosis, 11x relaps of disease). Freedom from progression interval (FFP) and overall survival (OS) were evaluated. Attenuation corrected PET imaging was done by dedicated ECAT EXACT PET scanner from base of the skull to the upper thighs 1 hour after intravenous administration of 18-FDG (7.6 +/- 1.3 MBq/kg). Statistical analysis was done using Kaplan-Meier method. Significance of differences between groups was determined by log-rank test on the level of 5%. After the induction therapy, 30 patients were in complete remission, 3 patients in partial remission and in 4 cases progression of disease were observed. Progression of disease was seen in 4 patients. Median follow up of living patients was 7 months (1-13 months) from the end of therapy. Progression, resp. relapse of disease occurred in 13 patients during this period, two patients died. PET performed after the second course of therapy was positive in 18 patients and negative in 19 patients. Two progressions, resp. relapses of disease were documented in PET-negative group and 11 in PET-positive group. FFP was significantly different in PET positive and PET negative groups (p < 0.05). The negative and positive predictive values of PET for malignant lymphoma relapse or progression were estimated 89%, 63% respectively. CONCLUSION: Regardless the short follow-up period, our preliminary results reflect very good prognostic value of PET performed after the second course of chemotherapy in malignant lymphoma patients.