Prospective comparison of 18F-FDG PET with conventional imaging modalities (CT, MRI, US) in lymph node staging of head and neck cancer.

Adams S, Baum RP, Stuckensen T, Bitter K, Hor G.     Eur J Nucl Med 1998 Sep;25(9):1255-60

Department of Nuclear Medicine, Johann Wolfgang Goethe University Medical Center, Frankfurt/Main, Germany.

The aims of this study were to investigate the detection of cervical lymph node metastases of head and neck cancer by positron emission tomographic (PET) imaging with fluorine-18 fluorodeoxyglucose (FDG) and to perform a prospective comparison with computed tomography (CT), magnetic resonance imaging (MRI), sonographic and histopathological findings. Sixty patients with histologically proven squamous cell carcinoma were studied by PET imaging before surgery. Preoperative endoscopy (including biopsy), CT, MRI and sonography of the cervical region were performed in all patients within 2 weeks preceding 18F-FDG whole-body PET. FDG PET images were analysed visually and quantitatively for objective assessment of regional tracer uptake. Histopathology of the resected neck specimens revealed a total of 1284 lymph nodes, 117 of which showed metastatic involvement. Based on histopathological findings, FDG PET correctly identified lymph node metastases with a sensitivity of 90% and a specificity of 94% (P<10(-6)). CT and MRI visualized histologically proven lymph node metastases with a sensitivity of 82% (specificity 85%) and 80% (specificity 79%), respectively (P<10(-6)). Sonography revealed a sensitivity of 72% (P<10(-6)). The comparison of 18F-FDG PET with conventional imaging modalities demonstrated statistically significant correlations (PET vs CT, P = 0.017; PET vs MRI, P = 0.012; PET vs sonography, P = 0.0001). Quantitative analysis of FDG uptake in lymph node metastases using body weight-based standardized uptake values (SUVBW) showed no significant correlation between FDG uptake (3.7+/-2.0) and histological grading of tumour-involved lymph nodes (P = 0.9). Interestingly, benign lymph nodes had increased FDG uptake as a result of inflammatory reactions (SUVBW-range: 2-15.8). This prospective, histopathologically controlled study confirms FDG PET as the procedure with the highest sensitivity and specificity for detecting lymph node metastases of head and neck cancer and has become a routine method in our University Medical Center. Furthermore, the optimal diagnostic modality may be a fusion image showing the increased metabolism of the tumour and the anatomical localization.

PET scan and double-independent pathologic investigations effectively support the detection of occult primary tumors

Esik O, Szentirmay Z, Marian T, Kasler M, Agoston P, Lengyel E, Pulay T, Tron L.    Orv Hetil 2002 May 26;143(21 Suppl 3):1262-5

Orszagos Onkologiai Intezet, Budapest.

Following the failure of conventional diagnostic procedures, whole-body FDG-PET investigations were carried out in 42 metastatic cancer patients to localize occult primary carcinomas. During the clinical follow-up, the presence of malignant tumor was ruled out in 3 cases, and 2 patients originally believed to have carcinoma were confirmed to be suffering from a malignant hematological disease. These false diagnoses were associated with the use of imaging methods only (2 cases) or cytology only (1 case), lack of double, independent pathological investigations (2 cases) or immunophenotyping (2 cases) and the occurrence of an unrecognized rare tumor in a hospital with a small patient turnover (1 case). The discovered 11 occult primaries (4 lung, 3 breast, 2 hypopharynx and 1 base of the tongue carcinomas and 1 non-Hodgkin lymphoma) led to a 28% diagnostic efficacy of PET (11/39 malignant pathological reports). This efficacy is doubled (60%) if PET reveals < or = 5 malignant lesions and the locations of the pathological foci are tumor-specific. We suggest PET investigations in the search for occult primaries following a controlled pathological diagnosis and the failure of conventional diagnostic procedures.

Detection of recurrent head and neck squamous cell carcinomas after radiation therapy with 2-18F-fluoro-2-deoxy-D-glucose positron emission tomography.

Farber LA, Benard F, Machtay M, Smith RJ, Weber RS, Weinstein GS, Chalian AA, Alavi A, Rosenthal DI. Laryngoscope 1999 Jun;109(6):970-5

Department of Radiation Oncology, Hospital of the University of Pennsylvania, Philadelphia 19104, USA.

OBJECTIVES/HYPOTHESIS: Fluorodeoxyglucose positron emission tomography (FDG-PET) has been proposed as a sensitive method to diagnose and stage various malignancies. We assessed the efficacy of FDG-PET imaging in distinguishing tumor persistence/recurrence from posttreatment changes following radiation therapy for squamous carcinomas of the head and neck STUDY DESIGN: Retrospective analysis of FDG-PET results compared with biopsy results or outcome, or both. METHODS: Twenty-eight patients who had undergone radiation therapy with or without surgery for treatment of squamous cell carcinoma were studied with FDG-PET imaging. There was clinical suspicion for recurrence in each patient, but no obvious mass or lesion to biopsy was found on physical examination or anatomic imaging. The results of FDG-PET imaging were compared with those of biopsy or clinical follow-up of at least 6 months, or both. RESULTS: FDG-PET imaging was positive in 13 patients, and the presence of active disease was confirmed in 12. Two thirds of the 12 received further cancer treatment. There were 15 negative FDG-PET images. Thirteen of these were confirmed true-negative images, but two studies were false-negative images. The sensitivity and specificity of FDG-PET were 86% and 93%, respectively, with positive and negative predictive values of 92% and 87%, respectively. The overall accuracy was 89%. CONCLUSION: FDG-PET imaging is a useful modality to distinguish tumor persistence/recurrence from radiation-induced tissue changes in the neck following treatment for head and neck cancer. FDG-PET can identify patients who may benefit from further treatment, and may lead to improved outcome for individual patients.

Experience in qualitative and quantitative FDG PET in follow-up of patients with suspected recurrence from head and neck cancer.

Lapela M, Eigtved A, Jyrkkio S, Grenman R, Kurki T, Lindholm P, Nuutinen J, Sutinen E, Solin O, Bjornskov I, Bretlau P, Friberg L, Holm S, Jensen M, Sand Hansen H, Minn H.    Eur J Cancer 2000 May;36(7):858-67

Department of Oncology and Radiotherapy, University of Turku, University Central Hospital, Turku, Finland. maria.lapela@leiras.fi

We evaluated positron emission tomography (PET) with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) in the detection of recurrent head and neck cancer, and compared visual and quantitative interpretation of PET images for their accuracy in the identification of tumour recurrence. Sixty-two FDG PET studies were performed in 56 patients having a total of 81 lesions, which were clinically suspected for recurrent carcinoma of the head and neck. The PET images were interpreted visually, and tracer uptake was quantitated as the standardised uptake value adjusted to body weight (SUV). Sensitivity of visual interpretation of the PET images for the presence of malignancy ranged from 84 to 95%, and specificity from 84 to 93%, respectively, depending on the selected scheme for grading of the lesions. Malignant lesions accumulated significantly more FDG than the benign ones (the median SUVs were 6.8 and 3.3, respectively, P<0.001). However, there was a wide overlap of the FDG uptake values between these two groups. Hence, the highest accuracy of quantitative analysis in correct identification of tumour recurrence (75% at Receiver Operating Curve analysis) was inferior to that of visual analysis (89%). FDG PET is feasible for the detection of recurrent head and neck cancer. Although quantitation of FDG uptake using SUV shows significantly higher tracer concentrations for malignant than benign lesions, the wide overlap of individual SUVs between these two groups is a serious concern in diagnostic evaluation. Therefore, in clinical practice it may be preferable to identify the presence of tumour recurrence within this patient group by qualitative interpretation of the PET images.

Monitoring of response to radiotherapy with fluorine-18 deoxyglucose PET of head and neck squamous cell carcinomas.

Sakamoto H, Nakai Y, Ohashi Y, Matsuda M, Sakashita T, Nasako Y, Kitayama H, Kawabe J, Okamura T, Ochi H.  Acta Otolaryngol Suppl 1998;538:254-60

Department of Otorhinolaryngology, Osaka City University Medical School, Japan. sakamoto@msic.med.osaka-cu.ac.jp

We examined the usefulness of positron emission tomography (PET) using fluorine-18 deoxyglucose (FDG) in determining the therapeutic effects of irradiation and chemotherapy on head and neck malignant tumors. Twenty-two patients with head and neck lesions who underwent histological examinations were studied. Squamous cell carcinoma was histologically diagnosed in all cases. Sixteen of them underwent radiotherapy with approximately 40 Gy in combination with carboplatin therapy. The remaining 6 patients underwent radiotherapy alone. After these treatments, 11 underwent surgery. For PET study, each patient was injected with intravenous FDG 185-370 MBq. We evaluated the degree of FDG accumulation using scanned images taken 40-55 min after the injection. We measured the standardized uptake value (SUV), a semiquantative evaluation, ROI activity divided by the dosage per weight of each patient. FDG-PET, CT and MRI were performed twice for each patient, before and after treatment. FDG uptake, but not the tumor size in CT or MRI, was significantly reduced in each patient after the treatment. Therefore, our findings have clearly demonstrated that FDG-PET provides for more valuable therapeutic outcomes than conventional imaging such as CT and MRI. FDG-PET should thus provide a new dimension in the management of head and neck malignant tumor

Can positron emission tomography improve the quality of care for head-and-neck cancer patients?

Schechter NR, Gillenwater AM, Byers RM, Garden AS, Morrison WH, Nguyen LN, Podoloff DA, Ang KK  Int J Radiat Oncol Biol Phys 2001 Sep 1;51(1):4-9.

Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA. nschecht@mdanderson.org

PURPOSE: Fluoro-2-deoxy-d-glucose-positron emission tomography (FDG-PET) is a functional imaging modality that measures the relative uptake of 18FDG with PET. The purpose of this review is to assess the potential contribution of FDG-PET scans to the treatment of head-and-neck cancer patients. METHODS AND MATERIALS: Data were assessed from the literature with attention to what additional information may be gained from the use of FDG-PET in four clinical settings: (1) detection of occult metastatic disease in the neck, (2) detection of occult primaries in patients with neck metastases, (3) detection of synchronous primaries or metastatic disease in the chest, and (4) detection of residual/recurrent locoregional disease. RESULTS: Although the data are somewhat conflicting, FDG-PET appears to add little additional value to the physical examination and conventional imaging studies (supplemented by biopsy when appropriate) for the detection of subclinical nodal metastases, unknown primaries, or disease in the chest. However, FDG-PET scans are quite useful in differentiating residual/recurrent disease from treatment-induced normal tissue changes. A positive FDG-PET scan at 1 month after radiotherapy is highly indicative of the presence of residual disease, and a negative scan at 4 months after treatment is highly predictive of tumor eradication. CONCLUSIONS: Large-scale studies using newer generation equipment and more defined methods are needed to more rigorously assess the potential of FDG-PET in the detection of subclinical primary or simultaneous secondary tumors and of nodal or systemic spread. Currently, however, FDG-PET can contribute to the detection of residual/early recurrent tumors, leading to the timely institution of salvage therapy or the prevention of unnecessary biopsies of irradiated tissues, which may aggravate injury.

FDG positron emission tomography in head and neck cancer: pitfall or pathology?

Stokkel MP, Bongers V, Hordijk GJ, van Rijk PP.  Clin Nucl Med 1999 Dec;24(12):950-4

Department of Nuclear Medicine, University Hospital Utrecht, The Netherlands.

PURPOSE: Fluorodeoxyglucose (FDG) positron emission tomography (PET) is a functional imaging technique used for imaging and staging malignant diseases. In many oncologic situations, however, abnormal changes seen on the PET studies are not caused by tumor, which is especially true in the head and neck region. The authors present an overview of the phenomena that may confound the interpretation of the images in head and neck cancer. MATERIALS AND METHODS: FDG PET studies were performed in patients with primary head and neck cancer and in patients in whom recurrent disease was likely. The results were correlated with clinical findings. Eight solitary cases were selected from a total of 180 patients studied. RESULTS AND CONCLUSIONS: Benign lesions and iatrogenic and physiologic changes may show increased FDG uptake. Therefore, clinical information on previous surgical interventions and optimal patient preparation are necessary for adequate interpretation. If these prerequisites can be met, benign lesions appear to be the only lesions that may interfere with the specificity of FDG PET.