The value of 18F-FDG PET in the detection of stage M0 carcinoma of the nasopharynx.

Distant metastasis is an important issue for nasopharyngeal carcinoma (NPC). The potential value of PET using 18F-FDG has not been well defined. This prospective study investigated the impact of 18F-FDG PET in NPC patients with stage M0 disease. METHODS: From April 2001 to June 2003, 140 NPC patients (118 primary and 22 primary recurrent) with stage M0 (negative results from chest radiography, liver sonography, and whole-body bone scanning) underwent 18F-FDG PET to check for distant metastases. Confirmatory MRI or CT was performed if any abnormal 18F-FDG uptake was found at distant sites. The distant lesion was confirmed pathologically, if feasible, and was followed up clinically and with imaging for at least 6 mo. RESULTS: 18F-FDG PET detected 26 true-positive metastatic sites in 18 (12.9%) of the 140 patients, among whom 14 had primary and 4 had recurrent tumors. The patient-based sensitivity and specificity of 18F-FDG PET for distant metastases were 100% and 86.9%, respectively. Mediastinal lymph nodes (n = 8) were the most common sites, followed by lung, liver, and bone (n = 5 each) and by other lymph nodes (n = 3). In patients with primary tumors, advanced nodal status (N2-3) was a statistically significant variable associated with development of distant metastases (P = 0.044). For recurrent NPC, neither age, sex, initial tumor stage, grade of differentiation, nor nodal stage showed a statistically significant difference between patients with and patients without distant metastases. CONCLUSION: 18F-FDG PET is valuable in avoiding aggressive locoregional radiotherapy in some NPC patients by the revelation of occult distant metastases, especially in patients with primary disease at a nodal stage of N2-3.     

Whole-body (18)F-FDG PET identifies high-risk myeloma.

The purpose of this study was to evaluate the clinical utility of whole-body PET with (18)F-FDG in patients with multiple myeloma and related monoclonal diseases. METHODS: Between July 1, 1996, and July 2000, 98 (18)F-FDG PET scans were obtained for 66 patients, with 25 patients having 2 or more scans. The results were compared with routine clinical and staging information, including CT and MRI scans, as indicated. Of the 66 patients, 16 had previously untreated active myeloma, 14 had monoclonal gammopathy of undetermined significance (MGUS), 10 had disease in remission, and 26 had relapsing disease. RESULTS: Negative whole-body (18)F-FDG PET findings reliably predicted stable MGUS. Of the 14 MGUS patients with follow-up of 3-43+ mo, myeloma has developed in only 1 (7%), at 8 mo. Conversely, the 16 previously untreated patients with active myeloma all had focal or diffusely positive scan findings. Four (25%) of 16 previously untreated patients with positive (18)F-FDG PET findings had negative full radiologic surveys. Another 4 (25%) of 16 patients had focal extramedullary disease. This was confirmed by biopsy or other imaging techniques. Extramedullary uptake also occurred in 6 (23%) of 26 patients with relapse. This extramedullary uptake was a very poor prognostic factor both before treatment and at relapse. For example, median survival was 7 mo for patients with disease relapse. Persistent positive (18)F-FDG PET findings after induction therapy predicted early relapse. In 13 (81%) of 16 patients with relapsing disease, new sites of disease were identified. The (18)F-FDG PET results were especially helpful in identifying focal recurrent disease in patients with nonsecretory or hyposecretory disease amenable to local irradiation therapy, which was used in 6 patients. CONCLUSION: Whole-body (18)F-FDG PET provides important prognostic information, which is clinically useful and complementary to conventional methods of evaluating plasma cell disorders. (18)F-FDG PET is a unique tool for evaluation of nonsecretory myeloma. Residual or recurrent disease after therapy, especially extramedullary disease, is a poor prognostic factor.     

18F-FDG PET/CT for staging of penile cancer.

The value of PET or PET/CT with (18)F-FDG for the staging of penile cancer has yet to be determined. The objective of this study was to investigate the pattern of (18)F-FDG uptake in the primary malignancy and its metastases and to determine the diagnostic value of (18)F-FDG PET/CT in the staging and restaging of penile cancer. METHODS: Thirteen patients (mean +/- SD age, 64 +/- 14.0 y) with suspected penile cancer or suspected recurrent disease were examined with a Gemini PET/CT system (200 MBq of (18)F-FDG). The reference standard was based on histopathologic findings obtained at biopsy or during surgery. RESULTS: Both the primary tumor and regional lymph node metastases exhibited a pattern of (18)F-FDG uptake typical for malignancy. Sensitivity in the detection of primary lesions was 75% (6/8), and specificity was 75% (3/4). On a per-patient basis, sensitivity in the detection of lymph node metastases was 80% (4/5), and specificity was 100% (8/8). On a nodal-group basis, PET/CT showed a sensitivity of 89% (8/9) in the detection of metastases in the superficial inguinal lymph node basins and a sensitivity of 100% (7/7) in the deep inguinal and obturator lymph node basins. The mean +/- SD maximum standardized uptake value for the 8 primary lesions was 5.3 +/- 3.7, and that for the 16 lymph node metastases was 4.6 +/- 2.0. CONCLUSION: According to our results, the main indication for (18)F-FDG PET in the primary staging or follow-up of penile cancer patients may be the prognostically crucial search for lymph node metastases. With the use of a PET/CT unit, the additional information provided by CT may be especially useful for planning surgery. Implementing (18)F-FDG PET and PET/CT in future staging algorithms may lead to a more precise and stage-appropriate therapeutic strategy. Furthermore, invasive procedures with a high morbidity rate, such as general bilateral lymphadenectomy, may be avoided.     

Usefulness of whole-body (18)F-FDG PET in patients with suspected metastatic brain tumors.

The aim of this study was to evaluate the diagnostic value of whole-body (18)F-FDG PET imaging in the differentiation of metastatic brain tumor from primary brain tumor and in the localization of the primary lesion in patients with metastatic brain tumor. METHODS: The subjects consisted of 127 patients (77 men, 50 women; mean age +/- SD, 55 +/- 12 y) with brain masses that were suspected to be metastatic brain tumors on radiologic studies: 77 with confirmed metastatic brain tumor and 50 with primary brain tumor. Whole-body (18)F-FDG PET was performed on all patients. When the abnormal lesion was detected outside the brain, we interpreted the brain lesion as metastatic brain tumor. RESULTS: In 61 of the 77 patients with metastatic brain tumor, primary lesions were detected using whole-body (18)F-FDG PET. Of the remaining 16 patients (all false-negative cases), 7 were classified as metastases of unknown origin. In 47 of the 50 patients with primary brain tumor, whole-body (18)F-FDG PET did not show any other abnormal lesions. The sensitivity, specificity, positive and negative predictive values, and accuracy of PET for the detection of primary origin were 79.2%, 94.0%, 95.3%, 74.6%, and 85.0%, respectively. The most common primary origin of metastatic brain tumors on PET examination was lung cancer (48/61, 78.7%). The concordance rate between (18)F-FDG PET and conventional radiologic work-up was 80% in identifying primary lesion. Unknown bone or bone marrow metastases and unsuspected distant metastases were found in 14 patients (18%) and 24 patients (31%), respectively, on PET examination. CONCLUSION: Screening the patients with suspected metastatic brain tumors using whole-body (18)F-FDG PET could be helpful in differentiating metastatic brain tumor from primary brain tumor and in detecting the primary lesion.     

The impact of 18F-FDG PET/CT on assessment of nasopharyngeal carcinoma at diagnosis

The aim of this study was to determine whether the use of whole-body (18)F-fluoro-2-deoxy-D-glucose ((18)F-FDG) positron emission tomography (PET)/CT alters staging and management of nasopharyngeal carcinoma (NPC) when compared with current staging practice. 52 patients with Stage III-IV NPC without distant metastases on chest X-ray/CT, abdominal ultrasound or bone scan were recruited for the study. Whole-body (18)F-FDG PET/CT and MRI of the head and neck were performed. The scans were compared for extent of the primary tumour (PT), cervical nodal metastases (CNM) and distant metastases (DM). Any discordance in results was assessed with respect to staging and impact on management. MRI and (18)F-FDG PET/CT scans were discordant in 28 (54%) patients. There was discordance in the extent of PT at 28 sites; in all sites, MRI showed more extensive tumour involving the nasopharynx (n = 8), skull base (n = 14), brain (n = 4) and orbit (n = 2). There was also variation among the extent of CNM in four nodes of the retropharyngeal region, with the nodes being positive on MRI. (18)F-FDG PET /CT did not identify any additional distant metastases but did identify a second primary tumour in the colon. The additional use of (18)F-FDG PET/CT did not "up-stage" the overall stage or change management in any patient. In conclusion, there is discordance between MRI and (18)F-FDG PET/CT, and the additional use of (18)F-FDG PET/CT for the current assessment of NPC at diagnosis does not appear to be justified in this cohort of patients.     

Clinical usefulness of 18F-FDG PET in nasopharyngeal carcinoma patients with questionable MRI findings for recurrence.

It has been reported that 18F-FDG PET is highly sensitive for the detection of recurrent head-and-neck cancer. The objective of our prospective study was to validate the ability of this technique to detect the presence of tumors in primary, nodal, and distant sites as well as to assess its overall clinical usefulness in patients with questionable MRI findings for residual or recurrent nasopharyngeal carcinoma (NPC). METHODS: From January 2002 to October 2003, a group of 37 NPC patients whose postradiation follow-up MRI examination showed questionable residual or recurrent disease was assessed with 18F-FDG PET. 18F-FDG PET was interpreted visually. Disease at primary, nodal, and distant sites was assessed. The final diagnosis was confirmed histopathologically or with clinical and imaging follow-up of at least 6 mo. RESULTS: Our results showed that the sensitivity and specificity of 18F-FDG PET for the detection of recurrent NPC were 91.6% and 76.0%, respectively, at the primary site; 90.0% and 88.9%, respectively, at nodal sites; and 100% and 90.6%, respectively, at distant sites. The overall sensitivity and specificity were 89.5% and 55.6%, respectively. Among the 37 patients, 18F-FDG PET added significant information to the MRI findings in 18, including offering true-negative findings in 10, revealing unexpected small metastatic adenopathy in 3, and disclosing distant metastatic foci in 5. CONCLUSION: 18F-FDG PET is highly sensitive and moderately specific for the detection of recurrent NPC in patients with questionable MRI findings. Overall, 18F-FDG PET appears to add significant information to MRI findings in about half of the NPC patients whose MRI examination shows questionable tumor recurrence.     

Detection of early recurrence with 18F-FDG PET in patients with cervical cancer.

This study investigated the feasibility of PET with (18)F-FDG to evaluate retrospectively early recurrence in patients with cervical cancer. METHODS: From September 1997 to March 2000, 249 patients with no evidence of cervical cancer after treatment were investigated with (18)F-FDG PET. (18)F-FDG PET scanning, beginning 50 min after injection of 370-555 MBq (18)F-FDG, was performed. (18)F-FDG uptake other than physiologic uptake was evaluated with the standardized uptake value and was analyzed by 2 observers who were unaware of CT or MRI data. CT or MRI and needle biopsies were performed to evaluate the positive lesions on (18)F-FDG PET, and all patients were monitored closely for 6 mo for recurrence. RESULTS: Of the 249 patients, 80 patients (32.1%) showed positive lesions with (18)F-FDG PET, and 28 patients (11.2%) were clinically or histologically confirmed as having recurrences. Eighty-two percent of recurrence was detected within 6-18 mo after diagnosis, and 89% of recurrence occurred in Fédération Internationale de Gynécologie et d'Obstétrique (FIGO) stage IIb and stage III patients. The sensitivity and specificity of (18)F-FDG PET for detection of early recurrence were 90.3% and 76.1%, respectively. The sensitivity of (18)F-FDG PET was high in mediastinal, hilar, and scalene lymph nodes, spine, and liver; however, the sensitivity was relatively low in lung, retrovesical lymph nodes, and paraaortic lymph nodes. Three false-negative cases were detected in lung, retrovesical lymph nodes, and paraaortic lymph nodes. CONCLUSION: (18)F-FDG PET was effective in detecting early recurrences in cervical cancer patients with no evidence of disease. (18)F-FDG PET may be a useful follow-up method for cervical cancer, thereby providing the patients with early opportunities for sophisticated treatments.     

Differential roles of 18F-FDG PET in patients with locoregional advanced nasopharyngeal carcinoma after primary curative therapy: response evaluation and impact on management.

This prospective study compares the efficacies of whole-body (18)F-FDG PET and a conventional work-up (CWU) in evaluating the treatment response for patients with locoregional advanced nasopharyngeal carcinoma (NPC) after primary curative therapy and investigates the impact of PET on patient management. METHODS: Patients who had locoregional advanced NPC (stages III and IVa-b, staged by (18)F-FDG PET and CWU) and who had completed primary curative therapy for 3 mo were enrolled. The curative therapy consisted of concurrent chemoradiotherapy with or without induction chemotherapy. All of the patients also underwent (18)F-FDG PET and CWU to evaluate the response. The criteria for final diagnosis were based on pathology or subsequent follow-up for at least 6 mo. Rates of detection by (18)F-FDG PET and CWU and the impact on management were determined on site and patient bases, respectively. RESULTS: From January 2002 to August 2005, 131 patients with NPC were eligible, including 71 patients with stage III NPC (group A) and 60 patients with stage IVa-b NPC (group B). Twelve patients were proven to have residual tumors. (18)F-FDG PET had a higher overall sensitivity than CWU in group A (100% vs. 25%) and group B (91.7% vs. 58.3%). The overall specificity of PET was significantly higher than that of CWU in group B (97.6% vs. 91.7%; P = 0.019) but was slightly lower in group A (95.7% vs. 96.7%). The overall accuracy of PET also was significantly higher than that of CWU in group B (97.2% vs. 89.4%; P = 0.002) but was similar to that of CWU in group A (95.8% vs. 95.3%). PET resulted in management changes in 11 patients (15.4%; 11/71) in group A, with positive and negative impacts on 3 and 8 patients, respectively. In group B, the management of 26 of 60 patients (43%) was changed as a result of PET and included positive impacts on 23 patients and negative impacts on 3 patients. CONCLUSION: (18)F-FDG PET plays differential roles in patients with stage III NPC and stage IVa-b NPC after primary curative therapy. PET has higher sensitivity and specificity in evaluating the response and results in better management of patients with stage IVa-b NPC. PET has a less prominent impact on patient management but higher sensitivity in patients with stage III NPC.     

Complementary roles of 18F-DOPA PET/CT and 18F-FDG PET/CT in medullary thyroid cancer

Serum calcitonin and carcinoembryonic antigen (CEA) are markers of recurrent or persistent disease in medullary thyroid cancer (MTC). However, conventional imaging often fails to localize metastatic disease. Our aim was to compare fluorine-labeled dihydroxyphenylalanine ((18)F-DOPA) and (18)F-FDG PET/CT with multidetector CT (MDCT) and MRI in recurrent or persistent MTC. METHODS: Nineteen MTC patients with increased calcitonin or CEA on follow-up (mean ± SD, 93 ± 91 mo; range, 4-300 mo) after primary therapy were prospectively imaged with 4 techniques: (18)F-DOPA PET/CT, (18)F-FDG PET/CT, MDCT, and MRI. Images were analyzed for pathologic lesions, which were surgically removed when possible. The correlation between the detection rate for each method and the calcitonin and CEA concentrations and histopathologic findings was investigated. Results: On the basis of histology and follow-up, one or more imaging methods accurately localized metastatic disease in 12 (63%) of 19 patients. The corresponding figures for (18)F-DOPA PET/CT, (18)F-FDG PET/CT, MDCT, and MRI were 11 (58%) of 19, 10 (53%) of 19, 9 (47%) of 19, and 10 (59%) of 17, respectively. Calcitonin and CEA correlated with (18)F-DOPA PET/CT (P = 0.0007 and P = 0.0263, respectively) and (18)F-FDG PET/CT findings (both P < 0.0001). In patients with an unstable calcitonin doubling time (n = 8), (18)F-DOPA and (18)F-FDG PET/CT were equally sensitive. In contrast, for patients with an unstable CEA doubling time (n = 4), (18)F-FDG PET/CT was more accurate. CONCLUSION: For most MTC patients with occult disease, (18)F-DOPA PET/CT accurately detects metastases. In patients with an unstable calcitonin level, (18)F-DOPA PET/CT and (18)F-FDG PET/CT are complementary. For patients with an unstable CEA doubling time, (18)F-FDG PET/CT may be more feasible. MRI is sensitive but has the highest rate of false-positive results.     

Imaging of gynecologic tumors: comparison of (11)C-choline PET with (18)F-FDG PET.

This study was designed to compare the value of PET using (11)C-choline with that of PET using (18)F-FDG for the diagnosis of gynecologic tumors. METHODS: We examined 21 patients, including 18 patients with untreated primary tumors and 3 patients with suspected recurrence of ovarian cancer. (11)C-choline PET and (18)F-FDG PET were performed within 2 wk of each other on each patient. The patients fasted for at least 5 h before the PET examinations, and PET was performed 5 min ((11)C-choline) and 60 min ((18)F-FDG) after injection of each tracer. PET images were corrected for the transmission data, and the reconstructed images were visually analyzed. Then, the standardized uptake value (SUV) was calculated for quantitative assessment of tumor uptake. PET results were compared with surgical histology or >6 mo of clinical observations. RESULTS: Of 18 untreated patients, (11)C-choline PET correctly detected primary tumors in 16 patients, whereas (18)F-FDG PET detected them in 14 patients. In 1 patient with small uterine cervical cancer and 1 diabetic patient with uterine corpus cancer, only (11)C-choline PET was true-positive. Both tracers were false-negative for atypical hyperplasia of the endometrium in 1 patient and were false-positive for pelvic inflammatory disease in 1 patient. For the diagnosis of recurrent ovarian cancer (n = 3), (11)C-choline PET and (18)F-FDG PET were true-positive in 1 patient, whereas neither tracer could detect cystic recurrent tumor and microscopic peritoneal disease in the other 2 patients. In the 15 patients with true-positive results for both tracers, tumor SUVs were significantly higher for (18)F-FDG than for (11)C-choline (9.14 +/- 3.78 vs. 4.61 +/- 1.61, P < 0.0001). In 2 patients with uterine cervical cancer, parailiac lymph node metastases were clearly visible on (18)F-FDG PET but were obscured by physiologic bowel uptake on (11)C-choline PET. CONCLUSION: The use of (11)C-choline PET is feasible for imaging of gynecologic tumors. Unlike (18)F-FDG PET, interpretation of the primary tumor on (11)C-choline PET is not hampered by urinary radioactivity; however, variable background activity in the intestine may interfere with the interpretation.     

Impact of whole-body 18F-FDG PET on staging and managing patients for radiation therapy.

Whole-body PET with (18)F-FDG has proven to be a very effective imaging modality for staging of malignant tumors. This study was performed to evaluate the impact of (18)F-FDG PET on staging and managing patients for radiation therapy. METHODS: The treatment records of 202 consecutive patients (98 male, 104 female; mean age, 56.9 y; age range, 8-91 y) with different malignant tumors were reviewed. Radiation therapy was intended for all patients. The diagnoses were head and neck tumors (n = 55), gynecologic tumors (n = 28), breast cancer (n = 28), lung cancer (n = 26), malignant lymphomas (n = 24), tumors of the gastrointestinal tract (n = 18), and others (n = 23). Whole-body PET was performed before radiation therapy. The alteration of PET on each patient's staging and management decisions for radiation therapy were determined. RESULTS: For 55 of 202 patients (27%), PET results changed the patients' management in radiation therapy. In 18 cases (9%), PET resulted in a cancellation of radiation therapy because of the detection of previously unknown distant metastases (8 patients), additional lymph node metastases (9 patients), residual tumor (6 patients), or the exclusion of active disease (2 patients). In 6 patients, >1 incremental reason was found for cancellation. In 21 PET examinations (10%), PET results changed the intention of radiation treatment (curative or palliative). The radiation dose was changed in 25 cases (12%). A change of radiation volume was necessary in 12 patients (6%). CONCLUSION: The results of this study show that (18)F-FDG PET has a major impact on the management of patients for radiation therapy, influencing both the stage and the management in 27% of patients.     

Positron emission tomography with 11C-acetate and 18F-FDG in prostate cancer patients

Visualisation of primary prostate cancer, its relapse and its metastases is a clinically relevant problem despite the availability of state-of-the-art methods such as CT, MRI, transrectal ultrasound and fluorine-18 fluorodeoxyglucose positron emission tomography ((18)F-FDG PET). The aim of this study was to evaluate the efficacy of carbon-11 acetate and (18)F-FDG PET in the detection of prostate cancer and its metastases. Twenty-five patients were investigated during the follow-up of primary prostate cancer, suspected relapse or metastatic disease using (11)C-acetate PET; 15 of these patients were additionally investigated using (18)F-FDG PET. Fourteen patients were receiving anti-androgen treatment at the time of the investigation. Lesions were detected in 20/24 (83%) patients using (11)C-acetate PET and in 10/15 (75%) patients using (18)F-FDG PET. Based on the results of both PET scans, one patient was diagnosed with recurrent lung cancer. Median (18)F-FDG uptake exceeded that of (11)C-acetate in distant metastases (SUV =3.2 vs 2.3). However, in local recurrence and in regional lymph node metastases, (11)C-acetate uptake (median SUVs =2.9 and 3.8, respectively) was higher than that of (18)F-FDG (median SUVs =1.0 and 1.1, respectively). A positive correlation was observed between serum PSA level and both (11)C-acetate uptake and (18)F-FDG uptake. (11)C-acetate seems more useful than (18)F-FDG in the detection of local recurrences and regional lymph node metastases. (18)F-FDG, however, appears to be more accurate in visualising distant metastases. There may be a role for combined (11)C-acetate/(18)F-FDG PET in the follow-up of patients with prostate cancer and persisting or increasing PSA.     

Detection of unexpected additional primary malignancies with PET/CT.

This study evaluated the yield of whole-body (18)F-FDG PET/CT for the detection of unexpected (18)F-FDG-avid additional primary malignant tumors in patients being evaluated by PET/CT for known or suspected malignances. METHODS: Reports from whole-body (18)F-FDG PET/CT scans from June 2001 to June 2003 were reviewed, and 1,912 patients (924 men and 988 women; mean age +/- SD, 58.9 +/- 13.9 y) who had been scanned for known or suspected malignant lesions were included in this study. The sites of known or suspected primary tumors included lung (28.6%), colon or rectum (12.4%), head or neck (12.1%), lymph nodes (10.9%), breast (7.6%), gynecologic organs (7.1%), genitourinary organs (4.2%), esophagus (3.6%), skin (melanoma) (3.5%), pancreas (2.5%), bone or soft tissue (2.2%), and other sites (5.4%). Lesions that were newly discovered on PET/CT, had not been previously detected by other modalities, and were atypical in location for metastases on the PET/CT study were interpreted as suggestive of a new primary malignant tumor. These abnormalities were compared with the final diagnosis obtained from the medical records, including pathologic reports. RESULTS: PET-positive lesions suggestive of new primary malignant tumors were found in 79 (4.1%) of 1,912 patients. In 22 (1.2%) of 1,912 patients, these lesions were pathologically proven to be malignant. Proven sites were lung (7 lesions), thyroid (6 lesions), colon (4 lesions), breast (2 lesions), esophagus (2 lesions), bile duct (1 lesion), and head and neck other than thyroid (1 lesion). Two new lesions in the lung and the thyroid were proven malignant in 1 patient. In 17 patients, the treatment plan was changed and the new lesion was surgically resected after the PET/CT examination. In 10 patients, PET was falsely positive after pathologic assessment. False-positive sites included thyroid (5 lesions), uterus (2 lesions), head and neck other than thyroid (2 lesions), and lung (1 lesion). In 8 patients, the PET-positive lesions were considered benign after clinical follow-up of at least 8 mo. In 39 patients, the follow-up record was not yet available and the final diagnosis of the detected lesion has not yet been resolved. CONCLUSION: Whole-body PET/CT detected new, unexpected (18)F-FDG-avid primary malignant tumors in at least 1.2% of patients with cancer.     

Early prediction of response to chemotherapy in metastatic breast cancer using sequential 18F-FDG PET.

Chemotherapy is currently the treatment of choice for patients with high-risk metastatic breast cancer. Clinical response is determined after several cycles of chemotherapy by changes in tumor size as assessed by conventional imaging procedures including CT, MRI, plain film radiography, or ultrasound. The aim of this study was to evaluate the use of sequential 18F-FDG PET to predict response after the first and second cycles of standardized chemotherapy for metastatic breast cancer. METHODS: Eleven patients with 26 metastatic lesions underwent 31 (18)F-FDG PET examinations (240-400 MBq of 18F-FDG; 10-min 2-dimensional emission and transmission scans). Clinical response, as assessed by conventional imaging after completion of chemotherapy, served as the reference. 18F-FDG PET images after the first and second cycles of chemotherapy were analyzed semiquantitatively for each metastatic lesion using standardized uptake values (SUVs) normalized to patients' blood glucose levels. In addition, whole-body 18F-FDG PET images were viewed for overall changes in the 18F-FDG uptake pattern of metastatic lesions within individual patients and compared with conventional imaging results after the third and sixth cycles of chemotherapy. RESULTS: After completion of chemotherapy, 17 metastatic lesions responded, as assessed by conventional imaging procedures. In those lesions, SUV decreased to 72% +/- 21% after the first cycle and 54% +/- 16% after the second cycle, when compared with the baseline PET scan. In contrast, 18F-FDG uptake in lesions not responding to chemotherapy (n = 9) declined only to 94% +/- 19% after the first cycle and 79% +/- 9% after the second cycle. The differences between responding and nonresponding lesions were statistically significant after the first (P = 0.02) and second (P = 0.003) cycles. Visual analysis of 18F-FDG PET images correctly predicted the response in all patients as early as after the first cycle of chemotherapy. As assessed by 18F-FDG PET, the overall survival in nonresponders (n = 5) was 8.8 mo, compared with 19.2 mo in responders (n = 6). CONCLUSION: In patients with metastatic breast cancer, sequential 18F-FDG PET allowed prediction of response to treatment after the first cycle of chemotherapy. The use of 18F-FDG PET as a surrogate endpoint for monitoring therapy response offers improved patient care by individualizing treatment and avoiding ineffective chemotherapy.     

18F-FDG PET in evaluation of adrenal lesions in patients with lung cancer.

The purpose of this study was to assess the role of PET with (18)F-FDG in differentiating benign from metastatic adrenal masses detected on CT or MRI scans of patients with lung cancer. METHODS: This retrospective study analyzed (18)F-FDG PET scans of patients with lung cancer who were found to have an adrenal mass on CT or MRI scans. One hundred thirteen adrenal masses (75 unilateral and 19 bilateral; size range, 0.8-4.7 cm) were evaluated in 94 patients. PET findings were interpreted as positive if the (18)F-FDG uptake of the adrenal mass was greater than or equal to that of the liver. PET findings were interpreted as negative if the (18)F-FDG uptake of the adrenal mass was less than that of the liver. All studies were reviewed independently by 3 nuclear medicine physicians, and the results were then correlated with clinical follow-up or biopsy results when available. RESULTS: PET findings were positive in 71 adrenal masses. Sixty-seven of these were eventually considered to be metastatic adrenal disease. In the remaining 4, no changes in lesion size were noted on follow-up examinations. PET findings were negative in 42 adrenal masses, of which 37 eventually proved to be benign. Among the 5 adrenal masses that were false-negative, one was a large necrotic metastasis; 1 was a 2.4-cm lesion with central hemorrhaging, and the remaining 3 were lesions of less than 11 mm. The sensitivity, specificity, and accuracy for detecting metastatic disease were 93%, 90%, and 92%, respectively. CONCLUSION: (18)F-FDG PET is an accurate, noninvasive technique for differentiating benign from metastatic adrenal lesions detected on CT or MRI in patients with lung cancer. In addition, PET has the advantage of assessing the primary cancer sites and detecting other metastases.     

Comparison of integrin alphaVbeta3 expression and glucose metabolism in primary and metastatic lesions in cancer patients: a PET study using 18F-galacto-RGD and 18F-FDG.

The expression of alpha(v)beta(3) and glucose metabolism are upregulated in many malignant lesions, and both are known to correlate with an aggressive phenotype. We evaluated whether assessment of alpha(v)beta(3) expression and of glucose metabolism with PET using (18)F-galacto-RGD and (18)F-FDG provides complementary information in cancer patients. METHODS: Eighteen patients with primary or metastatic cancer (non-small cell lung cancer [NSCLC], n = 10; renal cell carcinoma, n = 2; rectal cancer, n = 2; others, n = 4) were examined with PET using (18)F-galacto-RGD and (18)F-FDG. Standardized uptake values (SUVs) were derived by volume-of-interest analysis. (18)F-Galacto-RGD and (18)F-FDG PET results were compared using linear regression analysis for all lesions (n = 59; NSCLC, n = 39) and for primaries (n = 14) and metastases to bone (n = 11), liver (n = 10), and other organs (n = 24) separately. RESULTS: The sensitivity of (18)F-galacto-RGD PET compared with clinical staging was 76%. SUVs for (18)F-FDG ranged from 1.3 to 23.2 (mean +/- SD, 7.6 +/- 4.9) and were significantly higher than SUVs for (18)F-galacto-RGD (range, 0.3-6.8; mean +/- SD, 2.7 +/- 1.5; P < 0.001). There was no significant correlation between the SUVs for (18)F-FDG and (18)F-galacto-RGD for all lesions (r = 0.157; P = 0.235) or for primaries, osseous or soft-tissue metastases separately (P > 0.05). For the subgroup of lesions in NSCLC, there was a weak correlation between (18)F-FDG and (18)F-galacto-RGD uptake (r = 0.353; P = 0.028). CONCLUSION: Tracer uptake of (18)F-galacto-RGD and (18)F-FDG does not correlate closely in malignant lesions. Whereas (18)F-FDG PET is more sensitive for tumor staging, (18)F-galacto-RGD PET warrants further evaluation for planning and response evaluation of targeted molecular therapies with antiangiogenic or alpha(v)beta(3)-targeted drugs.     

18F-FDG PET can replace conventional work-up in primary M staging of nonkeratinizing nasopharyngeal carcinoma.

Conventional work-up (CWU) with chest radiography, abdominal ultrasonography, and skeletal scintigraphy has limited value in M staging of nonkeratinizing nasopharyngeal carcinoma (NPC). Our aim was to evaluate whether (18)F-FDG PET could replace CWU by comparing their diagnostic efficacies. METHODS: Patients with histologically proven nonkeratinizing NPC and no prior treatment were prospectively enrolled. All study participants underwent CWU and (18)F-FDG PET for primary M staging. Distant metastasis was considered to be present if there was any reliable evidence identified within 1 y after diagnosis. The comparative diagnostic efficacies of (18)F-FDG PET, CWU, and the combination of (18)F-FDG PET and CWU (PET+CWU) were evaluated using the areas under the receiver-operating-characteristic (ROC) curves. RESULTS: Sixty-one (20.3%) of 300 eligible patients were found to have distant metastases. On a patient-based analysis, (18)F-FDG PET was found to be more effective than CWU (P < 0.001), whereas it was equally effective with PET+CWU (P = 0.130). On region-based analyses, (18)F-FDG PET was more effective than skeletal scintigraphy and chest radiography for detecting bone metastases (P < 0.001) and chest metastases (P < 0.001), respectively. (18)F-FDG PET and abdominal ultrasound were equally effective for detecting hepatic metastases (P = 0.127). On region-based analyses, the combination of (18)F-FDG PET and CWU did not yield any noticeable increase in diagnostic efficacy. CONCLUSION: (18)F-FDG PET can replace CWU in primary M staging of nonkeratinizing NPC.     

Comparison of 18F-FDG PET and bone scintigraphy in detection of bone metastases of thyroid cancer.

We compared the efficacies of (18)F-FDG PET and (99m)Tc-bone scintigraphy for the detection of bone metastases in patients with differentiated thyroid carcinoma (DTC). METHODS: We examined 47 patients (32 women, 15 men; mean age +/- SD, 57.0 +/- 10.7 y) with DTC who had undergone total thyroidectomy and were hospitalized to be given (131)I therapy. All patients underwent both whole-body (18)F-FDG PET and (99m)Tc-bone scintigraphy. The skeletal system was classified into 11 anatomic segments and assessed for the presence of bone metastases. Bone metastases were verified either when positive findings were obtained on >2 imaging modalities--(201)Tl scintigraphy, (131)I scintigraphy, and CT--or when MRI findings were positive if vertebral MRI was performed. RESULTS: Bone metastases were confirmed in 59 of 517 (11%) segments in 18 (38%) of the 47 study patients. The sensitivities (visualization rate) for bone metastases on a segment basis using (18)F-FDG PET and (99m)Tc-bone scintigraphy were 50 of 59 (84.7%) and 46 of 59 (78.0%), respectively; the difference between these values was not statistically significant. There were only 2 (0.4%) false-positive cases in a total of 451 bone segments without bone metastases when examined by (18)F-FDG PET, whereas 39 (8.6%) were false-positive when examined by (99m)Tc-bone scintigraphy. Therefore, the specificities of (18)F-FDG PET and (99m)Tc-bone scintigraphy were 449 of 451 (99.6%) and 412 of 451 (91.4%), respectively; the difference between these values was statistically significant (P < 0.001). The overall accuracies of (18)F-FDG PET and (99m)Tc-bone scintigraphy were 499 of 510 (97.8%) and 458 of 510 (89.8%), respectively; the difference between these was also statistically significant (P < 0.001). CONCLUSION: The specificity and the overall accuracy of (18)F-FDG PET for the diagnosis of bone metastases in patients with DTC are higher than those of (99m)Tc-bone scintigraphy, whereas the difference in the sensitivities of both modalities is not statistically significant. In comparison with (99m)Tc-bone scintigraphy, (18)F-FDG PET is superior because of its lower incidence of false-positive results in the detection of bone metastases of DTC.     

The utility of (18)F-FDG PET for suspected recurrent non-small cell lung cancer after potentially curative therapy: impact on management and prognostic stratification.

After potentially curative therapy of non-small cell lung cancer (NSCLC), masses or symptoms suggestive of relapse are common but may be difficult to characterize. Early detection is important because salvage therapies are available for localized recurrence. This study evaluated whether (18)F-FDG PET is useful and predictive of outcome in this setting. METHODS: For 63 consecutive patients with suspected relapse >6 mo after definitive treatment of NSCLC, the apparent extent of disease on conventional restaging was compared with that on FDG PET. Patients with already confirmed systemic metastases were excluded unless locally aggressive treatment of these was being considered. Serial imaging and pathologic results were obtained during a median follow-up of 19 mo to validate diagnostic findings. Prognostic significance was tested using the Cox proportional hazards regression model. RESULTS: PET had positive findings in 41 of 42 patients with confirmed relapse (sensitivity, 98%). No disease was evident during a minimum follow-up of 12 mo in 14 of 15 patients with clinically suspected relapse but negative PET findings (negative predictive value, 93%). PET induced a major management change in 40 patients (63%), including 6 whose treatment was changed from curative to palliative, 3 whose treatment was changed from palliative to curative, and 9 for whom negative PET findings prevented active management. Both the presence (P = 0.012) and the extent (P < 0.0001) of relapse on PET were highly significant prognostic factors. There was also significant prognostic stratification based on the treatment delivered after the PET study (P = 0.011), but after adjustment for this treatment, PET status remained highly predictive of survival. CONCLUSION: PET better assesses the status of disease and stratifies prognosis than does conventional staging, affects patient management, and should be incorporated into paradigms for suspected recurrence of NSCLC.     

^18F-FDG PET/CT对可疑复发性宫颈癌的临床价值

目的 探讨^18F-FDG PET/CT在可疑复发性宫颈癌临床诊疗中的价值.方法 回顾性分析51例宫颈癌根治后随访期间临床可疑复发的患者,记录患者的治疗资料、可疑复发表现、18F-FDG PET/CT显像结果、同期常规影像检查结果、病理及临床随访结果、PET/CT结果对临床诊疗的影响.结果 PET/CT诊断宫颈癌复发43例,最终经病理检查及临床随访证实复发性宫颈癌40例,盆腔脓肿2例,放射性肠炎1例;PET/CT未见恶性征象8例,病理检查及临床随访均未见异常.PET/CT诊断复发性宫颈癌灵敏度为100.00%（40/40）,特异性为72.73%（8/11）,准确性为94.12%（48/51）.PET/CT指导制订临床诊疗及随访计划34例,改变治疗计划7例.与其他影像检查相比,PET/CT可发现更多的病灶.结论^18F-FDG PET/CT能有效诊断复发性宫颈癌,指导临床诊疗.