Value of FDG PET in papillary thyroid carcinoma with negative 131I whole-body scan.

The management of metastatic thyroid carcinoma patients with a negative 131I scan presents considerable problems. Fifty-four athyrotic papillary thyroid carcinoma patients whose 1311 whole-body scans were negative underwent 18F-fluorodeoxyglucose (FDG) PET; the purpose was to determine whether this procedure could localize metastatic sites. We also assessed its usefulness in the management of these patients. METHODS: Whole-body emission scan was performed 60 min after the injection of 370-555 MBq 18F-FDG, and additional regional attenuation-corrected scans were obtained. Metastasis was pathologically confirmed in 12 patients and was confirmed in other patients by overall clinical evaluation of the findings of other imaging studies and of the subsequent clinical course. RESULTS: In 33 patients, tumor had metastasized, whereas 21 patients were in remission. FDG PET revealed metastases in 31 patients (sensitivity 93.9%), whereas thyroglobulin levels were elevated in 18 patients (sensitivity 54.5%). FDG PET was positive in 14 of 15 metastatic cancer patients with normal thyroglobulin levels. In 20 of 21 patients in remission, FDG PET was negative (specificity 95.2%), whereas thyroglobulin levels were normal in 16 patients (specificity 76.1%). The sensitivity and specificity of FDG PET were significantly higher than those of serum thyroglobulin. In patients with negative 1311 scans, FDG PET detected cervical lymph node metastasis in 87.9%, lung metastasis in 27.3%, mediastinal metastasis in 33.3% and bone metastasis in 9.1%. In contrast, among 117 patients with 131I scan-positive functional metastases, 131I scan detected cervical lymph node metastasis in 61.5%, lung metastasis in 56.4%, mediastinal metastasis in 22.2% and bone metastasis in 16.2%. In all 5 patients in whom thyroglobulin was false-negative with negative antithyroglobulin antibody, PET showed increased 18F-FDG uptake in cervical lymph nodes, mediastinal lymph nodes, or both. Among patients with increased 18F-FDG uptake only in the cervical lymph nodes, the nodes were dissected in 11. Metastasis was confirmed in all, even in normal-sized lymph nodes. CONCLUSION: FDG PET scan localized metastatic sites in 131I scan-negative thyroid carcinoma patients with high accuracy. In particular, it was superior to 131I whole-body scan and serum thyroglobulin measurement for detecting metastases to cervical lymph nodes. FDG PET was helpful for determining the surgical management of these patients.     

The clinical impact of18F-FDG PET in papillary thyroid carcinoma with a negative131I whole body scan: A single-center study of 108 patients

OBJECTIVE: To assess whether FDG PET could localize the recurrent or metastatic lesions in papillary thyroid cancer patients with negative radioiodine scan. METHODS: Whole body PET was performed after injecting 370-555 MBq of 18F-FDG in 108 patients, who were suspected of having recurrence or metastasis and whose 131I whole body scans were negative. Recurrence or metastasis occurred in 63 patients by pathology or clinical assessment, whereas 45 patients remained in remission. RESULTS: FDG PET revealed recurrence or metastases in 59 patients (sensitivity 93.7%), whereas thyroglobulin (Tg) levels were elevated in 41 (sensitivity 65.1%). In 35 of 45 patients in remission, FDG PET was negative (specificity 77.8%). When patients positive for antithyroglobulin antibody were excluded, the sensitivity and specificity of serum Tg became 84.8% and 46.9%, respectively. Compared to Tg measurement, FDG PET detected more metastatic lesions in cervical lymph nodes. Of 40 patients with a negative radioiodine scan showing diffuse hepatic uptake, metastases occurred in 23 patients and remission in 17. FDG PET showed 100% sensitivity and 76.5% specificity in the detection of recurrence in these 40 patients. CONCLUSION: FDG PET is useful for localizing recurrent or metastatic lesions in 131I scan-negative thyroid cancer patients. In particular, it is superior to serum Tg measurement for identifying metastases to cervical lymph nodes. We recommend its use in cases of negative radioiodine scan with diffuse hepatic uptake.     

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.     

18F-FDG PET/CT在胃癌中的临床应用进展

胃癌是全球范围内最常见的恶性肿瘤之一。18F-氟脱氧葡萄糖（FDG）PET/CT在胃癌中的应用既有优点又有局限性。胃癌原发灶对18F-FDG的摄取与癌症分期、组织学分型和肿瘤大小密切相关。早期胃癌18F-FDG摄取阳性预示着内镜黏膜下剥离术的不可治愈性。进展期胃癌的最大标准化摄取值（SUV_max）在肠型与印戒细胞癌（SRC）或弥漫型胃癌间的差异显著,SRC的SUV_max与患者的总生存时间和无病生存时间呈负相关。18F-FDG PET/CT对区域淋巴结转移的诊断灵敏度较低,但其特异度很高,区域淋巴结对18F-FDG摄取呈阳性是预后不良的指征。18F-FDG PET/CT可检出隐匿的远处转移（7.2%~10.0%）,其中大部分（4.7%~8.8%）使用腹腔镜也不能检出。常规性应用18F-FDG PET/CT并联合腹腔镜检查对明确胃癌分期的意义重大。因此,笔者就18F-FDG PET/CT在胃癌中的临床应用进展进行综述。     

Evaluation of head and neck cancer with 18F-FDG PET: a comparison with conventional methods

The aim of this study was to evaluate the usefulness of 18F-FDG PET in the diagnosis and staging of primary and recurrent malignant head and neck tumours in comparison with conventional imaging methods [including ultrasonography, radiography, computed tomography (CT) and magnetic resonance imaging (MRI)], physical examination, panendoscopy and biopsies in clinical routine. A total of 54 patients (13 female, 41 male, age 61.3+/-12 years) were investigated retrospectively. Three groups were formed. In group I, 18F-FDG PET was performed in 15 patients to detect unknown primary cancers. In group II, 24 studies were obtained for preoperative staging of proven head and neck cancer. In group III, 18F-FDG PET was used in 15 patients to monitor tumour recurrence after radiotherapy and/or chemotherapy. In all patients, imaging was obtained at 70 min after the intravenous administration of 180 MBq 18F-FDG. In 11 of the 15 patients in group I, the primary cancer could be found with 18F-FDG, yielding a detection rate of 73.3%. In 4 of the 15 patients, CT findings were also suggestive of the primary cancer but were nonetheless equivocal. In these patients, 18F-FDG showed increased 18F-FDG uptake by the primary tumour, which was confirmed by histology. One patient had recurrence of breast carcinoma that could not be detected with 18F-FDG PET, but was detected by CT. In three cases, the primary cancer could not be found with any imaging method. Among the 24 patients in group II investigated for staging purposes, 18F-FDG PET detected a total of 13 local and three distant lymph node metastases, whereas the conventional imaging methods detected only nine local and one distant lymph node metastases. The results of 18F-FDG PET led to an upstaging in 5/24 (20.8%) patients. The conventional imaging methods were false positive in 5/24 (20.8%). There was one false positive result using 18F-FDG PET. Among the 15 patients of group III with suspected recurrence after radiotherapy and/or chemotherapy, 18F-FDG was true positive in 7/15 (46.6%) and true negative in 4/15 (26.6%). The conventional imaging methods were true positive in 5/15 (33.3%) and true negative in 4/15 (26.6%). One false negative (6.6%) and three false positive findings (20%) on 18F-FDG PET were due to inflamed tissue. The conventional imaging methods were false positive in three (20%) and false negative in three cases (20%). It is concluded that in comparison to conventional diagnostic methods, 18F-FDG PET provides additional and clinically relevant information in the detection of primary and metastatic carcinomas as well as in the early detection of recurrent or persistent head and neck cancer after radiotherapy and/or chemotherapy. 18F-FDG PET should therefore be performed early in clinical routine, usually before CT or MRI.     

Clinical role of (18)F-FDG PET for initial staging of patients with extrahepatic bile duct cancer

In extrahepatic bile duct cancer, preoperative evaluation is important because only surgical excision of all detectable tumours is associated with improvement in 5-year survival. However, morphological imaging techniques, including computed tomography (CT), are still insufficient for accurate staging. The purpose of this study was to assess the additional value, in relation to CT, of 2-[(18)F]fluoro-2-deoxy- D-glucose positron emission tomography ((18)F-FDG PET) for the evaluation of extrahepatic bile duct cancer. Thirty patients with extrahepatic bile duct cancer underwent both (18)F-FDG PET and CT for initial staging. The results of the two modalities for evaluation of primary tumours and regional lymph nodes were compared with the final diagnoses based on pathological or clinical findings. The primary tumours were interpreted as malignant on the basis of CT in 24 (80%) of the patients, while (18)F-FDG PET revealed increased (18)F-FDG uptake in 18 (60%) of them. On the other hand, (18)F-FDG PET showed focal accumulation of (18)F-FDG in the bile duct in three of the six patients with equivocal findings on CT. The sensitivity, specificity and accuracy of CT for regional lymph node metastases were 54%, 59% and 57%, while those of (18)F-FDG PET were 38%, 100% and 73%, respectively. The specificity of (18)F-FDG PET for regional lymph node metastases was significantly higher than that of CT ( P<0.01). Of 14 patients with N1 or N2 disease diagnosed by CT, only seven (50%) had a final diagnosis of regional lymph node metastasis. In these 14 patients, (18)F-FDG PET accurately evaluated the N component of the disease in 12 patients (86%). In conclusion, in the initial staging of patients with extrahepatic bile duct cancer, (18)F-FDG PET offers additional value in relation to CT in evaluating both the primary tumour and regional lymph nodes.     

Improved prognostic value of 18F-FDG PET using a simple visual analysis of tumor characteristics in patients with cervical cancer.

In patients with cervical cancer, it is important to estimate prognosis at the time of diagnosis. This study using PET with (18)F-FDG was undertaken to determine whether a simple and fast visual analysis of characteristics of the primary tumor before initiation of treatment could achieve this goal. METHODS: Forty-seven patients with cervical cancer who were to be treated by combined radiation therapy and chemotherapy were imaged before beginning treatment. They were then followed for up to 3 y for evidence of recurrence or death. Images of the chest, abdomen, and pelvis were obtained 40-90 min after administration of 370-555 MBq (10-15 mCi) (18)F-FDG. Three observers then independently graded the primary tumor for size (0 = small, 1 = moderate, 2 = large), shape (0 = spherical, 1 = nonspherical), heterogeneity of uptake (0 = none, 1 = moderate, 2 = marked), and presence of lymph nodes (0 = none, 1 = pelvic, 2 = paraaortic, 3 = distant). The scores were summed to achieve a total score. A statistical calculation demonstrated that a score cutoff of 4 best separated patients with a good prognosis from patients with a bad prognosis. Kaplan-Meier analysis was used to compute progression-free survival and overall survival. Evaluation of lymph nodes alone was compared with the grading of tumor characteristics. RESULTS: Observers 1 and 2 scored 26 patients as having a good prognosis and 21 as having a bad prognosis. Observer 3 scored 30 and 17, respectively, a statistically insignificant difference. Survival curves were almost identical for the 3 observers. For progression-free survival, approximately 12% of patients with a good score had disease recurrence whereas approximately 75% with a bad score had disease recurrence. For overall survival, approximately 10% (good) and 80% (bad) died. Evaluation of lymph nodes also separated the groups, but not as well as did visual analysis alone. The combination of the 2 was only slightly superior to visual assessment alone. CONCLUSION: A simple, rapid, and highly reproducible system is described for visual grading of characteristics of the primary tumor in patients with cervical cancer at the time of diagnosis. This approach separates patients with a poor prognosis from those who will do well, thus providing a new tool for accurate estimation of prognosis.     

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.     

^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.     

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.     

Prospective evaluation of fluorine-18 fluorodeoxyclucose positron emission tomography in breast cancer for staging of the axilla related to surgery and immunocytochemistry

The noninvasive staging of axillary lymph nodes for metastases is investigated in patients with breast cancer prior to surgery by positron emission tomography (PET) with fluorine- l8-fluoro-2-deoxy-d-glucose (¹⁸F-FDG). In 124 patients with newly diagnosed breast cancer, whole-body PET was performed to determine the average differential uptake ratio (DUR) of¹⁸F-FDG in the axillary lymph nodes. Results were correlated with the number of the dissected lymph nodes, size of the primary tumor, tumor type, tumor grade, estrogen and progesterone receptors, DNA ploidy, and the proportion of cells in the synthetic phase of the cell cycle (S-phase). In this prospective study of 124 patients with breast carcinoma, PET correctly categorized all 44 tumor-positive axillary lymph nodes, a sensitivity of 100%. Sixty tumor-negative axillary lymph nodes were negative by PET and 20 tumor-negative axillary lymph nodes were positive by PET. No false-negative PET findings were encountered. A weak correlation was found between DUR and tumor size as well as between DUR and the S-phase of the tumor. In patients with breast carcinoma,¹⁸F-FDG PET can be of value in evaluating axillary lymph nodes for metastatic involvement prior to surgery. It is of particular importance that no false-negative PET findings were encountered, and axillary lymph node dissection might not be necessary in patients without axillary uptake by PET. The DUR of the positive axillary lymph nodes seems to bear a relationship with some of the purported prognostic parameters of the primary tumor.     

11C-acetate PET imaging of prostate cancer: detection of recurrent disease at PSA relapse.

Patients with rising prostate-specific antigen (PSA) levels after definitive local therapy of prostate carcinoma present a diagnostic dilemma. A local recurrence would be amenable to additional local therapy with curative intent, whereas metastatic disease would require palliative androgen ablation therapy. In this study, we evaluated the effectiveness of PET with (11)C-acetate (AC PET) for evaluation of patients with rising PSA after radical prostatectomy or radiation therapy. We also compared the reliability of AC PET in detecting recurrent prostate cancer with that of PET with (18)F-FDG. METHODS: Two groups of patients with PSA recurrence were enrolled in this study: group A, 30 patients after prostatectomy, and group B, 16 patients after radiation therapy. After administration of 1,110 MBq (30 mCi) of (11)C-acetate, whole-body PET images were obtained. After allowing for (11)C decay, 555 MBq (15 mCi) of (18)F-FDG were administered and repeated whole-body imaging was performed. The PET findings were scored as positive or negative in each of the following regions: prostatic bed, pelvic nodes, paraaortic nodes, and other sites (bone or soft tissue). PET findings were correlated with those of CT, bone scintigraphy, and biopsy. RESULTS: Twenty-seven of 46 AC PET studies (59%) had positive findings, whereas only 8 (18)F-FDG PET studies had positive findings (17%). Limiting the analysis to patients with findings confirmed by CT, bone scintigraphy, or biopsy or considered highly likely to represent tumor, 14 (30%) had disease identified by AC PET, whereas only 4 (9%) had disease identified by (18)F-FDG PET. CT was performed on 22 patients and had positive findings in 3 (14%). Thirteen of 22 patients (59%) with serum PSA > 3 ng/mL had positive AC PET findings, whereas only 1 of 24 patients (4%) with serum PSA levels < or = 3 ng/mL had positive findings. CONCLUSION: AC PET demonstrates marked uptake in prostate cancer and has higher sensitivity than (18)F-FDG PET. These preliminary data show that (11)C-acetate is a promising tracer for detection of recurrent prostate cancer.     

Comparison of 18F-FLT PET and 18F-FDG PET in esophageal cancer.

18F-FDG PET has gained acceptance for staging of esophageal cancer. However, FDG is not tumor specific and false-positive results may occur by accumulation of FDG in benign tissue. The tracer 18F-fluoro-3'-deoxy-3'-L-fluorothymidine (18F-FLT) might not have these drawbacks. The aim of this study was to investigate the feasibility of 18F-FLT PET for the detection and staging of esophageal cancer and to compare 18F-FLT PET with 18F-FDG PET. Furthermore, the correlation between 18F-FLT and 18F-FDG uptake and proliferation of the tumor was investigated. METHODS: Ten patients with biopsy-proven cancer of the esophagus or gastroesophageal junction were staged with CT, endoscopic ultrasonography, and ultrasound of the neck. In addition, all patients underwent a whole-body 18F-FLT PET and 18F-FDG PET. Standardized uptake values were compared with proliferation expressed by Ki-67 positivity. RESULTS: 18F-FDG PET was able to detect all esophageal cancers, whereas 18F-FLT PET visualized the tumor in 8 of 10 patients. Both 18F-FDG PET and 18F-FLT PET detected lymph node metastases in 2 of 8 patients. 18F-FDG PET detected 1 cervical lymph node that was missed on 18F-FLT PET, whereas 18F-FDG PET showed uptake in benign lesions in 2 patients. The uptake of 18F-FDG (median standardized uptake value [SUV(mean)], 6.0) was significantly higher than 18F-FLT (median SUV(mean), 3.4). Neither 18F-FDG maximum SUV (SUV(max)) nor 18F-FLT SUV(max) correlated with Ki-67 expression in the linear regression analysis. CONCLUSION: In this study, uptake of 18F-FDG in esophageal cancer is significantly higher compared with 18F-FLT uptake. 18F-FLT scans show more false-negative findings and fewer false-positive findings than do 18F-FDG scans. Uptake of 18F-FDG or 18F-FLT did not correlate with proliferation.     

Lymph node staging of gastric cancer using (18)F-FDG PET: a comparison study with CT.

This study was performed to compare (18)F-FDG PET with CT for the evaluation of primary tumors and lymph node metastases in gastric cancer. METHODS: Eighty-one patients (28 women and 53 men; mean age, 56.6 y; age range; 32-82 y) who had undergone radical (n = 74) or palliative (n = 7) gastrectomy and lymph node dissection for the management of gastric cancer were included. Preoperative (18)F-FDG PET and CT were reviewed retrospectively for primary tumors of the stomach and lymph node metastases. Any increased (18)F-FDG uptake exceeding that of the adjacent normal gastric wall was considered positive for the primary tumor. Lymph nodes were classified into 3 groups based on their anatomic sites. Because perigastric lymph nodes (N1) were often not clearly differentiated from primary tumors, N1 lymph node metastases were determined when possible. Lymph nodes were considered positive or negative on the basis of the group as a whole. Final conclusions for primary tumors and lymph node metastases were based on histopathologic specimens in all patients. RESULTS: There were 17 patients with early gastric cancer (EGC) and 64 patients with advanced gastric cancer (AGC). For primary tumors, both PET and CT showed a sensitivity of 47% (8/17) for EGC and 98% (63/64) for AGC. The sensitivity of CT for N1 disease was significantly higher than that of PET. (18)F-FDG PET had a sensitivity, specificity, and accuracy of 34% (11/32), 96% (47/49), and 72% (58/81), respectively, for N2 metastases, whereas the corresponding CT values were 44% (14/32), 86% (42/49), and 69% (56/81). For N3 metastases, PET and CT had the same sensitivity, specificity, and accuracy: 50% (3/6), 99% (74/75), and 95% (77/81), respectively. Overall, the sensitivity, specificity, and accuracy of (18)F-FDG PET were not significantly different from those of CT for primary tumors or for N2 and N3 metastases. CONCLUSION: (18)F-FDG PET is as accurate as CT for the detection of primary tumors of either EGC or AGC. The low sensitivities of PET and CT were insufficient to allow decision making on the extent of lymphadenectomy. In contrast, the high specificity of PET for N disease appeared valuable, and the presence of N disease on PET may have a clinically significant impact on the choice of initial therapy.     

Assessing tumor hypoxia in cervical cancer by PET with 60Cu-labeled diacetyl-bis(N4-methylthiosemicarbazone)

Tumor hypoxia indicates a poor prognosis. This study was undertaken to confirm our prior pilot results showing that pretreatment tumor hypoxia demonstrated by PET with (60)Cu-labeled diacetyl-bis(N(4)-methylthiosemicarbazone) ((60)Cu-ATSM) is a biomarker of poor prognosis in patients with cervical cancer. Thirty-eight women with biopsy-proved cervical cancer underwent (60)Cu-ATSM PET before the initiation of radiotherapy and chemotherapy. (60)Cu-ATSM uptake was evaluated semiquantitatively as the tumor-to-muscle activity ratio (T/M). A log-rank test was used to determine the cutoff uptake value that was strongly predictive of prognosis. All patients also underwent clinical PET with (18)F-FDG before the institution of therapy. The PET results were correlated with clinical follow-up. Tumor (60)Cu-ATSM uptake was inversely related to progression-free survival and cause-specific survival (P = 0.006 and P = 0.04, respectively, as determined by the log-rank test). We found that a T/M threshold of 3.5 best discriminated patients likely to develop a recurrence from those unlikely to develop a recurrence; the 3-y progression-free survival of patients with normoxic tumors (as defined by T/M of < or = 3.5) was 71%, and that of patients with hypoxic tumors (T/M of > 3.5) was 28% (P = 0.01). Tumor (18)F-FDG uptake did not correlate with (60)Cu-ATSM uptake, and there was no significant difference in tumor (18)F-FDG uptake between patients with hypoxic tumors and those with normoxic tumors (P = 0.9). Pretherapy (60)Cu-ATSM PET provides clinically relevant information about tumor oxygenation that is predictive of outcome in patients with cervical cancer.     

18F-FDG PET/MRI与MRI在食管癌患者术前T、N分期中应用价值的对比分析

目的 比较18F-氟脱氧葡萄糖（FDG）PET/MRI与MRI在食管癌患者术前T、N分期中的应用价值。 方法 回顾性分析2018年1月至2019年12月于空军军医大学第二附属医院行食管癌根治术的30例患者的临床资料与影像学资料,其中男性25例、女性5例,年龄42~77（62.9±8.0）岁。患者均在术前2周内行18F-FDG PET/MRI检查,以术后组织病理学检查结果为分期的“金标准”。采用Kappa检验评估18F-FDG PET/MRI和MRI对食管癌患者术前T、N分期与术后组织病理学分期的一致性;18F-FDG PET/MRI与MRI对食管癌患者术前T、N分期准确率的比较采用χ2检验;转移性淋巴结与良性淋巴结最大标准化摄取值（SUV_max）、平均标准化摄取值（SUV_mean）、表观扩散系数最小值（ADC_min）、表观扩散系数平均值（ADC_mean）的比较采用独立样本t检验。 结果 18F-FDG PET/MRI与MRI对食管癌患者术前T分期和术后组织病理学分期的一致性均较强（Kappa值=0.757、0.698,均P<0.001）;18F-FDG PET/MRI和MRI对食管癌患者术前T分期诊断的准确率分别为83.3%（25/30）、80.0%（24/30）,差异无统计学意义（χ2=0.110,P>0.05）。18F-FDG PET/MRI对食管癌患者术前N分期的诊断准确率高于MRI [76.7%（23/30）对66.7%（20/30）],且差异有统计学意义（χ2=11.273,P<0.01）。转移性淋巴结的SUV_max和SUV_mean均明显高于良性淋巴结（5.77±2.66对2.79±1.29,3.16±1.28对1.78±1.01）,且差异均有统计学意义（t=6.39、5.96,均P<0.001）;转移性淋巴结的ADC_min较良性淋巴结低（1.02±0.33对1.20±0.24）,且差异有统计学意义（t=?3.81,P<0.001）;两者ADC_mean的比较,差异无统计学意义（t=?1.52,P>0.05）。 结论 18F-FDG PET/MRI在食管癌患者术前T分期中的价值与MRI相当,且其对食管癌患者术前N分期的诊断效能优于MRI,故可成为食管癌患者术前分期优选的无创检查方法。     

Evaluation of head and neck cancer with 18F-FDG PET: a comparison with conventional methods

The aim of this study was to evaluate the usefulness of ¹⁸F-FDG PET in the diagnosis and staging of primary and recurrent malignant head and neck tumours in comparison with conventional imaging methods [including ultrasonography, radiography, computed tomography (CT) and magnetic resonance imaging (MRI)], physical examination, panendoscopy and biopsies in clinical routine. A total of 54 patients (13 female, 41 male, age 61.3ᆠ years) were investigated retrospectively. Three groups were formed. In group I, ¹⁸F-FDG PET was performed in 15 patients to detect unknown primary cancers. In group II, 24 studies were obtained for preoperative staging of proven head and neck cancer. In group III, ¹⁸F-FDG PET was used in 15 patients to monitor tumour recurrence after radiotherapy and/or chemotherapy. In all patients, imaging was obtained at 70 min after the intravenous administration of 180 MBq ¹⁸F-FDG. In 11 of the 15 patients in group I, the primary cancer could be found with ¹⁸F-FDG, yielding a detection rate of 73.3%. In 4 of the 15 patients, CT findings were also suggestive of the primary cancer but were nonetheless equivocal. In these patients, ¹⁸F-FDG showed increased ¹⁸F-FDG uptake by the primary tumour, which was confirmed by histology. One patient had recurrence of breast carcinoma that could not be detected with ¹⁸F-FDG PET, but was detected by CT. In three cases, the primary cancer could not be found with any imaging method. Among the 24 patients in group II investigated for staging purposes, ¹⁸F-FDG PET detected a total of 13 local and three distant lymph node metastases, whereas the conventional imaging methods detected only nine local and one distant lymph node metastases. The results of ¹⁸F-FDG PET led to an upstaging in 5/24 (20.8%) patients. The conventional imaging methods were false positive in 5/24 (20.8%). There was one false positive result using ¹⁸F-FDG PET. Among the 15 patients of group III with suspected recurrence after radiotherapy and/or chemotherapy, ¹⁸F-FDG was true positive in 7/15 (46.6%) and true negative in 4/15 (26.6%). The conventional imaging methods were true positive in 5/15 (33.3%) and true negative in 4/15 (26.6%). One false negative (6.6%) and three false positive findings (20%) on ¹⁸F-FDG PET were due to inflamed tissue. The conventional imaging methods were false positive in three (20%) and false negative in three cases (20%). It is concluded that in comparison to conventional diagnostic methods, ¹⁸F-FDG PET provides additional and clinically relevant information in the detection of primary and metastatic carcinomas as well as in the early detection of recurrent or persistent head and neck cancer after radiotherapy and/or chemotherapy. ¹⁸F-FDG PET should therefore be performed early in clinical routine, usually before CT or MRI.     

18F-FDG uptake in squamous cell carcinoma of the cervix is correlated with glucose transporter 1 expression.

This prospective study investigates the relationship between glucose transporter-1 (Glut-1) expression and PET images using (18)F-FDG and its uptake and compares them with the tumor status (primary vs. recurrent or persistent), initial grade of histologic differentiation, and International Federation of Gynecologic Obstetrics (FIGO) staging for cervical cancer patients. METHODS: A dual-phase (18)F-FDG PET scan was performed on 51 participants within the 2 wk before surgery or biopsy. (18)F-FDG uptake was quantified by calculating standardized uptake values (SUVs). After (18)F-FDG PET scanning, 51 histologically proven squamous cell carcinoma specimens were examined to determine their degree of differentiation, using hematoxylin and eosin staining, and the expression of Glut-1 by an immunohistochemical stain. Twenty normal cervical and 20 cervical intraepithelial neoplasia (CIN) sets of tissue were also used to compare the results of Glut-1 expression in these tissues. The expression of Glut-1 was the product of (the intensity [with grades 0-3, defined qualitatively]) with (percentages of the lesion area that were positive). The results of Glut-1 expression were analyzed in combination with the SUVs (SUV1 was that at 40 min and SUV2 was that at 3 h), tumor status, initial cell differentiation, and FIGO staging. RESULTS: Significant overexpression of Glut-1 was noted in 48 of the 51 (94.1%) cancer specimens. None or only minimal expression of Glut-1 was observed in basal layers of normal and CIN tissues. Significant positive correlation was observed between Glut-1 expression and the SUVs in cervical cancer specimens (r = 0.74, P < 0.000 for SUV1 and r = 0.65, P < 0.000 for SUV2). In recurrent or persistent tumor, tumor size was significantly associated with both Glut-1 expression (r = 0.508, P = 0.011) and SUV1 (r = 0. 456, P = 0.025). For recurrent or persistent tumor, only SUV1 reached statistical significance when compared with lymph node metastasis (P = 0.0226). CONCLUSION: Glut-1 expression was related to (18)F-FDG uptake in cervical cancer patients. Recurrent or persistent cervical cancer tumor had significantly higher Glut-1 expression than metastatic lymph nodes. The values of SUV and the expression of Glut-1 did not correlate with the initial grade of histologic differentiation and FIGO staging.     

Comparison of (11)C-choline and (18)F-FDG PET in primary diagnosis and staging of patients with thoracic cancer.

PET with (18)F-FDG is used for detection and staging of thoracic cancer; however, more specific PET radiopharmaceuticals would be welcome. (11)C-labeled choline (CHOL) is a new radiopharmaceutical potentially useful for tumor imaging, since it is incorporated into cell membranes as phosphatidylcholine. The aim of this study was to investigate whether (11)C-CHOL PET has advantages over (18)F-FDG PET in patients with thoracic cancer. METHODS: We evaluated 17 patients with thoracic cancer both with (11)C-CHOL PET and (18)F-FDG PET. After transmission scanning, (11)C-CHOL was injected intravenously, and whole-body scanning was started after 5 min. Immediately thereafter, (18)F-FDG was injected intravenously, followed after 90 min by interleaved attenuation-corrected whole-body scanning. Scans were performed from crown to femur. Visual and quantitative (standardized uptake value) analyses of (11)C-CHOL PET and (18)F-FDG PET were performed and compared with results of traditional staging and follow-up. RESULTS: The most prominent features of normal (11)C-CHOL distribution were high uptake in liver, renal cortex, and salivary glands. Except for some uptake in choroid plexus and pituitary gland, brain uptake was negligible. All primary thoracic tumors were detected with (11)C-CHOL PET and (18)F-FDG PET. Both (11)C-CHOL PET and (18)F-FDG PET correctly identified all 16 patients with lymph node involvement. However, in a lesion-to-lesion analysis, (11)C-CHOL PET detected only 29 of 43 metastatic lymph nodes, whereas (18)F-FDG PET detected 41 of 43. (11)C-CHOL PET detected fewer intrapulmonary and pleural metastases than (18)F-FDG PET (27/47 vs. 46/47). More brain metastases were detected with (11)C-CHOL PET (23/23) than with (18)F-FDG PET (3/23). For primary tumors, the median (range) standard uptake values of (11)C-CHOL and (18)F-FDG were 1.68 (0.98-3.22) and 4.22 (1.40-8.26), respectively (P = 0.001). CONCLUSION: (11)C-CHOL PET can be used to visualize thoracic cancers. Although detection of lymph node metastases with (11)C-CHOL PET was inferior compared with (18)F-FDG PET, the detection of brain metastases was superior.     

Role of 18F-FDG PET/CT in the prediction of gastric cancer recurrence after curative surgical resection

Purpose

The study evaluated the role of preoperative ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT in the prediction of recurrent gastric cancer after curative surgical resection.

Methods

A total of 271 patients with gastric cancer who underwent ¹⁸F-FDG PET/CT and subsequent curative surgical resection were enrolled. All patients underwent follow-up for cancer recurrence with a mean duration of 24?±?12?months. ¹⁸F-FDG PET/CT images were visually assessed and, in patients with positive ¹⁸F-FDG cancer uptake, the maximum standardized uptake value (SUV_max) of cancer lesions was measured. ¹⁸F-FDG PET/CT findings were tested as prognostic factors for cancer recurrence and compared with conventional prognostic factors. Furthermore, ¹⁸F-FDG PET/CT findings were assessed as prognostic factors according to histopathological subtypes.

Results

Of 271 patients, 47 (17?%) had a recurrent event. Positive ¹⁸F-FDG cancer uptake was shown in 149 patients (55?%). Tumour size, depth of invasion, presence of lymph node metastasis, positive ¹⁸F-FDG uptake and SUV_max were significantly associated with tumour recurrence in univariate analysis, while only depth of invasion, positive ¹⁸F-FDG uptake and SUV_max had significance in multivariate analysis. The 24-month recurrence-free survival rate was significantly higher in patients with negative ¹⁸F-FDG uptake (95?%) than in those with positive ¹⁸F-FDG uptake (74?%; p?18F-FDG uptake was a significant prognostic factor in patients with tubular adenocarcinoma (p?=?0.003) or poorly differentiated adenocarcinoma (p?=?0.0001). However, only marginal significance was shown in patients with signet-ring cell carcinoma and mucinous carcinoma (p?=?0.05).

Conclusion

¹⁸F-FDG uptake of gastric cancer is an independent and significant prognostic factor for tumour recurrence. ¹⁸F-FDG PET/CT could provide effective information on the prognosis after surgical resection of gastric cancer, especially in tubular adenocarcinoma and poorly differentiated adenocarcinoma.