Setsu Sakamoto

Preoperative nodal staging of uterine cancer: is contrast-enhanced PET/CT more accurate than non-enhanced PET/CT or enhanced CT alone?

ObjectiveTo determine whether contrast-enhanced PET/CT is more accurate than either non-enhanced PET/CT or enhanced CT alone for nodal staging of uterine cancer.MethodsForty patients with endometrial cancer and cervical cancer underwent conventional PET/CT scan with low-dose CT (ldCT), followed by full-dose CT with IV contrast (ceCT) before radical hysterectomy with pelvic and, when applicable, para-aortic lymphadenectomy. Three data sets of PET/ldCT, PET/ceCT, and enhanced CT images were interpreted separately by two readers. For region-specific comparisons, para-aortic and pelvic lymph nodes were divided into the bilateral para-aortic, common iliac, external iliac, internal iliac, and obturator areas. Based on histopathological findings as the gold standard, we compared the diagnostic accuracy between the three methods using McNemar test with Bonferroni’s adjustment.ResultsOf the 40 patients, 21 underwent pelvic lymphadenectomy only. Region-based analysis showed that the sensitivity, specificity, and accuracy of PET/ceCT were 61.4% (27/44), 98.1% (308/314), and 93.6% (335/358), respectively, whereas those of PET/ldCT were 52.3% (23/44), 96.8% (304/314), and 91.3% (327/358), respectively, and those of enhanced CT were 40.9% (18/44), 97.8% (307/314), and 90.8% (325/358), respectively. Although PET/ceCT had the best sensitivity among the three imaging modalities, a significant difference was observed only between PET/ceCT and enhanced CT (pxa0=xa00.0027). Although PET/ceCT had better sensitivity and accuracy than PET/ldCT, the differences between the two imaging methods did not reach statistical significance (pxa0=xa00.046 and pxa0=xa00.047, respectively).ConclusionPET/ceCT is slightly but not significantly superior to PET/ldCT for nodal staging of uterine cancer. Nodal metastasis cannot be excluded even if PET/ceCT gives negative findings.

Present and future of FDG-PET/CT in ovarian cancer.

Integrated FDG-PET/CT has been used successfully for the diagnosis, staging, restaging, therapy monitoring and prognostic prediction of ovarian cancer as well as various other malignant tumors. Compared with conventional PET/non-contrast CT images, combined PET/contrast-enhanced CT images with intravenous iodine contrast medium and sufficient radiation dose may contribute to a more accurate diagnosis with higher confidence. In the future, tracers other than FDG and integrated PET/MRI will be realized. We herein review the place and role of FDG-PET/CT in the management of ovarian cancer, discussing its usefulness and limitations in the imaging of these patients.

FDG-PET/CT imaging of elastofibroma dorsi

ObjectiveThe purpose of this study was to assess retrospectively the characteristics of FDG uptake in elastofibroma dorsi using integrated PET/CT.MethodsFrom 10,261 oncology FDG-PET/CT scans performed over a 2-year period, findings suggestive of elastofiboma dorsi were observed in 46 FDG-PET/CT scans of 34 patients. As 20 patients had bilateral lesions and 14 had unilateral lesions, a total of 75 elastofibroma dorsi lesions on images were identified in this study. For visual analysis of intensity of FDG uptake , a four-point grading system was used: grade 0 for no uptake, grade 1 for less uptake than the liver, grade 2 for uptake comparable to the liver, and grade 3 for intense uptake greater than the liver. For quantitative analysis, the standardized uptake value (SUV) was calculated. The relationships between SUV and age, blood glucose level, lesion size, and related symptoms were also assessed.ResultsAmong the 75 lesions, 4 had an uptake grade of 0, 41 had grade 1, 25 had grade 2, and 5 had grade 3. The mean SUV (±SD) of the 75 lesions was 2.0u2009±u20090.63 (range 0–5.1). The Pearson correlation coefficient test indicated a weak positive correlation between SUV and lesion size and no correlation between SUV and either age or blood glucose level. The SUVs of patients with symptoms due to the disease and patients without symptoms were almost the same.ConclusionMild and moderate uptake of FDG is frequently observed in elastofibroma dorsi, which should not be misinterpreted as abnormal accumulation observed in malignant lesions.

Established, emerging and future applications of FDG-PET/CT in the uterine cancer

Integrated positron emission tomography/computed tomography (PET/CT) with 2-[¹⁸F]fluoro-2-deoxy-D-glucose (FDG) is a useful technique to acquire both glucose metabolic and anatomic imaging data using a single device in a single diagnostic session and has opened a new field in clinical oncologic imaging. FDG-PET/CT has been used successfully for the staging, optimization of treatment, re-staging, therapy monitoring, and prognostic prediction of uterine cervical cancer and endometrial cancer as well as various malignant tumours. The present review discusses the current role of FDG-PET/CT in the management of uterine cancer, discussing its usefulness and limitations in the imaging of these patients.

Nuclear medicine practice in Japan: a report of the seventh nationwide survey in 2012

ObjectiveThe Subcommittee on the Survey of Nuclear Medical Practice in Japan has performed a nationwide survey of nuclear medicine practice every 5xa0years since 1982 to survey contemporary nuclear medicine practice and its changes over the years.MethodsThe subcommittee sent questionnaires, including the number and category of examinations as well as the kind and dose of the radiopharmaceuticals during the 30xa0days of June 2012, to all the nuclear medicine institutes. The total numbers for the year 2012 were then estimated.ResultsA total of 1,167 institutes responded to the survey, including the 14 in vitro assay institutes and 266 PET centers. The recovery rate was 92xa0%. The number of gamma cameras installed was 1,425 in total, with 9xa0% decrease in 5xa0years. Dual-head cameras and hybrid SPECT/CT scanners accounted for 84 and 10.5xa0%, respectively. The number of single-photon tracer studies in 2012 was 1.15 million which means decrease in 19xa0% in 5xa0years and 29xa0% in 10xa0years. All but cerebral perfusion study and sentinel lymphoscintigraphy have decreased. Bone scintigraphy was a leading examination (38.7xa0%), followed by cardiac studies (29.4xa0%) and cerebral perfusion study (18.5xa0%) in order. SPECT studies showed an increase from 42.3 to 47.2xa0%. PET centers have also increased from 212 to 295, as compared to the last survey. The 135 PET centers have installed one or two in-house cyclotrons. PET studies showed 25.5xa0% increase in 5xa0years, with oncology accounting for 96.3xa0%. 18F-FDG accounted for 98.2xa0% (505,990 examinations). PET examinations using 11C-methionine have been increasing, with 3,352 examinations in 2012. The number of new PET studies using 11C-PIB PET was 695. 131I-radioiodine targeted therapies showed an increase, including 3,644 patients (53.6xa0%) for thyroid cancer and 4,889 patients (17.9xa0%) for hyperthyroidism. Out-patient thyroid bed ablation therapy with 30xa0mCi of 131I accounted for 21.0xa0% of cancer patients. The number of admission rooms decreased from 158 to 135 in 5xa0years. In vitro radioassays have been declining continuously since 1992, with the number of studies of 9.0 million in 2012.ConclusionsSingle-photon examinations showed a continuous tendency toward a decline in the survey. In contrast, the number of hybrid SPECT/CT scanner examinations has increased. PET/CT study in the oncology field and radionuclide targeted therapy have steadily increased.

Clinically significant association between the maximum standardized uptake value on 18F-FDG PET and expression of phosphorylated Akt and S6 kinase for prediction of the biological characteristics of renal cell cancer

BackgroundThe relationship between the clinicopathological features and molecular changes associated with standardized uptake value (SUV) determined by Positron emission tomography (PET) with [18F] fluorodeoxyglucose (18F-FDG PET) in human renal cell carcinoma (RCC) has not been elucidated. On the other hand, overactivation of the phosphatidylinositol 3’kinase (PI3K), serine/threonine kinase Akt, and mammalian target of rapamycin (mTOR) pathway has been detected in a variety of human cancers, including RCC. So far, little is known about the relationship between the SUV and these proteins in human RCC. Thus, it is important to study the relevance of SUV with clinicopathological features in human RCCs from a molecular point of view.MethodsSeventy-seven consecutive patients with RCC who underwent nephrectomy and pretreatment determination of the maximum SUV (SUVmax) by 18F-FDG PET were analyzed. We investigated the relationship between the SUVmax, phosphorylated-Akt (Ser-473) (pAkt(Ser-473)), phosphorylated-Akt (Thr-308) (pAkt(Thr-308), and phosphorylated-S6 ribosomal protein (Ser-235/236) (pS6) protein levels in the primary tumor and various clinicopathological features.ResultsThe average SUVmax of the primary tumor was 6.9 (1.5 to 40.3). A higher SUVmax was correlated with higher expression of pAkt(Ser-473), pAkt (Thr-308), and pS6 protein in the primary tumor. A higher SUVmax and increased expression of pAkt (Ser-473), pAkt (Thr-308), and pS6 of the primary tumor was associated with less tumor differentiation, a higher pT stage, regional lymph node involvement, microscopic vascular invasion, and distant metastasis, as well as with early relapse following radical nephrectomy in patients who had localized or locally advanced RCC without distant metastasis (cTanyNanyM0) and with shorter overall survival in all patients.ConclusionsA higher SUVmax on 18F-FDG PET is associated with elevated tumor levels of pAkt and pS6 protein and with aggressive behavior and metastatic potential of RCC, as well as with early relapse following radical nephrectomy and shorter overall survival. These findings suggest that SUVmax may be useful for predicting the biological characteristics of RCC.

18F-fluorodeoxyglucose positron emission tomography for evaluation of thymic epithelial tumors: utility for World Health Organization classification and predicting recurrence-free survival

Objectives18F-fluorodeoxyglucose positron emission tomography (FDG-PET) plays an important role in many oncological settings. In this study, we assessed the utility of 18F-FDG-PET for predicting the histological classification, stage and survival of thymic epithelial tumors.MethodsWe retrospectively analyzed 37 patients with thymic epithelial tumors who underwent PET before surgical resection and investigated the relationship between the maximum of standardized uptake value (SUVmax) of each tumor and the WHO classification, recurrence-free survival, and tumor-related gene expressions.ResultsThe study included 15 males and 22 females, ranging in age from 22 to 81xa0years (mean 64xa0years). The tumor histology of 31 tumors was thymoma and that of the remaining tumors was thymic carcinoma. The Masaoka tumor stage was as follows: stage I in 18, II in 9, III in 5 and IV in 5 patients. The patients were divided into three groups according to a simplified histologic classification: low-risk thymoma (types A, AB and B1, nxa0=xa021), high-risk thymoma (types B2 and B3, nxa0=xa010) and thymic carcinoma (nxa0=xa06). The SUVmax of low-risk group (SUVmax ≤4.27) was significantly lower than that of high-risk group (pxa0=xa00.0114) and that of thymic carcinomas (SUVmax >4.27) was also significantly higher than that of thymomas (pxa0<xa00.0001). The group of high SUVmax (SUVmax >4.27) had significantly inferior recurrence-free survival to that of less value (SUVmax ≤4.27) (pxa0=xa00.0009). The SUVmax were not correlated with tumor-related gene expressions.ConclusionThe SUVmax of 18F-FDG-PET reflects WHO classification of thymic epithelial tumors. High SUVmax predicts lower recurrence-free survival of the tumors.

Utility of FDG-PET/CT in the Evaluation of the Response of Locally Advanced Breast Cancer to Neoadjuvant Chemotherapy

Neoadjuvant chemotherapy (NAC) is effective in down-staging a primary tumor before surgery, and quick differentiation between responders to NAC and nonresponders is needed. We investigated the utility of [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) and computed tomography (CT) in evaluating the therapeutic effectiveness of NAC. We investigated 25 patients who underwent NAC for stage II and III noninflammatory breast cancer. FDG-PET/CT was undertaken before and after NAC to determine the maximum standardized uptake value (SUVmax) reduction rate. Findings were compared with postoperative histopathologic evaluation of therapeutic response. It was not possible to accurately assess tumor response to NAC using CT. However, using the SUVmax reduction rate, we noted a significant difference (P=0.0420) between patients who were responsive and nonresponsive to NAC. The sensitivity and specificity were as high as 83.3% and 78.9%, respectively. This study demonstrated that FDG-PET/CT can differentiate responders from nonresponders. This improves patient management by avoiding unnecessary chemotherapy.

Radical nephrectomy and regional lymph node dissection for locally advanced type 2 papillary renal cell carcinoma in an at-risk individual from a family with hereditary leiomyomatosis and renal cell cancer: a case report

BackgroundHereditary leiomyomatosis and renal cell carcinoma (HLRCC) is an autosomal dominant tumor susceptibility syndrome, and the disease-related gene has been identified as fumarate hydratase (fumarase, FH). HLRCC-associated kidney cancer is an aggressive tumor characterized by early metastasis to regional lymph nodes and distant organs. Since early diagnosis and provision of definitive therapy is thought to be the best way to reduce the tumor burden, it is widely accepted that germline testing and active surveillance for an at-risk individual from a family with HLRCC is very important. However, it still remains controversial how we should treat HLRCC-associated kidney cancer. We successfully treated the patient with locally advanced HLRCC-associated kidney cancer, who has received active surveillance because of at-risk individual, by radical nephrectomy and extended retroperitoneal lymph node dissection, and examined surgically resected samples from a molecular point of view.Case presentationWe recommended that 13 at-risk individuals from a family with HLRCC should receive active surveillance for early detection of renal cancer. A 48-year-old woman with a left renal tumor and involvement of multiple regional lymph nodes with high accumulation of fluorine-18-deoxyglucose on positron emission tomography was treated with axitinib as a neoadjuvant therapy. Preoperative axitinib induced the shrinkage of the tumor with decreased fluorine-18-deoxyglucose accumulation. Resected samples showed two thirds tumor tissue necrosis as well as high expression of serine/threonine kinase Akt and low expression of nuclear factor E2-related factor 2 (Nrf2) which activates anti-oxidant response and protects against oxidative stress in viable cancer cells. Targeted next-generation sequencing revealed that FH mutation and loss of the second allele were completely identical between blood and tumor samples, suggesting that FH mutation plays a direct role in FH-deficient RCC. She has remained well after radical operation for over 33xa0months.ConclusionsFH mutation plays a role in tumorigenic feature, a metabolic shift to aerobic glycolysis, and increased an anti-oxidant response phenotype in HLRCC-associated kidney cancer.

Usefulness of 18F-Fluorodeoxyglucose Positron Emission Tomography for Follow-Up of 13-cis-Retinoic Acid Treatment for Residual Neuroblastoma After Myeloablative Chemotherapy.

Abstract 13-cis-retinoic acid (13-cis-RA) treatment is used as a second-line treatment for residual or recurrent neuroblastoma. However, determining the duration of 13-cis-RA treatment for residual and recurrent neuroblastoma can be a problem because it is difficult to evaluate the effectiveness of the treatment. We performed 13-cis-RA treatment to remove residual active neuroblastoma cells in an 8-year-old boy with stage 4 neuroblastoma that developed from a left sympathetic ganglion and had been treated with chemotherapy, surgery, autologous peripheral blood stem-cell transplantation, and radiotherapy. 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) and iodine-123 metaiodobenzylguanidine (123I-MIBG) scintigraphy obtained immediately before 13-cis-RA treatment both showed positive findings in the area of the primary lesion. At 18 months after 13-cis-RA treatment, there was accumulation on 123I-MIBG scintigraphy but no uptake on 18F-FDG-PET, and 13-cis-RA treatment was suspended. The patient has been in complete remission for 3 years. In comparing the effectiveness of the 2 imaging modalities for monitoring the response to 13-cis-RA treatment, we considered that 18F-FDG-PET was superior to 123I-MIBG scintigraphy because 18F-FDG-PET images were not affected by the cell differentiation induced by 13-cis-RA treatment in our case. Thus, 18F-FDG-PET was useful for determining the treatment response and outcomes. We have reported a case of residual neuroblastoma treated with differentiation-inducing 13-cis-RA therapy. Different results were produced with 18F-FDG-PET and 123I-MIBG scintigraphy. The cessation of 13-cis-RA treatment was based on 18F-FDG-PET findings and there has been no relapse for 3 years.