Optimized Whole-Body PET MRI Sequence Workflow in Pediatric Hodgkin Lymphoma Patients.

18F-FDG PET/MRI might be the diagnostic method of choice for Hodgkin lymphoma patients, as it combines significant metabolic information from PET with excellent soft-tissue contrast from MRI and avoids radiation exposure from CT. However, a major issue is longer examination times than for PET/CT, especially for younger children needing anesthesia. Thus, a targeted selection of suitable whole-body MRI sequences is important to optimize the PET/MRI workflow. Methods: The initial PET/MRI scans of 84 EuroNet-PHL-C2 study patients from 13 international PET centers were evaluated. In each available MRI sequence, 5 PET-positive lymph nodes were assessed. If extranodal involvement occurred, 2 splenic lesions, 2 skeletal lesions, and 2 lung lesions were also assessed. A detection rate was calculated dividing the number of visible, anatomically assignable, and measurable lesions in the respective MRI sequence by the total number of lesions. Results: Relaxation time-weighted (T2w) transverse sequences with fat saturation (fs) yielded the best result, with detection rates of 95% for nodal lesions, 62% for splenic lesions, 94% for skeletal lesions, and 83% for lung lesions, followed by T2w transverse sequences without fs (86%, 49%, 16%, and 59%, respectively) and longitudinal relaxation time-weighted contrast-enhanced transverse sequences with fs (74%, 35%, 57%, and 55%, respectively). Conclusion: T2w transverse sequences with fs yielded the highest detection rates and are well suited for accurate whole-body PET/MRI in lymphoma patients. There is no evidence to recommend the use of contrast agents.

PET/CT in malignant melanoma: a two-tiered healthcare system? Updated healthcare situation regarding initial staging of malignant melanoma with PET/CT.

BACKGROUND: Patients with stage IIC malignant melanoma are recommended to undergo cross-sectional imaging for initial staging. PET/CT is superior to other methods regarding its diagnostic accuracy of the tumor spread in stage III. So far there is no meaningful data on the nationwide availability, usage and cost recovery of this imaging technique. PATIENTS AND METHODS: Questionnaires on the healthcare situation in 2018 were sent to all German dermatology clinics and PET/CT centers in March and April 2019. RESULTS: 61.2 % of the dermatology clinics (71/115) and 48.2 % of the PET/CT centers (77/160) took part in the survey. A total of 22,645 patients with malignant melanoma were seen in these clinics in 2018. 16.8 % of the patients with stage IIC melanoma received a PET/CT for primary staging. The costs of this examination were covered for all statutory and privately insured patients in 40 % and 68 % of dermatology clinics (20/50 and 34/50), respectively. 68.0 % (34/50) of all dermatology clinics reported relevant changes of treatment according to PET/CT findings. Long examination periods by the health insurance companies and the time required to submit the application were the most common reasons for dermatology clinics to reject a request for PET/CT. Relevant incidental findings were reported in 90.2 % (47/51) of all PET/CT centers. CONCLUSIONS: There are clear differences in the nationwide availability and cost coverage of PET/CT in primary staging for stage IIC melanoma. For these reasons, a two-tiered healthcare system may be assumed.

Interim PET Evaluation in Diffuse Large B-Cell Lymphoma Using Published Recommendations: Comparison of the Deauville 5-Point Scale and the ΔSUVmax Method.

The value of interim 18F-FDG PET/CT (iPET)-guided treatment decisions in patients with diffuse large B-cell lymphoma (DLBCL) has been the subject of much debate. This investigation focuses on a comparison of the Deauville score and the change-in-SUVmax (ΔSUVmax) approach-2 methods to assess early metabolic response to standard chemotherapy in DLBCL. Methods: Of 609 DLBCL patients participating in the PET-Guided Therapy of Aggressive Non-Hodgkin Lymphomas trial, iPET scans of 596 patients originally evaluated using the ΔSUVmax method were available for post hoc assessment of the Deauville score. A commonly used definition of an unfavorable iPET result according to the Deauville score is an uptake greater than that of the liver, whereas an unfavorable iPET scan with regard to the ΔSUVmax approach is characterized as a relative reduction of the SUVmax between baseline and iPET staging of less than or equal to 66%. We investigated the 2 methods' correlation and concordance by Spearman rank correlation coefficient and the agreement in classification, respectively. We further used Kaplan-Meier curves and Cox regression to assess differences in survival between patient subgroups defined by the prespecified cutoffs. Time-dependent receiver-operating-characteristic curve analysis provided information on the methods' respective discrimination performance. Results: Deauville score and ΔSUVmax approach differed in their iPET-based prognosis. The ΔSUVmax approach outperformed the Deauville score in terms of discrimination performance-most likely because of a high number of false-positive decisions by the Deauville score. Cutoff-independent discrimination performance remained low for both methods, but cutoff-related analyses showed promising results. Both favored the ΔSUVmax approach, for example, for the segregation by iPET response, where the event-free survival hazard ratio was 3.14 (95% confidence interval, 2.22-4.46) for ΔSUVmax and 1.70 (95% confidence interval, 1.29-2.24) for the Deauville score. Conclusion: When considering treatment intensification, the currently used Deauville score cutoff of an uptake above that of the liver seems to be inappropriate and associated with potential harm for DLBCL patients. The ΔSUVmax criterion of a relative reduction in SUVmax of less than or equal to 66% should be considered as an alternative.

Impact of complete surgical resection on outcome in aggressive non-Hodgkin lymphoma treated with immunochemotherapy.

BACKGROUND: Surgical resection is considered to be of purely diagnostic value in aggressive lymphoma. Evidence for an impact on outcome is scant and restricted to retrospective observations. METHODS: In the "Positron Emission Tomography-guided Therapy of Aggressive non-Hodgkin Lymphomas" (PETAL) trial, patients with a negative baseline positron emission tomography (PET) scan were documented in a prospective observational substudy. Baseline PET-negative patients with the absence of lymph node enlargement on computed tomography and a negative bone marrow biopsy were considered to have undergone complete lymphoma resection. RESULTS: Eighty-two of 1,041 patients (7.9%) had a negative baseline PET scan, and 67 were included in this analysis. All were treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP), plus rituximab for CD20-positive lymphomas. Among 52 patients with diffuse large B-cell lymphoma (DLBCL), 48 had completely resected disease. Their outcome tended to be better than that of 115 baseline PET-positive stage I DLBCL patients treated in the main part of the PETAL trial (2-year progression-free survival 92.7% [95% confidence interval 84.7-100] versus 88.4% [82.5-94.3], P = .056; 2-year overall survival 92.7% [84.7-100] versus 93.7% [89.2-98.2], P = .176), but this was restricted to patients below the age of 60 years (2-year progression-free survival 100% versus 92.2% [84.8-99.6], P = .031; 2-year overall survival 100% versus 95.9% [90.2-100], P = .075). In peripheral T-cell lymphoma, eight of 11 patients had completely resected disease. In contrast to DLBCL, complete resection was not associated with improved outcome compared to the control. CONCLUSION: Young patients with early stage DLBCL may benefit from complete lymphoma resection prior to immunochemotherapy.

Baseline and interim PET-based outcome prediction in peripheral T-cell lymphoma: A subgroup analysis of the PETAL trial.

The prospective randomized Positron Emission Tomography (PET)-Guided Therapy of Aggressive Non-Hodgkin Lymphomas (PETAL) trial was designed to test the ability of interim PET (iPET) to direct therapy. As reported previously, outcome remained unaffected by iPET-based treatment changes. In this subgroup analysis, we studied the prognostic value of baseline total metabolic tumor volume (TMTV) and iPET response in 76 patients with T-cell lymphoma. TMTV was measured using the 41% maximum standardized uptake value (SUV41max ) and SUV4 thresholding methods. Interim PET was performed after two treatment cycles and evaluated using the ΔSUVmax approach and the Deauville scale. Because of significant differences in outcome, patients with anaplastic lymphoma kinase (ALK)-positive lymphoma were analyzed separately from patients with ALK-negative lymphoma. In the latter, TMTV was statistically significantly correlated with progression-free survival, with thresholds best dichotomizing the population, of 232 cm3 using SUV41max and 460 cm3 using SUV4 . For iPET response, the respective thresholds were 46.9% SUVmax reduction and Deauville score 1-4 vs 5. The proportion of poor prognosis patients was 46% and 29% for TMTV by SUV41max and SUV4 , and 29% and 25% for iPET response by ΔSUVmax and Deauville, respectively. At diagnosis, the hazard ratio (95% confidence interval) for poor prognosis vs good prognosis patients according to TMTV was 2.291 (1.135-4.624) for SUV41max and 3.206 (1.524-6.743) for SUV4 . At iPET, it was 3.910 (1.891-8.087) for ΔSUVmax and 4.371 (2.079-9.187) for Deauville. On multivariable analysis, only TMTV and iPET response independently predicted survival. Patients with high baseline TMTV and poor iPET response (22% of the population) invariably progressed or died within the first year (hazard ratio, 9.031 [3.651-22.336]). Due to small numbers and events, PET did not predict survival in ALK-positive lymphoma. Baseline TMTV and iPET response are promising tools to select patients with ALK-negative T-cell lymphoma for early allogeneic transplantation or innovative therapies.

Six versus eight doses of rituximab in patients with aggressive B cell lymphoma receiving six cycles of CHOP: results from the "Positron Emission Tomography-Guided Therapy of Aggressive Non-Hodgkin Lymphomas" (PETAL) trial.

Standard first-line treatment of aggressive B cell lymphoma comprises six or eight cycles of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) plus eight doses of rituximab (R). Whether adding two doses of rituximab to six cycles of R-CHOP is of therapeutic benefit has not been systematically investigated. The Positron Emission Tomography-Guided Therapy of Aggressive Non-Hodgkin Lymphomas (PETAL) trial investigated the ability of [18F]-fluorodesoxyglucose PET scanning to guide treatment in aggressive non-Hodgkin lymphomas. Patients with B cell lymphomas and a negative interim scan received six cycles of R-CHOP with or without two extra doses of rituximab. For reasons related to trial design, only about a third underwent randomization between the two options. Combining randomized and non-randomized patients enabled subgroup analyses for diffuse large B cell lymphoma (DLBCL; n = 544), primary mediastinal B cell lymphoma (PMBCL; n = 37), and follicular lymphoma (FL) grade 3 (n = 35). With a median follow-up of 52 months, increasing the number of rituximab administrations failed to improve outcome. A non-significant trend for improved event-free survival was seen in DLBCL high-risk patients, as defined by the International Prognostic Index, while inferior survival was observed in female patients below the age of 60 years. Long-term outcome in PMBCL was excellent. Differences between FL grade 3a and FL grade 3b were not apparent. The results were confirmed in a Cox proportional hazard regression model and a propensity score matching analysis. In conclusion, adding two doses of rituximab to six cycles of R-CHOP did not improve outcome in patients with aggressive B cell lymphomas and a fast metabolic treatment response.

[Development of a national competency-based learning objective catalogue for undergraduate medical education in Germany]. / Entwicklung eines kompetenzbasierten Lernzielkatalogs Nuklearmedizin für das Studium der Humanmedizin in Deutschland.

AIMS: Implementation of the guidelines on the Competency-based Learning Objective Catalogue for Undergraduate Medical Education for a Nuclear Medicine curriculum on behalf of the committee on professional training and continuing education of the German Association of Nuclear Medicine (DGN) METHODS:: In 7 domains 100 learning objectives (LOs) were subject to a prioritization in 3 categories (A, B and C) by means of a questionnaire as part of a Delphi method, in collaboration with all members of the DGN holding a "venia legendi" as experts. Category A defined the essential LOs for each medical practitioner. The prioritization was made by ranking the frequency of the A-classifications. In the 2nd step of the Delphi method, a list of LOs with the ranking positions 1-5 in each domain was presented to the first round's experts as a core curriculum, asking either for acceptance or modifications. RESULTS: The results of the 1st step of the Delphi method deliver a return rate of 29% of the questionnaires (55 out of 184). The 2nd round shows a return rate of 30.9% (57 out of 184) and full approval of the proposed LOs in all LO domains by in median 72 % of the experts consulted (61%-81%). The present final version contains 37 competency-based LOs in the LO domains "legal basis and radiation protection", "basic science", indications and contra-indications for "PET/CT", "scintigraphy and SPECT", "patient preparation", "image interpretation" as well as "therapy". CONCLUSION: The Competency-based Learning Objective Catalogue for Nuclear Medicine describes the knowledge and competencies, every physician should have at the end of his medical studies. The LO catalogue is a living document, which needs to be adapted continuously to the progress of the medical and technological development.

Positron Emission Tomography-Guided Therapy of Aggressive Non-Hodgkin Lymphomas (PETAL): A Multicenter, Randomized Phase III Trial.

Purpose Interim positron emission tomography (PET) using the tracer, [18F]fluorodeoxyglucose, may predict outcomes in patients with aggressive non-Hodgkin lymphomas. We assessed whether PET can guide therapy in patients who are treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP). Patients and Methods Newly diagnosed patients received two cycles of CHOP-plus rituximab (R-CHOP) in CD20-positive lymphomas-followed by a PET scan that was evaluated using the ΔSUVmax method. PET-positive patients were randomly assigned to receive six additional cycles of R-CHOP or six blocks of an intensive Burkitt's lymphoma protocol. PET-negative patients with CD20-positive lymphomas were randomly assigned or allocated to receive four additional cycles of R-CHOP or the same treatment with two additional doses rituximab. The primary end point was event-free survival time as assessed by log-rank test. Results Interim PET was positive in 108 (12.5%) and negative in 754 (87.5%) of 862 patients treated, with statistically significant differences in event-free survival and overall survival. Among PET-positive patients, 52 were randomly assigned to R-CHOP and 56 to the Burkitt protocol, with 2-year event-free survival rates of 42.0% (95% CI, 28.2% to 55.2%) and 31.6% (95% CI, 19.3% to 44.6%), respectively (hazard ratio, 1.501 [95% CI, 0.896 to 2.514]; P = .1229). The Burkitt protocol produced significantly more toxicity. Of 754 PET-negative patients, 255 underwent random assignment (129 to R-CHOP and 126 to R-CHOP with additional rituximab). Event-free survival rates were 76.4% (95% CI, 68.0% to 82.8%) and 73.5% (95% CI, 64.8% to 80.4%), respectively (hazard ratio, 1.048 [95% CI, 0.684 to 1.606]; P = .8305). Outcome prediction by PET was independent of the International Prognostic Index. Results in diffuse large B-cell lymphoma were similar to those in the total group. Conclusion Interim PET predicted survival in patients with aggressive lymphomas treated with R-CHOP. PET-based treatment intensification did not improve outcome.

End-of-Treatment Positron Emission Tomography After Uniform First-Line Therapy of B-Cell Posttransplant Lymphoproliferative Disorder Identifies Patients at Low Risk of Relapse in the Prospective German PTLD Registry.

BACKGROUND: Fluorine-18 fluorodeoxyglucose (18F-FDG)-positron emission tomography (PET) is a recommended standard in the staging and response assessment of 18F-FDG-avid lymphoma. Posttransplant lymphoproliferative disorder (PTLD) can be detected by 18F-FDG-PET at diagnosis with high sensitivity and specificity. However, the role of response assessment by end-of-treatment (EOT) PET has only been addressed in small case series. METHODS: We performed a retrospective, multicenter study of 37 patients with CD20-positive PTLD after solid organ transplantation treated with uniform, up-to-date, first-line protocols in the prospective German PTLD registry who had received EOT 18F-FDG-PET between 2006 and 2014. Median follow-up was 5.0 years. Any nonphysiological 18F-FDG uptake (Deauville score greater 2) was interpreted as PET-positive. RESULTS: By computed tomography (CT) final staging, 18 of 37 patients had a complete response, 18 had a partial response and 1 patient had stable disease. EOT PET was negative in 24 of 37 patients and positive in 13 of 37 patients. The positive predictive value of EOT PET for PTLD relapse was 38%, and the negative predictive value was 92%. Time to progression (TTP) and progression-free-survival were significantly longer in the PET negative group (P = 0.019 and P = 0.013). In the 18 patients in a partial response by CT staging, we noted highly significant differences in overall survival (P = 0.001), time to progression (P = 0.007), and progression-free survival (P < 0.001) by EOT PET. CONCLUSIONS: Even without baseline imaging, EOT PET in PTLD identifies patients at low risk of relapse and offers clinically relevant information, particularly in patients in a partial remission by CT staging.

Low Malignancy Rates in Fine-Needle Aspiration Cytologies in a Primary Care Setting in Germany.

BACKGROUND: Reported results for thyroid nodule fine-needle aspiration (FNA) cytology mainly originate from tertiary centers. However, thyroid nodule FNA cytology is mainly performed in primary care settings for which the distribution of FNA Bethesda categories and their respective malignancy rates are largely unknown. Therefore, this study investigated FNA cytology malignancy rates of a large primary care setting to determine to what extent current evidence-based strategies for the malignancy risk stratification of thyroid nodules are applied and applicable in such primary care settings. METHODS: In a primary care setting, 9460 FNAs of thyroid nodules were retrospectively analyzed from 8380 patients evaluated by one cytologist (I.R.) during a period of two years. The 8380 FNA cytologies were performed by 64 physicians in different private practices throughout Germany in primary care settings. RESULTS: The cytopathologic results were classified according to the Bethesda System as non-diagnostic in 19%, cyst/cystic nodule in 21%, benign (including thyroiditis) in 48%, atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) in 6%, follicular neoplasms/suspicious for follicular neoplasm (FN/SFN) in 4%, suspicious for malignancy (SFM) in 1%, and malignant in 1%. The proportion of patients proceeding to surgery or with a follow-up of at least one year and the observed risks of malignancy were 22%/8% for AUS/FLUS, 69%/17% for FN/SFN, 78%/86% for SFM, and 71%/98% for malignant. For 112 cytologically suspicious and malignant FNAs, there were 102 true positives and 10 false positives, considering histology as gold standard. CONCLUSION: At variance with other data mostly originating from tertiary centers, these data demonstrate low percentages for malignant, SFM, FN/SFN, and AUS/FLUS, and high percentages for cysts/cystic nodules in this primary care setting in Germany. The risks of malignancy for malignant, SFM, AUS/FLUS, and FN/SFN FNA cytologies are according to Bethesda recommendations.

Evaluation of a Two-Year Routine Application of Molecular Testing of Thyroid Fine-Needle Aspirations Using a Seven-Gene Panel in a Primary Referral Setting in Germany.

BACKGROUND: Major differences with respect to the diagnostic performance of a "ruling in" approach in the presurgical diagnosis of indeterminate thyroid fine-needle aspirations (FNAs) have been reported. Therefore, the aim of this prospective multicenter study was to investigate the specific diagnostic impact of mutation testing using a seven-gene panel in a routine primary referral setting analyzing FNAs from endocrinology and nuclear medicine practices in Germany. METHODS: RNA and DNA was extracted from 564 routine air-dried FNA smears obtained from 64 physicians and cytologically graded by one experienced cytopathologist. PAX8/PPARG and RET/PTC rearrangements were detected by quantitative polymerase chain reaction, while BRAF and RAS mutations were detected by pyrosequencing. Molecular data were compared to histology and follow-up >1 year, which were available for 322/348 patients undergoing surgery and 33/74 patients having follow-up. Histology results were obtained from the local routine pathologists who were blinded to the molecular test results. RESULTS: BRAF and RET/PTC mutations were associated with carcinoma in 98% and 100% of samples, respectively. RAS and PAX8/PPARG mutations were associated with carcinoma in 31% and 0% of samples, respectively. Thirty-six percent of the carcinomas were identified by molecular testing in the atypia of undetermined significance/follicular lesion of undetermined significance and follicular neoplasm/suspicious for a follicular neoplasm categories, with malignancy rates of 15% and 17%, respectively. Due to a low percentage of RAS mutation-positive carcinomas in combination with a rather high percentage of RAS mutation-positive benign nodules, the positive predictive values of 41% and 36% in the atypia of undetermined significance/follicular lesion of undetermined significance and follicular neoplasm/suspicious for a follicular neoplasm categories offer only limited diagnostic potential. CONCLUSION: In conclusion, the data suggest that the application of the current seven-gene panel in a routine primary referral setting does not improve the presurgical diagnosis of thyroid FNAs. While the diagnostic relevance of RAS mutations in thyroid tumors needs further investigation, more comprehensive mutation panels with more cancer-specific mutations may improve the presurgical diagnosis of thyroid FNAs.

Combined PET/MR: Where are we now? Summary report of the second international workshop on PET/MR imaging April 8-12, 2013, Tubingen, Germany.

This workshop was held a year after the initial positron emission tomography/magnetic resonance (PET/MR) workshop in Tübingen, which was recently reported in this journal. The discussions at the 2013 workshop, however, differed substantially from those of the initial workshop, attesting to the progress of combined PET/MR as an innovative imaging modality. Discussions were focused on the search for truly novel, unique clinical and research applications as well as technical issues such as reliable and accurate approaches for attenuation and scatter correction of PET emission data. The workshop provided hands-on experience with PET and MR imaging. In addition, structured and moderated open discussion sessions, including six dialogue boards and two roundtable discussions, provided input from current and future PET/MR imaging users. This summary provides a snapshot of the current achievements and challenges for PET/MR.

Impact of PET-CT on primary staging and response control on multimodal treatment of esophageal cancer.

BACKGROUND: The predictive value of positron emission tomography-computed tomography (PET-CT) in primary staging and response control in patients with esophageal carcinoma (EC) is under discussion. In the present study initial staging and metabolic response of PET-CT was correlated with tumor regression and survival in patients with multimodal treatment of EC. METHODS: The authors conducted a retrospective analysis on a prospective database for 83 patients with EC (42 squamous cell, 39 adenocarcinoma, 2 anaplastic carcinoma) undergoing PET-CT for primary staging. Twenty-four of the patients underwent primary esophagectomy, 9 had palliative treatment, and 50 neoadjuvant radiochemotherapy (cisplatin, 5-fluorouracil; 50.4 Gy). The PET-CT study was repeated 6 weeks after induction of chemotherapy and compared with endoscopic ultrasound (EUS). For response control, the metabolic response (tumor standardized uptake value [SUV] reduction) was correlated with histopathologic (ypT0-4) and histomorphologic response (tumor regression) and survival. RESULTS: At primary staging 81 of 83 EC (97.5%) showed an increased SUV uptake correlating with the EUS tumor stage. Suspicious lymph nodes were detected in 51 (61.4%) patients by PET-CT and 66 (79.5%) were detected by EUS. Fifteen patients had additional findings on PET-CT examination leading to a change in therapy in 9 patients (10.3%). Of 50 patients receiving a second PET-CT study, a SUV reduction >50% correlated with major histomorphologic response (tumor regression grade 4, <10% vital tumor cells) and histopathologic response (ypT0 ypN0). Furthermore, these patients showed a significantly increased survival (33.1 ± 3.5 months) compared to non-responders (21.7 ± 3.3 months; p = 0.02) and patients after primary surgery (29 ± 3.2 months; p = 0.05). CONCLUSIONS: The present study shows that PET-CT is a valuable tool for primary staging and response control in multimodal treatment of patients with EC.

Assessment of histological response of paediatric bone sarcomas using FDG PET in comparison to morphological volume measurement and standardized MRI parameters.

PURPOSE: The objective of this study was to evaluate positron emission tomography (PET) using (18)F-fluoro-2-deoxy-D-glucose (FDG) in comparison to volumetry and standardized magnetic resonance imaging (MRI) parameters for the assessment of histological response in paediatric bone sarcoma patients. METHODS: FDG PET and local MRI were performed in 27 paediatric sarcoma patients [Ewing sarcoma family of tumours (EWS), n = 16; osteosarcoma (OS), n = 11] prior to and after neoadjuvant chemotherapy before local tumour resection. Several parameters for assessment of response of the primary tumour to therapy by FDG PET and MRI were evaluated and compared with histopathological regression of the resected tumour as defined by Salzer-Kuntschik. RESULTS: FDG PET significantly discriminated responders from non-responders using the standardized uptake value (SUV) reduction and the absolute post-therapeutic SUV (SUV2) in the entire patient population (SUV, p = 0.005; SUV2, p = 0.011) as well as in the subgroup of OS patients (SUV, p = 0.009; SUV2, p = 0.028), but not in the EWS subgroup. The volume reduction measured by MRI/CT did not significantly discriminate responders from non-responders either in the entire population (p = 0.170) or in both subgroups (EWS, p = 0.950; OS, p = 1.000). The other MRI parameters alone or in combination were unreliable and did not improve the results. Comparing diagnostic parameters of FDG PET and local MRI, metabolic imaging showed high superiority in the subgroup of OS patients, while similar results were observed in the population of EWS. CONCLUSION: FDG PET appears to be a useful tool for non-invasive response assessment in the group of OS patients and is superior to MRI. In EWS patients, however, neither FDG PET nor volumetry or standardized MRI criteria enabled a reliable response assessment to be made after neoadjuvant treatment.

[18F]Fluorodeoxyglucose positron emission tomography in nonseminomatous germ cell tumors after chemotherapy: the German multicenter positron emission tomography study group.

PURPOSE: In patients with metastatic nonseminomatous germ cell cancer (NSGCT), residual masses after chemotherapy (CTX) can consist of vital carcinoma, mature teratoma, or necrosis. This prospective trial has evaluated the accuracy of [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) for the prediction of histology compared with computed tomography (CT) and serum tumor markers (STM). PATIENTS AND METHODS: A total of 121 patients with stage IIC or III NSGCT scheduled for secondary resection after cisplatin-based CTX were included. FDG-PET was performed after completion of CTX. All results were confirmed by histopathology and correlated to STM and CT. RESULTS: Prediction of tumor viability with FDG-PET was correct in 56%, which did not reach the expected clinically relevant level of 70%, and was not better than the accuracy of CT (55%) or STM (56%). Sensitivity and specificity of FDG-PET were 70% and 48%. The positive predictive values were not significantly different (55%, 61%, and 59% for CT, STM, and PET, respectively). Judging only vital carcinoma as a true malignant finding, the negative predictive value increased to 83% for FDG-PET. CONCLUSION: The presence of vital carcinoma and mature teratoma is common (55%) in residual masses in patients with NSGCT, and CT and STM cannot reliably predict absence of disease. In contrast to prior studies, this prospective trial, which is the only with histologic confirmation in all patients, demonstrated that FDG-PET is unable to give a clear additional clinical benefit to the standard diagnostic procedures, CT and STM, in the prediction of tumor viability in residual masses.

Diagnostic impact of 18F-FDG PET-CT evaluating solid pancreatic lesions versus endosonography, endoscopic retrograde cholangio-pancreatography with intraductal ultrasonography and abdominal ultrasound.

PURPOSE: This prospective single-centre phase II trial assessed the diagnostic impact of (18)F-FDG PET-CT in the evaluation of solid pancreatic lesions (phi >or= 10 mm) compared to endosonography (EUS), endoscopic retrograde cholangio-pancreatography (ERCP) with intraductal ultrasound (IDUS), abdominal ultrasound (US) and histopathological reference. METHODS: Forty-six patients (32 men/14 women, phi 61.7 years) with suspected pancreatic neoplasms underwent PET-CT with contrast-enhanced biphasic multi-detector CT of the upper abdomen followed by a diagnostic work-up with EUS, ERCP with IDUS and US within 3 weeks. PET-CT data sets were analysed by two expert readers in a consensus reading. Histology from surgery, biopsy/fine-needle aspiration and/or clinical follow-up >or=12 months served as standard of reference. RESULTS: Twenty-seven pancreatic malignancies were histopathologically proven; 19 patients had benign diseases: 36/46 lesions (78%) were detected in the head of the pancreas, 7/46 and 3/46 in the body and tail region, respectively. Sensitivity and specificity of PET-CT were 89% and 74%, respectively; positive predictive value (PPV) and negative predictive value (NPV) were 83% and 82%, respectively. Sensitivity (81-89%), specificity (74-88%), PPV (83-90%) and NPV (77-82%) achieved by EUS, ERCP and US were not significantly different. PET analysis revealed significantly higher maximum mean standardised uptake values (SUV(max) 6.5+/-4.6) in patients with pancreatic malignancy (benign lesions: SUV(max) 4.2+/-1.5; p<0.05). PET-CT revealed cervical lymphonodal metastasis from occult bronchogenic carcinoma and a tubular colon adenoma with intermediate dysplasia on polypectomy, respectively. CONCLUSIONS: (18)F-FDG PET-CT achieves a comparably high diagnostic impact evaluating small solid pancreatic lesions versus conventional reference imaging modalities. Additional clinical diagnoses are derived from concomitant whole-body PET-CT imaging.

The role of positron emission tomography in the evaluation of residual masses after chemotherapy for advanced stage seminoma.

PURPOSE: Treatment in patients with seminoma who have residual or recurrent masses following chemotherapy is still a matter of debate. Surgical resection is currently the most common recommendation for masses greater than 3 cm, resulting in overtreatment in up to 70% of those affected. We analyzed the accuracy of preoperative positron emission tomography for predicting viable tumor residuals in patients with seminoma. MATERIALS AND METHODS: In a prospective, multicenter trial computerized tomography and FDG (2-(F-18)-fluoro-2-deoxy-D-glucose) positron emission tomography were performed before surgical resection for residual or recurrent masses in 20 patients who had undergone chemotherapy for stage IIb, IIc or III seminoma. Histopathological findings were directly correlated with positron emission tomography results. RESULTS: Of the patients 18 presented with residual masses and 2 had recurrent masses following chemotherapy. Histopathological assessment revealed viable tumor in 3 patients and benign lesions in 17. All patients with viable tumor were identified correctly by positron emission tomography. No false-negative results were observed but 9 patients had false-positive positron emission tomography results. This resulted in a negative predictive value of 1 (95% CI 0.63-1) and a positive predictive value of 0.25 (95% CI 0.05-0.57) for FDG-positron emission tomography in our patient cohort. CONCLUSIONS: Our data indicate that FDG-positron emission tomography is capable of excluding viable disease in residual masses, even those exceeding 3 cm. Therefore, it may be considered an additional tool to improve patient counseling. However, the decision to perform surgical resection of the residual mass should not be based exclusively on a positive positron emission tomography image since false-positive results appear to be common.