Predicting malignancy in patients with adrenal tumors using 18 F-FDG-PET/CT SUVmax.

BACKGROUND AND OBJECTIVES: 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (18 F-FDG-PET/CT) parameters may help distinguish malignant from benign adrenal tumors, but few have been externally validated or determined based on definitive pathological confirmation. We determined and validated a threshold for 18 F-FDG-PET/CT maximum standard uptake value (SUVmax) in patients who underwent adrenalectomy for a nonfunctional tumor. METHODS: Database review identified patients with 18 F-FDG-PET/CT images available (training cohort), or only SUVmax values (validation cohort). Discriminative accuracy was assessed by area under the curve (AUC), and the optimal cutoff value estimated by maximally selected Wilcoxon rank statistics. RESULTS: Of identified patients (n = 171), 86 had adrenal metastases, 20 adrenal cortical carcinoma, and 27 adrenal cortical adenoma. In the training cohort (n = 96), SUVmax was significantly higher in malignant versus benign tumors (median 8.3 vs. 3.0, p < .001), with an AUC of 0.857. Tumor size did not differ. The optimal cutoff SUVmax was 4.6 (p < .01). In the validation cohort (n = 75), this cutoff had a sensitivity of 75% and specificity 55%. CONCLUSIONS: 18 F-FDG-PET/CT SUVmax was associated with malignancy. Validation indicated that SUVmax ≥ 4.6 was suggestive of malignancy, while lower values did not reliably predict benign tumor.

Prognostic significance of baseline metabolic tumor volume in relapsed and refractory Hodgkin lymphoma.

Identification of prognostic factors for patients with relapsed/refractory Hodgkin lymphoma (HL) is essential for optimizing therapy with risk-adapted approaches. In our phase 2 study of positron emission tomography (PET)-adapted salvage therapy with brentuximab vedotin (BV) and augmented ifosfamide, carboplatin, and etoposide (augICE), we assessed clinical factors, quantitative PET assessments, and cytokine and chemokine values. Transplant-eligible patients with relapsed/refractory HL received 2 (cohort 1) or 3 (cohort 2) cycles of weekly BV; PET-negative patients (Deauville score ≤2) proceeded to autologous stem cell transplantation (ASCT) whereas PET-positive patients received augICE before ASCT. Serum cytokine and chemokine levels were measured at baseline and after BV. Metabolic tumor volume (MTV) and total lesion glycolysis were measured at baseline, after BV, and after augICE. Sixty-five patients enrolled (45, cohort 1; 20, cohort 2); 49 (75%) achieved complete response and 64 proceeded to ASCT. Three-year overall survival and event-free survival (EFS) were 95% and 82%, respectively. Factors predictive for EFS by multivariable analysis were baseline MTV (bMTV) (P < .001) and refractory disease (P = .003). Low bMTV (<109.5 cm3) and relapsed disease identified a favorable group (3-year EFS, 100%). For patients who received a transplant, bMTV and pre-ASCT PET were independently prognostic; 3-year EFS for pre-ASCT PET-positive patients with low bMTV was 86%. In this phase 2 study of PET-adapted therapy with BV and augICE for relapsed/refractory HL, bMTV and refractory disease were independent prognostic factors for EFS. Furthermore, bMTV improved the predictive power of pre-ASCT PET. Future studies should optimize efficacy and tolerability of salvage therapy by stratifying patients according to risk factors such as bMTV.

Selumetinib-enhanced radioiodine uptake in advanced thyroid cancer.

BACKGROUND: Metastatic thyroid cancers that are refractory to radioiodine (iodine-131) are associated with a poor prognosis. In mouse models of thyroid cancer, selective mitogen-activated protein kinase (MAPK) pathway antagonists increase the expression of the sodium-iodide symporter and uptake of iodine. Their effects in humans are not known. METHODS: We conducted a study to determine whether the MAPK kinase (MEK) 1 and MEK2 inhibitor selumetinib (AZD6244, ARRY-142886) could reverse refractoriness to radioiodine in patients with metastatic thyroid cancer. After stimulation with thyrotropin alfa, dosimetry with iodine-124 positron-emission tomography (PET) was performed before and 4 weeks after treatment with selumetinib (75 mg twice daily). If the second iodine-124 PET study indicated that a dose of iodine-131 of 2000 cGy or more could be delivered to the metastatic lesion or lesions, therapeutic radioiodine was administered while the patient was receiving selumetinib. RESULTS: Of 24 patients screened for the study, 20 could be evaluated. The median age was 61 years (range, 44 to 77), and 11 patients were men. Nine patients had tumors with BRAF mutations, and 5 patients had tumors with mutations of NRAS. Selumetinib increased the uptake of iodine-124 in 12 of the 20 patients (4 of 9 patients with BRAF mutations and 5 of 5 patients with NRAS mutations). Eight of these 12 patients reached the dosimetry threshold for radioiodine therapy, including all 5 patients with NRAS mutations. Of the 8 patients treated with radioiodine, 5 had confirmed partial responses and 3 had stable disease; all patients had decreases in serum thyroglobulin levels (mean reduction, 89%). No toxic effects of grade 3 or higher attributable by the investigators to selumetinib were observed. One patient received a diagnosis of myelodysplastic syndrome more than 51 weeks after radioiodine treatment, with progression to acute leukemia. CONCLUSIONS: Selumetinib produces clinically meaningful increases in iodine uptake and retention in a subgroup of patients with thyroid cancer that is refractory to radioiodine; the effectiveness may be greater in patients with RAS-mutant disease. (Funded by the American Thyroid Association and others; ClinicalTrials.gov number, NCT00970359.).

Prospective evaluation of 18F-fluorodeoxyglucose positron emission tomography in patients receiving hepatic arterial and systemic chemotherapy for unresectable colorectal liver metastases.

BACKGROUND: The prognostic and predictive abilities of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) coupled with conventional computed tomography (CT) have not been studied in patients with unresectable colorectal liver metastases (uCRLM) treated with combined hepatic arterial infusion (HAI) and systemic chemotherapy. OBJECTIVES: The ability of PET-CT metabolic response parameters to predict conversion to resectability and oncologic outcome in this setting was evaluated. METHODS: Thirty-eight patients undergoing serial PET-CT as part of a Phase II trial of HAI and systemic chemotherapy for uCRLM were included. Metabolic response was determined as the percentage change in standard uptake value (SUV) and total lesion glycolysis (TLG). Conversion to resection, overall survival (OS), progression-free survival (PFS) and recurrence-free survival were evaluated using standard statistics. RESULTS: Volumetric response sufficient to facilitate resection was seen in 53% of patients after a median of 5 months of therapy. Median follow-up was 38 months (range: 32-52 months). Median OS was not reached [95% confidence interval (CI) 32 months-unknown] and 3-year OS was 54% (range: 33-71%). Median PFS was 13 months (95% CI 6-21 months) and 3 year PFS was 10% (range: 3-20%). Neither baseline values nor the percentage change in any of the metabolic parameters evaluated correlated with conversion to resection, survival variables or hepatic recurrence on Cox regression analysis. CONCLUSIONS: Pre- and post-treatment PET-related metabolic parameters do not predict conversion to resection or oncologic outcome in patients with uCRLM treated with HAI and systemic chemotherapy. Metabolic parameters should not be used to monitor response or to determine prognosis in these patients.

Utility of FDG-PET in clinical neuroendocrine prostate cancer.

BACKGROUND: Fluorodeoxyglucose (FDG) positron emission tomography (PET) has well-characterized limitations in prostate adenocarcinoma (PCA). However, data assessing the utility of PET in neuroendocrine prostate cancer (NEPC) is limited to isolated case reports. Herein, we describe the first case series to assess the utility of FDG-PET in NEPC. METHODS: Inclusion criteria consisted of clinically progressive metastatic PCA in the setting of a chromogranin-A levels >1.5× the upper limit of normal, and ≥1 FDG-PET scan after the diagnosis of NEPC, which yielded 23 patients. All metastatic lesions on CT, PET, and bone scan were read by two independent physicians. RESULTS: Five hundred ninety two unique lesions were identified across all imaging modalities, 510 were bone metastases, and 82 were soft tissue metastases. Of bone lesions, 22.2%, 92.7%, and 77.6% were detected by PET, CT, and bone scan, respectively. Of soft tissue lesions, 95.1% and 97.5% were detected by PET and CT, respectively. Stratified by the median survival from NEPC diagnosis, patients who survived <2.2 versus ≥2.2 years had more PET avid bone (8 vs. 2, P = 0.06) and soft tissue lesions (7 vs. 1, P = 0.01), and higher average SUVmax of bone (5.49 vs. 3.40, P = 0.04) and soft tissue lesions (8.02 vs. 3.90, P = 0.0002). CONCLUSIONS: In patients with clinical NEPC, we demonstrate that FDG-PET has clinical utility in the detection of metastatic disease. In addition to detection, PET allows for treatment response to determine tumor viability. With novel therapies on the horizon to treat NEPC, consideration to investigate the use of FDG-PET to monitor response is warranted.

Targeted Radiopharmaceutical Therapy for Bone Metastases.

Radiopharmaceutical approaches for targeting bone metastasis have traditionally focused on palliation of pain. Several agents have been clinically used over the last several decades and have proven value in pain palliation providing pain relief and improving quality of life. The role is well established across several malignancies, most commonly used in osteoblastic prostate cancer patients. These agents have primarily based on targeting and uptake in bone matrix and have mostly included beta emitting isotopes. The advent alpha emitter and FDA approval of 223Ra-dichloride has created a paradigm shift in clinical approach from application for pain palliation to treatment of bone metastasis. The approval of 223Ra-dichloride given the survival benefit in metastatic prostate cancer patients, led to predominant use of this alpha emitter in prostate cancer patients. With rapid development of radiopharmaceutical therapies and approval of other targeted agents such as 177Lu-PSMA the approach to treatment of bone metastasis has further evolved and combination treatments have increasingly been applied. Novel approaches are needed to improve and expand the use of such therapies for treatment of bone metastasis. Combination therapies with different targeting mechanisms, combining chemotherapies and cocktail of alpha and beta emitters need further exploration.

Does enzalutamide related PSMA upregulation affect outcomes of lutetium-177 PSMA radioligand therapy?

BACKGROUND: Enzalutamide is an antiandrogen drug used prior to lutetium-177 prostate specific membrane antigen (Lu-PSMA) radioligand therapy and has shown promising results for upregulating the PSMA expression on prostate cancer cells. In this study, we aim to compare prostate specific antigen (PSA) level changes in prostate cancer patients who received enzalutamide to those who did not. METHODS: Prostate cancer patients who underwent Lu-PSMA between 2021 and 2023 were retrospectively included. Patients were grouped based on prior enzalutamide therapy: those who received enzalutamide (EZ+) for at least 14 days and those who did not (EZ-). PSA changes and F-18 DCFPyL SUV (Standardized Uptake Values) were compared. RESULTS: Thirty-seven patients were included, 18 EZ+ and 19 EZ-. The median age, Gleason score, and prior chemo/hormonal therapies were similar for EZ+ and EZ-, except for radium-223. Eleven patients (61%) in EZ+ and 13 patients (68%) in EZ- showed a decrease in PSA after the first cycle (p = 0.64). Four patients (22%) in EZ+ and seven patients (37%) in EZ- had more than 50% decrease in PSA after the first cycle (p = 0.33). The average percent decline at the end of the treatment was 23.3% in EZ+ and 50.4% in EZ- (p = 0.4). There was no difference in terms of lesion with highest SUVmax, mean SUV, total tumor volume or activity on pre-therapy PSMA imaging. CONCLUSION: Enzalutamide treatment prior to Lu-PSMA does not improve patient outcomes when applied remotely. Larger studies evaluating the combination therapies and the timing of enzalutamide are needed to assess its correlation with Lu-PSMA outcomes.

18F-FDG PET/CT in left ventricular assist device infections: In-depth characterization and clinical implications.

BACKGROUND: Previous retrospective studies suggest a good diagnostic performance of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET)/computed tomography (CT) in left ventricular assist device (LVAD) infections. Our aim was to prospectively evaluate the role of PET/CT in the characterization and impact on clinical management of LVAD infections. METHODS: A total of 40 patients (aged 58 [53-62] years) with suspected LVAD infection and 5 controls (aged 69 [64-71] years) underwent 18F-FDG-PET/CT. Four LVAD components were evaluated: exit site and subcutaneous driveline (peripheral), pump pocket, and outflow graft. The location with maximal uptake was considered the presumed site of infection. Infection was confirmed by positive culture (exit site or blood) and/or surgical findings. RESULTS: Visual uptake was present in 40 patients (100%) in the infection group vs 4 (80%) control subjects. For each individual component, the presence of uptake was more frequent in the infection than in the control group. The location of maximal uptake was most frequently the pump pocket (48%) in the infection group and the peripheral components (75%) in the control group. Maximum standard uptake values (SUVmax) were higher in the infection than in the control group: SUVmax (average all components): 6.9 (5.1-8.5) vs 3.8 (3.7-4.3), p = 0.002; SUVmax (location of maximal uptake): 10.6 ± 4.0 vs 5.4 ± 1.9, p = 0.01. Pump pocket infections were more frequent in patients with bacteremia than without bacteremia (79% vs 31%, p = 0.011). Pseudomonas (32%) and methicillin-susceptible Staphylococcus aureus (29%) were the most frequent pathogens and were associated with pump pocket infections, while Staphylococcus epidermis (11%) was associated with peripheral infections. PET/CT affected the clinical management of 83% of patients with infection, resulting in surgical debridement (8%), pump exchange (13%), and upgrade in the transplant listing status (10%), leading to 8% of urgent transplants. CONCLUSIONS: 18F-FDG-PET/CT enables the diagnosis and characterization of the extent of LVAD infections, which can significantly affect the clinical management of these patients.

FDG-PET/MRI for the preoperative diagnosis and staging of peritoneal carcinomatosis: a prospective multireader pilot study.

PURPOSE: To assess the diagnostic performance of FDG-PET/MRI for the preoperative diagnosis and staging of peritoneal carcinomatosis (PC) using surgical Sugarbaker's PC index (PCI) as the reference in a multireader pilot study. METHODS: Fourteen adult patients (M/F: 3/11, mean age: 57 ± 12 year) with PC were prospectively included in this single-center study. Patients underwent FDG-PET/MRI prior to surgery (mean delay: 14 d, range: 1-63 d). Images were reviewed independently by 2 abdominal radiologists and 2 nuclear medicine physicians. The radiologists assessed contrast-enhanced abdominal MR images, while the nuclear medicine physicians assessed PET images fused with T2-weighted images. The abdomen was divided in 13 regions, scored from 0 to 3. A hybrid FDG-PET/MRI radiological PCI was created by combining the study data. Radiological PCI was compared to the surgical PCI on a per-patient and per-region basis. Inter-reader agreement was evaluated. RESULTS: Mean surgical PCI was 10 ± 8 (range: 0-24). Inter-reader agreement was almost perfect for all sets for radiologic PCI (Kappa: 0.81-0.98). PCI scores for all reading sets significantly correlated with the surgical PCI score (r range: 0.57-0.74, p range: < 0.001-0.003). Pooled per-patient sensitivity, specificity, and accuracy were 75%/50%/71.4% for MRI, 66.7%/50%/64.3% for FDG-PET, and 91.7%/50%/85.7% for FDG-PET/MRI, without significant difference (p value range 0.13-1). FDG-PET/MRI achieved 100% sensitivity and 100% specificity for a cutoff PCI of 20. Per-region sensitivity and accuracy were lower: 37%/61.8% for MRI, 17.8%/64.3% for FDG-PET, and 52.7%/60.4% for FDG-PET/MRI, with significantly higher sensitivity for FDG-PET/MRI. Per-region specificity was higher for FDG-PET (95%) compared to MRI (78.4%) and FDG-PET/MRI (66.5%). CONCLUSION: FDG-PET/MRI achieved an excellent diagnostic accuracy per-patient and weaker performance per-region for detection of PC. The added value of PET/MRI compared to MRI and FDG-PET remains to be determined.

18F-FDG and 18F-Fluciclovine Uptake in Poorly Differentiated Lung Adenocarcinoma in the Setting of Biochemically Recurrent Prostatic Adenocarcinoma.

ABSTRACT: A 64-year-old man with a history of Gleason 7 (3 + 4) pT2cN0 prostatic adenocarcinoma status post prostatectomy underwent a fluciclovine PET/CT that showed a tracer-avid right upper lobe spiculated solitary pulmonary nodule. Follow-up FDG PET/CT showed a hypermetabolic right upper lobe spiculated solitary pulmonary nodule. Fine-needle aspiration was consistent with primary lung adenocarcinoma. Subsequently, right upper lobectomy was performed, and poorly differentiated lung adenocarcinoma was confirmed.

Asymptomatic SARS-CoV-2 infection: Incidental findings on FDG PET/CT.

RATIONALE AND OBJECTIVES: Identify the incidental findings of Covid-19 pneumonitis on 18F-FDG PET/CT scan in asymptomatic oncologic patients. The goal was to detect clinically unsuspected Covid-19 infections to prevent community spread. MATERIALS AND METHODS: Retrospective analysis was conducted to recognize the pattern of metabolic and radiographic alterations on 18F-FDG PET/CT scans in Covid-19 patients. 492 18F-FDG PET/CT scans were reviewed for pulmonary and systemic abnormalities. RESULTS: 18F-FDG PET/CT demonstrated new lung infiltrates in 29 asymptomatic patients. 13/29 patients had Covid-19 infection confirmed by nasopharyngeal nucleic acid PCR test. The most common lung abnormality was pure ground-glass opacity (GGO) (90%) in peripheral distribution (100%), involving 1 lobe in four patients (30.8%), 2-3 lobes in four patients, and 4-5 lobes in five patients (38.4%). Mean SUVmax was 4.7 (range 1.3-13.1). Ten patients developed symptoms, mainly fever, fatigue, and dry cough, within 6.4 ± 7.8 days (range 1-24). Of the available laboratory data of 12 patients, eight developed lymphopenia, and five patients had neutrophilia. Five patients required hospitalization, and two died of complications. CONCLUSION: For a given geographic region in the later stage of a pandemic, such as Covid-19, community spread of the disease is common. Therefore, it is not surprising to find it in asymptomatic being imaged for other indications. Recognition of its manifestation and effectively mounting mitigation protocols is essential to further reduce SARS-CoV-2 spread, especially to susceptible groups, predominantly the elderly and people with comorbidities.

Neurocognitive and hypokinetic movement disorder with features of parkinsonism after BCMA-targeting CAR-T cell therapy.

B-cell maturation antigen (BCMA) is a prominent tumor-associated target for chimeric antigen receptor (CAR)-T cell therapy in multiple myeloma (MM). Here, we describe the case of a patient with MM who was enrolled in the CARTITUDE-1 trial ( NCT03548207 ) and who developed a progressive movement disorder with features of parkinsonism approximately 3 months after ciltacabtagene autoleucel BCMA-targeted CAR-T cell infusion, associated with CAR-T cell persistence in the blood and cerebrospinal fluid, and basal ganglia lymphocytic infiltration. We show BCMA expression on neurons and astrocytes in the patient's basal ganglia. Public transcriptomic datasets further confirm BCMA RNA expression in the caudate of normal human brains, suggesting that this might be an on-target effect of anti-BCMA therapy. Given reports of three patients with grade 3 or higher parkinsonism on the phase 2 ciltacabtagene autoleucel trial and of grade 3 parkinsonism in the idecabtagene vicleucel package insert, our findings support close neurological monitoring of patients on BCMA-targeted T cell therapies.

Feasibility and diagnostic performance of hybrid PET/MRI compared with PET/CT for gynecological malignancies: a prospective pilot study.

PURPOSE: The purpose of the study was to assess the feasibility and diagnostic performance of FDG-PET/MR imaging compared to PET/CT for staging of patients with a gynecological malignancy. METHODS: 25 patients with a gynecological malignancy were prospectively enrolled into this pilot study. Patients underwent sequential full-body PET/CT and PET/MR of the abdomen and pelvis after administration of a single dose of F-18 FDG. PET/MRI and PET/CT images were independently reviewed by two expert radiologists. Readers were blinded to the results of the other imaging procedures. Clinical and pathologic information was abstracted from medical charts. RESULTS: 18 patients were included in the final analysis with a median age of 62 years (range 31-88). 61% of patients (11/18) had cervical cancer, while the remaining patients had endometrial cancer. PET/MRI as compared to PET/CT detected all primary tumors, 7/7 patients with regional lymph nodes, and 1/1 patient with an abdominal metastasis. Two patients had additional lymph nodes outside of the abdominopelvic cavity detected on PET/CT that were not seen on PET/MRI, whereas 6 patients had parametrial invasion and one patient had invasion of the bladder seen on PET/MRI not detected on PET/CT. Five cervical cancer patients had discordant clinical vs. radiographic staging based on PET/MRI detection of soft tissue involvement. Management changed for two patients who had clinical stage IB1 and radiographic stage IIB cervical cancer. CONCLUSIONS: PET/MRI is feasible and has at least comparable diagnostic ability to PET/CT for identification of primary cervical and endometrial tumors and regional metastases. PET/MRI may be superior to PET/CT for initial radiographic assessment of cervical cancers.

Positron Emission Tomography/Computed Tomography-Based Assessments of Androgen Receptor Expression and Glycolytic Activity as a Prognostic Biomarker for Metastatic Castration-Resistant Prostate Cancer.

IMPORTANCE: Androgen receptor-signaling inhibitor (ARSi) drugs prolong life in metastatic castration-resistant prostate cancer (mCRPC), but such tumors eventually become resistant and progress. Comprehensive positron emission tomography/computed tomography (PET/CT) imaging using fluoro-2-D-deoxyglucose F 18 ([18F]-FDG) for glycolysis (Glyc) and fluorodihydrotestosterone F 18 ([18F]-FDHT) for androgen receptor (AR) expression determine heterogeneity of imaging phenotypes, which may be useful in distinguishing patients who will benefit from ARSi drugs from those who need alternative treatments. OBJECTIVE: To test the hypothesis that PET/CT-based assessments of AR expression and glycolytic activity would reveal heterogeneity affecting prognosis. DESIGN, SETTING, AND PARTICIPANTS: Between April 6, 2007, and October 4, 2012, patients with mCRPC underwent imaging with both [18F]-FDG and [18F]-FDHT at Memorial Sloan Kettering Cancer Center. The patients were naive to ARSi treatment with enzalutamide or abiraterone acetate and were referred during documented disease progression. Image-directed biopsy determined the presence or absence of prostate cancer at positive imaging sites. INTERVENTIONS: PET/CT imaging was performed with [18F]-FDHT and [18F]-FDG; select individual lesions were biopsied to correlate imaging phenotype with histologic findings. MAIN OUTCOMES AND MEASURES: All metabolically active lesions were interpreted as [18F]-FDHT-positive (AR1) or [18F]-FDHT-negative (AR0) and as [18F]-FDG-positive (Glyc1) or [18F]-FDG-negative (Glyc0). Correlation was performed with overall survival for both individual lesion imaging phenotype as well as patient-specific imaging phenotype. RESULTS: The mean (SD) age of the 133 patients was 68 (8.6) years. Imaging phenotypes of 2405 PET/CT-positive lesions (median, 12.0 per patient) included 1713 (71.2%) AR1Glyc1, 386 (16.0%) AR1Glyc0, and 306 (12.7%) AR0Glyc1. On multivariate analysis, each phenotype had an independent negative impact effect on survival, most pronounced for AR0Glyc1 lesions (hazard ratio [HR], 1.11; 95% CI, 1.05-1.16; P < .001), followed by AR1Glyc1 lesions (HR, 1.05; 95% CI, 1.03-1.06; P < .001) and AR1Glyc0 lesions (HR, 1.03; 95% CI, 1.00-1.05; P = .048). When sorted by lesion type, 4 patient-specific groups emerged: (1) concordant, with all AR1Glyc1 (34 patients [25.6%]); (2) AR predominant, with AR1Glyc1 and varying numbers of AR1Glyc0 (33 [24.8%]); (3) Glyc predominant, with AR1Glyc1 and varying numbers of AR0Glyc1 (40 [30.1%]); and (4) mixed, with AR1Glyc1 plus a mixture of varying numbers of AR1Glyc0 and AR0Glyc1 (26 [19.5%]). CONCLUSIONS AND RELEVANCE: Heterogeneity of PET/CT imaging phenotype has clinical relevance on a lesion and individual patient level. With regard to mCRPC lesions, most express ARs, consistent with initial benefit of ARSi drugs. On a patient basis, 49% (groups 3 and 4) had at least 1 AR0Glyc1 lesion-the imaging phenotype with the most negative effect on survival, possibly due to ARSi resistance.

Multifocal Osteosarcoma: Unusual Presentation and Imaging Findings.

Multifocal osteosarcoma is usually defined as the occurrence of a tumor at 2 or more sites in a patient without pulmonary metastases and may be synchronous with more than one lesion seen at presentation or metachronous with new tumors developing after the initial treatment. It is difficult to determine whether these represent synchronous multiple primary lesions or metastases. We present a rare case of widespread synchronous multifocal osteosarcoma and a brief review of the literature.

Metabolic tumor volume and total lesion glycolysis on FDG-PET/CT can predict overall survival after (90)Y radioembolization of colorectal liver metastases: A comparison with SUVmax, SUVpeak, and RECIST 1.0.

PURPOSE: To compare the performance of 4 metrics of metabolic response on FDG-PET/CT against RECIST 1.0 for determining response and predicting overall survival (OS) following (90)Y resin microspheres radioembolization of colorectal liver metastases (CLM). METHODS: We conducted an IRB-waived retrospective review of our radioembolization database to identify patients with unresectable CLM treated between December 2009 and December 2013. We included patients who had both PET/CT and contrast enhanced CT (CECT) available at baseline and on the first follow-up post-radioembolization. On baseline CECT up to five target tumors were chosen per patient according to RECIST 1.0. Four metrics of FDG-avidity (SUVmax, SUVpeak, metabolic tumor volume (MTV), and total lesion glycolysis (TLG)) on PET/CT were measured for the same target tumors. Using RECIST 1.0, patients were classified as no progression (partial response or stable disease) and progression. For each PET metric, a cut-off point of ≥30% decrease was chosen to define response. OS was calculated from the time of radioembolization using Kaplan-Meier methodology. The log-rank test was used for univariate analysis to identify predictors of OS. RESULTS: The study enrolled 49 patients with 119 target tumors; a median of 2 (range: 1-5) tumors were selected per patient. Median OS was 12.7 months (95%CI: 7.2-16.7). Response by MTV (P=0.035) and TLG (P=0.044) reached statistical significance in predicting OS. Response by SUVmax (P=0.21), SUVpeak (P=0.20) or no progression by RECIST 1.0 (P=0.44) did not predict OS. CONCLUSION: Metabolic response based on changes in MTV and TLG can predict OS post-radioembolization of CLM.

Prospective Study of 3'-Deoxy-3'-18F-Fluorothymidine PET for Early Interim Response Assessment in Advanced-Stage B-Cell Lymphoma.

UNLABELLED: Current clinical and imaging tools remain suboptimal for early assessment of prognosis and treatment response in aggressive lymphomas. PET with 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) can be used to measure tumor cell proliferation and treatment response. In a prospective study in patients with advanced-stage B-cell lymphoma, we investigated the prognostic and predictive value of (18)F-FLT PET in comparison to standard imaging with (18)F-FDG PET and clinical outcome. METHODS: Sixty-five patients were treated with an induction/consolidation regimen consisting of 4 cycles of R-CHOP-14 (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone) followed by 3 cycles of ICE (ifosfamide, carboplatin, etoposide). (18)F-FLT PET was performed at baseline and at interim (iPET) after 1-2 cycles of therapy. (18)F-FDG PET was performed at baseline, after cycle 4, and at the end of therapy. The relationship between PET findings, progression-free survival (PFS) and overall survival (OS) was investigated. RESULTS: With a median follow-up of 51 mo, PFS and OS were 71% and 86%, respectively. (18)F-FLT iPET, analyzed visually (using a 5-point score) or semiquantitatively (using SUV and ΔSUV) predicted both PFS and OS (P < 0.01 for all parameters). Residual (18)F-FLT SUVmax on iPET was associated with an inferior PFS (hazard ratio, 1.26, P = 0.001) and OS (hazard ratio, 1.27, P = 0.002). When (18)F-FDG PET was used, findings in the end of treatment scan were better predictors of PFS and OS than findings on the interim scan. Baseline PET imaging parameters, including SUV, proliferative volume, or metabolic tumor volume, did not correlate with outcome. CONCLUSION: (18)F-FLT PET after 1-2 cycles of chemotherapy predicts PFS and OS, and a negative (18)F-FLT iPET result may potentially help design risk-adapted therapies in patients with aggressive lymphomas. In contrast, the positive predictive value of (18)F-FLT iPET remains too low to justify changes in patient management.

Positron emission tomography (PET) evaluation after initial chemotherapy and radiation therapy predicts local control in rhabdomyosarcoma.

PURPOSE: 18-fluorodeoxyglucose positron emission tomography (PET) is already an integral part of staging in rhabdomyosarcoma. We investigated whether primary-site treatment response characterized by serial PET imaging at specific time points can be correlated with local control. PATIENTS AND METHODS: We retrospectively examined 94 patients with rhabdomyosarcoma who received initial chemotherapy 15 weeks (median) before radiotherapy and underwent baseline, preradiation, and postradiation PET. Baseline PET standardized uptake values (SUVmax) and the presence or absence of abnormal uptake (termed PET-positive or PET-negative) both before and after radiation were examined for the primary site. Local relapse-free survival (LRFS) was calculated according to baseline SUVmax, PET-positive status, and PET-negative status by the Kaplan-Meier method, and comparisons were tested with the log-rank test. RESULTS: The median patient age was 11 years. With 3-year median follow-up, LRFS was improved among postradiation PET-negative vs PET-positive patients: 94% vs 75%, P=.02. By contrast, on baseline PET, LRFS was not significantly different for primary-site SUVmax≤7 vs >7 (median), although the findings suggested a trend toward improved LRFS: 96% for SUVmax≤7 vs 79% for SUVmax>7, P=.08. Preradiation PET also suggested a statistically insignificant trend toward improved LRFS for PET-negative (97%) vs PET-positive (81%) patients (P=.06). CONCLUSION: Negative postradiation PET predicted improved LRFS. Notably, 77% of patients with persistent postradiation uptake did not experience local failure, suggesting that these patients could be closely followed up rather than immediately referred for intervention. Negative baseline and preradiation PET findings suggested statistically insignificant trends toward improved LRFS. Additional study may further understanding of relationships between PET findings at these time points and outcome in rhabdomyosarcoma.

Practical approach for comparative analysis of multilesion molecular imaging using a semiautomated program for PET/CT.

UNLABELLED: We propose a standardized approach to quantitative molecular imaging (MI) in cancer patients with multiple lesions. METHODS: Twenty patients with castration-resistant prostate cancer underwent (18)F-FDG and (18)F-16ß-fluoro-5-dihydrotestosterone ((18)F-FDHT) PET/CT scans. Using a 5-point confidence scale, 2 readers interpreted coregistered scan sets on a workstation. Two hundred three sites per scan (specified in a lexicon) were reviewed. (18)F-FDG-positive lesion bookmarks were propagated onto (18)F-FDHT studies and then manually accepted or rejected. Discordance-positive (18)F-FDHT lesions were similarly bookmarked. Lesional SUV(max) was recorded. Tracer- and tissue-specific background correction factors were calculated via receiver-operating-characteristic analysis of 65 scan sets. RESULTS: Readers agreed on more than 99% of (18)F-FDG- and (18)F-FDHT-negative sites. Positive-site agreement was 83% and 85%, respectively. Consensus-lesion maximum standardized uptake value (SUV(max)) was highly reproducible (concordance correlation coefficient > 0.98). Receiver-operating-characteristic curves yielded 4 correction factors (SUV(max) 1.8-2.6). A novel scatterplot (Larson-Fox-Gonen plot) depicted tumor burden and change in SUV(max) for response assessments. CONCLUSION: Multilesion molecular imaging is optimized with a 5-step approach incorporating a confidence scale, site lexicon, semiautomated PET software, background correction, and Larson-Fox-Gonen graphing.