Random survival forest to predict transplant-eligible newly diagnosed multiple myeloma outcome including FDG-PET radiomics: a combined analysis of two independent prospective European trials.

PURPOSE: Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) is included in the International Myeloma Working Group (IMWG) imaging guidelines for the work-up at diagnosis and the follow-up of multiple myeloma (MM) notably because it is a reliable tool as a predictor of prognosis. Nevertheless, none of the published studies focusing on the prognostic value of PET-derived features at baseline consider tumor heterogeneity, which could be of high importance in MM. The aim of this study was to evaluate the prognostic value of baseline PET-derived features in transplant-eligible newly diagnosed (TEND) MM patients enrolled in two prospective independent European randomized phase III trials using an innovative statistical random survival forest (RSF) approach. METHODS: Imaging ancillary studies of IFM/DFCI2009 and EMN02/HO95 trials formed part of the present analysis (IMAJEM and EMN02/HO95, respectively). Among all patients initially enrolled in these studies, those with a positive baseline FDG-PET/CT imaging and focal bone lesions (FLs) and/or extramedullary disease (EMD) were included in the present analysis. A total of 17 image features (visual and quantitative, reflecting whole imaging characteristics) and 5 clinical/histopathological parameters were collected. The statistical analysis was conducted using two RSF approaches (train/validation + test and additional nested cross-validation) to predict progression-free survival (PFS). RESULTS: One hundred thirty-nine patients were considered for this study. The final model based on the first RSF (train/validation + test) approach selected 3 features (treatment arm, hemoglobin, and SUVmaxBone Marrow (BM)) among the 22 involved initially, and two risk groups of patients (good and poor prognosis) could be defined with a mean hazard ratio of 4.3 ± 1.5 and a mean log-rank p value of 0.01 ± 0.01. The additional RSF (nested cross-validation) analysis highlighted the robustness of the proposed model across different splits of the dataset. Indeed, the first features selected using the train/validation + test approach remained the first ones over the folds with the nested approach. CONCLUSION: We proposed a new prognosis model for TEND MM patients at diagnosis based on two RSF approaches. TRIAL REGISTRATION: IMAJEM: NCT01309334 and EMN02/HO95: NCT01134484.

[18F]-Fluciclovine PET/CT for preoperative nodal staging in high-risk primary prostate cancer: final results of a prospective trial.

PURPOSE: The conventional imaging flowchart for prostate cancer (PCa) staging may fail in correctly detecting lymph node metastases (LNM). Pelvic lymph node dissection (PLND) represents the only reliable method, although invasive. A new amino acid PET compound, [18F]-fluciclovine, was recently authorized in suspected PCa recurrence but not yet included in the standard staging work-up of primary PCa. A prospective monocentric study was designed to evaluate [18F]-fluciclovine PET/CT diagnostic performance for preoperative LN staging in primary high-risk PCa. METHODS: Consecutive patients (pts) with biopsy-proven PCa, standard staging (including [11C]choline PET/CT), eligible for PLND, were enrolled to undergo an investigational [18F]-fluciclovine PET/CT. Nodal uptake higher than surrounding background was reported by at least two readers (blinded to [11C]choline) using a visual 5-point scale (1-2 probably negative; 4-5 probably positive; 3 equivocal); SUVmax, target-to-background (aorta-A; bone marrow-BM) ratios (TBRs), were also calculated. PET results were validated with PLND. [18F]-fluciclovine PET/CT performance using visual score and semi-quantitative indexes was analyzed both per patient and per LN anatomical region, compared to conventional [11C]choline and clinical predictive factors (to note that diagnostic performance of [18F]-fluciclovine was explored for LNM but not examined for intrapelvic or extrapelvic M1 lesions). RESULTS: Overall, 94 pts underwent [18F]-fluciclovine PET/CT; 72/94 (77%) high-risk pts were included in the final analyses (22 pts excluded: 8 limited PLND; 3 intermediate-risk; 2 treated with radiotherapy; 4 found to be M1; 5 neoadjuvant hormonal therapy). Median LNM risk by Briganti nomogram was 19%. LNM confirmed on histology was 25% (18/72 pts). Overall, 1671 LN were retrieved; 45/1671 (3%) LNM detected. Per pt, median no. of removed LN was 22 (mean 23 ± 10; range 8-51), of LNM was 2 (mean 3 ± 2; range 1-10). Median LNM size was 5 mm (mean 5 ± 2.5; range 2-10). On patient-based analyses (n = 72), diagnostic performance for LNM resulted significant with [18F]-fluciclovine (AUC 0.66, p 0.04; 50% sensitivity, 81% specificity, 47% PPV, 83% NPV, 74% accuracy), but not with [11C]choline (AUC 0.60, p 0.2; 50%, 70%, 36%, 81%, and 65% respectively). Briganti nomogram (OR = 1.03, p = 0.04) and [18F]-fluciclovine visual score (≥ 4) (OR = 4.27, p = 0.02) resulted independent predictors of LNM at multivariable analyses. On region-based semi-quantitative analyses (n = 576), PET/CT performed better using TBR parameters (TBR-A similar to TBR-BM; TBR-A fluciclovine AUC 0.61, p 0.35, vs choline AUC 0.57 p 0.54; TBR-BM fluciclovine AUC 0.61, p 0.36, vs choline AUC 0.58, p 0.52) rather than using absolute LN SUVmax (fluciclovine AUC 0.51, p 0.91, vs choline AUC 0.51, p 0.94). However, in all cases, diagnostic performance was not statistically significant for LNM detection, although slightly in favor of the experimental tracer [18F]-fluciclovine for each parameter. On the contrary, visual interpretation significantly outperformed PET semi-quantitative parameters (choline and fluciclovine: AUC 0.65 and 0.64 respectively; p 0.03) and represents an independent predictive factor of LNM with both tracers, in particular [18F]-fluciclovine (OR = 8.70, p 0.002, vs OR = 3.98, p = 0.03). CONCLUSION: In high-risk primary PCa, [18F]-fluciclovine demonstrates some advantages compared with [11C]choline but sensitivity for metastatic LN detection is still inadequate compared to PLND. Visual (combined morphological and functional), compared to semi-quantitative assessment, is promising but relies mainly on readers' experience rather than on unquestionable LN avidity. TRIAL REGISTRATION: EudraCT number: 2014-003,165-15.

Practice and prospects for PET/CT guided interventions.

During the past 10 years, performing real-time molecular imaging with positron emission tomography (PET) in combination with computed tomography (CT) during interventional procedures has undergone rapid development. Keeping in mind the interest of the nuclear medicine readers, an update is provided of the current workflows using real-time PET/CT in percutaneous biopsies and tumor ablations. The clinical utility of PET/CT guided biopsies in cancer patients with lung, liver, lymphoma, and bone tumors are reviewed. Several technological developments, including the introduction of new PET tracers and robotic arms as well as opportunities provided through acquiring radioactive biopsy specimens are briefly reviewed.

Diagnostic accuracy of positron emission tomography/computed tomography-driven biopsy for the diagnosis of lymphoma.

INTRODUCTION: Biopsy of affected tissue is required for lymphoma diagnosis and to plan treatment. Open incisional biopsy is traditionally the method of choice. Nevertheless, it requires hospitalization, availability of an operating room, and sometimes general anesthesia, and it is associated with several drawbacks. Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) can be potentially used to drive biopsy to the most metabolically active area within a lymph node or extranodal masses. METHODS: A study of diagnostic accuracy was conducted to assess the performance of a PET-driven needle biopsy in patients with suspect active lymphoma. RESULTS: Overall, 99 procedures have been performed: three (3.0%) were interrupted because of pain but were successfully repeated in two cases. Median SUVmax of target lesions was 10.7. In 84/96 cases, the tissue was considered adequate to formulate a diagnosis (diagnostic yield of 87.5%) and to guide the following clinical decision. The target specimen was a lymph node in 60 cases and an extranodal site in 36. No serious adverse events occurred. The sensitivity of this procedure was 96%, with a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 75%. CONCLUSION: Patients can benefit from a minimally invasive procedure which allows a timely and accurate diagnosis of lymphoma at onset or relapse.

[18F]Fluciclovine PET/CT: joint EANM and SNMMI procedure guideline for prostate cancer imaging-version 1.0.

The aim of this guideline is to provide standards for the recommendation, performance, interpretation, and reporting of [18F]Fluciclovine PET/CT for prostate cancer imaging. These recommendations will help to improve accuracy, precision, and repeatability of [18F]Fluciclovine PET/CT for prostate cancer essentially needed for implementation of this modality in science and routine clinical practice.

Functional Imaging for Therapeutic Assessment and Minimal Residual Disease Detection in Multiple Myeloma.

Serum markers and bone marrow examination are commonly used for monitoring therapy response in multiple myeloma (MM), but this fails to identify minimal residual disease (MRD), which frequently persists after therapy even in complete response patients, and extra-medullary disease escape. Positron emission tomography with computed tomography using 18F-deoxyglucose (FDG-PET/CT) is the reference imaging technique for therapeutic assessment and MRD detection in MM. To date, all large prospective cohort studies of transplant-eligible newly diagnosed MM patients have shown a strong and independent pejorative prognostic impact of not obtaining complete metabolic response by FDG-PET/CT after therapy, especially before maintenance. The FDG-PET/CT and MRD (evaluated by flow cytometry or next-generation sequencing at 10-5 and 10-6 levels, respectively) results are complementary for MRD detection outside and inside the bone marrow. For patients with at least a complete response, to reach double negativity (FDG-PET/CT and MRD) is a predictive surrogate for patient outcome. Homogenization of FDG-PET/CT interpretation after therapy, especially clarification of complete metabolic response definition, is currently underway. FDG-PET/CT does not allow MRD to be evaluated when it is negative at initial workup of symptomatic MM. New PET tracers such as CXCR4 ligands have shown high diagnostic value and could replace FDG in this setting. New sensitive functional magnetic resonance imaging (MRI) techniques such as diffusion-weighted MRI appear to be complementary to FDG-PET/CT for imaging MRD detection. The goal of this review is to examine the feasibility of functional imaging, especially FDG-PET/CT, for therapeutic assessment and MRD detection in MM.

18F-fluciclovine PET-CT and 68Ga-PSMA-11 PET-CT in patients with early biochemical recurrence after prostatectomy: a prospective, single-centre, single-arm, comparative imaging trial.

BACKGROUND: National Comprehensive Cancer Network guidelines consider 18F-fluciclovine PET-CT for prostate cancer biochemical recurrence localisation after radical prostatectomy, whereas European Association of Urology guidelines recommend prostate-specific membrane antigen (PSMA) PET-CT. To the best of our knowledge, no prospective head-to-head comparison between these tests has been done so far. The aim of this study was to compare prospectively paired 18F-fluciclovine and PSMA PET-CT scans for localising biochemical recurrence of prostate cancer after radical prostatectomy in patients with low prostate-specific antigen (PSA) concentrations (<2·0 ng/mL). METHODS: This was a prospective, single-centre, open-label, single-arm comparative study done at University of California Los Angeles (Los Angeles, CA, USA). Patients older than 18 years of age with prostate cancer biochemical recurrence after radical prostatectomy and PSA levels ranging from 0·2 to 2·0 ng/mL without any prior salvage therapy and with a Karnofsky performance status of at least 50 were eligible. Patients underwent 18F-fluciclovine (reference test) and PSMA (index test) PET-CT scans within 15 days. Detection rate of biochemical recurrence at the patient level and by anatomical region was the primary endpoint. A statistical power analysis demonstrated that a sample size of 50 patients was needed to show a 22% difference in detection rates in favour of PSMA (test for superiority). Each PET scan was interpreted by three independent masked readers and a consensus majority interpretation was generated (two vs one) to determine positive findings. This study is registered with ClinicalTrials.gov, number NCT02940262, and is complete. FINDINGS: Between Feb 26, 2018, and Sept 20, 2018, 143 patients were screened for eligibility, of whom 50 patients were enrolled into the study. Median follow-up was 8 months (IQR 7-9). The primary endpoint was met; detection rates were significantly lower with 18F-fluciclovine PET-CT (13 [26%; 95% CI 15-40] of 50) than with PSMA PET-CT (28 [56%; 41-70] of 50), with an odds ratio (OR) of 4·8 (95% CI 1·6-19·2; p=0·0026) at the patient level; in the subanalysis of the pelvic nodes region (four [8%; 2-19] with 18F-fluciclovine vs 15 [30%; 18-45] with PSMA PET-CT; OR 12·0 [1·8-513·0], p=0·0034); and in the subanalysis of any extrapelvic lesions (none [0%; 0-6] vs eight [16%; 7-29]; OR non-estimable [95% CI non-estimable], p=0·0078). INTERPRETATION: With higher detection rates, PSMA should be the PET tracer of choice when PET-CT imaging is considered for subsequent treatment management decisions in patients with prostate cancer and biochemical recurrence after radical prostatectomy and low PSA concentrations (≤2·0 ng/mL). Further research is needed to investigate whether higher detection rates translate into improved oncological outcomes. FUNDING: None.

Contribution of PET imaging to mortality risk stratification in candidates to lead extraction for pacemaker or defibrillator infection: a prospective single center study.

PURPOSE: 18F-FDG PET/CT is an emerging technique for diagnosis of cardiac implantable electronic devices infection (CIEDI). Despite the improvements in transvenous lead extraction (TLE), long-term survival in patients with CIEDI is poor. The aim of the present study was to evaluate whether the extension of CIEDI at 18F-FDG PET/CT can improve prediction of survival after TLE. METHODS: Prospective, monocentric observational study enrolling consecutive candidates to TLE for a diagnosis of CIEDI. 18F-FDG PET/CT was performed in all patients prior TLE. RESULTS: There were 105 consecutive patients with confirmed CIEDI enrolled. An increased 18F-FDG uptake was limited to cardiac implantable electrical device (CIED) pocket in 56 patients, 40 patients had a systemic involvement. We had nine negative PET in patients undergoing prolonged antimicrobial therapy (22.5 ± 14.0 days vs. 8.6 ± 13.0 days; p = 0.005). Implementation of 18F-FDG PET/CT in modified Duke Criteria lead to reclassification of 23.8% of the patients. After a mean follow-up of 25.0 ± 9.0 months, 31 patients died (29.5%). Patients with CIED pocket involvement at 18F-FDG PET/CT presented a better survival independently of presence/absence of systemic involvement (HR 0.493, 95%CI 0.240-0.984; p = 0.048). After integration of 18F-FDG PET/CT data, absence of overt/hidden pocket involvement in CIEDI and a (glomerular filtration rate) GFR < 60 ml/min were the only independent predictors of mortality at long term. CONCLUSIONS: Patient with CIEDI and a Cold Closed Pocket (i.e., a CIED pocket without skin erosion/perforation nor increased capitation at 18F-FDG PET/CT) present worse long-term survival. Patient management can benefit by systematic adoption of pre-TLE 18F-FDG PET/CT through improved identification of CIED related endocarditis (CIEDIE) and hidden involvement of CIED pocket.

Role of 18F-FLT PET/CT in suspected recurrent or residual lymphoma: final results of a pilot prospective trial.

PURPOSE: To evaluate the role of F-18-Fluorothymidine (FLT) PET/CT in lymphoma patients with suspected recurrent or residual disease. METHODS: Adult lymphoma patients presenting with positive or equivocal F-18-FDG PET/CT at end-treatment or follow-up were prospectively addressed to an additional F-18-FLT-PET/CT. SUV max and tumour-to-background ratios (TBRs) were recorded for the most avid lesion. Biopsy or, when not available, clinical or imaging assessment were employed as standard of reference. RESULTS: Overall 52 patients were recruited. Histology was available in 20/52 patients (38%), proliferation-index (Ki-67) in 14/20. Disease was excluded in 13/52 patients (25%) (one reactive follicular hyperplasia, five reactive-inflammatory tissues, four reactive nodes, two nodal sarcoid-like and one non-specific peri-caecal finding). FDG and FLT scans were concordant in disease restaging in 34/52 patients (65%), whereas in 18/52 cases (35%) relevant discrepancies were recorded. SUV max and TBR were significantly higher in the disease versus the disease-free group, with both tracers (p = 0.0231 and 0.0219 for FDG; p = 0.0008 and 0.0016 for FLT). FLT-SUVmax demonstrated slightly better performance in discriminating benign from malignant lesions (ROC-AUC: 0.8116 and 0.7949 for FLT-SUV max and TBR; 0.7120 and 0.7140 for FDG). Optimal FLT-SUV max cut-offs were searched: three would lead to 95% sensitivity, 81% accuracy, and 39% specificity, whereas seven led to 100%, 41%, and 56% respectively. No statistically significant correlation was observed between the two FLT indices and Ki-67. CONCLUSIONS: According to our results in a clinical setting of recurrent or residual lymphoma, FLT is not significantly superior to FDG and it is unlikely that it will be employed independently. FLT may be restricted to a few specific cases, as complementary to standard FDG imaging, to confirm a diagnosis or to define a better target to biopsy. However, due to FLT suboptimal performance, many findings would remain inconclusive, requiring further diagnostic procedures and reducing the effectiveness of performing an additional FLT scan.

State-of-the-art imaging techniques in the management of preoperative staging and re-staging of prostate cancer.

We aimed to review the current state-of-the-art imaging methods used for primary and secondary staging of prostate cancer, mainly focusing on multiparametric magnetic resonance imaging and positron-emission tomography/computed tomography with new radiotracers. An expert panel of urologists, radiologists and nuclear medicine physicians with wide experience in prostate cancer led a PubMed/MEDLINE search for prospective, retrospective original research, systematic review, meta-analyses and clinical guidelines for local and systemic staging of the primary tumor and recurrence disease after treatment. Despite magnetic resonance imaging having low sensitivity for microscopic extracapsular extension, it is now a mainstay of prostate cancer diagnosis and local staging, and is becoming a crucial tool in treatment planning. Cross-sectional imaging for nodal staging, such as computed tomography and magnetic resonance imaging, is clinically useless even in high-risk patients, but is still suggested by current clinical guidelines. Positron-emission tomography/computed tomography with newer tracers has some advantage over conventional images, but is not cost-effective. Bone scan and computed tomography are often useless in early biochemical relapse, when salvage treatments are potentially curative. New imaging modalities, such as prostate-specific membrane antigen positron-emission tomography/computed tomography and whole-body magnetic resonance imaging, are showing promising results for early local and systemic detection. Newer imaging techniques, such as multiparametric magnetic resonance imaging, whole-body magnetic resonance imaging and positron-emission tomography/computed tomography with prostate-specific membrane antigen, have the potential to fill the historical limitations of conventional imaging methods in some clinical situations of primary and secondary staging of prostate cancer.

Prognostic value of posttreatment 18F-FDG PET/CT and predictors of metabolic response to therapy in patients with locally advanced cervical cancer treated with concomitant chemoradiation therapy: an analysis of intensity- and volume-based PET parameters.

PURPOSE: To investigate the prognostic value of posttreatment 18F-FDG PET/CT in patients with locally advanced cervical cancer (LACC) treated with concomitant chemoradiation therapy (CCRT). The secondary aim was to assess the possible role of intensity-based and volume-based PET parameters including SUVmax, SUVmean, MTV and TLG, and clinical parameters including age, pathology, FIGO stage and nodal involvement as factors predicting response to treatment. METHODS: This retrospective study included 82 patients affected by LACC treated with CCRT. All patients underwent 18F-FDG PET/CT both before and after treatment. The posttreatment PET/CT scans were used to classify patients as complete metabolic responders (CMR) or non-complete metabolic responders (N-CMR) according to the EORTC criteria. Kaplan-Meier analysis was used to evaluate differences in overall survival (OS) between the CMR and N-CMR groups. Student's t test, Pearson's chi-squared test and logistic regression were used to investigate the possible value of PET and clinical parameters as predictors of metabolic response to therapy. RESULTS: Kaplan-Meier analysis showed a highly significant difference in OS between the CMR and N-CMR groups (log-rank test p < 0.0001). Significant independent predictors of response to therapy were MTV (p = 0.019, odds ratio = 1.015, 95% CI = 1.002-1.028, Nagelkerke R2 = 0.110), TLG (p = 0.045, odds ratio = 1.001, 95% CI = 1.000-1.002, Nagelkerke R2 = 0.081) and nodal involvement (p = 0.088, odds ratio = 2.361, 95% CI = 0.879-6.343, Nagelkerke R2 = 0.051). CONCLUSION: 18F-FDG PET/CT-based response assessment using the EORTC criteria reliably predicts OS in LACC patients treated with CCRT. In our cohort of patients, pretreatment MTV and TLG and nodal involvement were predictors of response to therapy. MTV was the best predictor of response. However, its additional risk value seems to be low (MTV odds ratio = 1.015).

Interpretation criteria for FDG PET/CT in multiple myeloma (IMPeTUs): final results. IMPeTUs (Italian myeloma criteria for PET USe).

ᅟ: FDG PET/CT (18F-fluoro-deoxy-glucose positron emission tomography/computed tomography) is a useful tool to image multiple myeloma (MM). However, simple and reproducible reporting criteria are still lacking and there is the need for harmonization. Recently, a group of Italian nuclear medicine experts defined new visual descriptive criteria (Italian Myeloma criteria for Pet Use: IMPeTUs) to standardize FDG PET/CT evaluation in MM patients. The aim of this study was to assess IMPeTUs reproducibility on a large prospective cohort of MM patients. MATERIALS AND METHODS: Patients affected by symptomatic MM who had performed an FDG PET/CT at baseline (PET0), after induction (PET-AI), and the end of treatment (PET-EoT) were prospectively enrolled in a multicenter trial (EMN02)(NCT01910987; MMY3033). After anonymization, PET images were uploaded in the web platform WIDEN® and hence distributed to five expert nuclear medicine reviewers for a blinded independent central review according to the IMPeTUs criteria. Consensus among reviewers was measured by the percentage of agreement and the Krippendorff's alpha. Furthermore, on a patient-based analysis, the concordance among all the reviewers in terms of positivity or negativity of the FDG PET/CT scan was tested for different thresholds of positivity (Deauville score (DS 2, 3, 4, 5) for the main parameters (bone marrow, focal score, extra-medullary disease). RESULTS: Eighty-six patients (211 FDG PET/CT scans) were included in this analysis. Median patient age was 58 years (range, 35-66 years), 45% were male, 15% of them were in stage ISS (International Staging System) III, and 42% had high-risk cytogenetics. The percentage agreement was superior to 75% for all the time points, reaching 100% of agreement in assessing the presence skull lesions after therapy. Comparable results were obtained when the agreement analysis was performed using the Krippendorff's alpha coefficient, either in every single time point of scanning (PET0, PET-AI or PET-EoT) or overall for all the scans together. DS proved highly reproducible with the highest reproducibility for score 4. CONCLUSIONS: IMPeTUs criteria proved highly reproducible and could therefore be considered as a base for harmonizing PET interpretation in multiple myeloma. A prospective clinical validation of IMPeTUs criteria is underway.

A review discussing fluciclovine (18F) PET/CT imaging in the detection of recurrent prostate cancer.

A significant number of patients radically treated for prostate cancer (PCa) will develop prostate-specific antigen recurrence (27-53%). Localizing the anatomical site of relapse is critical, in order to achieve the optimal treatment management. To date the diagnostic accuracy of standard imaging is low. Several desirable features have been identified for the amino-acid-based PET agent, fluciclovine (18F) including: long 18F half-life which allows more practical use in centers without a cyclotron onsite; acting as a substrate for amino acid transporters upregulated in PCa or associated with malignant phenotype; lacking of incorporation into protein; and limited urinary excretion. Fluciclovine (18F) is currently approved both in USA and Europe with specific indication in adult men with suspected recurrent PCa based on elevated prostate-specific antigen following prior treatment.

Role of 18F-FDG PET/CT in the diagnosis and management of multiple myeloma and other plasma cell disorders: a consensus statement by the International Myeloma Working Group.

The International Myeloma Working Group consensus aimed to provide recommendations for the optimal use of 18fluorodeoxyglucose (18F-FDG) PET/CT in patients with multiple myeloma and other plasma cell disorders, including smouldering multiple myeloma and solitary plasmacytoma. 18F-FDG PET/CT can be considered a valuable tool for the work-up of patients with both newly diagnosed and relapsed or refractory multiple myeloma because it assesses bone damage with relatively high sensitivity and specificity, and detects extramedullary sites of proliferating clonal plasma cells while providing important prognostic information. The use of 18F-FDG PET/CT is mandatory to confirm a suspected diagnosis of solitary plasmacytoma, provided that whole-body MRI is unable to be performed, and to distinguish between smouldering and active multiple myeloma, if whole-body X-ray (WBXR) is negative and whole-body MRI is unavailable. Based on the ability of 18F-FDG PET/CT to distinguish between metabolically active and inactive disease, this technique is now the preferred functional imaging modality to evaluate and to monitor the effect of therapy on myeloma-cell metabolism. Changes in FDG avidity can provide an earlier evaluation of response to therapy compared to MRI scans, and can predict outcomes, particularly for patients who are eligible to receive autologous stem-cell transplantation. 18F-FDG PET/CT can be coupled with sensitive bone marrow-based techniques to detect minimal residual disease (MRD) inside and outside the bone marrow, helping to identify those patients who are defined as having imaging MRD negativity.

Multisite Experience of the Safety, Detection Rate and Diagnostic Performance of Fluciclovine (18F) Positron Emission Tomography/Computerized Tomography Imaging in the Staging of Biochemically Recurrent Prostate Cancer.

PURPOSE: Sensitive detection of cancer foci in men experiencing biochemical recurrence following initial treatment of prostate cancer is of great clinical significance with a possible impact on subsequent treatment choice. We describe a multisite experience of the efficacy and safety of the positron emission tomography/computerized tomography agent fluciclovine (18F) after biochemical recurrence. MATERIALS AND METHODS: A total of 596 patients underwent fluciclovine (18F) positron emission tomography/computerized tomography at 4 clinical sites. Detection rate determinations were stratified by the baseline prostate specific antigen value. Diagnostic performance was assessed against a histological reference standard in 143 scans. RESULTS: The subject level fluciclovine (18F) positron emission tomography/computer tomography detection rate was 67.7% (403 of 595 scans). Positive findings were detected in the prostate/bed and pelvic lymph node regions in 38.7% (232 of 599) and 32.6% of scans (194 of 596), respectively. Metastatic involvement outside the pelvis was detected in 26.2% of scans (155 of 591). The subject level detection rate in patients in the lowest quartile for baseline prostate specific antigen (0.79 ng/ml or less) was 41.4% (53 of 128). Of these patients 13 had involvement in the prostate/bed only, 16 had pelvic lymph node involvement without distant disease and 24 had distant metastases. The positive predictive value of fluciclovine (18F) positron emission tomography/computerized tomography scanning for all sampled lesions was 62.2%, and it was 92.3% and 71.8% for extraprostatic and prostate/bed involvement, respectively. Fluciclovine (18F) was well tolerated and the safety profile was not altered following repeat administration. CONCLUSIONS: Fluciclovine (18F) is well tolerated and able to detect local and distant prostate cancer recurrence across a wide range of prostate specific antigen values.

Therapy assessment in multiple myeloma with PET.

Multiple myeloma is a plasma cell dyscrasia producing bone lytic lesions. In recent years, a wide spectrum of therapeutic approaches are available to treat the disease: an accurate therapy assessment has, therefore, become of utmost importance. In this field, imaging is becoming a cornerstone, especially in association with clinical parameters. Among imaging procedures, FDG PET/CT is recognized to provide reliable information, achieved in a very safe and fast procedure.  The literature has produced very concordant results from different groups assessing the value of FDG PET/CT as a prognostic factor in general and in therapy assessment, but some issues remain regarding a standardization of image interpretation especially in borderline cases. So far, no data regarding nor other imaging compounds and the use of hybrid tomographs PET/MR are available to define therapy assessment in PET.