Carfilzomib-lenalidomide-dexamethasone therapy is tolerable and demonstrates high rates of MRD negativity in NDMM, translating into longer progression-free survival in patients achieving MRD negativity. Carfilzomib-lenalidomide-dexamethasone therapy also demonstrates efficacy in high-risk SMM.

We evaluated the kinetics of 18F-sodium fluoride (NaF) and reassessed the recommended dose, optimal uptake period, and reproducibility using a current-generation PET/CT scanner. Methods In this prospective study, 73 patients (31 patients with multiple myeloma or myeloma precursor disease and 42 with prostate cancer) were injected with a mean administered dose of 141 MBq of 18F-NaF. Sixty patients underwent 3 sequential sessions of 3-dimensional PET/CT of the torso beginning ~15 min after 18F-NaF injection, followed by a whole-body 3-dimensional PET/CT at 2 h. The remaining 13 prostate cancer patients were imaged only at 2 and 3 h after injection. Twenty-one prostate cancer patients underwent repeat baseline studies (mean interval, 5.9 d) to evaluate reproducibility. Results The measured effective dose was 0.017 mSv/MBq, with the urinary bladder, osteogenic cells, and red marrow receiving the highest doses at 0.080, 0.077, and 0.028 mGy/MBq, respectively. Visual analysis showed that uptake in both normal and abnormal bone increased with time; however, the rate of increase decreased with time. A semiautomated workflow provided objective uptake parameters, including the mean standardized uptake value of all pixels within bone with SUVs greater than 10 and the average of the mean SUV of all malignant lesions identified by the algorithm. The values of these parameters for the images beginning at ~15 min and ~35 min were significantly different (0.3% change/minute). Differences between the later imaging time points were not significant (P < 0.01). Repeat baseline studies showed high intraclass correlations (>0.9) and relatively low critical percent change (the value above which a change can be considered real) for these parameters. The tumor-to-normal bone ratio, based on the SUVmax of identified malignant lesions, decreased with time; however, this difference was small, estimated at ~0.16%/min in the first hour. Conclusion 18F-NaF PET/CT images obtained with modest radiation exposures can result in highly reproducible imaging parameters. Although the tumor-to-normal bone ratio decreases slightly with time, the high temporal dependence during uptake periods < 30 min may limit accurate quantitation. An uptake period of 60 ± 30 min has limited temporal dependence while maintaining high tumor-to-normal bone ratio.

Purpose: To investigate the factors predicting scan positivity and disease location in patients with biochemical relapse (BCR) prostate cancer (PCa) after primary local therapy using prostatespecific membrane antigen (PSMA)-targeted 18 F-DCFPyL-PET/CT. Methods: This is a two-institution study including 245 BCR PCa patients after primary local therapy and negative conventional imaging. Patients underwent 18 F-DCFPyL-PET/CT. Lesion detection rate and disease location were correlated with patient's tumor characteristics, time from the initial therapy, prostate-specific-antigen (PSA) and PSA doubling time (PSAdt). Multivariate logistic regression analyses were used to determine predictors of a positive scan. Regression-based coefficients were used to develop nomograms predicting scan positivity and extra-pelvic disease.Results: Overall, 79.2% (194/245) of patients had a positive 18 F-DCFPyL-PET/CT, with detection rates of 48.2% (27/56), 74.3% (26/35), 84% (37/44), 96.7% (59/61) and 91.8% (45/49) for PSA <0.5, 0.5 to <1.0, 1.0 to <2.0, 2.0 to <5.0 and ≥5.0 ng/mL, respectively. Patients with lesions confined to the pelvis had lower PSAs than those with distant sites (1.6±3.5 vs. 3.0±6.3 ng/mL, p<0.001). In patients treated with prostatectomy (n=195), 24.1% (47/195) had a negative scan, 46.1% (90/195) showed intra-pelvic disease and 29.7% (58/195) extra-pelvic disease. In the postradiation subgroup (n=50), 18 F-DCFPyL-PET/CTs were always negative at PSA lower than 1.0 ng/mL and extra-pelvic disease was seen only when PSA >2.0 ng/mL. At multivariate analysis, PSA, PSAdt were independent predictive factors of scan positivity and the presence of extra-pelvic disease in post-surgical patients, with area under the curve (AUC) of 78% and 76%, respectively. PSA and PSAdt were independent predictors of the presence of extra-pelvic disease in the postradiation cohort, with AUC of 85%. Time from treatment to scan was significantly longer for prostatectomy-bed-only recurrences than for those with bone or visceral disease (6.2±6.4 vs. 2.4±1.3 years, p<0.001). Conclusion:18 F-DCFPyL-PET/CT offers high detection rates in BCR PCa patients. PSA and PSAdt are able to predict scan positivity and disease location. Furthermore, the presence of bone/visceral lesions are associated with shorter intervals from treatment compared to prostatebed-only recurrences. These tools might guide clinicians to select the most suitable candidates for 18 F-DCFPyL-PET/CT imaging.