The feasibility of in vivo quantitative imaging in (223)Ra therapy was confirmed. The lesion uptake of (223)Ra-dichloride was significantly correlated with that of (99m)Tc-MDP. The D RBE to lesions per unit administered activity was much higher than that of other bone-seeking radiopharmaceuticals, but considering a standard administration of 21 MBq (six injections of 50 kBq/kg to a 70-kg patient), the mean cumulative value of D RBE was about 19 Gy, and was therefore in the range of those of other radiopharmaceuticals. The macrodosimetry of bone metastases in treatments with (223)Ra-dichloride is feasible, but more work is needed to demonstrate its helpfulness in predicting clinical outcomes.

Purpose To combine peripheral blood indices and clinical factors in a prognostic score for metastatic castration-resistant prostate cancer (mCRPC) patients treated with radium-223 dichloride ([223Ra]RaCl2). Patients and methods Baseline neutrophil-to-lymphocyte ratio (NLR), derived NLR (donor), lymphocyte-to-monocyte ratio (LMR), platelet-to-lymphocyte ratio (PLR), systemic inflammation index (SII), Eastern Cooperative Oncology Group performance status (ECOG PS), Gleason score (GS) group, number of bone metastases, prostate-specific antigen (PSA), alkaline phosphatase (ALP), line of therapy, previous chemotherapy, and the presence of lymphadenopathies were collected from seven Italian centers between 2013 and 2020. Lab and clinical data were assessed in correlation with the overall survival (OS). Inflammatory indices were then included separately in the multivariable analyses with the prognostic clinical factors. The model with the highest discriminative ability (c-index) was chosen to develop the BIO-Ra score. Results Five hundred and nineteen mCRPC patients (median OS: 19.9 months) were enrolled. Higher NLR, dNLR, PLR, and SII and lower LMR predicted worse OS (all with a p < 0.001). The multivariable model including NLR, ECOG PS, number of bone metastases, ALP, and PSA (c-index: 0.724) was chosen to develop the BIO-Ra score. Using the Schneeweiss scoring system, the BIO-Ra score identified three prognostic groups (36%, 27.3%, and 36.6% patients, respectively) with distinct median OS (31, 26.6, and 9.6 months, respectively; hazard ratio: 1.62, p = 0.008 for group 2 vs. 1 and 5.77, p < 0.001 for group 3 vs. 1). Conclusions The BIO-Ra score represents an easy and widely applicable tool for the prognostic stratification of mCRPC patients treated with [223Ra]RaCl2 with no additional costs.

Radium-223 has improved overall survival (OS) and reduced symptomatic skeletal events (SSE) in patients with metastatic castration-resistant prostate cancer (mCRPC) and bone metastases (ALSYMPCA trial). Our aim was to assess clinical and biochemical factors related to survival, safety and survival outcomes of Radium-223 in a clinical practice setting. We retrospectively analysed 32 mCRPC patients treated with Radium-223, assessing bone scan, pain reduction, alkaline phosphatase (ALP) and prostate-specific antigen (PSA) response (≥30% reduction). At scintigraphic assessment, 41% had partial response with a disease control rate of 91%; 56% had ALP response and 25% had PSA response; 41% had pain reduction with pain control of 72%. Scintigraphic response and stability were correlated with longer median progression-free survival (mPFS) (13 and 12 vs. 6 months; P=0.002) and mOS (16 and 12 vs. 6 months; P=0.003). ALP response was associated with longer mPFS (13 vs. 12 months; P=0.2) and mOS (16 vs. 12 months; P=0.2). PSA response was associated with longer mPFS (13 vs. 12 months; P=0.02), whereas mOS could not be computed. Pain response and stability were associated with survival benefit according to mPFS (13 and 12 vs. 9 months) and mOS (both 16 vs. 12 months) without statistical significance. Baseline ALP <220 UI/l, Eastern Cooperative Oncology Group (ECOG) performance status 0 and absence of previous chemotherapy correlated with statistically significantly longer survival outcomes. Skeletal-related events (SRE) occurred in three patients and median time to first SRE was 9.5 months, mPFS was 12 months and mOS 14 months. G3-G4 toxicities developed in 16% of patients. Our results are in line with those reported in the pivotal trial and in other retrospective studies. In conclusion, Radium-223 was associated with high scintigraphic, biochemical and pain response rates and was tolerated well by most patients. Response to Radium-223 and better baseline factors correlated to longer survival in clinical practice experience as in the clinical trial setting.

Supermagnetic Iron Oxide Nanoparticles (SPIONs) are nanoparticles that have an iron oxide core and a functionalized shell. SPIONs have recently raised much interest in the scientific community, given their exciting potential diagnostic and theragnostic applications. The possibility to modify their surface and the characteristics of their core make SPIONs a specific contrast agent for magnetic resonance imaging but also an intriguing family of tracer for nuclear medicine. An example is 68Ga-radiolabeled bombesin-conjugated to superparamagnetic nanoparticles coated with trimethyl chitosan that is selective for the gastrin-releasing peptide receptors. These receptors are expressed by several human cancer cells such as breast and prostate neoplasia. Since the coating does not interfere with the properties of the molecules bounded to the shell, it has been proposed to link SPIONs with antibodies. SPIONs can be used also to monitor the biodistribution of mesenchymal stromal cells and take place in various applications. The aim of this review of literature is to analyze the diagnostic aspect of SPIONs in magnetic resonance imaging and in nuclear medicine, with a particular focus on sentinel lymph node applications. Moreover, it is taken into account the possible toxicity and the effects on human physiology to determine the SPIONs' safety.Keywords SPION . Iron oxide nanoparticles . Review . 68Ga-radiolabeled bombesin . Molecular imaging * Viviana Frantellizzi