Safety of Prostatic Artery Embolization via Transradial Access versus Transfemoral Access.

PURPOSE: To compare prostatic artery embolization (PAE) via transradial access (TRA-PAE) versus transfemoral access (TFA-PAE) to assist access selection. MATERIAL AND METHODS: Procedural outcomes and adverse events were evaluated in 998 patients who underwent PAE at a single center from April 2014 to August 2022; 821 (82%) underwent TRA-PAE (Group R) and 177 (18%) underwent TFA-PAE (Group F). Mean age and prostate size of Groups R and F were 69.2 years (SD ± 8.4) and 117.4 g (SD ± 63.1) and 75.2 years (SD ± 12.1) and 127.2 g (SD ± 83.6), respectively (P < .01 and P = .16; postpropensity matching: P = .38 and P = .35, respectively). Indications for PAE included lower urinary tract symptoms, acute or chronic urinary retention, and hematuria. Procedural and patient-specific metrics were reviewed. Technical success was defined as bilateral PAE. Adverse events were recorded according to the Society of Interventional Radiology (SIR) adverse events classification. Statistical significance was defined as P < .05. RESULTS: Technical success was achieved in 798 (97.2%) patients in Group R and 165 (93.2%) patients in Group F. Mean procedural time, single- and continuous-rotation fluoroscopy time, dose area product, and air kerma were significantly lower in Group R than in Group F (P < .001). Moreover, 6 (0.7%) patients in Group R and 9 (5.5%) patients in Group F had access site ecchymoses, whereas 5 (0.6%) patients in Group R and 6 (3.6%) in Group F had access site hematomas. Two patients experienced transient ischemic attacks (TIAs) after TRA-PAE and recovered without intervention. Two occult radial artery occlusions were noted, but no patient experienced hand ischemia. CONCLUSIONS: In a large single interventional radiologist cohort, TRA-PAE demonstrated similar technical success to that of TFA-PAE with lower access site hemorrhagic complications and radiation requirements; however, TIA and occult radial artery occlusions remain a concern.

For Hepatocellular Carcinoma Treated with Yttrium-90 Microspheres, Dose Volumetrics on Post-Treatment Bremsstrahlung SPECT/CT Predict Clinical Outcomes.

In transarterial radioembolization (TARE) of hepatocellular carcinoma (HCC) with Yttrium-90 (Y-90) microspheres, recent studies correlate dosimetry from bremsstrahlung single photon emission tomography (SPECT/CT) with treatment outcomes; however, these studies focus on measures of central tendency rather than volumetric coverage metrics commonly used in radiation oncology. We hypothesized that three-dimensional (3D) isodose coverage of gross tumor volume (GTV) is the driving factor in HCC treatment response to TARE and is best assessed using advanced dosimetry techniques applied to nuclear imaging of actual Y-90 biodistribution. We reviewed 51 lobar TARE Y-90 treatments of 43 HCC patients. Dose prescriptions were 120 Gy for TheraSpheres and 85 Gy for SIR-Spheres. All patients underwent post-TARE Y-90 bremsstrahlung SPECT/CT imaging. Commercial software was used to contour gross tumor volume (GTV) and liver on post-TARE SPECT/CT. Y-90 dose distributions were calculated using the Local Deposition Model based on post-TARE SPECT/CT activity maps. Median gross tumor volume (GTV) dose; GTV receiving less than 100 Gy, 70 Gy and 50 Gy; minimum dose covering the hottest 70%, 95%, and 98% of the GTV (D70, D95, D98); mean dose to nontumorous liver, and disease burden (GTV/liver volume) were obtained. Clinical outcomes were collected for all patients by chart and imaging review. HCC treatment response was assessed according to the modified response criteria in solid tumors (mRECIST) guidelines. Kaplan-Meier (KM) survival estimates and multivariate regression analyses (MVA) were performed using STATA. Median survival was 22.5 months for patients achieving objective response (OR) in targeted lesions (complete response (CR) or partial response (PR) per mRECIST) vs. 7.6 months for non-responders (NR, stable disease or disease progression per mRECIST). On MVA, the volume of underdosed tumor (GTV receiving less than 100 Gy) was the only significant dosimetric predictor for CR (p = 0.0004) and overall survival (OS, p = 0.003). All targets with less than CR (n = 39) had more than 20 cc of underdosed tumor. D70 (p = 0.038) correlated with OR, with mean D70 of 95 Gy for responders and 60 Gy for non-responders (p = 0.042). On MVA, mean dose to nontumorous liver trended toward significant association with grade 3+ toxicity (p = 0.09) and correlated with delivered activity (p < 0.001) and burden of disease (p = 0.05). Dosimetric models supplied area under the curve estimates of > 0.80 predicting CR, OR, and ≥grade 3 acute toxicity. Dosimetric parameters derived from the retrospective analysis of post-TARE Y-90 bremsstrahlung SPECT/CT after lobar treatment of HCC suggest that volumetric coverage of GTV, not a high mean or median dose, is the driving factor in treatment response and that this is best assessed through the analysis of actual Y-90 biodistribution.