Nuclear Medicine

Quantitative PSMA PET/CT improves prediction of extraprostatic extension

In 223 intermediate/high-risk prostate cancer patients, quantitative PSMA PET/CT parameters improved local T-staging versus visual miT-stage alone. Longest capsule contact was the only independent imaging predictor of pT3a disease on multivariable analysis. For ≥ pT3b disease, models combining miT-stage, longest capsule contact, and PSMA-vol achieved an AUC of 0.79. These data support routinely reporting quantitative capsular contact and PSMA-vol to refine extraprostatic extension risk and surgical planning. 1

[11C]Choline PET/CT as first-line imaging is cost-effective in pHPT

A decision-tree cost-utility model compared first-line [11C]choline PET/CT with a stepwise cervical ultrasound plus MIBI SPECT/CT pathway in primary hyperparathyroidism. Using trial-based diagnostic performance and a 24-year horizon, [11C]choline PET/CT produced higher QALYs at lower total costs (€10,394 vs €10,907). The incremental cost-utility ratio of -€18,846/QALY indicated [11C]choline PET/CT was both less costly and more effective in this centre. Sensitivity analyses showed cost-effectiveness was most sensitive to [11C]choline PET/CT price, and shared R code allows local adaptation. 2

[225Ac]Ac-PSMA-617 shows activity after [177Lu]Lu-PSMA failure in mCRPC

Eighteen mCRPC patients intolerant or refractory to [177Lu]Lu-PSMA received 1–5 cycles of [225Ac]Ac-PSMA-617 with mean 6.1 MBq per cycle. Any PSA decline occurred in 72%, with ≥50% and ≥80% PSA reductions in 56% and 39%, and disease control on PSMA PET in 39%. Median progression-free and overall survival were 4 and 17 months respectively after starting [225Ac]Ac-PSMA-617. Toxicity was mostly grade I–III, anemia was the main hematologic event, and xerostomia occurred in all patients. Longer prior [177Lu]Lu-PSMA exposure and deeper PSA responses correlated with longer progression-free survival. 3