To evaluate the patterns of relapse and impact on the intended treatment when using
Ga-prostate-specific membrane antigen (PSMA) ligand positron emission tomography/computed tomography (PET/CT) ...imaging for restaging of disease in patients with biochemical relapse after radical prostatectomy (RP) before salvage radiotherapy (sRT).
In all, 39 patients with biochemical recurrence after RP who had no primary indication for adjuvant RT due to the absence of biologically unfavorable disease (e.g., extracapsular extension, seminal vesicle invasion, positive margins, or lymph node involvement) underwent a
Ga-PSMA ligand PET/CT for planning of sRT.
PET/CT was positive in 84.6% (33/39) of patients. A total of 61 lesions were observed in these patients (on average 1.8 lesions per patient); 30.3% (10/33) of patients had locally recurrent disease in the prostatic bed. The clinical TNM stage (TNM: tumour-lymph nodes-metastasis-classification) was altered in 69.7% (23/33) of patients following PET, resulting in individualized treatment concepts. A prostate-specific antigen (PSA) >1.0 ng/mL was significantly associated with an increased risk of extrapelvic metastatic disease (p = 0.048). The PSA level at the time of PSMA ligand PET/CT correlated with the peak standardized uptake value (SUV
; p = 0.002). According to current clinical guidelines, the remaining 15.4% (6/39) of patients without evidence of disease on PET received sRT with a dose of 66.0 Gy.
Our results suggest that in patients with biochemical recurrence who did not receive early sRT, a
Ga-PSMA ligand PET/CT for restaging of disease allows for tailoring and individualizing treatment. Particularly in patients with PSA levels above 1.0 ng/mL, a
Ga-PSMA ligand PET/CT should be performed for therapy planning, since patients often have metastases not confined to the pelvis.
GaTris(hydroxypyridinone)(THP)-PSMA is a novel radiopharmaceutical for one-step kit-based radiolabelling, based on direct chelation of
Ga
at low concentration, room temperature and over a wide pH ...range, using direct elution from a
Ge/
Ga-generator. We evaluated the clinical detection rates of
GaTHP-PSMA PET/CT in patients with biochemically recurrent prostate cancer after prostatectomy.
Consecutive patients (n=99) referred for evaluation of biochemical relapse of prostate cancer by
GaTHP-PSMA PET/CT were analyzed retrospectively. Patients underwent a standard whole-body PET/CT (1 h p.i.), followed by delayed (3 h p.i.) imaging of the abdomen. PSA-stratified cohorts of positive PET/CT results, standardized uptake values (SUVs) and target-to-background ratios (TBRs) were analyzed, and compared between standard and delayed imaging.
At least one lesion suggestive of recurrent or metastatic prostate cancer was identified on PET images in 52 patients (52.5%). Detection rates of
GaTHP-PSMA PET/CT increased with increasing PSA level: 94.1% for a PSA value of ≥10 ng/mL, 77.3% for a PSA value of 2 to <10 ng/mL, 54.5% for a PSA value of 1 to <2 ng/mL, 14.3% for a PSA value of 0.5 to <1 ng/mL, 20.0% for a PSA value of >0.2 to <0.5, and 22.2% for a PSA value of 0.01 to 0.2 ng/mL.
GaTHP-PSMA uptake (SUVs) in metastases decreased over time, whereas TBRs improved. Delayed imaging at 3 h p.i. exclusively identified pathologic findings in 2% of
GaTHP-PSMA PET/CT scans. Detection rate was higher in patients with a Gleason score ≥8 (P=0.02) and in patients receiving androgen deprivation therapy (P=0.003).
In this study,
GaTHP-PSMA PET/CT showed suitable detection rates in patients with biochemical recurrence of prostate cancer and PSA levels ≥ 2 ng /mL. Detections rates were lower than in previous studies evaluating other PSMA ligands, though prospective direct radiotracer comparison studies are mandatory particularly in patients with low PSA levels to evaluate the relative performance of different PSMA ligands.
ABSTRACT
Pollen starch granules (PSGs) are allergen particles that get into contact with pulmonary surfactant and phagocytes in the terminal airways. In this study, the effects of surfactant protein ...D (SP-D) on the interaction of PSGs with phagocytes and on the pulmonary clearance of PSGs were determined. Fluorescently labeled PSGs were incubated in vitro with murine lung macrophages or dendritic cells (DCs) ± recombinant rat SP-D (rrSP-D). In addition, the effect of SP-D on uptake of PSGs by lung macrophages and DCs was studied in vivo. Furthermore, PSGs were instilled in Balb/c mice and the effects of SP-D on total lung clearance were assessed by optical imaging. SP-D treatment increased the number of PSG-positive macrophages and DCs in vitro. Furthermore, SP-D accelerated uptake/binding by alveolar macrophages and reduced the number of PSG-positive tissue macrophages and DCs at 24 hours. However, SP-D did not affect total lung clearance of PSGs and it did not enhance the T-cell proliferation induced by PSG-positive DCs. In conclusion, SP-D increased PSG-positive cells in vitro and accelerated PSG binding/uptake in vivo. The observed effects were limited to cellular clearance mechanisms and did not affect the total clearance of PSGs from the lung.
From: 15th Annual SCMR Scientific Sessions Orlando, FL, USA 2-5 February 2012 Author details1-Radiology, Hannover Medical School, Hannover, GermanyEMPTY2-Radiology, Johns Hopkins University, ...Baltimore, MD, USAEMPTY3-Division of Cardiology, Johns Hopkins University, Baltimore, MD, USAEMPTY4-Institute for Biometry, Hannover Medical School, Hannover, GermanyEMPTY5-Radiology, Washington University School of Medicine, St Louis, MO, USAEMPTY6-Department of Mathematics, University of California, Los Angeles, Los Angeles, CA, USAEMPTY7-National Institutes of Health, Department of Radiology and Imaging Sciences, Bethesda, MD, USAEMPTY Supplemental Information: The purpose of this study was to quantify the distribution of resting left ventricular (LV) myocardial blood flow (MBF) by MRI and to determine its relationship to important parameters of disease such as LV wall thickness, myocardial delayed enhancement (MDE), T2-signal abnormalities, LV outflow tract obstruction and age.
PDF
