Clinical Impact of Lower-Limb Imaging in ⁶⁸Ga-PSMA PET/CT for Patients with Prostate Cancer

Abstract

Our purpose was to determine whether there is a clinical benefit to add lower-limb imaging in 68 Ga-labeled prostate-specific membrane antigen (PSMA) PET/CT scans for patients with prostate cancer. Methods: In total, 701 patients with prostate cancer who underwent 68 Ga-PSMA PET/CT were evaluated retrospectively. All patients underwent additional lower-limb imaging. Images were reanalyzed by experienced nuclear medicine physicians, and metastatic sites were documented. The prostate-specific antigen (PSA) level and Gleason score were also compared with 68 Ga-PSMA PET/CT findings. Results: In 601 patients (85.7%), at least 1 tumoral lesion was observed on 68 Ga-PSMA PET/CT. The number of patients with bone metastasis in 2 forms was 278 patients (39.6%); 108 (15.4%) were oligometastatic (,4 metastases) and 170 (24.2%) were multimetastatic (≥4 metastases). In lower-limb imaging, bone metastasis was detected in 61 patients (8.7%), the specific locations of which were as follows: middle-distal femur (n 5 54), tibia (n 5 19), fibula (n 5 24), and calcaneus (n 5 1). Lower-limb metastasis was detected mostly in symptom-positive patients (70.1%) but in only 4% of the symptom-negative group. All patients with lower-extremity metastasis also had multiple bone metastases shown on limited whole-body 68 Ga-PSMA PET/CT. The median PSA level was significantly higher in multimetastatic patients with lower-limb metastasis than in those without lower-limb metastasis (P , 0.001, Mann-Whitney U test), but no statistical differences was found in terms of Gleason score (χ 2 5 0.042, P 5 0.837). According to receiver-operatingcharacteristic analysis, PSA has a good predictive value for detecting lower-limb metastasis, with 76.6% sensitivity and 72% specificity (using a reference cutoff PSA level of 24 ng/mL [area under the curve, 0.81; 95% confidence interval, 0.74-0.87]). Conclusion: Lower-limb imaging did not change the metastatic status of disease or significantly affect the therapeutic approach. However, if multimetastatic patients present relevant symptoms for lower-limb metastasis, it could be beneficial to consider including lower-limb imaging for possible palliative therapies.

Total-Body 68Ga-PSMA-11 PET/CT for Bone Metastasis Detection in Prostate Cancer Patients: Potential Impact on Bone Scan Guidelines

“…All but one of these patients had already known extensive bone disease, and planned management was changed in this only one patient. Simsek et al also evaluated the clinical impact of including the lower limbs in 68 Ga-PSMA-11 PET/CT scans for prostate cancer patients (29). They similarly found that lower-limb imaging did not change the metastatic status of disease or significantly affect the therapeutic approach.…”

“…Thus, a significant and useful impact of total-body versus whole-body imaging appears unlikely. Of note, in a symptomatic patient, it could be beneficial to include lower-limb imaging for possible palliative therapies (29).…”

Clinical impact of whole-body 68Ga-PSMA I&T PET/CT: lesion frequency and added benefit in lower extremities

“…These observations were in line with two smaller-scaled studies. Simsek et al reported in 701 PCa patients also low rates (8.7 % , n = 61) of positive lesions in the lower extremities [3]. Similarly, Pomykala et al analyzed 388 PCa patients and reported 5.0 %-rate (n = 18) of positive lesions in the lower extremities [4].…”

“…In these patients multiple metastases in other locations were present. The authors concluded that imaging of the lower extremities were not mandatory due to missing therapeutic consequences [3]. However, these studies were limited by the smaller study cohort.…”

Yüksek Ri̇skli̇ Prostat Kanseri̇nde 68ga-Psma Pet/Bt’ni̇n Tedavi̇ Yöneti̇mi̇ne Etki̇si̇

“…68Ga-PSMA PET-CT was performed at 45-60 min after an intravenous injection of approximately 185 MBq of 68Ga-PSMA on a dedicated PET-CT scanner (Biograph TruePoint PET/CT; Siemens Healthcare. Erlangen, Germany), as we described previously (19). An iodine-based oral contrast agent was administered to all patients.…”