Diagnostic Performance of PSMA-Based 18 F-DCFPyL PET/CT in Prostate Cancer Patients After Definitive Treatment With PSA Level ≤0.2 ng/mL.

PURPOSE: The aim of this study was to investigate the role of 18 F-DCFPyL PET/CT in the evaluation of prostate cancer (PC) patients after definitive treatment and with low-level prostate-specific antigen (PSA) level of ≤0.2 ng/mL. PATIENTS AND METHODS: This retrospective study was conducted in PC patients who received definitive treatments with PSA level of ≤0.2 ng/mL and underwent 18 F-DCFPyL PET/CT within a 1-week interval of PSA examination, and without interval treatment change or history of other cancer. Patient and tumor characteristics at initial diagnosis, treatment regimens, and findings on 18 F-DCFPyL PET/CT were collected. Patients with minimal 6-month (median, 11 months; range, 6-21 months) follow-up or definitive biopsy results of the suspected PET/CT findings were included. Imagine findings were reached with consensus among experienced board-certified nuclear medicine physicians. Comprehensive follow-up and/or biopsy results were used as definitive determination of presence or absence of disease. Comparisons between groups of positive and negative 18 F-DCFPyL PET/CT were done by using descriptive statistics. RESULTS: A total of 96 18 F-DCFPyL PET/CTs from 93 patients met the inclusion criteria. The median Gleason score (GS) of positive group is 8 (range, 6-10), whereas negative group is 7 (range, 6-10). The median age of positive group is 71 (range, 50-90), whereas negative group is 69 (range, 45-88). There were 49 positive (51%) and 47 negative 18 F-DCFPyL PET/CTs (49%). Detection rates at PSA level of ≤0.1 and 0.2 ng/mL were 58.7% (27/46) and 44% (22/50), respectively. The scan-based sensitivity, specificity, positive predictive value, and negative predictive value are 100%, 95%, 96%, and 100% in group with PSA level of ≤0.1 ng/mL, and 100%, 97%, 95%, and 100% in group with PSA level of 0.2 ng/mL, respectively. Sites of involvement on positive 18 F-DCFPyL PET/CTs were prostate bed, pelvic lymph nodes, bone, chest and supraclavicular lymph nodes, lung, and adrenal glands. The SUV max value on positive lesions ranged from 1.9 to 141.4; the smallest positive lymph node was 0.4 cm. High GS of 8-10, known metastatic status (M1), presence of extraprostatic extension, presence of seminal vesicle invasion, and very high-risk PC are significantly associated with positive 18 F-DCFPyL PET/CT results ( P < 0.05). Of all analyzed treatment regimes, upfront surgery (radical prostatectomy with or without pelvic lymph node dissection) had strong correlation with negative PET/CT results ( P < 0.001). If patients received ADT only, or ADT plus chemotherapy, the PET/CT results were most likely positive ( P = 0.026). For other treatment regimes, there were no statistical differences between the groups ( P > 0.05). CONCLUSIONS: In the presence of low PSA level in PC patients after definitive treatment, 18 F-DCFPyL PET/CT is most beneficial in detection of disease in patients with GS of 8 or higher at the time of diagnosis, and the ones who have history of ADT only, or ADT plus chemotherapy. There is excellent negative prediction value of 18 F-DCFPyL PET/CT. However, there is no cutoff PSA level for 18 F-DCFPyL PET/CT indication and no correlation between PSA level and SUV max of positive lesions on 18 F-DCFPyL PET/CT.

Comparison of PSMA-based 18F-DCFPyL PET/CT and Tc-99m MDP bone scan in detection of bone metastasis in prostate cancer.

While Tc-99m MDP bone scan (BS) remains the conventional standard for detection of bone metastasis in prostate cancer, newly FDA-approved imaging with PSMA-based 18F-DCFPyL PET/CT has shown promise for early detection of metastatic disease. However, a paucity of data remains in the diagnostic accuracy of PSMA PET/CT in detecting bone metastasis compared to BS. This retrospective study included 91 patients who received both BS and PSMA PET/CT within a 3-month interval from August 2021 to February 2022. Separate concurrent primary cancer, interval PSA levels greater than a 2-fold difference (or absolute difference >1 ng/ml) between the two studies were excluded. All abnormal bone lesions on either scan were compared. The findings were verified by pathological findings and/or 6-month clinical follow-up. High concordance (78%) was found between modalities with discordant findings (20/91, 22%) demonstrating more false positives (4/20, 20%) and false negatives (3/20, 15%) on BS compared to PET/CT. Additionally, more bone metastases were detected on PSMA PET/CT (13/20, 65%) with all true positive BS lesions also detected PET/CT. The sensitivity, specificity, PPV and NPV for BS were 89%, 91%, 80%, and 95% respectively; and 100%, 97%, 93%, and 100% for 18F-DCFPyL PET/CT respectively. Our results demonstrate that 18F-DCFPyL PET/CT identified more bone metastases while also identifying all bone metastases identified on BS. With the added diagnostic value of detecting primary tumor and soft tissue metastasis, 18F-DCFPyL PET/CT may render BS unnecessary to investigate bone metastases in patients with prostate cancer.

Acetabular Reconstruction With the Medial Protrusio Technique for Complex Primary and Revision Total Hip Arthroplasties.

BACKGROUND: In the setting of acetabular deficiency during total hip arthroplasty (THA), the medial protrusio technique (MPT) allows for increased component coverage while avoiding excessive component abduction or elevation of the hip center. The technique involves controlled reaming through the medial acetabular wall while maintaining the continuity of the anterior and posterior columns. The purpose of this study is to analyze the results of the largest reported series to date of primary and revision THAs using the MPT. METHODS: A retrospective review of THAs performed by a single surgeon from July 2004 to July 2010 identified 102 patients who underwent THA necessitating the use of the MPT (primary 86 and revision 16), with at least 2 years follow-up. RESULTS: This study reports the largest series to date of primary and revision THAs using the MPT for acetabular deficiency. Postoperatively, mean Harris hip score was 86 (range 31-96). There was no correlation with degree of medialization and change in Harris hip score (P = .12). At mean follow-up of 41.1 months (range 24-92 months), there were no intrapelvic structure injuries and no acetabular components required revision. The MPT provided a safe and effective method for addressing acetabular deficiency and avoiding component malposition. CONCLUSION: The MPT provided a safe and effective method for addressing acetabular deficiency in this large series of patients. The technique was successful at improving component coverage while maintaining an anatomic hip center and avoiding excessive component abduction. Fixation remained durable with no cases of loosening at final follow-up.