Identification of incidental brain tumors in prostate cancer patients via PSMA PET/CT.

PURPOSE: Brain metastases are rare in patients with prostate cancer and portend poor outcome. Prostate-specific membrane antigen positron emission tomography (PSMA PET)/CT scans including the brain have identified incidental tumors. We sought to identify the incidental brain tumor detection rate of PSMA PET/CT performed at initial diagnosis or in the setting of biochemical recurrence. METHODS: An institutional database was queried for patients who underwent 68Ga-PSMA-11 or 18F-DCFPyL (18F-piflufolastat) PET/CT imaging at an NCI-designated Comprehensive Cancer Center from 1/2018 to 12/2022. Imaging reports and clinical courses were reviewed to identify brain lesions and describe clinical and pathologic features. RESULTS: Two-thousand seven hundred and sixty-three patients underwent 3363 PSMA PET/CT scans in the absence of neurologic symptoms. Forty-four brain lesions were identified, including 33 PSMA-avid lesions: 10 intraparenchymal metastases (30%), 4 dural-based metastases (12%), 16 meningiomas (48%), 2 pituitary macroadenomas (6%), and 1 epidermal inclusion cyst (3%) (incidences of 0.36, 0.14, 0.58, 0.07, and 0.04%). The mean parenchymal metastasis diameter and mean SUVmax were 1.99 cm (95%CI:1.25-2.73) and 4.49 (95%CI:2.41-6.57), respectively. At the time of parenchymal brain metastasis detection, 57% of patients had no concurrent extracranial disease, 14% had localized prostate disease only, and 29% had extracranial metastases. Seven of 8 patients with parenchymal brain metastases remain alive at a median 8.8 months follow-up. CONCLUSION: Prostate cancer brain metastases are rare, especially in the absence of widespread metastatic disease. Nevertheless, incidentally detected brain foci of PSMA uptake may represent previously unknown prostate cancer metastases, even in small lesions and in the absence of systemic disease.

11C-Choline PET/CT in Recurrent Prostate Cancer: Retrospective Analysis in a Large U.S. Patient Series.

Our purpose was to evaluate the performance of 11C-choline PET/CT in detecting biochemically recurrent prostate cancer (PCa) in a large non-European cohort (in the context of emerging evidence for prostate-specific membrane antigen PET in this setting) and to map patterns of PCa recurrence. Methods: We retrospectively analyzed 11C-choline PET/CT scans from 287 patients who were enrolled in an imaging protocol based on rising prostate-specific antigen (PSA) levels (mean, 3.43 ng/mL; median, 0.94 ng/mL; range, 0.15-89.91 ng/mL) and suspected recurrent PCa. A total of 187 patients had undergone primary radical prostatectomy (RP) (79/187 had secondary radiotherapy), 30 had undergone primary radiotherapy, and 70 had a persistent PSA elevation after receiving initial treatment (69 after RP, 1 after radiotherapy). The level of suspicion for recurrence on 11C-choline PET/CT was scored (0, negative; 1, equivocal; 2, positive) by 2 readers. The correlation between 11C-choline PET/CT positivity and initial treatment, Gleason score, National Comprehensive Cancer Network stage, PSA level, PSA doubling time, PSA velocity, and time between initial treatment and PET imaging was evaluated. Prostate Cancer Molecular Imaging Standardized Evaluation (PROMISE) criteria were used to map 11C-choline recurrence patterns. Results: Considering scores 1 and 2 as positives, consensus between the 2 readers deemed 66% of the 11C-choline PET/CT scans as positive. When sorted by PSA level, 45% of patients with a PSA of less than 0.5 ng/mL, 56% of patients with a PSA of 0.5-0.99 ng/mL, 70% of patients with a PSA of 1.0-1.99 ng/mL, and 90% of patients with a PSA of at least 2.0 ng/mL scored either 1 or 2 on 11C-choline PET/CT scans. When considering scores of 2 only, 11C-choline PET/CT positivity was 54% (28%, 46%, 62%, and 81%, respectively, for patients with PSA < 0.5 ng/mL, 0.5-0.99 ng/mL, 1.0-1.99 ng/mL, and ≥ 2.0 ng/mL). In multivariate analysis, only PSA level was significantly associated with scan positivity. Pattern analysis showed that pelvic lymph nodes were the most common site of recurrence, and 28% of patients had 11C-choline-positive suspected recurrences outside the initial treatment field. Conclusion:11C-choline PET/CT can detect PCa recurrence even among patients with low PSA levels when interpretation accounts for the clinical context, providing a certain pretest probability. Until prostate-specific membrane antigen agents are fully approved for PCa, choline PET/CT may provide clinical utility.

Assessment of 68Ga-PSMA-11 PET Accuracy in Localizing Recurrent Prostate Cancer: A Prospective Single-Arm Clinical Trial.

IMPORTANCE: In retrospective studies, 68Ga-PSMA-11 positron emission tomographic (PET) imaging improves detection of biochemically recurrent prostate cancer compared with conventional imaging. OBJECTIVE: To assess 68Ga-PSMA-11 PET accuracy in a prospective multicenter trial. DESIGN, SETTING, AND PARTICIPANTS: In this single-arm prospective trial conducted at University of California, San Francisco and University of California, Los Angeles, 635 patients with biochemically recurrent prostate cancer after prostatectomy (n = 262, 41%), radiation therapy (n = 169, 27%), or both (n = 204, 32%) underwent 68Ga-PSMA-11 PET. Presence of prostate cancer was recorded by 3 blinded readers on a per-patient and per-region base. Lesions were validated by histopathologic analysis and a composite reference standard. MAIN OUTCOMES AND MEASURES: Endpoints were positive predictive value (PPV), detection rate, interreader reproducibility, and safety. RESULTS: A total of 635 men were enrolled with a median age of 69 years (range, 44-95 years). On a per-patient basis, PPV was 0.84 (95% CI, 0.75-0.90) by histopathologic validation (primary endpoint, n = 87) and 0.92 (95% CI, 0.88-0.95) by the composite reference standard (n = 217). 68Ga-PSMA-11 PET localized recurrent prostate cancer in 475 of 635 (75%) patients; detection rates significantly increased with prostate-specific antigen (PSA): 38% for <0.5 ng/mL (n = 136), 57% for 0.5 to <1.0 ng/mL (n = 79), 84% for 1.0 to <2.0 ng/mL (n = 89), 86% for 2.0 to <5.0 ng/mL (n = 158), and 97% for ≥5.0 ng/mL (n = 173, P < .001). Interreader reproducibility was substantial (Fleiss κ, 0.65-0.78). There were no serious adverse events associated with 68Ga-PSMA-11 administration. PET-directed focal therapy alone led to a PSA drop of 50% or more in 31 of 39 (80%) patients. CONCLUSIONS AND RELEVANCE: Using blinded reads and independent lesion validation, we establish high PPV for 68Ga-PSMA-11 PET, detection rate and interreader agreement for localization of recurrent prostate cancer. TRIAL REGISTRATION: ClinicalTrials.gov identifiers: NCT02940262 and NCT03353740.

Coronary artery disease after radiation therapy for Hodgkin's lymphoma: coronary CT angiography findings and calcium scores in nine asymptomatic patients.

OBJECTIVE: Long-term survivors of Hodgkin's lymphoma treated with radiation therapy have an increased incidence of coronary artery disease. The purpose of this study is to describe the coronary CT angiography findings and calcium scores of asymptomatic patients who had mediastinal irradiation for Hodgkin's lymphoma and to evaluate the impact of coronary CT angiography on patient management. MATERIALS AND METHODS: We evaluated nine consecutive patients, age range 35-60 years, who had been treated for Hodgkin's lymphoma by radiation therapy between the ages of 11 and 27 years. The total mediastinal dose ranged from 34 to 45 Gy. All patients were evaluated with 64-MDCT with calcium scoring followed by CT angiography of the coronary arteries. Imaging findings and clinical follow-up were analyzed. RESULTS: Eight of nine patients had coronary artery disease. CT showed long segments of diffuse disease; areas of stenosis from soft plaque; and calcification in the proximal right coronary, left anterior descending, and left circumflex arteries. Calcium scores were significantly higher than in other patients of this age group. Additional tests, including selective coronary angiography, were necessary in patients with diffuse disease with calcifications. CT evaluation led to bypass surgery and angioplasty in two patients. CONCLUSION: Coronary CT angiography and calcium scores are useful tools for evaluation of irradiation-related coronary artery disease. Complementary tests might be necessary in selected patients. Prospective larger studies are needed to better define the role of coronary CT angiography and calcium scores and to establish an algorithm for evaluation and treatment of these patients.