Nathan, Mark A.

Radiologists are uniquely positioned to play a critical role in the detection, surveillance, and characterization of hereditary abdominal cancer syndromes.

Evaluate the quantitative, subjective (Deauville score [DS]) and reader agreement differences between standard ordered subset expectation maximization (OSEM) and Bayesian penalized likelihood (BPL) positron emission tomography (PET) reconstruction methods. A retrospective review of 104 F-18 fluorodeoxyglucose PET/computed tomography (CT) exams among 52 patients with diffuse large B-cell lymphoma. An unblinded radiologist moderator reviewed both BPL and OSEM PET/CT exams. Four blinded radiologists then reviewed the annotated cases to provide a visual DS for each annotated lesion. Significant (P < .001) differences in BPL and OSEM PET methods were identified with greater standard uptake value (SUV) maximum and SUV mean for BPL. The DS was altered in 25% of cases when BPL and OSEM were reviewed by the same radiologist. Interobserver DS agreement was higher for OSEM (>1 cm lesion = 0.89 and ≤1 cm lesion = 0.84) compared to BPL (>1 cm lesion = 0.85 and ≤1 cm lesion = 0.81). Among the 4 readers, average intraobserver visual DS agreement between OSEM and BPL was 0.67 for lesions >1cm and 0.4 for lesions ≤1 cm. F-18 Fluorodeoxyglucose PET/CT of diffuse large B-cell lymphoma reconstructed with BPL has higher SUV values, altered DSs and reader agreement when compared to OSEM. This report finds volumetric PET measurements such as metabolic tumor volume to be similar between BPL and OSEM PET reconstructions. Efforts such as adoption of European Association Research Ltd accreditation should be made to harmonize PET data with an aim at balancing the need for harmonization and sensitivity for lesion detection.

Abstract Purpose: Outcomes for resistant metastatic castration-resistant prostate cancer (CRPC) are poor. Stereotactic ablative radiotherapy (SABR) induces antitumor immunity in clinical and preclinical studies, but immunologic biomarkers are lacking. Patients and Methods: Eighty-nine patients with oligometastatic CRPC were identified by 11C-Choline-PET (Choline-PET) from August 2016 to December 2019 and treated with SABR. Prespecified coprimary endpoints were 2-year overall survival (OS) and PSA progression. Secondary endpoints included 2-year SABR-treated local failure and 6-month adverse events. Correlative studies included peripheral blood T-cell subpopulations before and after SABR. Results: 128 lesions in 89 patients were included in this analysis. Median OS was 29.3 months, and 1- and 2-year OS were 96% and 80%, respectively. PSA PFS was 40% at 1 year and 21% at 2 years. Local PFS was 84.4% and 75.3% at 1 and 2 years, respectively, and no grade ≥3 AEs were observed. Baseline high levels of tumor-reactive T cells (TTR; CD8+CD11ahigh) predicted superior local, PSA, and distant PFS. Baseline high levels of effector memory T cells (TEM; CCR7−CD45RA−) were associated with improved PSA PFS. An increase in TTR at day 14 from baseline was associated with superior OS. Conclusions: This is the first comprehensive effector T-cell immunophenotype analysis in a phase II trial before and after SABR in CRPC. Results are favorable and support the incorporation of immune-based markers in the design of future randomized trials in patients with oligometastatic CRPC treated with SABR.

The use of immune checkpoint inhibitors has been increasing rapidly. Numerous untoward immune-related adverse events due to immune checkpoint inhibitors have been reported. Acute interstitial nephritis due to immune checkpoint inhibitors is one of these immune-related adverse events. Although gold standard, it is not always straightforward to perform a kidney biopsy in oncological patients. Helpful diagnostic methods are lacking. In this case report, we discuss the potential role of positron emission tomography–computed tomography on supporting the diagnosis of acute interstitial nephritis or ruling it out in the setting of acute kidney injury following treatment with immune checkpoint inhibitors. Studies are needed to assess the possible role of positron emission tomography–computed tomography for the diagnosis of acute interstitial nephritis in these subjects.

SummaryObjectiveEvidence on the diagnostic performance of adrenal imaging is limited. We aimed to assess the diagnostic performance of unenhanced computed tomography (CT) and 18F‐fluorodeoxyglucose (18FDG) positron emission tomography (PET)/CT imaging in a high‐risk population for adrenal malignancy using an optimal reference standard.DesignRetrospective cohort study.MethodsImaging studies of patients with adrenal nodules who underwent adrenal biopsy and/or adrenalectomy between 1994 and 2014 were reviewed and compared to the reference standard of histology. Eighty % of patients presented with known or suspected extra‐adrenal malignancy.ResultsUnenhanced abdominal CT was performed in 353 patients with adrenal lesions; median size was 3 (0.7‐15) cm and median radiodensity was 33 (−21‐78) Hounsfield units (HU). Radiodensity of >10 HU diagnosed malignancy with a sensitivity of 100%, specificity of 33%, positive predictive value (PPV) of 72% and negative predictive value (NPV) of 100%. 18FDG‐PET/CT was performed in 89 patients; median tumour size was 2.1 (0.7‐9.2) cm. Maximum standardized uptake (SUV max) was higher in malignant lesions when compared to benign lesions (median=10 [2.3‐29.4] vs 3.7 [1.4‐24.5], respectively, P<.0001). Similarly, median SUV max lesion to SUV max liver ratio (ALR) in malignant lesions was higher than in benign lesions (median=3 [0.74‐13.4] vs 1.2 [0.5‐6.6], respectively, P<.0001). 18FDG‐PET/CT ALR >1.8 diagnosed malignancy with a sensitivity of 87%, specificity of 84%, PPV of 85% and NPV of 86%.ConclusionNoncontract CT radiodensity of ≤10 HU excludes malignancy even in a high‐risk population. For indeterminate adrenal lesions, given a superior specificity, 18FDG‐PET/CT could be considered as a second stage imaging study.

SummaryObjectiveThe role of percutaneous adrenal biopsy in a high‐risk population for adrenal malignancy has not been fully investigated. Our aim was to describe the clinical presentation leading to the adrenal biopsy and evaluate the diagnostic performance, complications and non diagnostic rate of adrenal biopsy.DesignSingle‐centre, retrospective cohort study.Patients and MeasurementsMedical records of patients who underwent adrenal biopsy between 1994 and 2014 were reviewed. Adrenal biopsy outcome was compared to a predefined reference standard.ResultsBiopsy was performed in 418 patients [62% men, median age 69 years (range, 15–91)] on 419 adrenal lesions, median size 3·1 cm (range, 0·6–24). The main indication for adrenal mass biopsy was (349/419, 83%) suspected adrenal metastasis from a known or suspected extra‐adrenal primary source. Only 116 of 419, 28% of cases had prebiopsy biochemical testing for pheochromocytoma. Biopsy‐related complications occurred in 4% of the patients. Histology revealed a metastasis in 231 of 419 (55%), benign adrenal tissue in 137 of 419 (33%), adrenocortical carcinoma in eight of 419 (2%), other lesions in 23 of 419 (5%) including seven cases of pheochromocytoma and six cases of infectious process. Biopsy was nondiagnostic in 20 of 419 (5%). All adrenal masses with unenhanced radiodensity ≤10 HU (42/137, 31%) proved to be benign adrenal adenomas. Adrenal biopsy diagnosed malignancy with a sensitivity of 88·5%, specificity of 91·5%, positive predictive value of 93·4% and negative predictive value of 85·5%.ConclusionWhen used in the appropriate clinical setting, adrenal biopsy is a powerful tool in the diagnostic algorithm of the evaluation of adrenal masses with features suspicious for malignancy. Efforts to increase awareness to perform biochemical testing for pheochromocytoma prior to adrenal biopsy are needed.

AbstractProstate cancer is the most common non‐cutaneous malignancy among men in the Western world, and continues to be a major health problem. Imaging has recently become more important in the clinical management of prostate cancer patients, including diagnosis, staging, choice of optimal treatment strategy, treatment follow up and restaging. Positron emission tomography, a functional and molecular imaging technique, has opened a new field in clinical oncological imaging. The most common positron emission tomography radiotracer, 18F‐fluorodeoxyglucose, has been limited in imaging of prostate cancer. Recently, however, other positron emission tomography tracers, such as 11C‐acetate and 11C‐ or 18F‐choline, have shown promising results. In the present review article, we overview the potential and current use of positron emission tomography or positron emission tomography/computed tomography imaging employing the four most commonly used positron emission tomography radiotracers, 18F‐fluorodeoxyglucose, 11C‐acetate and 11C‐ or 18F‐choline, for imaging evaluation of prostate cancer.