Faculty Bibliography

BACKGROUND:To evaluate whether quantitative craniospinal MRI assessment of baseline tumor burden provides prognostic value in patients with recurrent, previously irradiated medulloblastoma undergoing MEMMAT (Metronomic Antiangiogenic) therapy. METHODS:We analyzed craniospinal MRI of 40 patients with recurrent, previously irradiated medulloblastoma enrolled in the MEMMAT trial (April 1, 2014, and March 31, 2021). Ependymal, leptomeningeal, and local relapse lesions were retrospectively manually segmented on T1-contrast-enhanced (T1CE) and diffusion-weighted imaging (DWI) at baseline and follow-up (best response). Lesion count and volume were quantified. Bland-Altman analyses and intraclass correlation coefficients (ICC) assessed inter-sequence agreement., logistic regression evaluated associations between baseline tumor burden and progressive disease. RESULTS:Patients achieving Complete Response (n = 6/40) showed mean monthly decreases of - 12.7% in T1CE lesion count and - 12.9% in volume. Partial Response patients (n = 9/40) showed similar declines (-10.3% and - 13.0%). Stable Disease patients (n = 5/40) demonstrated minimal decreases (-0.8% and - 2.3%). Progressive Disease patients (n = 16/40) showed increases of 33.7% in lesion count and 56.2% in volume. Logistic regression indicated trends toward higher baseline tumor burden predicting PD (volume OR 1.18, p = 0.08; lesion count OR 1.05, p = 0.075). Agreement between T1CE and DWI was limited (ICC 0.35 for lesion count, 0.47 for volume), with 23% of patients misclassified using either modality alone. Survival analyses demonstrated significantly shorter overall survival in patients with baseline lesion volumes ≥ 5.5 ml (log-rank p = 0.003), while a similar association for progression-free survival did not reach statistical significance (p = 0.053). CONCLUSIONS:Combined intracranial and intraspinal T1CE and intracranial DWI assessment improves response evaluation. Exploratory analyses suggested that higher baseline tumor burden may be associated with progression, although the observed associations were of borderline statistical significance and require validation in larger cohorts.

RATIONALE/BACKGROUND:Ga-PSMA PET/CT in detecting biochemically recurrent prostate cancer and evaluate associations of PET imaging findings with alterations on genomic profiling. METHODS: RESULTS:Ga-PSMA PET/CT was 59.2% (357/603), with a positive predictive value of 0.98 (95% CI, 0.94-0.99), and a sensitivity of 0.60 (95% CI, 0.54-0.66). When analysed by PSA level, 43.8% of patients with PSA < 0.5 ng/mL, 64.1% with PSA 0.5-0.99 ng/mL, 73.6% with PSA 1.0-1.99 ng/mL, and 87% with PSA > 2.0 ng/mL were PET positive. Inter-reader agreement was excellent with κ-coefficient of 0.884. SUVmax was significantly higher in patients with higher PSA (P < 0.001), and extra-pelvic nodal metastases (P < 0.001). Patients with persistently elevated PSA, higher TNM stage, higher Gleason score, and without RT at baseline (all P < 0.001) had shorter time to PCBR. In patients with genetic alteration available, TP53 mutations were significantly associated with time to PCBR (alteration, n = 38; wildtype, n = 200; median time 4.3 versus 5.3 years, P = 0.04), and borderline significantly associated with SUVmax (median 11 versus 7, n = 33 and 121, P = 0.054). CONCLUSION/CONCLUSIONS:

PURPOSE OF THE REPORT/OBJECTIVE:To determine the prevalence, etiology, and clinical significance of incidental focal small bowel FDG uptake in patients undergoing PET/CT for staging of non-small bowel cancers. MATERIAL AND METHODS/METHODS:Retrospective review of consecutive FDG PET/CT examinations obtained for cancer staging with incidental focal small bowel radiotracer uptake was performed. Exclusion criteria included known small bowel pathology or insufficient reference standard. Imaging findings assessed included lesion location, number, CT correlate, SUVmax, and presence of metastases outside the bowel. Clinical data included age, sex, cancer clinical setting, origin, and stage. Focal small bowel FDG uptake etiology (benign vs. metastatic) was determined by composite reference standard (histopathology, clinical, and imaging follow-up). Statistical analyses included Wilcoxon rank-sum test, Pearson's χ2 test, Fisher exact test, and ROC curve analyses. RESULTS:In a review of 147,516 PET/CT examinations, incidental focal small bowel FDG uptake was rare, with a prevalence of 0.1% (88/147,516). Most cases were metastatic, 60.2% (53/88), most commonly spread from lymphoma [32.1% (17/53)] and melanoma [30.2% (16/53)]. Metastatic lesions were evenly distributed throughout the ileum [47.2% (25/53)] and jejunum [39.6% (21/53)]. Metastatic focal small bowel FDG uptake was associated with presence of other sites of distant metastases, higher SUVmax, and presence of a CT correlate (P <0.01). CONCLUSIONS:Incidental focal small bowel FDG uptake is rare. Most small bowel hypermetabolic foci are metastatic and are predominantly encountered with melanoma and lymphoma. Multiple imaging and clinical factors helped differentiate between benign and metastatic focal small bowel FDG uptake.

The mucosal-associated lymphoid tissue (MALT)-International Prognostic Index (IPI) is widely applied to estimate outcomes in patients with extranodal marginal zone lymphoma (EMZL) of MALT. Although it was developed in the context of the IELSG-19 trial exclusively in patients treated with chlorambucil, rituximab, or their combination, it is commonly used across virtually all disease settings. However, its applicability beyond contexts resembling the IELSG-19 trial remains debated, and several studies have proposed modifications to improve prognostic precision in EMZL. Here, we retrospectively analyzed 498 patients with newly diagnosed EMZL at the Medical University of Vienna with the dual objective of evaluating the prognostic performance of the MALT-IPI across clinical subgroups, and to assess whether incorporation of autoimmunity could refine risk stratification. Stratification by the MALT-IPI revealed significantly longer progression-free survival (PFS) and overall survival (OS) in patients who were low-risk compared with intermediate- and high-risk groups (P< .001) in unselected patients. However, in subgroup analyses, its discriminatory capacity was restricted to patients with extragastric disease, particularly patients with EMZL of the ocular adnexa or the parotid gland or intestinal EMZL, as well as those receiving systemic therapy. On the contrary, patients with gastric EMZL or those managed with Helicobacter pylori eradication, local therapy, or watch-and-wait approaches did not derive consistent prognostic separation. Incorporation of autoimmunity identified a small subgroup with inferior PFS and OS, but provided limited incremental prognostic power beyond the established index in most patients. Our results support context-specific applicability of the MALT-IPI, and highlight autoimmunity as a prognostically relevant factor in a small cohort of patients.

Not available.

INTRODUCTION/BACKGROUND:Focal dose intensification strategies targeting the dominant intra-prostatic lesion (DIL) improve outcomes of patients with prostate cancer. The purpose was to determine whether the 6-month multiparametric (mp)MRI response of the DIL is associated with post-treatment prostate-specific antigen (PSA) kinetics after MRI linear accelerator (LINAC) guided stereotactic body radiotherapy (SBRT) with focal dose intensification. METHODS:), and PSA ≤ 1.0 ng/mL. RESULTS:(100.0% vs 82.9%, p = 0.010) and PSA ≤ 1.0 ng/mL (45.9% vs 11.4%, p = 0.001) compared to those without mpMRI CR. In 10 patients without 6-month mpMRI CR but had further MRI follow-up (median 13 months), DILs either further decreased in size (30.0%) or resolved (70.0%). CONCLUSION/CONCLUSIONS:Initial 6-month mpMRI response correlates with PSA kinetics, which is associated with important clinical outcomes. mpMRI can be used for post-SBRT evaluation to gauge local tumor response of the DIL, where most recurrences occur.

OBJECTIVE:Indeterminate lesions on prostate-specific membrane antigen (PSMA)-PET are challenging to address. We aimed to develop, implement, and evaluate a multidisciplinary consensus algorithm that integrates existing interpretation systems with multimodality imaging and clinicopathological information for interpreting indeterminate bone and lymph node lesions on PSMA-PET. MATERIALS AND METHODS/METHODS:This was a retrospective single-center study on a prospectively implemented algorithm. We included all consecutive prostate cancer patients whose PSMA-PET findings for indeterminate bone lesions or lymph nodes were discussed at a multidisciplinary tumor board (MDT) in 2024-2025. An algorithm determining the level of suspicion for metastasis was developed in a multidisciplinary fashion, incorporating lesion location, conventional imaging features, PSMA-PET characteristics, and clinicopathological information. The application of the algorithm and outcomes were documented, compared against a composite reference standard. Comparisons were made with PSMA-RADS and PROMISE V2 PSMA-expression scores. RESULTS:81 patients (median age 68, interquartile range 64-75) were included. Algorithm results were benign (48.1% [39/81]), equivocal (4.9% [4/81]), metastasis (40.7% [33/81]), and mixed (benign and metastatic lesions, 6.2% [5/81]). The algorithm was correct in 94.1% (64 of 68 patients with a sufficient reference standard). The algorithm was discordant with PSMA-RADS in 54.3% (44/81) and with PROMISE V2 PSMA-expression score in 71.6% (58/81). The frequency of equivocal lesions was lower using the algorithm (4.9% [4/81]) compared with PSMA-RADS (53.1% [43/81]) and PSMA-expression score (64.2% [52/81]). CONCLUSION/CONCLUSIONS:A multidisciplinary consensus algorithm for interpreting indeterminate bone lesions and lymph nodes on PSMA-PET was developed and implemented. Integrating clinicopathological information and multimodality imaging in an MDT setting reduced equivocal interpretations. KEY POINTS/CONCLUSIONS:Question While prostate-specific membrane antigen (PSMA)-PET has become essential in the management of prostate cancer, indeterminate bone lesions and lymph nodes remain challenging to address. Findings A multidisciplinary algorithm for interpreting indeterminate bone lesions and lymph nodes on PSMA-PET, incorporating clinicopathological information and multimodality imaging, reduced the frequency of equivocal interpretations. Clinical relevance An algorithm for interpreting indeterminate bone lesions and lymph nodes on PSMA-PET, incorporating clinicopathological information and multimodality imaging in a multidisciplinary tumor board setting, decreases the frequency of equivocal interpretations and can potentially help management decisions.

OBJECTIVE:To develop a tool for the clinical hybrid imaging workflow which combines morphologic and functional measurements. And to quantify the number of clicks saved per positron emission tomography/computed tomography (PET/CT) interpretation. METHODS:A tool was developed where a volume of interest (VOI) is automatically created around line distance measurements. VOI statistics for both PET and CT component, and line distances are generated and displayed. Usage data for the first two months after introduction of the tool was analyzed. RESULTS:Eleven radiologists and nuclear medicine physicians used the tool in 364 PET/CTs. In 19% of examinations, the novel tool was the only tool that needed to be used. The novel combined tool was used 1001 times, whereas the traditional spherical VOI had been placed 1131 times. The usage ratio of new to traditional tool differed significantly between examinations with ≤ 6 annotations (ratio 1.0) versus > 6 annotations (ratio 0.63, p = 0.030). The average number of saved clicks per PET/CT was estimated at 16.5. CONCLUSION/CONCLUSIONS:A novel combined measurement tool for hybrid imaging was implemented and saved on average 16.5 clicks per examination. These improvements contribute to a smoother workflow and demonstrate the positive impact of thoughtful software design in medical practice.

Liquid biopsy helps detect cells and cell-derived metabolites, proteins, nucleic acids, and vesicles that are shed into body fluids by tumors. This diagnostic test requires only approximately 10 mL of blood or urine. It has received considerable attention as a minimally invasive tool for whole-body tumor interrogation for use in patients with cancer. It poses an attractive and potentially cost-effective alternative to invasive tissue sampling through tissue biopsies, especially serial assessments, such as for treatment response evaluation and mutations that occur during cancer treatment. Cell-free and circulating tumor DNA are the most frequently tested liquid biopsy analytes, and have shown promise for cancer screening, assessment of residual disease after treatment, and clinical outcome prediction and prognostication. Whereas liquid biopsy is less sensitive than imaging in early tumor stages, it is more specific and may help detect treatment response earlier than the Response Evaluation Criteria in Solid Tumors, or RECIST. Aimed primarily at radiologists, this review article provides an update on recent developments in the use of liquid biopsy, including findings from landmark clinical trials and U.S. regulatory approvals as companion diagnostic tests for clinical use, particularly in four malignancies: lymphoma, breast cancer, prostate cancer, and melanoma. Finally, current challenges for the clinical implementation of liquid biopsy are discussed.