Contribution of Histopathologic Tissue Composition to Quantitative MR Spectroscopy and Diffusion-weighted Imaging of the Prostate

Purpose To determine associations of metabolite levels derived from magnetic resonance (MR) spectroscopic imaging (ie, hydrogen 1 [(1)H] MR spectroscopic imaging) and apparent diffusion coefficients (ADCs) from diffusion-weighted imaging with prostate tissue composition assessed by digital image analysis of histologic sections. Materials and Methods Institutional ethical review board approved this retrospective study and waived informed consent. Fifty-seven prostate cancer patients underwent an MR examination followed by prostatectomy. One hematoxylin and eosin-stained section of the resected prostate per patient was digitized and computationally segmented into nuclei, lumen, and combination of epithelial cytoplasm and stroma. On each stained section, regions of interest (ROIs) were chosen and matched to the corresponding ADC map and (1)H MR spectroscopic imaging voxels. ADC and two metabolite ratios (citrate [Cit], spermine [Spm], and creatine [Cr] to choline [Cho] and Cho to Cr plus Spm) were correlated with percentage areas of nuclei, lumen, and cytoplasm and stroma for peripheral zone (PZ), transition zone (TZ), and tumor tissue in both zones of the prostate by using a linear mixed-effect model and Spearman correlation coefficient (rho). Results ADC and (Cit + Spm + Cr)/Cho ratio showed positive correlation with percentage area of lumen (rho = 0.43 and 0.50, respectively) and negative correlation with percentage area of nuclei (rho = -0.29 and -0.26, respectively). The Cho/(Cr + Spm) ratio showed negative association with percentage area of lumen (rho = -0.40) and positive association with area of nuclei (rho = 0.26). Percentage areas of lumen and nuclei, (Cit + Spm + Cr)/Cho ratio, and ADC were significantly different (P < .001) between benign PZ (23.7 and 7.7, 8.83, and 1.58 x 10(-3) mm(2)/sec, respectively) and tumor PZ tissue (11.4 and 12.5, 5.13, and 1.20 x 10(-3) mm(2)/sec, respectively). These parameters were also significantly different between benign TZ (20.0 and 8.2, 6.50, and 1.26 x 10(-3) mm(2)/sec, respectively) and tumor TZ tissue (9.8 and 11.2, 4.36, and 1.03 x 10(-3) mm(2)/sec, respectively). Conclusion The observed correlation of (Cit + Spm + Cr)/Cho ratio and ADC of the prostate with its tissue composition indicates that components of this composition, such as percentage luminal area, contribute to the value of these MR parameters. ((c)) RSNA, 2015

Malignant extracranial germ cell tumors in the Netherlands between 1990 and 2018: Stable incidence and improved survival

Background: Population-based studies assessing long-term patterns of incidence and disease characteristics of germ cell tumors (GCTs) in children are scarce. We investigated incidence and survival trends of malignant extracranial GCTs in children using population-based nationwide data from the Netherlands. Methods: All malignant extracranial GCTs diagnosed in patients aged 0–18 years between 1990 and 2018 were selected from the Netherlands Cancer Registry. Incidence rates were calculated as the average annual number of cases per 1 million person-years. Five-year overall survival (OS) was calculated. Results: A total of 815 cases were identified. Gonadal GCTs (n=665, testis n=485, ovarian n=180) were more common than extragonadal GCTs (n=149). Stage distribution for testicular and extragonadal GCTs shifted between 1990 and 2004 and 2005–2018 towards more localized disease. The overall incidence remained stable over time, but a significant increase was noted for extragonadal GCTs in the 0–9 years age group. Survival of extragonadal GCTs (5-year OS 84.1%, 95% CI 77.1–89.1), in particular mediastinal GCTs (5-year OS 66.7%, 95% CI 45.7–81.1), was lower than that of gonadal GCTs (5-year OS testis 95.0%, 95% CI 92.7–96.7;ovary 97.8%, 95% CI 94.2–99.2). The 5-year OS of our entire cohort was 93.6% (95% CI 91.7–95.1). Five-year OS significantly increased from 89.5% (95% CI 86.1–92.2) in 1990–2004–97.4% (95% CI 95.3–98.5) in 2005–2018. Conclusions: Although the incidence of all malignant pediatric extracranial GCTs remained stable during 1990–2018, an increase was observed for extragonadal GCTs in younger children (0–9 years). There was a shift towards more localized disease for testicular and extragonadal GCTs. Five-year OS increased over time exceeding 90% (91.4%, 95% CI 82.7–95.8) in the most recent diagnostic period. Mediastinal GCTs had the lowest OS, supporting the need for future research

A randomised, blinded, trial of clopidogrel versus aspirin in patients at risk of ischaemic events (CAPRIE). CAPRIE Steering Committee

Many clinical trials have evaluated the benefit of long-term use of antiplatelet drugs in reducing the risk of clinical thrombotic events. Aspirin and ticlopidine have been shown to be effective, but both have potentially serious adverse effects. Clopidogrel, a new thienopyridine derivative similar to ticlopidine, is an inhibitor of platelet aggregation induced by adenosine diphosphate. METHODS: CAPRIE was a randomised, blinded, international trial designed to assess the relative efficacy of clopidogrel (75 mg once daily) and aspirin (325 mg once daily) in reducing the risk of a composite outcome cluster of ischaemic stroke, myocardial infarction, or vascular death; their relative safety was also assessed. The population studied comprised subgroups of patients with atherosclerotic vascular disease manifested as either recent ischaemic stroke, recent myocardial infarction, or symptomatic peripheral arterial disease. Patients were followed for 1 to 3 years. FINDINGS: 19,185 patients, with more than 6300 in each of the clinical subgroups, were recruited over 3 years, with a mean follow-up of 1.91 years. There were 1960 first events included in the outcome cluster on which an intention-to-treat analysis showed that patients treated with clopidogrel had an annual 5.32% risk of ischaemic stroke, myocardial infarction, or vascular death compared with 5.83% with aspirin. These rates reflect a statistically significant (p = 0.043) relative-risk reduction of 8.7% in favour of clopidogrel (95% Cl 0.3-16.5). Corresponding on-treatment analysis yielded a relative-risk reduction of 9.4%. There were no major differences in terms of safety. Reported adverse experiences in the clopidogrel and aspirin groups judged to be severe included rash (0.26% vs 0.10%), diarrhoea (0.23% vs 0.11%), upper gastrointestinal discomfort (0.97% vs 1.22%), intracranial haemorrhage (0.33% vs 0.47%), and gastrointestinal haemorrhage (0.52% vs 0.72%), respectively. There were ten (0.10%) patients in the clopidogrel group with significant reductions in neutrophils (< 1.2 x 10(9)/L) and 16 (0.17%) in the aspirin group. INTERPRETATION: Long-term administration of clopidogrel to patients with atherosclerotic vascular disease is more effective than aspirin in reducing the combined risk of ischaemic stroke, myocardial infarction, or vascular death. The overall safety profile of clopidogrel is at least as good as that of medium-dose aspirin