Prosteria - National Trends and Outcomes of More Frequent Than Guideline Recommended Prostate Specific Antigen Screening.

OBJECTIVE: To characterize national trends in and associated outcomes of more often than annual prostate-specific antigen (PSA) screening, which we term "prosteria." METHODS: Men in the Optum Clinformatics Data Mart with ≥2 years from first PSA test to censoring at the end of insurance or available data (January 2003 to June 2019) or following exclusionary diagnoses or procedures, such as PCa treatment, were included. PSAs within 90 days were treated as one PSA. Prosteria was defined as having ≥3 PSA testing intervals of ≤270 days. RESULTS: A total of 9,734,077 PSAs on 2,958,923 men were included. The average inter-PSA testing interval was 1.5 years, and 4.5% of men had prosteria, which increased by 0.53% per year. Educated, wealthy, non-White patients were more likely to have prosteria. Men within the recommended screening age (ie 55-69) had lower rates of prosteria. Prosteria patients had higher average PSA values (2.5 vs 1.4 ng/mL), but lower values at PCa diagnosis. Prosteria was associated with biopsy and PCa diagnosis; however, there were comparable rates of treatment within 2 years of diagnosis. CONCLUSION: In this large cohort study, prosteria was common, increased over time, and was associated with demographic characteristics. Importantly, there were no clinically meaningful differences in PSA values at diagnosis or rates of early treatment, suggesting prosteria leads to both overdiagnosis and overtreatment. These results support current AUA and USPTF guidelines and can be used to counsel men seeking more frequent PSA screening.

Resource-ratio theory applied to large herbivores.

The theoretical description of exploitation competition, known as resource competition theory (RCT) or resource-ratio theory, has been tested in terrestrial plant communities and microorganisms in laboratory cultures. Applications in animal ecology have been rare, although the theory itself is generic. A major difficulty is that the description of resources in RCT is fundamentally different from that used in classical studies of animal competition. In presenting the first fully specified RCT models for terrestrial animals, we distinguish between positive attributes (mineral elements) and negative attributes (plant defenses) as indicators of quality in animal resources. Using the latter we apply RCT to ungulate communities that exploit just two resources: the cell wall and cell contents of plant material. We show how coexistence in the same habitats depends on the strategy of resource exploitation. Ungulate species that differ in body size adopt a "demand-minimizing" strategy that permits them to coexist on ratios of the two resources by acquiring less of the resource that most limits their competitor. Ungulates that differ in mouth width adopt an "extraction-maximizing" strategy that leads to competitive exclusion because they acquire more of the resource that most limits their competitor. We conclude that differential resource utilization permits grazing herbivores of different body size to coexist on the same grassland habitats, but that the full diversity of grazing communities depends on spatial heterogeneity in plant defenses at the landscape level.