This analysis suggests that delaying biopsy to allow additional PSA testing can provide useful information about PSA trends. The study found that the potential reduction in unnecessary biopsies by observing subsequent PSA trends was 72-80%. PSA trends that showed substantial deceleration or decreases were less likely to require biopsy. The fastest growth in PSA per year, over 100% increase, was the most likely to see decreases and had the potential for a 93% reduction in biopsies. Higher annual exponential growth rates in cancer PSA were significantly associated with increased all-cause and cancer-specific mortality in a large cohort, indicating faster growing cancers were more deadly. Observing PSA trends may help distinguish potentially deadly cancers warranting early