Browsing by Author "Pylväläinen, Juho"

Background MRI (magnetic resonance imaging) of the prostate has become increasingly common in prostate cancer diagnostics. How clinicians should proceed after a non-suspicious MRI result is still unclear. This study compares the risk of clinically significant and insignificant prostate cancer in men with a non-suspicious MRI of the prostate with the general population. In addition, the correlation of PSA density with risk of prostate cancer is also evaluated. Methods In this retrospective population based cohort study 1682 men between 50-79 years of age with non-suspicious MRI results were identified. The cohort's age standardized incidence of clinically significant prostate cancer and the odds of clinically insignificant prostate cancer is compared with a local age and sex matched population, which consisted of 230,458 men. The comparison is made by calculating the incidence ratio and the odds ratio with 95% confidence intervals. The follow up period was six years. The comparison was repeated for those men with both non-suspicious MRI and low PSA density (<0.15ng/ml). Results The incidence of clinically significant prostate cancer in men with a non-suspicious MRI was significantly higher compared with the general population (1852 vs. 552 per 100,000 person-years, incidence ratio 3.4). By combining low PSA density with non-suspicious MRI results, the incidence dropped significantly (778 vs 552 per 100,000 person-years, incidence ratio 1.4). The odds ratio for clinically insignificant prostate cancer was 2.4 for all men with non-suspicious MRI and 5.0 for those men who also had low PSA density. Conclusions The risk of clinically significant prostate cancer is elevated even after a non-suspicious MRI compared with the general population. Low PSA density significantly reduced the risk of clinically significant prostate cancer. The odds ratio for clinically insignificant prostate cancer increased with low PSA density, which in turn increases the risk of overdiagnosis. The decision to biopsy the prostate should base on more risk factors than only non-suspicious MRI results.