Prostatic cancer can be a silent tumor, with no symptoms remaining undetectable throughout life . But when it keeps growing, enough to produce symptoms such as bladder neck obstruction, invasion of adjacent organs or distant metastasis, curative treatment is usually impossible. Since PSA emerges, data shows a dramatic increasing in the diagnosis of prostatic cancer, specially low risk tumor. Since then, We are wondering which tumors are suitable to be treated and which ones remain asymptomatic without treatment. Analysing the natural history of prostate cancer, helps us to choose the best atitude treating the tumor, this subjet has been in constant discusión in the last decade. Our article consistes of a reviewing the main publications treating natural history of prostate cancer in prehyphen;and post-PSA era. The indicated studied suggest that most prostate tumors diagnosed today are low grade cancer, as a result with a low mortality. This conclusión shows us the importance of modifying the algorithm of treatment of these tumors.