In the United States, prostate cancer will be diagnosed in one out of seven men in his lifetime. Most cases are localized, and only one in 39 men will die from the disease. Prostate cancer is most often detected using serum prostate-specific antigen testing. The National Comprehensive Cancer Network guidelines use four main factors to stratify risk of disease progression or recurrence and to determine the recommended treatment: clinical stage, pathologic grade, prostate-specific antigen level, and comorbidity-adjusted life expectancy. Radical prostatectomy or external beam radiation therapy should be considered for patients with high-risk prostate cancer regardless of comorbidity-adjusted life expectancy. These treatments are almost equivalent in effectiveness but have different adverse effect profiles. Patients who undergo radical prostatectomy are more likely to experience urinary incontinence and trouble obtaining or sustaining an erection compared with patients who opt for radiation therapy. Brachytherapy is an option for patients with low-risk disease and some patients with intermediate-risk disease. Active surveillance is an option for patients with low-risk and very low-risk disease. With active surveillance, patients are closely followed and undergo invasive treatments only if the cancer progresses. Prostate cancer progression may be indicated by an increase in the pathologic grade, a significant rise in serum prostate-specific antigen level, or an abnormality on digital rectal examination.