Tran rectal ultrasonography revealed that the primary tumor was located in less than one-half of one lobe of the prostate gland. MRI scans showed that prostate cancer had not spread to any lymph nodes...

Tran rectal ultrasonography revealed that the primary tumor was located in less than one-half of one lobe of the prostate gland. MRI scans showed that prostate cancer had not spread to any lymph nodes or other organs but had remained confined exclusively to the prostate. Furthermore, there was no sign that the tumor had penetrated the capsule of the prostate. To which stage has this prostate cancer progressed?