Prostate cancer can become life-threatening if not treated at an early stage. Various factors influence the risk of developing prostate cancer. Men above the age of 50 and those with other risk factors like a family history of the condition should talk to a doctor to understand the diagnosis and stages of prostate cancer. This article includes some basics everyone should know.

1. Diagnosis of prostate cancer
The following tests are common diagnostic methods for determining the prostate cancer stage:

• Initial screening and physical examination
  Digital Rectal Exam (DRE) is where the doctor physically examines the prostate gland by feeling for any anomalies in shape or size. Prostate-Specific Antigen (PSA) is a blood test used to check for abnormally high levels of PSA in the blood. A diagnosis is prescribed if the doctor notices anomalies in any of these screening tests.
• Magnetic Resonance Imaging (MRI)
  An MRI helps create detailed images of soft tissues using radio waves and strong magnets. MRI scans of the prostate gland can provide doctors with a clear picture of the prostate and surrounding areas. A doctor might recommend a biopsy if required, depending on the results.
• Transrectal ultrasound (TRUS)
  For accurate observation of the tumor, a probe is inserted through the rectum to view the ultrasound images of the prostate gland. It is often used to look for suspicious areas in the prostate in men with an abnormal DRE or PSA test result, or it may be used during a prostate biopsy to guide the needles correctly.
• Biopsy
  Core needle biopsy is a procedure wherein a thin, hollow needle is used to extract a small amount of tissue from the prostate gland. Multiple tissue samples are extracted from different sections of the gland.

2. The stages of prostate cancer
Understanding the stages of prostate cancer can facilitate diagnosis and help doctors understand how far the disease has spread. A cumulative number, called the Gleason score, is derived from the combined test results and denotes how likely the cancer is to grow and spread rapidly.

• Stage I
  Blood tests indicate low PSA levels, and it is hard to identify infected cells at this stage. The cancer is usually on one side of the prostate, and it grows slowly.
• Stage II
  Blood tests indicate a slightly moderate increase in PSA levels, and the tumor can be felt by the doctor in the DRE or seen in imaging tests like TRUS. It has not spread outside the prostate gland at this stage.
• Stage III
  Blood tests show high PSA levels, which comes as a warning sign. A biopsy might indicate multiple sections in the gland with infected cells. At this stage, cancer has grown and spread to the seminal vesicles or other tissues around the prostate.
• Stage IV
  This is the most advanced stage of prostate cancer, wherein the cancer cells have spread to nearby lymph nodes or further to other parts of the body, like distant lymph nodes, bones, or other organs.