How is prostate cancer diagnosed?

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A number of tests may be performed to investigate symptoms of prostate cancer and confirm a diagnosis. Some of the more common tests include:[4][5] 

  • medical history, family history and physical examination 
  • digital rectal examination – where the doctor inserts a gloved finger into your rectum to feel the prostate through the rectal wall 
  • blood test to check for prostate-specific antigen (PSA), a protein produced by the prostate; the level of PSA can be higher than normal in people with prostate cancer (but also in people with other prostate conditions that are not cancer) 
  • genetic tests that look for inherited gene changes 
  • transrectal ultrasound – where a probe is inserted into the rectum that uses sound waves to create a picture of the prostate inside the body 
  • imaging tests such as a CT scan and a bone scan to look at whether the cancer has spread beyond the prostate gland and help to guide management. 
  • multiparametric magnetic resonance imaging (mpMRI), a specialised type of medical scan that combines three MRI images for greater detail 
  • Nuclear medicine imaging such as a PET scan or a bone scan. A PET-scan – a specialised type of scan which involves injecting a weak radioactive substance into the body to allow the cancer cells to show up on the scan. Prostate cancer often does not show up on standard PET scans, and a PSMA-PET scan may be done to specifically look for prostate cancer activity. PSMA stands for prostate specific membrane antigen, a protein found on the surface of prostate cells. 
  • biopsy (usually after having an MRI scan) – where a small sample of tissue is removed using a special needle guided by transrectal ultrasound and examined under a microscope; the needle is commonly inserted through the skin between the anus and scrotum (called a transperineal biopsy) but can also be inserted through the rectum (transrectal biopsy). 

The tissue taken during a biopsy will be given a score that indicates how quickly the cancer may grow or spread. This may be done using the Gleason scoring system, where a score is given to the types of cancer seen under the microscope. These are given a low score meaning that the cancer is less likely to spread or a high score meaning it is most likely to spread. The two most common types of cancer found in the sample are given scores up to 5 and these are added together to give the Gleason Score (up to 10). The cancer may also be scored using the International Society of Urological Pathologists (ISUP) Grade Group system, which grades prostate cancer from 1 (least aggressive) to 5 (most aggressive).[4] 

Staging

If you are diagnosed with prostate cancer, you might have more tests to determine the stage of the disease and whether the cancer has spread to other parts of the body. Knowing the stage of the disease helps your medical team plan the best treatment for you. 

Prostate cancer is staged using the following information: 

  • size and extent of the tumour 
  • whether the cancer has spread to nearby lymph nodes 
  • whether the cancer has spread to other organs or tissues in the body 
  • PSA level at diagnosis 
  • score from the prostate biopsy. 

Stages of prostate cancer are:[4][6] 

  • Stage I (early or localised prostate cancer): the tumour has not spread outside the prostate. The tumour is small and may or may not be able to be felt during a digital rectal exam or seen with medical imaging tests. If it can be seen in tests, the tumour is in half or less of the prostate and on one side only. The cancer is low risk as it is slow growing and not aggressive. The Gleason score is 6 or less, the Grade Group score is 1, and the PSA level is less than 10. 
  • Stage II (early or localised prostate cancer): The tumour has not spread outside the prostate. This can be further subdivided into the following substages: 
  • Stage IIA : The tumour may be in more than half of the prostate. The cancer is low risk as it is slow growing and not aggressive. The Gleason score is 6 or less, the Grade Group score is 1, and the PSA level is less than 20. 
  • Stage IIB : The tumour is in one or both sides of the prostate. The cancer is intermediate risk as it is likely to grow faster and be mildly to moderately aggressive. The Gleason score is 7, the Grade Group score is 2, and the PSA level is less than 20. 
  • Stage IIC :The tumour is in one or both sides of the prostate. The cancer is intermediate to high risk as it is likely to grow faster and be more aggressive. The Gleason score is 7 or 8, the Grade Group score is 3 or 4, and the PSA level is less than 20. 
  • Stage III prostate cancer: the tumour has either spread to both sides of the prostate or to nearby structures or organs.
  • Stage IIIA (localised prostate cancer): the tumour has not spread outside the prostate. The tumour is in one or both sides of the prostate. The Gleason score is less than 8, the Grade Group score is 1, 2, 3 or 4, and the PSA level is at least 20. 
  • Stage IIIB (locally advanced prostate cancer): the tumour has spread beyond the prostate to the seminal vesicles or to nearby tissues or organs, such as the bladder, rectum or pelvic wall. It has not spread to nearby lymph nodes. The Gleason score is less than 8, the Grade Group score is 1, 2, 3 or 4, and the PSA level can be any number.