A suspicion of prostate cancer usually arises on the basis of an elevated level of plasma PSA (prostate-specific antigen). In prostate cancer, the level of PSA in plasma rises (PSA ”leaks” from cancer cells into blood circulation), but PSA levels can also be raised by benign prostatic hyperplasia and infections, for example. Hence, a PSA level above reference values does not automatically indicate prostate cancer. In this case, a new measurement is usually needed. In addition to PSA, the level of free PSA, indicated as a percentage, can also be used. The lower the percentage of free PSA, the greater the suspicion of prostate cancer. The threshold for further examinations is usually ≤ 15%.
In practice, local prostate cancer does not cause any symptoms. Men who suffer from local prostate cancer often simultaneously have benign prostate hyperplasia, which causes urinary symptoms. These lead to further examinations, such as a PSA measurement and, consequently, a possible suspicion of prostate cancer. In the case of metastatic prostate cancer, the symptoms may include bone pain, urinary problems, and a weakened general condition.
A prostate cancer diagnosis is based on needle aspirate samples of the prostate, taken under ultrasound guidance through the rectum. The patient is given antibiotics before the procedure to prevent infection. The prostate is anesthetized before the samples are taken. The examination takes about 20 minutes, and there is no need for sick leave afterwards. The procedure is usually painless. The most common symptoms after the procedure are mild hematuria (blood in the urine) or blood in the semen. It is increasingly common to perform an MRI scan of the prostate and take a “targeted” biopsy already during the diagnosis phase.
A pathologist examines the biopsy samples for cancer. If the pathologist finds cancer, they will assess the aggressiveness of the cancer using the international Gleason grading system. The Gleason score is one of the most important prognostic factors for prostate cancer.
In assessing the prognosis of prostate cancer, the following risk group categorization, based on the clinical spread of the disease (T category), the Gleason score as evaluated by the pathologist, and the PSA level of plasm, is used:
- Low-risk category:
Clinical T1–T2a, N0, M0 and Gleason score < 7 and PSA level < 10 µg/l
- Medium-risk category:
T2b or Gleason score 7 (3+4) or PSA level 10–20 µg/l
- High-risk category:
T2c, clinical T3a, or Gleason score 7 (4+3) or 8–10, or PSA level > 20 µg/l
- Extremely high-risk category:
Clinical T3b–T4 or any T category, N1
If a low-risk cancer is found in a patient with no symptoms, no routine metastasis examinations are required. In the case of medium or high-risk cancers, or if the patient has symptoms, further examinations may be made to determine the spread of the disease (radioisotope bone scan, CT scan of the body, MRI scan of the prostate, or, in certain cases, a PET scan).