Prostate cancer screening & diagnosis at a glance
- Prostate cancer screening involves different types of testing to find possible cancer in patients before symptoms occur.
- Oncologists declare a prostate cancer diagnosis when they are certain cancer is present and then evaluate the cancer to determine the best treatment.
- Prostate cancer screenings, such as the prostate-specific antigen (PSA) test, can help find cancers at an early stage when they have not spread and are generally easier to treat.
- When cancer is suspected based on screening tests or symptoms, oncologists perform a prostate biopsy, which is the only way to confirm a diagnosis of prostate cancer.
- Because of ongoing concerns about the benefits versus the limits and risks of screening, the American Cancer Society recommends that patients discuss this with their physicians and evaluate their options before undergoing screening.
What is prostate cancer screening & diagnosis?
Prostate cancer screening, like screenings for any cancer, attempts to identify the presence of the disease before any symptoms appear. This usually means the cancer detected is in an early stage and will respond better to treatment.
Doctors give a patient a diagnosis of prostate cancer when they are certain it is present, which can only be determined through a biopsy of suspected cancerous tissue. A laboratory must identify the presence, or absence, of prostate cancer in the tissue sample.
As part of their diagnosis, oncologists generally rank the cancer using the Gleason system. They may use additional tests and analyze all aspects possible as they seek to identify the stage of the cancer.
The stage of the cancer indicates its composition and extent in the prostate, whether it has spread and how far it may have spread in the body. These steps are described later in this article.
Prostate cancer screening
The American Cancer Society (ACS) recommends that men should decide whether or not to screen for prostate cancer only after discussing it with their physician and reviewing available information on the benefits, limits and risks of prostate cancer screening. Scientists and oncologists continue to study the effectiveness of screening for prostate cancer.
For instance, the National Cancer Institute (NCI) states, “there is no routine screening test for prostate cancer.” NCI lists these risks from prostate cancer screening:
- Finding prostate cancer through screening may not improve the health of the man or his chance of living longer
- A biopsy still must be done
- Screenings can return false-positive results (says cancer is present when it isn’t) and false-negatives (detects no cancer when there actually is).
These factors can result in men receiving unneeded treatments, risking those side effects and facing emotional and financial stress. They can also result in putting off treatment due to a false negative, and possibly increasing the damage the cancer does, including death. Doctors may have differing opinions on how often prostate cancer screening should be conducted, depending on several factors, including the individual’s risk factors.
For these reasons, patients should make their own determination in consultation with their oncologist or other physicians. They should also consider getting a second opinion on prostate cancer treatment.
Types of prostate cancer screening tests
If a physician suspects prostate cancer, he or she will ask the patient questions regarding possible symptoms, personal medical history and family medical history. The doctor may conduct a physical exam, as well.
The following screenings and other tests may be part of an evaluation for prostate cancer.
PSA blood test screening
Prostate cancer may be found before symptoms happen by testing the amount of prostate-specific antigen (PSA) in a man’s blood. The levels of PSA in the blood can be higher in men who have prostate cancer.
According to the ACS, most men without prostate cancer have PSA levels under four nanograms per milliliter (ng/mL) of blood. The chance of having prostate cancer generally goes up as PSA rises.
Digital rectal exam (DRE) screening
In a DRE screening for prostate cancer, the doctor puts a gloved, lubricated finger into the rectum to feel the prostate gland for bumps, texture and any abnormalities.
Transrectal ultrasound
Oncologists usually preform this test when the man has an abnormal DRE result or has a high PSA level. In a transrectal ultrasound, a small probe inserted into the rectum exerts high-energy sound waves (like an ultrasound) that create echoes. The probe picks up the echoes that are bounced off the prostate to create a black and white picture of the prostate called a sonogram.
Prostate biopsy
If the PSA test, the DRE or symptoms suggest the man has prostate cancer, oncologists will perform a prostate biopsy. The diagnosis of prostate cancer can only be made with a prostate biopsy.
A small piece of suspected cancerous tissue is removed from the prostate and examined under a microscope to detect cancer cells. The procedure uses a thin, hollow needle passed through the wall of the rectum and into the prostate. A small cylinder of the prostate tissue is removed when the needle is withdrawn. The biopsy takes about 10 minutes and involves a local anesthesia that minimizes pain.
Gleason score & cancer staging
Pathologists determine the Gleason score at the time of the prostate biopsy. If there is a cancer, the Gleason scoring system indicates how likely it is to spread based on the abnormality present in the cells.
The score generally ranges from 2-10. If the cancer looks like normal prostate tissue and has a low risk of spreading, the pathologist assigns a grade of 2-4. A Gleason score of 5-7 indicates immediate risk and one of 8-10 indicates cells that look nothing like normal cells and cancer that is likely aggressive.
Gleason scores are considered reliable but not perfect, and an oncologist may conduct an additional biopsy and/or imaging tests. These include X-rays, bone scans, computed tomography (CT) scans and magnetic resonance imaging (MRI) scans that examine the body for additional cancerous areas beyond the prostate.
Prostate cancer staging
Prostate cancer diagnosis can involve many variables, including PSA, DRE and biopsy results, tumor type and an individual’s specific condition. Oncologists employ a prostate cancer staging system, used in diagnosing many forms of cancer, that evaluates the cancer based on these variables. The stage of the cancer generally dictates the course of treatment.
Prostate cancer stages:
- Stage I, low-grade cancer cells in less than 5 percent of the prostate tissue
- Stage II, more extensive cancer but still confined to the prostate
- Stage III, the tumor has grown beyond the capsule of connective tissue that surrounds the prostate
- Stage IV, prostate cancer has spread to other organs in the body.
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