Screening for Prostate Cancer
Prostate cancer at the early stages does not usually show symptoms, and therefore, most of the prostate cancers are first found during screening tests. Two types of tests are used for screening purposes.
- Digital rectal exam (DRE)
- Prostate-specific antigen (PSA) blood test
Digital rectal exam (DRE)
While performing a DRE, a lubricated, gloved finger is inserted into the rectum to check for any hard areas or bumps. Prostate cancer usually begins to develop in the posterior part of the prostate, and as the rectum is just behind the prostate gland, the digital examination can prove to be a useful way of detecting prostate cancers at an early stage. However, the digital rectal exam is less effective than prostate-specific antigen testing.
The examination might be painful if the individual has hemorrhoids. Otherwise, it is a painless procedure which takes only a minute or two.
Prostate-specific Antigen (PSA)
PSA is an antigen formed by the normal and cancerous cells of the prostate gland. Mostly found in semen, PSA is present only in small amounts in the blood. The PSA levels in the blood are less than 4 ng/mL for men without prostate cancer. The levels higher than 4 ng/mL may be an indication of prostate cancer. However, almost 15 % of men with PSA levels lower than 4 ng/mL are still diagnosed with prostate cancer on biopsy. PSA levels of more than 10 ng/mL increase the chances of having a prostate cancer by more than 50 %.
Recommendations for Screening
According to the ACS recommendations, the decision for screening should be made only after providing information on the risks and benefits of prostate cancer screening to the patient. The criteria for screening discussion for prostate cancer is given in Table 1.0.
Table 1.0. American Cancer Society (ACS) Recommendations for Prostate Cancer Early Detection:
|50 years||Average risk||All men|
|45 years||High risk||African Americans and other men who have a first-degree relative diagnosed with prostate cancer at an age younger than 65 years.|
|40 years||High risk||African Americans and other men who have more than one first-degree relative diagnosed with prostate cancer at an early age.|
Age, however, is not the only decision-making factor for screening. The overall health of the patient is equally important to be considered. If prostate cancer is not found as a result of first screening, the time interval for future screening is as follows:
- PSA of < 5 ng/mL requires retesting every 2 years
- PSA equal to higher than 5 ng/mL requires retesting every year
Men whose life expectancy is not more than a decade and have no symptoms of Prostate cancer should not be offered the screening tests as they are not likely to benefit.
The decision for a screening test is based on baseline history of the patient and physical examination. Baseline history includes family history, medications, and a history of the prostate disease or a screening test performed prior to the present visit. The pros and cons of screening must be discussed with the patient. Digital rectal examination (DRE) is carried out before PSA testing.
If DRE yields normal results, following criteria is to be followed:
Baseline PSA testing if the man is between 45—49 years old
- If PSA levels are below 1.0 ng/mL, retesting is required at 2—4 year intervals
- If PSA levels are equal to or higher than 1.0 ng/mL, annual or biannual retesting is recommended
- For patients who are 50—70 years old, normal DRE, and PSA levels below 3 ng/mL, retesting every 1—2 years is required
- After the age of 75, screening option is taken only for a few selected cases
AUA recommends against the prostate-specific antigen (PSA) based screening for prostate cancer in the following groups:
- All men with a life expectancy of fewer than 10—15 years
- Men who are less than 40 years old
- Average risk men who are from the age group of 40 to 54 years
- Mne who are more than 70 years old
For those men who are 55 to 69 years old, the decision to undergo PSA screening involves weighing the benefits and risks. The guidelines for age group 55 to 69 years are based on weighing the pros and cons of PSA screening.
- Shared-decision making based on patients preferences
- Those men who have had a PSA screening test based on shared decision making should be retested every 2
U.S. Preventive Services Task Force (USPSTF), American College of Physicians, and American Academy of Family Physicians recommend against the prostate-specific antigen (PSA)–based screening for prostate cancer.
Randomized Trials of prostate cancer screening
Prostate, Lung, Colorectal, and Ovarian (PLCO) Screening Trial results showed that 76,693 men between 65-74 years in U.S had prostate cancer. No difference in prostate cancer mortality in the screening group and the control groups was found. More cancer cases were detected in the screening group.There was 52 % contamination of the control group with Prostate-specific antigen testing.
European randomized study of screening for prostate cancer:
160,000 men between 55 and 69 years had a prostate cancer. Statistically significant reduction in prostate cancer mortality with screening is possible.
Efficacy: 1.28 deaths reduced per 1000 men. 27 cancers would have to be treated to prevent another death.
More than 90 % of the diagnosed prostate cancer patients undergo curative treatment. Following are the curative treatments:
It is either done by open surgery or laparoscopic surgery via the small intestine.
Radical Prostatectomy is an effective treatment option, but it results in urinary incontinence in up to 12 % of the cases and erectile dysfunction in about 50 % of the cases.
Two types of radiation therapies are used for prostate cancer:
- External beam radiotherapy (EBRT)
- Brachytherapy (seed implantation / interstitial radiation therapy)
Radiation therapy results in erectile dysfunction in about 50 % of the cases. There are also rare incidences of chronic loose stool and urethra strictures.