- Screening for Prostate Cancer
- Digital Rectal Exam (DRE)
- PSA Test
- Prostate Biopsy
- Percent Free PSA
- Imaging for Prostate Cancer
- What are the benefits of Prostate Cancer Screening
- Potential risks of Screening for Prostate Cancer
- Who should consider getting screened
- Reducing the risk of Prostate Cancer
The prostate is a walnut-sized gland located in the lower abdomen just below the urinary bladder.
It is the primary source of fluid in semen and serves to both lubricate and transport sperm cells produced by the testicles when a man ejaculates.
The prostate surrounds the urethra through which urine produced by the kidneys and stored in the bladder is eliminated.
Since it surrounds the urethra, swelling or enlargement of the gland from either benign disease or caused by cancer often causes urinary issues, especially in older men.
Symptoms of an enlarged prostate include:
- Frequent urination.
- Dribbling at the end of urination.
- Painful urination/ painful ejaculation.
- Difficulty passing urine.
- Night-time urination (nocturia).
- Weak urine stream or a stream that stops and starts.
- Urinary tract infection.
- Blood in the urine (hematuria).
In young men, the prostate is about the size of a walnut, but as a man ages, the organ may cause several problems.
Common medical conditions associated with it are prostatitis, benign prostatic hyperplasia (BPH), and prostate cancer. These conditions may be isolated, but a man may experience one or more of them at the same time.
The most serious problem is prostate cancer. In some men, it can spread (become metastatic) to other areas or organs of the body and be life-threatening. However, some cases of prostate cancer are slow-growing and not life-threatening.
According to multiple studies, prostate cancer is both over-diagnosed and over-treated in most areas of the Western world today.
Screening for Prostate Cancer
There are several conventional methods of screening used for prostate cancer. The two most commonly used are the digital rectal examination (DRE) and the prostate-specific antigen (PSA) test.
When the PSA is higher than normal, or the DRE result is suspicious, other tests might be initiated before ordering an invasive prostate biopsy. These tests can help determine if a biopsy is necessary.
Digital Rectal Exam (DRE)
The Digital Rectal Exam (DRE) is an in-office test where the medical practitioner feels the man′s prostate through the rectum using a gloved and lubricated finger.
This allows the doctor to feel the surface of the prostate, albeit through the rectal wall. However, a skilled urologist can detect many irregularities of the prostate in this manner.
The PSA is a blood test that measures the level of prostate-specific antigen (PSA) in the blood. Prostate-specific antigen, as its name implies, is a protein produced only by the human prostate gland. It is produced by a normal gland but tends to increase substantially in the presence of prostate cancer.
However, a high PSA can result from many causes other than prostate cancer, especially recent sexual activity or bike riding.
Neither of these tests can firmly diagnose prostate cancer, but an abnormal result in either is typically followed by other tests, most commonly a prostate biopsy.
A prostate biopsy is an invasive procedure in which a series of hollow needles are inserted through a man′s rectum and into the prostate. Each needle fills with a core of prostate tissue, which is then examined in the laboratory by a pathologist for cancer.
A biopsy carries several side effects, the most serious of which is an infection.
The introduction of bacteria passed into the prostate as the needle mechanism traverses the rectum can cause a severe infection.
Such severe infections occur in about 3 to 4 percent of men and minor infections in about 15 to 20 percent. Severe infections may require hospitalization and can be life-threatening. Other frequent consequences of prostate biopsy include chronic pain and chronic bleeding in the urinary tract.
In some cases, a CT scan may be recommended. This is used to determine where the cancer is and whether it has spread. CT scans can show whether cancer has spread to the area around the prostate gland or into nearby lymph nodes.
Percent Free PSA
Free PSA occurs in two forms in the blood. One that is attached to other blood proteins (the typical measurement, called total PSA), while the other circulates unattached to other blood elements (called free PSA).
A test called the percent-free PSA measures the ratio of free PSA compared to the total PSA circulating in the blood, expressing it as a percentage.
The free PSA percentage is typically lower in men with prostate cancer.
This test is often used to help decide if whether a biopsy is needed.
However, since the test is done on the same blood sample, does not substantially increase costs, and does provide valuable information, it should be done routinely as part of the typical total PSA test.
A lower percent-free PSA means that the chance of finding prostate cancer is higher and is an indicator that a biopsy is in order.
Most doctors recommend biopsies for men whose percent-free PSA is 12 percent or less. A man whose free PSA is over 25 percent can, especially if his PSA is less than 10, typically avoid a prostate biopsy.
This test detects the PCA3 gene in the urine. PCA3 is a prostate-specific RNA gene that is present in the prostate and excreted in the urine. If the gene is elevated in the urine, it may indicate prostate cancer.
Like the PSA and DRE tests, the PCA3 test is not definitive, and an abnormal result does not specifically indicate cancer is present. Studies suggest the PCA3 test will be abnormal in about 80 percent of men with prostate cancer.
Like the free PSA test, the PCA3 tests can be used to provide additional information for a decision of whether or not to order a biopsy.
Imaging for Prostate Cancer
There are many different stages of prostate cancer. In the past, all prostate cancer was considered to be dangerous and life-threatening.
However, modern doctors have come to realize that many men with small, low-grade lesions, can be considered to have a type of prostate cancer that is not clinically relevant.
Such small, low-grade lesions, called indolent prostate cancer, are both slow-growing and unlikely to cause symptoms or problems in the future. Many studies have found that men with indolent prostate cancer can live the rest of their lives without significant progression of cancer.
In cases of low-risk of prostate cancer, which has a low risk of spreading (localized prostate cancer), active surveillance may be used.
Active surveillance is a means of monitoring prostate cancer when it hasn’t yet spread outside of the prostate. Active surveillance includes grade group 1 or Gleason Score 6, a PSA level <10, cancer that is confined to the prostate.
In the past, it was believed that imaging of the prostate was unreliable because it was prone to miss small, low-grade lesions.
However, within the confines of this new knowledge, imaging, while often missing small, low-grade lesions, is quite good at finding the larger, higher-grade lesions that are clinically relevant
High-resolution Color Doppler Ultrasound is a type of prostate imaging which is commonly used to help diagnose prostate cancer. It is two images in one: A standard grey-scale image and a color Doppler image.
The Doppler effect is often used to describe an increase or decrease in the pitch (frequency) of sound as an observer and source move closer or further from the source.
The effect causes a noticeable change in pitch – Think – a passing freight train or auto horn. In the body, the Doppler effect can be seen in an image as blood flow increases or decreases to an area, typically a tumor.
Since cancerous tumors tend to call for increased blood supply to survive, color Doppler imaging can detect the blood flow increase to a tumor, accurately pinpointing it.
This process is currently widely used in thermography of the breast, allowing earlier diagnosis of breast cancer by means of increased blood flow to a growing tumor.
This has two significant advantages. First, imaging permits accurate measurement of prostate gland size.
Second, Doppler color imaging can detect prostate cancers large enough to be clinically significant. They can also be used to guide a biopsy to the exact point at which there appears to be a significant lesion.
Using color Doppler imaging can thus reduce the risk of false-positive biopsies as well as reducing the inevitable damage to the prostate caused by biopsy needles taking random, unguided core samples from it. This inherently increases biopsy safety, reduces side effects such as bleeding and infection, and makes the biopsy itself more accurate.
What are the benefits of Prostate Cancer Screening
Screening may detect prostate cancer early. Most cancer is easier to treat and is more likely to be cured if it is diagnosed in the early disease stages. This fact is used to justify screening.
However, because of the inherent slow-growing nature of prostate cancer, not all cancers need treatment.
Indolent prostate cancer is the type found most often via the screening of asymptomatic men. Unfortunately, many men are treated aggressively simply because the diagnosis is prostate cancer.
A recent study in a prestigious medical journal found that nearly 80 percent of aggressive treatments for prostate cancer were unnecessary. These aggressive treatments leave many men that did not need treatment to suffer serious side effects for the rest of their lives.
In 2018, the U.S. Preventive Services Task Force (USPSTF) issued a recommendation that men 70 and older should not be routinely screened for prostate cancer.
Potential risks of Screening for Prostate Cancer
Screening for prostate cancer has taken an enormous leap forward in the recent past. This has led to a dramatic increase in the incidence of prostate cancer and treatment.
For some men, screening introduces peace of mind when the screen comes back clear. Others, whose screening is inconclusive, may face a plethora of emotional concerns as well as additional testing, screening, or invasive procedures.
Screening may find prostate cancer in men who might never have symptoms or adverse effects of cancer.
Treatment of such can cause serious complications or side effects without any significant benefit, except the mental satisfaction of knowing cancer has been treated.
This over-diagnosis might be emotionally satisfying for some men, but distressing for others, especially those that lose sexual or other functionality because of the unnecessary treatment.
Many experts are now noting that overdiagnosis and overtreatment of prostate cancer have led to a deterioration of the quality of life for many men.
The most common treatment for prostate cancer, radical prostatectomy, is a surgical procedure that causes serious and permanent side effects, mostly to a man′s sexual ability. While there are other treatments, virtually all treatments for prostate cancer result in serious side effects, some immediately and some years later.
Multiple autopsy studies performed on men who expired from various causes have confirmed a high prevalence of undiagnosed, asymptomatic prostate cancer. The risk of prostate cancer increases with age.
This begs the question of whether these men have not been screened, have either refused to screen or have not been seen in the recent past by a medical professional.
Who should consider getting screened
Screening of prostate cancer should be performed in the following group of patients:
- Male patients older than 55 years old.
- Male patients with lower urinary tract symptoms.
- Patients with a family history of cancer or personal medical history of relevance to increase their risk.
Keep in mind that prostate cancer is not meant to be a routine yearly exam in every patient unless they meet the characteristics we have mentioned above or any others that might become relevant in the medical interview.
Screening is also performed in patients who have a concern about prostate cancer and expressly request for screening.
Reducing the risk of Prostate Cancer
The risks of acquiring prostate cancer are essentially the same as for any cancer.
Specifically, having a close male relative already diagnosed with prostate cancer adds to the usual risk factors.
Up to date, studies seem to suggest it is a disease for which the only well-established risk factors aside from diet and exercise, are those that are non-modifiable (age, race, and family history).
Unfortunately, many chemicals in today’s environment can contribute to the development of cancer. For example, it is well known that long-term exposure to certain insecticides can cause various cancers, including prostate cancer.
It is well established that prostate cancer is widely over-diagnosed and over-treated today.
Many doctors do not yet recommend additional testing or imaging if a man′s PSA or DRE is suspicious.
Instead, it is simpler and safer for them to recommend a biopsy where many cores of the prostate are randomly taken.
A multiple needle biopsy may miss significant cancers if the needle at which the core sample is taken misses the actual tumor.
Thus, while a biopsy is considered a definitive diagnostic tool, a significant, aggressive cancer can result in a routine biopsy. While this is not a typical situation, it is feasible.
Certain forms of cancer may spread out of the prostate after a biopsy, but not every case is concealed in the prostatic capsule.
Prostate cancer that is not limited by the prostatic capsule may undergo biopsies without increasing the risks, because they are equally high, and they are a useful diagnostic tool that will guide treatment.
Conversely, prostate cancer that is limited by the prostatic capsule may be treated with chemotherapy before performing biopsies to reduce the chance of spreading. In any case, doctors will evaluate the risk-benefit of every decision.
On the other hand, it is true that prostatic biopsies are sometimes used incorrectly in false-positive cases.
More significantly, a small, insignificant lesion may result in a positive biopsy that results in a diagnosis of prostate cancer and subsequent aggressive treatment.
For this reason, other tests have been established to increase sensitivity in prostate cancer detection, including transrectal ultrasound, and comparing the clinical signs and symptoms of the patient to his current and past levels of PSA.
These screening tools along with rectal examination provide enough information to detect prostate cancer before biopsies are taken. Thus, biopsies are made as a confirmatory test in order to stage cancer and make therapeutic decisions.”
Prior to any testing, men should educate themselves and discuss with their doctors the specific handling of prostate testing.