Prostate cancer occurs when cells grow abnormally in the prostate gland to form tumors. The prostate is a walnut-sized gland located in front of the rectum and under the bladder that secretes the fluid that carries sperm.
Prostate cancer is the most common cancer in men, excluding skin cancer. About 220,800 new cases are expected to be diagnosed in 2015, according to the American Cancer Society (ACS). Fortunately, prostate cancer has a very high survival rate when discovered early.
More than 90% of all prostate cancers are discovered while they are either localized (confined to the prostate) or regional (nearby). The five-year survival rate for men diagnosed with prostate tumors discovered at these stages is nearly 100%.
Choosing an experienced prostate cancer doctor and the right cancer center can maximize your chances of a successful outcome and help preserve your quality of life, including sexual function.
Symptoms of Prostate Cancer
There are usually no specific signs or symptoms of early prostate cancer. A prostate-specific antigen (PSA) blood test and digital rectal exam (DRE) can provide the best chance of identifying prostate cancer in its earliest stages, but these tests can have drawbacks. Talk to your doctor about whether prostate cancer screening is right for you.
The following are the most common symptoms of prostate cancer. However, each individual may experience symptoms differently.
Symptoms may include:
- Weak or interrupted flow of urine
- Urinating often (especially at night)
- Difficulty urinating or holding back urine
- Inability to urinate
- Pain or burning when urinating
- Blood in the urine or semen
- Nagging pain in the back, hips, or pelvis
- Painful ejaculation
The symptoms of prostate cancer may resemble other conditions or medical problems. Always consult your doctor for a diagnosis.
As a man gets older, his prostate may grow bigger and obstruct the flow of urine, or interfere with sexual function. An enlarged prostate gland—a condition called benign prostatic hyperplasia—may require treatment with medicine or surgery to relieve symptoms. This common benign prostate condition, which is not cancer, can cause many of the same symptoms as prostate cancer.
Digital rectal examination
Digital Rectal Exam
A digital rectal exam (DRE) is an exam of the rectum. During a digital rectal examination, a doctor or healthcare provider inserts a gloved and lubricated finger into the rectum to feel for anything unusual or abnormal, such as a tumor. This test can detect cancers of the rectum and the prostate gland, but not the colon. DREs may be conducted annually for men over the age of 50 who choose to be screened. Men in high-risk groups, such as African Americans, or those with a strong family history of prostate cancer, should consult their physician about being tested at a younger age or more often.
PSA (Prostate-Specific Antigen)
PSA is a blood test that measures the level of prostate specific antigen. The use of PSA in clinical practice was pioneered here at Stanford. PSA is a substance produced by the prostate gland, which may be found in higher amounts in men who have prostate cancer. The PSA test may be done annually for men over the age of 50 who choose to be screened. Men in high-risk groups, such as African Americans, or those with a strong family history of prostate cancer, should consult their doctor about being tested at a younger age or more often.
What Is Magnetic Resonance Imaging (MRI)?
A magnetic resonance (REZ-oh-nans) imaging scan is usually called an MRI. An MRI does not use radiation (X-rays) and is a noninvasive medical test or examination. The MRI machine uses a large magnet and a computer to take pictures of the inside of your body. Each picture or “slice” shows only a few layers of body tissue at a time. The pictures can then be examined on a computer monitor.
Pictures taken this way may help caregivers find and see problems in your body more easily. The scan usually takes between 15 to 90 minutes. Including the scan, the total examination time usually takes between 1.5 to 3 hours.
A substance called gadolinium is injected into a vein to help the physicians see the image more clearly. The gadolinium collects around cancer cells so they show up brighter in the picture. Sometimes a procedure called magnetic resonance spectroscopy (MRS) is done during the MRI scan. An MRS is used to diagnose tumors based on their chemical make-up.
How does MRI work?
The MRI machine is a large, cylindrical (tube-shaped) machine that creates a strong magnetic field around the patient. This magnetic field, along with a radiofrequency, alters the hydrogen atoms’ natural alignment in the body.
A magnetic field is created and pulses of radio waves are sent from a scanner. The radio waves knock the nuclei of the atoms in the body out of their normal position; as the nuclei realign back into proper position, they send out radio signals.
These signals are received by a computer that analyzes and converts them into an image of the part of the body being examined. This image appears on a viewing monitor. Some MRI machines look like narrow tunnels, while others are more open.
MRI may be used instead of a CT scan in situations where organs or soft tissue are being studied, because with MRI scanning bones do not obscure the images of organs and soft tissues, as does CT scanning.
Other related procedures that are used to assess the heart may include:
- Resting or exercise electrocardiogram (ECG)
- Signal-averaged electrocardiogram (ECG)
- Holter monitor
- Cardiac catheterization
- Chest X-ray
- Computed tomography (CT scan) of the chest
- Electrophysiological studies
- Myocardial perfusion scans
- Radionuclide angiography
- Ultrafast CT scans
A test using sound wave echoes to create an image of the prostate gland to visually inspect for abnormal conditions. A transrectal ultrasound can show if the prostate gland is enlarged or if there are any growths in or around the prostate. Ultrasound may also be used to guide a needle for biopsies of the prostate gland and/or to guide the nitrogen probes in cryosurgery.
A test in which where the doctor inserts thin, hollow needles into the prostate to get samples for examination under a microscope to determine if cancer cells are present. The methods of prostate biopsy were developed by Stanford researchers.
Targeted prostate biopsy
What is a targeted prostate biopsy?
Computed Tomography Scan (CT Scan)
Radionuclide bone scan
Radionuclide Bone Scan
A nuclear imaging method that helps to show whether the cancer has spread from the prostate gland to the bones. The test involves injecting a radioactive material into a vein that helps to locate diseased bone cells throughout the entire body.
Lymph node biopsy
Lymph Node Biopsy
A procedure in which tissue samples are removed (with a needle or during surgery) from the lymph nodes for examination under a microscope; to determine if cancer or other abnormal cells are present.
Prostate Cancer Staging/Grading
Determining the extent of prostate cancer is important for predicting the course of the disease and in choosing the best treatment. The TNM (tumor, nodes, metastasis) staging system is used to describe a cancer’s clinical stage, or how far it has spread.
TNM staging system
T categories (clinical)
There are 4 categories for describing the local extent of a prostate tumor, ranging from T1 to T4. Most of these have subcategories as well.
T1: Your doctor can’t feel the tumor or see it with imaging such as transrectal ultrasound.
- T1a: Cancer is found incidentally (by accident) during a transurethral resection of the prostate (TURP) that was done for benign prostatic hyperplasia (BPH). Cancer is in no more than 5% of the tissue removed and low grade (Gleason Grade 3+3=6 or less).
- T1b: Cancer is found during a TURP but is in more than 5% of the tissue removed or is Gleason grade 7 or above.
- T1c: Cancer is found by needle biopsy that was done because of an increased PSA.
T2: Your doctor can feel the cancer with a digital rectal exam (DRE) or see it with imaging such as transrectal ultrasound, but it still appears to be confined to the prostate gland.
- T2a: The cancer is in one half or less of only one side (left or right) of your prostate.
- T2b: The cancer is in more than half of only one side (left or right) of your prostate.
- T2c: The cancer is in both sides of your prostate.
T3:The cancer has begun to grow and spread outside your prostate and may have spread into the seminal vesicles.
- T3a: The cancer extends outside the prostate but not to the seminal vesicles.
- T3b: The cancer has spread to the seminal vesicles.
T4: The cancer has grown into tissues next to your prostate (other than the seminal vesicles), such as the urethral sphincter (muscle that helps control urination), the rectum, the bladder, and/or the wall of the pelvis.
N categories describe whether the cancer has spread to nearby (regional) lymph nodes.
NX: Nearby lymph nodes were not assessed.
N0: The cancer has not spread to any nearby lymph nodes.
N1: The cancer has spread to one or more nearby lymph nodes in the pelvis.
M categories describe whether the cancer has spread to distant parts of the body. The most common sites of prostate cancer spread are to the bones and to distant lymph nodes, although it can also spread to other organs, such as the lungs and liver.
M0: The cancer has not spread past nearby lymph nodes.
M1: The cancer has spread beyond the nearby lymph nodes.
- M1a: The cancer has spread to distant (outside of the pelvis) lymph nodes.
- M1b:The cancer has spread to the bones.
- M1c:The cancer has spread to other organs such as lungs, liver, or brain (with or without spread to the bones).
Gleason grading system
The Gleason grading system is used to help evaluate the prognosis of men with prostate cancer. Together with other parameters, it is incorporated into a strategy of prostate cancer staging which predicts prognosis and helps guide therapy. A Gleason score is given to prostate cancer based upon its microscopic appearance. Cancers with a higher Gleason score are more aggressive and have a worse prognosis.
The urologist or radiologist performs a prostate needle biopsy, in which a cylindrical sample of prostate tissue is removed through the rectum, using hollow needles, and prepares microscope slides. After a prostate is removed in surgery, a pathologist will slice the prostate for a final examination.
Grades and scores
The pathologist assigns a grade to the most common tumor pattern, and a second grade to the next most common tumor pattern. The two grades are added together to get a Gleason Score.
Traditional Gleason scoring uses a 1–5 scale. However, updated guidelines state that patterns 1 and 2 should be rarely used if ever, and these numbers are no longer typically assigned in typical prostate needle biopsies. The lowest Gleason grade assigned in clinical practice is 3+3=6.
Research at Stanford has demonstrated that the amount of Gleason pattern 4 in the cancer is indicative of cancer aggressiveness. Therefore a Gleason 3+4=7 cancer is less aggressive than a Gleason 4+3=7 cancer, even though their sum is the same.