Diagnosis of prostate cancer
Diagnosis is the process of finding out the cause of a health problem. Diagnosing prostate cancer usually begins with a visit to your family doctor. Your doctor will ask you about any symptoms you have and do a physical exam. Based on this information, your doctor may refer you to a specialist (called a urologist) or order tests to check for prostate cancer or other health problems.
The process of diagnosis may seem long and frustrating. It’s normal to worry, but try to remember that other health conditions can cause the same symptoms as prostate cancer. It’s important for the healthcare team to rule out other reasons for a health problem before making a diagnosis of prostate cancer.
The following tests are usually used to rule out or diagnose prostate cancer. Many of the same tests used to diagnose cancer are used to find out the stage (how far the cancer has progressed). Your doctor may also order other tests to check your general health and to help plan your treatment.
Health history and physical exam
Your health history is a record of your symptoms, risk factors and all the medical events and problems you have had in the past.
Your doctor will ask questions about your history of symptoms that suggest prostate cancer, such as changes in bladder habits.
Your doctor may also ask about a family history of:
- prostate cancer
- risk factors for prostate cancer
- other cancers
Your doctor will also do a physical exam to look for any signs of prostate cancer. During a physical exam, your doctor may:
- do a digital rectal exam (DRE) to check the size and shape of the prostate and feel for any lumps or abnormal areas
- check other areas of your body, including the abdomen
Prostate-specific antigen (PSA) test
The PSA test is used to measure the level of PSA in the blood. PSA is a protein made by the prostate. When the PSA level is higher than normal, it may mean that a man has prostate cancer. For this reason, PSA is also a tumour marker.
PSA levels may also be high in men with non-cancerous conditions of the prostate, such as benign prostatic hyperplasia or prostatitis.
If you’ve been diagnosed with prostate cancer, your healthcare team will use the PSA test to measure your response to treatment or to check for signs that the cancer has come back (recurred) after treatment.
Find out more about the prostate-specific antigen (PSA) test.
Transrectal ultrasound (TRUS)
An ultrasound uses high-frequency sound waves to make images of structures in the body. A transrectal ultrasound (TRUS) uses an ultrasound probe placed in the rectum to make images of the prostate. It is used to:
- guide a needle used to take tissue from the prostate during a biopsy
- measure the size of the prostate
- look for abnormal areas of the prostate
Find out more about a transrectal ultrasound (TRUS).
During a biopsy, the doctor removes tissues or cells from the body so they can be tested in a pathology lab. The report from the pathologist will confirm whether or not cancer cells are present in the sample.
A prostate biopsy may be done if the doctor finds an abnormal area during a digital rectal exam (DRE) or transrectal ultrasound (TRUS). It may also be done if the PSA level is higher than normal or has gone up over time.
The type of biopsy used is called a core biopsy because the doctor uses a thin, hollow needle or probe to collect tissue samples (called cores). In most cases the doctor takes 10 to 12 samples (called cores) from several areas of the prostate, including any abnormal areas. Collecting the samples can cause some discomfort, so the doctor may inject an anesthetic into the prostate before doing the biopsy. Find out more about core biopsies.
Doctors use imaging tests to help them guide the needle into the prostate gland. Most prostate biopsies are done using TRUS, but sometimes an MRI is used. They can collect samples from the prostate through the wall of the rectum, the perineum or the urethra.
Men who have a prostate biopsy will be given antibiotics to prevent an infection (called prophylactic antibiotics) since there is a greater risk of infection with this type of biopsy.
Transrectal biopsy uses TRUS to guide the needle through the wall of the rectum and into the prostate.
Transperineal biopsy uses TRUS to guide the needle through the skin of the perineum (the area between the scrotum and the rectum). This technique is sometimes used when the rectum and anus have been removed. A transperineal biopsy may also be used if the PSA level continues to rise and a transrectal biopsy didn’t show any signs of prostate cancer (it showed a negative biopsy result).
The samples collected during a prostate biopsy are sent to the lab. The pathology report will say if cancer cells are in the sample. If there is cancer, the pathologist will also give a Gleason score (grade) of prostate cancer. The Gleason score describes how fast the prostate tumour is growing and how likely it is the cancer will spread.
Transurethral biopsy uses a cystoscope (a tube-like instrument with a light and tiny video camera) passed through the urethra to reach the prostate. The doctor collects samples with tools passed through the cystoscope. A transurethral biopsy is not usually used to diagnose prostate cancer.
The following biopsies may be used to find out if cancer has spread to lymph nodes or other areas of the body outside of the prostate.
Laparoscopic biopsy uses a laparoscope, which is a thin, tube-like instrument with a light and tiny video camera. The doctor makes a small incision (surgical cut), in the abdomen to insert the laparoscope. The doctor uses a special tool on the laparoscope to remove samples or abnormal tissue from inside the abdomen or pelvis. A laparoscopic biopsy can also be used to remove lymph nodes in the pelvis so they can be checked for cancer.
Fine needle aspiration (FNA) uses a very thin needle and syringe to remove a small amount of fluid or cells. Doctors may use FNA to collect samples from lymph nodes around the prostate. Sometimes they use a CT scan to guide the biopsy needle. Find out more about a fine needle aspiration (FNA).
Complete blood count (CBC)
A CBC measures the number and quality of white blood cells, red blood cells and platelets. It is done to check your general health and for signs of infection.
Find out more about a complete blood count (CBC).
Blood chemistry tests
Blood chemistry tests measure certain chemicals in the blood. They show how well certain organs or parts of the body are working. Blood chemistry tests that can help stage prostate cancer include the following.
Blood urea nitrogen (BUN) and serum creatinine are measured to check kidney function. If they are higher than normal, it may mean that the prostate is blocking the tubes that carry urine from the kidneys to the bladder (called the ureters).
Calcium and alkaline phosphatase levels in the blood may be measured. Higher than normal levels may mean that prostate cancer has spread to the bones and damaged them.
Find out more about blood chemistry tests.
Magnetic resonance imaging (MRI) uses powerful magnetic forces and radiofrequency waves to make cross-sectional images of organs, tissues, bones and blood vessels. A computer turns the images into 3-D pictures. Sometimes a dye (called a contrast medium) is injected into a vein before the MRI. The dye helps structures in the body show up better in the images.
Sometimes the images from MRI and TRUS are digitally combined to help identify men who are at risk of developing more aggressive disease.
An MRI is used to:
- look for cancer in the front of the prostate that may be missed with other tests
- look for prostate cancer when the doctor thinks it might be present but it isn’t found with a biopsy
- measure the size of the prostate or a tumour in the prostate
- plan radiation therapy to treat prostate cancer
- guide the needle during a prostate biopsy
An MRI can also be used to see if cancer has spread outside of the prostate, such as to lymph nodes in the pelvis. This may be done for men who have higher than normal PSA levels, an abnormal area that was felt during a DRE and a high Gleason score because these factors mean the cancer is more likely to have spread.
The following specialized types of MRI may be used to diagnose prostate cancer.
Multiparametric MRI uses several different types of MRI tests (called MRI sequences) that show different details on the MRI image. While a standard MRI can find a tumour in the prostate, a multiparametric MRI gives more details about the exact location of the tumour, how aggressive it is and whether or not it has spread outside of the prostate. A multiparametric MRI can also help a doctor better target an abnormal area during a prostate biopsy when an MRI is used. It can also help doctors decide which men with prostate cancer should be treated right away and which men may benefit most from active surveillance.
MRI using an endorectal coil uses a thin wire surrounded by a small, inflated balloon that is placed inside the rectum. This type of MRI is sometimes used to get a better image of the prostate than a standard MRI. You may be given a mild sedative or a muscle relaxant to help make you more comfortable if you have an MRI using an endorectal coil.
Find out more about MRIs.
A bone scan uses bone-seeking radioactive materials (called radiopharmaceuticals) and a computer to create a picture of the bones. It is used to look for prostate cancer that has spread to the bones. Doctors don’t usually do a bone scan if you have a low PSA level, a normal DRE and a low Gleason score because these factors mean that the cancer is very unlikely to spread outside the prostate.
A bone scan is also used to monitor response to treatment in men with metastatic prostate cancer.
Find out more about bone scans.
A computed tomography (CT) scan uses special x-ray equipment to make 3-D and cross-sectional images of organs, tissues, bones and blood vessels inside the body. A computer turns the images into detailed pictures. Sometimes a dye (called a contrast medium) is given by mouth or injected into a vein before the CT scan. The dye can help the doctor see structures of the body better.
A CT scan can be used to look for cancer that has spread outside of the prostate, such as to the chest, abdomen or pelvis. Doctors don’t usually do a CT scan to look for cancer spread if you have a low PSA level, a normal DRE and a low Gleason score because these factors mean that the cancer is less likely to have spread outside of the prostate. A CT scan can also be used to guide a needle during a biopsy of lymph nodes near the prostate.
Find out more about CT scans.
Questions to ask your healthcare team
The study of disease, including causes, development and effects on the body.
The symptoms, processes or conditions of a disease.
A doctor who specializes in the causes and nature of disease is called a pathologist. Pathologists help determine diagnosis, prognosis and treatment by studying cells and tissues under a microscope and using laboratory tests.
Pathological means referring to or having to do with pathology. It can also refer to something related to or caused by a disease, as in pathological fracture.
A drug that causes anesthesia (the loss of some or all feeling or awareness).
General anesthetics put a person to sleep. Regional anesthetics cause a loss of feeling in a part of the body, such as an arm or leg, but the person does not lose awareness. Local anesthetics numb only a small area of the body.
Treatment that uses regular and frequent tests to closely watch a slow-growing cancer. The goal of active surveillance is to help keep a good quality of life while delaying other treatments that can cause side effects for as long as possible. When test results show that the cancer is getting worse, treatments such as surgery or chemotherapy are offered.
What’s the lifetime risk of getting cancer?
The latest Canadian Cancer Statistics report shows about half of Canadians are expected to be diagnosed with cancer in their lifetime.