Diagnosing Types and Stages of Prostate Cancer
If you’re a man older than 50, you may have had a screening test for prostate cancer. Doctors can use the digital rectal exam (DRE), the prostate-specific antigen (PSA) test, or both tests to check for signs of the disease before symptoms appear. When the results suggest a problem, your doctor will need to run more tests to make a prostate cancer diagnosis. In some cases, men have symptoms, such as urinary problems, which start the diagnostic process.
What is prostate cancer?
Prostate cancer affects a man’s prostate gland. About one in 9 American men will develop prostate cancer during their lifetime. This makes it the second most common cancer in men after skin cancer.
What are the types of prostate cancer?
The most common type of prostate cancer is adenocarcinoma. It accounts for almost all cases of prostate cancer. There are four other rare types of the disease.
The first step in diagnosing prostate cancer is to verify if cancer is present or not. Abnormal screening exam results can also occur with an enlarged prostate (benign prostatic hyperplasia, or BPH), which is not cancer. If it turns out to be prostate cancer, your doctor will need to know the stage and grade of it. This information guides your treatment options. It also tells your doctor about your outlook, or prognosis.
What are the stages of prostate cancer?
Cancer staging is basically a description of how widespread the cancer is. There are four prostate cancer stages: I, II, III and IV. Lower stages generally have a more favorable outlook because the cancer is less extensive. Stage IV is advanced prostate cancer or metastatic prostate cancer. It has spread to nearby lymph nodes or organs.
Doctors also grade cancer. In assigning grade, doctors look at the cancer cells under the microscope to see how closely they resemble normal cells. Very abnormal-looking cells translate to a higher grade. Higher grade tumor are more aggressive. Some prostate cancers can be quite aggressive. However, some grow very slowly and aren’t much of a health threat. In fact, many men with slow-growing prostate cancer end up dying from other causes.
Prostate cancer is complicated because the tumor can have areas with different grades. Doctors use a Gleason score of 1 to 5 to rate the areas. They add the two most common scores in the tumor for a total score—or Gleason sum—that is usually six or above. On a pathology report, you may see Gleason scores or sums of 6 or less, 7, or 8 to 10. You may also see Grade Groups. There are five grade groups that provide more detail to your doctor about the tumor and your prognosis.
Diagnosing the stages and grades of prostate cancer consists of the following tests:
Transrectal ultrasound (TRUS)
The PSA test is a blood test. It is a screening test for prostate cancer in men without symptoms. A high level may be an indicator of prostate cancer. But it can be high for other reasons, such as BPH. If your level is high, your doctor may recommend repeating it. Whether a man decides to be screened for prostate cancer depends on his risk factors for prostate cancer, personal preference, and his physician’s advice.
The PSA is also useful when diagnosing prostate cancer. Doctors use the results to decide if a prostate biopsy is necessary. They also use PSA levels as part of the staging process and to monitor treatment and disease progress.
Ultrasound uses sound waves to make images of the inside of the body. Most ultrasounds use a transducer moving on the skin’s surface to make the pictures. For a transrectal ultrasound, the transducer is a thin probe for insertion into the rectum. It produces images of the prostate and can measure its size. You may have this exam in your doctor’s office or in an imaging clinic or center. Your doctor will also use TRUS during a prostate biopsy.
A prostate biopsy takes a sample of cells to test it for cancer. It is the only way to know for sure whether you have prostate cancer. Doctors typically use a core needle biopsy for prostate biopsies. A core needle withdraws a small cylinder of prostate tissue.
Most doctors inject a local anesthetic to numb the area before the biopsy. Your doctor will use TRUS to precisely locate the area of the prostate to biopsy. Then, the doctor inserts the needle through the wall of the rectum into the prostate to retrieve the core sample. This happens very quickly because the core needle device uses a spring-load to deliver the needle. In most cases, doctors take about 12 cores.
A lab will examine the core samples and produce a pathology report. This will include information about the grade, or Gleason score. It will also tell you how many cores had cancer and how much cancer was in each core. Your doctor will review the report with you and help you understand what it means for your treatment and outlook.
Results from your prostate biopsy and PSA test will tell your doctor if you need additional imaging exams. These exams can show your doctor if the cancer has spread. They include:
Bone scan can show if cancer has spread to the bones. This is a common site for prostate cancer to spread.
CT (computed tomography) makes cross-sectional images of the prostate. It can show more detailed information than standard X-rays.
MRI (magnetic resonance imaging) uses magnetic fields to make detailed images. MRI is more useful than CT in making clear pictures of the prostate and surrounding tissues. Your doctor may recommend this test when you are planning your treatment.
Not all men will need these tests, especially if the chance of the cancer spreading beyond the prostate is low.
Once your doctor has all the results from diagnostic testing, you can plan a course of action. For some men, this may be no action. This option—watchful waiting—means delaying treatment until the tumor causes symptoms. Certain men with slow-growing and low-grade tumors that are not causing bothersome symptoms may choose this approach with the doctor’s consent. The goal is to avoid treatments you don’t need. Another option is active surveillance, which involves more closely monitoring the disease to see if it is progressing. You would have regular blood tests and a biopsy within a year of diagnosis.
Both watchful waiting and active surveillance can be stressful for some men. Also, there is no strict definition or consensus among doctors as to what the terms mean. For some doctors, watchful waiting and active surveillance mean the same thing and you are continually monitored for any changes—either that you notice through your symptoms or that the doctor can determine with PSA tests and biopsies. If your preference is to treat the cancer, talk with your doctor about your treatment options.
Surgery and radiation therapy are common treatments for early prostate cancers. Other possible treatment options include hormone therapy, immunotherapy, and chemotherapy. Talk with your doctor about the pros and cons of all your options. Your doctor can help you weigh them against things like your overall health and your age. A second opinion can be useful if you are unsure about your treatment decisions. Another perspective can increase your confidence about your treatment plan.