The question of screening for prostate cancer is both personal and complex. It is important for each man to talk with his doctor to decide if screening is right for him.With no unanimous opinion in the medical community regarding the benefits of prostate cancer screening, recent discussions and debates are shaping the field of prostate cancer on a continuous basis.
Ultimately, the decision about screening (whether PSA test or DRE exam) should be a personal decision based on a man’s level of risk, overall health and life expectancy, and his desire for eventually treatment if he is diagnosed with the disease
When to begin screening
The question of when to begin, and stop, screening for prostate cancer is another matter based on individual risk. The Coalition to Cure Prostate Cancer suggests that men with the highest risk of developing prostate cancer begin screening at age 40. Guidelines differ for men at average risk. Some recommend an initial PSA and DRE at age 40, and others recommend starting at age 50. In general, all men should create a proactive prostate health plan that is right for them based on their lifestyle and family history.
Some groups suggest men stop screening for prostate cancer at age 75. However, other groups suggest this is an individual decision that should be based on life expectancy and overall current health. Useful resources for making these decisions can be made at the U.S. Centers for Disease Control and Prevention site.
Screening and Biopsy
After a PSA blood test or digital rectum exam (DRE), a doctor may be prompted to recommend a biopsy. There are other supplementary tests and considerations that can help a man who is undergoing screening decide if a biopsy is necessary, including:
- Lower vs. higher free PSA test
- PSA velocity (rate of rise over time)
- PSA density (PSA per volume of prostate)
- Family history
- Prior biopsy findings
- Digital rectum exam results
- Different forms of PSA (i.e. bPSA, pro-PSA)
- In general, a lower free PSA percentage indicates a higher risk of finding cancer at biopsy, as does a higher PSA velocity and PSA density.
Understanding Your Diagnosis
After a close exam of biopsy cells through a microscope, a doctor can typically diagnose prostate cancer. Each cell within the prostate contributes to the development, architecture and function of the prostate. However, cancerous prostate cells look different than normal prostate cells. Pathologists look for these cellular differences first to detect the presence of cancer and then to determine the cancer grade.
Prostate tumor cells have five distinct patterns, which are known as the Gleason grading system. The cells are scored on a scale from 1 to 5:
- Low-grade tumor cells (those closest to 1) tend to look very similarto normal cells
- High-grade tumor cells (those closest to 5) have mutated so much that they often barely resemble normal looking cells
A pathologist assigned to review your biopsy sample assigns one Gleason grade to the most similar pattern in your biopsy, and a second Gleason grade to the second most similar pattern. The two grades added together determine your Gleason score (between 2 and 10).
Cancers with lower Gleason scores (between 2 and 4) typically tend to be less aggressive, while cancers with higher Gleason scores (between 7 and 10) tend to be more aggressive. It is also important to note that if any Gleason 5 is present, it will be reported because it puts a man at higher risk of recurrence.
Knowing the stage of disease can help to determine how aggressively the disease needs to be treated, and how likely it is to be eradicated by the available treatment options.
- Localized prostate cancer: cancer is confined within the prostate
- Locally advanced prostate cancer: cancer is confined within the prostate but some has started to escape to the immediate surrounding tissues—such as the capsule or seminal vesicles.
- Metastatic disease: prostate cancer is growing outside of the prostate and its immediate environs, often to lymph nodes, but possible to more distant organs.
The lymph nodes are normal parts of the body that fight off infection and each body has hundreds. Lymphatic ducts connect organs like the prostate to lymph nodes, and in some cases, prostate cancer can move along these ducts to spread into lymph nodes. Prostate cancer tends to spread first, if at all, to lymph nodes in the lower abdomen and pelvis, which can typically be seen, using imagining studies.
Metastatic disease can also be detected through imaging studies, and often can be detected in the lymph nodes. Cancers that spread to more distant organs tend to travel through the lymph system, a circulatory system similar to the blood stream that carries cells important in fighting infection and disease. During a biopsy, or, more often, during surgery, lymph nodes will be removed and examined for the presence of cancer cells.
staging the disease to determine the extent of prostate cancer
Traditional imaging studies: These include CT scans, MRIs, x-rays or bone scans. These tests are not used to detect very small groups of cancer cells and cannot to used alone to determine the stage of the disease, to guide treatment options or to predict outcomes.
important tests to determine prostate cancer stages
- Localized disease is known as stages T1 to T4, which describes how much the prostate cancer has spread within the prostate and its surrounding structures
- Metastatic disease is known as stages N1 and M1
- The N score describes if lymph nodes are involved with cancer
- The M score describes if cancer has spread to areas outside of the pelvis, like bone
- Also referred to is a clinical staging score, which can be performed before surgery or radiation, and a surgical staging score, which can only be provided after surgery.
- Clinical stage T1c is what most men are diagnosed with. This means that their cancers were diagnosed by PSA screening only and are not detectable by imaging or by examination.
In general, we also talk about localized prostate cancer based on risk. Men with low risk prostate cancer will have a clinical T1c-T2a stage, a PSA under 10 ng/dl, and a Gleason sum of under 7. These men have a very low risk of dying from prostate cancer and generally do well with most forms of therapy, including active surveillance. Current clinical trials are attempting to show which of these men need definitive therapy and which men can be safely observed. This is the most common form of prostate cancer.
Men with high risk prostate cancer have clinical T2c and higher stage, Gleason 8 or higher grade, and PSA over 20 ng/dl. These men have a much higher risk of recurrence with surgery or radiation or surveillance, and often benefit from more aggressive combination approaches, and often clinical trials are attempting to improve upon these outcomes.
Men with intermediate risk prostate cancer fall in between, and have a PSA between 10 and 20 ng/dl, a clinical stage of T2b, and a Gleason 7 grade. Men with this kind of cancer are likely to benefit from treatment (surgery, radiation, seeds) and do well with this treatment.