The PSA test standsfor Prostate-Specific Antigen test. It checks a blood sample for the level of PSA, a substance produced by the prostate gland. If the PSA test detects a higher than normal value (above 4.0ng/ml) it may indicate prostate infection, enlargement of the prostate gland, or cancer.
The New York Times published an article on October 7, 2011 announcing the results of the United States Preventive Services Task Force (USPSTF) regarding prostate cancer screenings and the PSA test. The USPSTF is a Department of Health panel charged with the task of assembling evidence-based guidelines for health screening. The article highlights the growing fear that routine PSA tests are resulting in unnecessary anxiety and stress, without impacting overall survival. The study implies that ignorance about one’s cancer status might be the best course in order to avoid the anxieties related to a cancer diagnoses. But one cannot forget that 30,000 men die every year from the disease. It is not a benign disease that can just be ignored.
Screening tests fall into two categories: those that screen for prostate cancer and those that help determine the stage of the disease. These tests include:
In “staging” the disease, the doctor needs to determine the following about the cancer:
There are several different staging systems for prostate cancer. The most widely used system is the TNM system, which describes the extent of the primary tumor (T stage), whether or not the cancer has spread to nearby lymph nodes (N stage), and the absence or presence of distant metastasis (M stage). “Metastasis” refers to the spread of cancer cells from the prostate gland to another part of the body.
There are four categories that describe the prostate tumor’s (T) stage, ranging from T1 to T4, or Stage A to D, indicated as follows:
Gleason grade scores range from 1 to 5 and are based on the degree of differentiation among the cells. A Gleason grade of 1 indicates that the cancer cell clusters resemble the small, regular, evenly spaced prostate tissue.
Grade 1 – Small, uniform cells, tightly packed
Grade 2 – Varied cell sizes and shapes, loosely packed
Grade 3 – Increased cell size and shape irregularity, less distinction between cells
Grade 4 – Large, irregular fused cells
Grade 5 – Irregular, fused cells that have invaded surrounding connective tissue cells
DRE – by touch, the doctor can tell if the cancer is T1, T2, or beyond T2.
Biopsy – small samples of tissue are taken from the prostate and the tissue is evaluated by a pathologist who assigns a Combined Gleason Grade Score (CGS) ranging from 2 through 10. The higher the number, the more aggressive the cancer.
Prostatic Acid Phosphatase (PAP) blood test – determines if the cancer has spread beyond or is confined to the prostate.
Computed tomography (CT) scan – produces detailed cross-sectional images of the body using hundreds of X-ray like images to determine if the prostate cancer has spread into other organs. While CT scans are ideal for determining skeletal structures, they have a limited mass size resolution.
Magnetic resonance imaging (MRI) – uses strong magnetic fields to produce an image of the body based on cellular oscillation emitted energy. MRI scans produce a very clear picture of the prostate gland and can show whether the cancer has spread beyond it.
Endorectal MRI – helpful in determining if the cancer is confined to the gland and detecting the site of the cancer in men whose prostate cancer cannot be diagnosed with other routine tests.
Radionuclide bone scan – can determine whether cancer has spread from the prostate to the bones. It is common for prostate cancer to spread first to skeletal structures before other organs in the body.
ProstaScint scan – detects the spread of prostate cancer to lymph nodes and other soft (non-bone) organs. It can distinguish from other cancers and benign disorders; however, its sensitivity and specificity are relatively low.
Lymph node sampling – another way of finding if the cancer has spread to nearby lymph nodes and is typically performed when there is a high suspicion of spreading.
Symptoms are not always present with prostate cancer and, conversely, the presence of symptoms does not always mean it exists. However, one or more of the following symptoms, particularly if one is at higher risk for prostate cancer, should prompt a visit to the doctor: