Diagnosis for Prostate Cancer

Tests for Prostate Cancer
Normally, patients are diagnosed with prostate cancer when they are screened with a prostate-specific antigen (PSA) blood test or a digital rectal exam (DRE). At early stages, patients may not realized they have prostate cancer as the symptoms are not obvious while at advanced stages, patients may suspect they have prostate cancer due to more apparent symptoms. In order to confirm the diagnosis, tests are required. Prostate biopsy is the only accurate, actual diagnosis of prostate cancer. These are some of the general tests for prostate cancer and I will explain some in detail, for example:

Medical history and physical examination
PSA blood test
Transrectal ultrasound (TRUS)
Prostate biopsy- Grade (Gleason score) of prostate cancer
Imaging tests to look for prostate cancer spread
Lymph node biopsy

Medical history and physical examination
Doctors will ask if you have any urinary or sexual problems, and how long you have had them as they are the common symptoms of prostate cancer. They may also asked for your family history as it is considered a possible risk factor. Doctors will examine through the DRE. If the patient is tested positive, the DRE can sometimes help identify if it’s only on one side of the prostate, if it’s on both sides, it’s likely to have spread beyond the prostate to nearby tissues. Doctors may examined other parts of the body and order additional tests.

PSA blood test
Although PSA is used mainly to screen for prostate cancer in men without symptoms, it’s one of the first tests done in men who have symptoms that might be caused by prostate cancer. Generally, men without prostate cancer have PSA levels under 4 nanograms per milliliter (ng/mL) of blood. The chance of having prostate cancer increases as the PSA level increases.

Prostate biopsy- Grade (Gleason score) of prostate cancer
Prostate cancers are graded according to the Gleason system. This system assigns a Gleason grade based on how similar the cancer prostate tissue is compared to the normal prostate tissue.
If the cancer prostate tissue is very similar to normal prostate tissue, a grade of 1 is assigned.
If the cancer prostate tissue is very different, it is given a grade of 5.
Grades 2-4 have features in between these extremes.
Generally, prostate cancer is grade 3 or higher, and grades 1 and 2 are not regarded.

Imaging tests to look for prostate cancer spread
Imaging tests use x-rays, magnetic fields, sound waves, or radioactive substances to create pictures of the inside of patient's body.
Bone Scan:
If prostate cancer spreads to distant sites, it often goes to the bones first. A bone scan can help show whether cancer has reached the bones.
For bone scan, patients are injected with a small amount of low-level radioactive material, which settles in damaged areas of bone throughout the body. A special camera detects the radioactivity and creates a picture of patients' skeletons.
A bone scan may suggest cancer in the bone, but to make an more accurate diagnosis, other tests such as plain x-rays, CT or MRI scans, or even a bone biopsy are recommended.
Computed tomography (CT) scan:
A CT scan uses x-rays to make detailed, cross-sectional images of your body. It can sometimes help tell if prostate cancer has spread into nearby lymph nodes. If your prostate cancer has relapsed after treatment, the CT scan can often tell if it is growing into other organs or structures in your pelvis.
However, MRI is a better choice for looking at the prostate gland itself.
Magnetic resonance imaging (MRI):
Similar to CT scans, MRI scans show detailed images of soft tissues in the body. However, MRI scans use radio waves and strong magnets instead of x-rays. Hence, the patient is very safe as he or she is not exposed to radiation. A contrast material called gadolinium may be injected into a vein before the scan to better see details.
MRI scans can give a very clear picture of the prostate and show if the cancer has spread outside the prostate into the seminal vesicles or other nearby structures. This can be paramount in determining the treatment options. 
To improve the accuracy of the MRI, you might have a probe, called an endorectal coil, placed inside your rectum for the scan. This can be uncomfortable. If needed, medicine can be given before the scan to make the patient feel sleepy (sedation).

Lymph node biopsy
In a lymph node biopsy, one or more lymph nodes are removed to look for the presence of cancer cells. It can be used to find out if the cancer has spread from the prostate to nearby lymph nodes.

For more information, check out this website:
 http://www.cancer.org/cancer/prostatecancer/detailedguide/prostate-cancer-diagnosis