A diagnosis of prostate cancer can be confirmed only by biopsy. During a biopsy, a urologist (a doctor who specializes in diseases of urinary and sex organs in men, and urinary organs in women) removes tissue samples, usually with a needle. This is generally done in the doctor’s office with local anesthesia. Then, a pathologist (a doctor who identifies diseases by studying tissues under a microscope) checks for cancer cells.
Men may have blood tests to see if the cancer has spread. Some men also may need the following imaging tests:
* Bone scan: A doctor injects a small amount of a radioactive substance into a blood vessel, and it travels through the bloodstream and collects in the bones. A machine called a scanner detects and measures the radiation. The scanner makes pictures of the bones on a computer screen or on film. The pictures may show cancer that has spread to the bones.
* Computerized tomography (CT) scan: An x-ray machine linked to a computer takes a series of detailed pictures of areas inside the body. Doctors often use CT scans to see the pelvis or abdomen.
* Magnetic resonance imaging (MRI): A strong magnet linked to a computer is used to make detailed pictures of areas inside the body.
Prostate cancer is described by both grade and stage.
* Grade describes how closely the tumor resembles normal glandular tissue of the prostate. Based on the microscopic appearance of the tumor tissue, pathologists may describe it as low-, medium-, or high-grade cancer. One way of grading prostate cancer, called the Gleason system, uses scores of 2 to 10. Another system uses G1 through G4. In both systems, the higher the score, the higher the grade of the tumor. High-grade tumors generally grow more quickly and are more likely to spread than low-grade tumors.
* Stage refers to the extent of the cancer. Early prostate cancer, stages I and II, is localized. It has not spread outside the prostate gland. Stage III prostate cancer, often called locally advanced disease, extends outside the gland and may be in the seminal vesicles. Stage IV means the cancer has spread beyond the seminal vesicles to lymph nodes and/or to other tissues or organs.
Source: the National Cancer Institute