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Prostate Cancer: Introduction

Prostate Cancer: Introduction

Closeup cross section of bladder, prostate, and rectum showing urethra going through prostate and seminal vesicle above prostate. Tumor is in prostate near rectum.

Prostate cancer is the most common cancer in men (not counting skin cancer) in the U.S. It tends to occur mainly in older men. In most cases prostate cancer is found before it has spread to other parts of the body. Cancer that hasn’t spread is easier to treat and cure.

What is the prostate gland?

The prostate is a sex gland in men. The prostate is about the size of a walnut, but it can grow larger as men age. It sits below the bladder and in front of the rectum. It surrounds the upper part of the urethra. This is the tube that carries urine and semen out of the body. The prostate is part muscle and part gland. It has ducts that open into the urethra.

The prostate gland’s main purpose is to secrete a fluid that makes up most of semen. This is the fluid that carries sperm. It’s made in the gland cells of the prostate. During a man’s orgasm, the muscle parts of the prostate help to send the fluid into the urethra. It’s mixed with other fluids and sperm that were made in the testicles to form semen. The semen then leaves the body through the tip of the penis during ejaculation.

Types of growth in the prostate gland

Growths can happen in the prostate. Some types of growth are not cancer (benign). Others may turn into cancer. The types of growths include:

  • Benign prostatic hyperplasia. As a man ages, the prostate can grow larger. This is called benign prostatic hyperplasia (BPH). It’s a common condition. BPH is not prostate cancer. It does not turn into prostate cancer. But BPH can cause the prostate to press on the urethra. This can lead to symptoms, such as trouble urinating, which might need to be treated. 

  • Prostatic intraepithelial neoplasia (PIN). This is an abnormal prostate growth that may be found with a prostate biopsy. It is not prostate cancer. PIN can be low grade or high grade. Low-grade PIN is common, especially as men get older. Most health care providers don’t consider it to be a concern. Men who have high-grade PIN have a chance that cancer is somewhere else in the prostate.

  • Prostate cancer. Cancer is tumors or growths that can grow into nearby tissues and spread to other parts of the body. Nearly all types of prostate cancer start in the gland cells. These are the cells that make the prostate fluid. These types of cancer are called adenocarcinoma. Other types of cancer can also start in the prostate. These include small cell carcinoma, transitional cell carcinoma, and sarcoma. But these types of cancer rare. Most men with prostate cancer have adenocarcinoma.

Prostate cancer growth and spread

Prostate cancer tends to grow slowly. It can often be found and treated while it is still just in the prostate. In fact, some cases of prostate cancer may not need to be treated right away. But other cases of prostate cancer can grow quickly. The first place cancer grows in the body is called the primary site or primary tumor.

If prostate cancer is not treated and continues to grow, it can grow into other parts of the prostate. Over time it may grow outside of the prostate and into nearby tissues, such as the seminal vesicles. When cancer spreads to other parts of the body, this is called metastasis. Once the cancer has grown outside the prostate, it can spread to nearby lymph nodes. These are bean-sized glands all around the body that are part of the immune system. If prostate cancer spreads to distant parts of the body, most often it goes to the bones first. It may also spread to other organs, such as the lungs, liver, or brain.

 

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