Prostate Cancer

Prostate cancer is a disease in which malignant (cancer) cells form in the tissues of the prostate. It is the most common cancer (excluding skin cancer) and the second leading cause of cancer-related death in men in the United States.

Introduction

The prostate is a gland in the male reproductive system located just below the bladder (the organ that collects and empties urine) and in front of the rectum (the lower part of the intestine). It is about the size of a walnut and surrounds part of the urethra (the tube that empties urine from the bladder). The prostate gland produces fluid that makes up part of the semen.

Prostate cancer is found mainly in older men. As men age, the prostate may get bigger and block the urethra or bladder. This may cause difficulty in urination or can interfere with sexual function. The condition is called benign prostatic hyperplasia (BPH), and although it is not cancer, surgery may be needed to correct it. The symptoms of benign prostatic hyperplasia or of other problems in the prostate may be similar to symptoms of prostate cancer.

Symptoms and Diagnosis

These and other symptoms may be caused by prostate cancer. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:

• Weak or interrupted flow of urine.
• Frequent urination (especially at night).
• Trouble urinating.
• Pain or burning during urination.
• Blood in the urine or semen.
• A pain in the back, hips, or pelvis that doesn't go away.
• Painful ejaculation.

The following tests and procedures may be used:

Digital rectal exam (DRE): An exam of the rectum. The doctor or nurse inserts a lubricated, gloved finger into the rectum and feels the prostate through the rectal wall for lumps or abnormal areas.

Prostate-specific antigen (PSA) test: A test that measures the level of PSA in the blood. PSA is a substance made by the prostate that may be found in an increased amount in the blood of men who have prostate cancer. PSA levels may also be high in men who have an infection or inflammation of the prostate or BPH (an enlarged, but noncancerous, prostate).

Transrectal ultrasound: A procedure in which a probe that is about the size of a finger is inserted into the rectum to check the prostate. The probe is used to bounce high-energy sound waves (ultrasound) off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. Transrectal ultrasound may be used during a biopsy procedure.

Biopsy: The removal of cells or tissues so they can be viewed under a microscope by a pathologist. The pathologist will examine the biopsy sample to check for cancer cells and determine the Gleason score which ranges from 2-10 and describes how likely it is that a tumor will spread. The lower the number, the less likely the tumor is to spread.

Causes

All cancers are caused by dysfunctions of proteins involved in cell division, apoptosis, or DNA repair (see general characteristics). Dysfunctional proteins may arise from gene mutations or protein interactions with environments. Several genes associated with prostate cancer have been identified (more info).

Reference:

National Cancer Institute, USA.