Prostate Definition

The prostate is a small, glandular, male reproductive organ whose secretions comprise ejaculate. The three common conditions involving the prostate are benign prostatic hypertrophy, prostatitis and prostate cancer. Examination of the prostate can include a digital rectal exam or prostate specific antigen.

Location

• The prostate is a small organ located within the male pelvic cavity underneath the bladder, behind the pubic symphysis, and in front of the rectum. This location makes it easy to palpate it during a rectal exam. It develops from the epithelium of the urethra as a series of glands; as a result, the mature prostate surrounds a portion of the urethra as it approaches the shaft of the penis. The prostate secretes substances necessary for ejaculation and fertilization.

  For description purposes, there are two ways to divide the prostate, both which divide it into five sections. Lowsley's system describes it as: right and left lateral, anterior and posterior, and median. McNeal's system includes: central, peripheral and transitional zones, an anterior segment and a preprostatic sphincteric zone.

  The prostate receives its blood supply from the inferior vesical artery, a branch of the anterior trunk of the internal iliac artery (which branches directly from the abdominal aorta). Blood is drained from the prostate by the pelvic plexus of veins, which drain into the internal iliac veins, then into the hepatic portal system.

Benign Prostatic Hypertrophy

• A common benign condition of older age is benign prostatic hypertrophy (BPH). This condition involves excess growth of the prostate. It is thought to result from increased sensitivity to androgens, causing proliferation of prostatic cells or decreased cell death. The symptoms of BPH include trouble urinating--either getting a stream started or completely emptying--along frequency and urgency in the absence of any sort of urinary tract infection, neurologic disorder (stroke, cauda equina syndrome) or malignancy. BPH can be treated with alpha-blockers or 5-alpha reductase inhibitors. More complicated cases can be treated surgically. Minimally invasive techniques include laser therapy or ablation therapy to dissolve parts of the prostate.

Prostitis

• Prostatitis is another common condition typically manifested by difficulty or pain with urination or ejaculation. It can be caused by a bacterial infection; in this instance, other symptoms include fever and chills. This, however, accounts for only a fraction of cases. Diagnosis and treatment are determined by a digital rectal exam (DRE) and examination of prostatic secretions. Bacterial prostatitis is treated with antibiotics. There are no proven optimal therapies for non-bacterial prostatitis, but the prostatitis may resolve by itself.

Prostate Cancer

• Prostate cancer is newly diagnosed in more than 218,000 patients every year. According to "Current Medical Diagnosis and Treatment 2009, "an American man has a 40 percent chance of developing latent (silent) prostate cancer, 16 percent for developing clinically significant cancer and 2.9 percent risk for dying of prostate cancer. Risk factors include black race, high dietary fat intake and a family history of cancer. There are no specific symptoms of prostate cancer except in rare cases, where prostatic growth may metastasize or compress the spinal cord, leading to back pain or neurologic symptoms.
  Prostate cancer can be detected with a digital rectal exam as areas of induration or focal nodules. Prostate specific antigen (PSA) can be used to stage and monitor the progress of cancer. Neither DRE nor PSA, however, are diagnostic as a biopsy will provide a definitive diagnosis. Treatment for prostate cancer includes radical prostatectomy, which is complete removal of the prostate along with accessory glands, along with radiotherapy, surveillance (observation) and cryosurgery, which is freezing the prostate leading to tissue destruction. Treatment for metastatic disease will include androgen deprivation to control growth.

Prostate Exams

• Digital rectal exams are recommended yearly for men older than 50 who have at least a 10-year life expectancy. Men at high risk for developing prostate cancer should begin earlier, at age 45, including African-Americans and those with a first-degree family history of prostate cancer diagnosed before age 65. This would include the patient's father, brother or son.

  A blood test for PSA can also be used to screen for or monitor prostate cancer. A high PSA is not diagnostic of cancer, but indicates a need for further examination.