RECENT DATA SHOW that 93% of men diagnosed with prostate cancer survive at least 10 years and 77% survive at least 15 years,butit's still the most common cause of cancer deaths among American men. Improved tests are detecting prostate cancer earlier, giving men more choices and better treatments for fighting back effectively. In this article, we'll outline what you need to know about prostate cancer screening, treatment, and prevention.
A part of the male reproductive system, the walnut-sized prostate gland is located in front of the rectum and underneath the bladder; it surrounds part of the urethra. Cancer of the prostate, which tends to be slow growing, usually develops in the gland's peripheral zone, where it can be palpated with a digital rectal exam (DRE). Almost all prostate cancer arises from the glandular cells; this type of cancer is called adenocarcinoma. It can spread into the seminal vesicles, bladder, rectum, pelvic wall, and regional lymph nodes. Prostate cancer can also spread to distant lymph nodes, bone, and organs such as the lungs, liver, or brain.
About 66% of men who've been diagnosed are older than 65. African-Americans have the highest mortality rate and a 60% higher incidence rate than whites or Hispanics; incidence is lowest among Asians. Having a father or brother with prostate cancer more than doubles a man's risk.
Besides age, race, and family history, other risk factors being investigated for prostate cancer include having a vasectomy, eating a high-fat diet that's heavy on red meat, skimping on fruits and vegetables, and coming up short on vitamins D and E, lycopene, and the mineral selenium.
Early in the disease, a man probably won't have symptoms. As the tumor grows, however, it may cause urinary symptoms that mimic those of benign prostatic hyperplasia (BPH): urgency, frequency, dribbling, hesitancy, nocturia, interruption of urinary stream, and inability to urinate. (For more information about BPH, see "The ABCs of BPH," in the October issue of Nursing2005.) If the prostate cancer is advanced, he may have blood in his urine (hematuria) or ejaculate, or he may be impotent. If the cancer has metastasized to bone, he may have pain in his hips, spine, ribs, or other areas.
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Because prostate cancer may not produce warning signs in the early stage, all men age 50 or older who have at least a 10-year life expectancy should be offered a yearly DRE and prostate-specific antigen (PSA) blood test. Men who have a high risk of prostate cancer should start testing at age 45; this includes African-Americans and men with a first-degree relative who had prostate cancer before age 65. Men at even higher risk could begin testing at age 40; for instance, men with several first-degree relatives who had prostate cancer at an early age.
Depending on the tumor's location and size, the practitioner may not be able to feel it during the DRE. That's why the PSA blood test is important. The PSA is a substance made by the normal prostate gland. According to the American Cancer Society (ACS), normal PSA rises with age but it's usually 0 to 4 nanograms (ng)/ml. However, 15% of men with a PSA of less than 4 ng/ml will be found to have prostate cancer on biopsy. If the level is 4 to 10 ng/ml, a man has a 25% chance of having cancer; if it's greater than 10 ng/ml, his risk is greater than 50%. The ACS now recommends an age-dependent PSA, which measures how quickly PSA increases from year to year (velocity). Besides cancer, other possible causes of an elevated PSA include prostatitis and BPH.
If a patient's PSA level is elevated or if his practitioner found an abnormality during the DRE, the patient may need more testing. By itself, neither test confirms cancer, but if both tests are positive, a cancer diagnosis is more likely.
The percent-free PSA test compares free PSA with total PSA. Men with prostate cancer have a lower percentage of free PSA than men who don't have prostate cancer. However, the only reliable way to confirm the diagnosis is with a biopsy of the prostate gland. This is usually done using image guidance with transrectal ultrasonography. The patient may also undergo further studies such as magnetic resonance imaging, bone scans, and computed tomography to determine the extent of metastasis.
After diagnosis, prostate cancer is differentiated into one of four stages. The higher the stage, the more advanced the cancer.For instance, in stage 4, cancer has spread to the bladder's external sphincter, rectum, pelvic wall, lymph nodes, or more distant body sites.
Prostate cancers are also graded (Gleason grading system) from 2 to 10, with lower numbers for well-differentiated cells (those closely resembling normal cells) and higher numbers for poorly differentiated cells, which are highly abnormal. The more poorly differentiated the cells, the more aggressive the tumor is likely to be. Stage, grade, and the patient's age and overall health help the practitioner determine treatment.
The patient and his practitioner should discuss all available treatment options. If the patient has a limited life expectancy, a significant comorbidity, and a low-grade or low-stage tumor, he may choose the conservative approach: watchful waiting, also called expectant management, usually every 6 months, with frequent PSA levels and DREs to monitor his progress. If his condition changes during "watchful waiting," active treatment can be initiated. Patients with low-grade prostate cancer may choose this option to avoid the adverse reactions of other treatments, such as erectile dysfunction (ED) and urinary incontinence.
To improve the odds for long-term survival, a radical prostatectomy is the most effective surgical procedure. This procedure can be performed via a laparoscopic, retropubic, or perineal approach. Along with the entire prostate, the surgeon usually removes the seminal vesicles, part of the bladder neck, and the regional lymph nodes.
Because part of the bladder neck is removed, seminal fluid moves upward into the bladder instead of downward to the urethra, causing sterility. (A man wanting to father children could bank sperm before surgery.) Erectile dysfunction can result if pudendal nerves are damaged or removed.
Cryosurgery is a minimally invasive surgical technique that eradicates malignant cells by freezing them. After the patient is anesthetized, the surgeon inserts liquid nitrogen probes into the prostate. Cryosurgery can be used as initial or second-line treatment. Possible complications include impotence, urinary incontinence, and fistula between the rectum and bladder. The patient may have mild postoperative pain.
Transurethral resection of the prostate doesn't require a surgical incision. This palliative procedure may be indicated to relieve urinary obstructions in some patients with higher stage tumors.
Radiation therapy is an important treatment option, particularly for low-grade cancer still confined within the prostate gland. The two main forms are external beam radiation and brachytherapy (implanted interstitial radioactive seeds).
Androgen deprivation therapy can be effective because prostate cancer depends on androgens for tumor growth. One type involves removing both testes (bilateral orchiectomy) to reduce testosterone levels and make the prostate cancer shrink or grow more slowly. Adverse reactions include ED, loss of sex drive, weight gain, and decreased muscle mass. Other options include luteinizing hormone-releasing hormone (LHRH) analogues, LHRH antagonists, antiandrogens, and other androgen-suppressing drugs.
A patient in an advanced stage of prostate cancer with metastasis who doesn't respond to hormone therapy may have chemotherapy for palliation.
Teach patients about the risks of prostate cancer and encourage them to undergo regular screening. Early detection and treatment save lives. Let's get the word out!!
SELECTED WEB SITE
National Cancer Institute, prostate cancer
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Last accessed on April 6, 2006.
American Cancer Society. Prostate Cancer. Revised February 9, 2006. http://documents.cancer.org/117.00/117.00.pdf. Accessed March 16, 2006.
Wallace M. Uncertainty and quality of life of older men who undergo watchful waiting for prostate cancer. Oncology Nursing Forum. 30(2):303-309, March-April 2003.