CANCER OF THE PROSTATE
Prostate cancer is the most common cancer in men other thannonmelanoma skin cancer and the second most common cause of cancer deaths in American men older than 55 years of age (Greenlee et al., 2001). About one in five men in the United States develop prostate cancer. It is estimated that 189,000 new cases of prostate cancer and 30,200 deaths occur annually (American Cancer Society, 2002). Prostate cancer rates are twice as high in African American men than in Caucasian men, and African American men are more likely to die of prostate cancer than men in any other racial or ethnic group. To address this issue, Agho and Lewis (2001) assessed knowledge of prostate cancer and the use of prostate cancer screening services among 108 African American men. The men were unable to answer most of the 21 questions on the test with more than 70% accu-racy, although individuals younger than 40 years of age were more knowledgeable than older men. Despite their increased risk for prostate cancer, only 47% of the men in the sample who were 40 years or older had prostate cancer screening as part of their annual physical examination. Knowledge about prostate cancer was found to be negatively correlated with education, age, and income. A culturally sensitive promotional campaign has been identified as an important strategy to increase aware-ness of the racial disparities in the incidence of prostate cancer and mortality rates. Nurses are in an ideal position to use these research findings to improve the health of African American men by teaching and counseling them about prostate cancer, screening, and treatment.
Risk factors for prostate cancer include increasing age: the incidence of prostate cancer increases rapidly after the age of 50 years, and more than 70% of cases occur in men over 65 years of age. African American men have the highest incidence of prostate cancer in the world. Prostate cancer is common in the United States and northwestern Europe but is rare in Asia, Africa, Central America, and South America. A familial predisposition may occur in 5% to 10% of cases of prostate cancer. Having a fa-ther or brother with prostate cancer doubles the risk; the risk in-creases further if several relatives have had prostate cancer and if the relatives were young at diagnosis. A diet high in red meat and fat increases the risk for prostate cancer (American Cancer Soci-ety, 2002). Large-scale studies are in progress to determine if prostate cancer can be prevented by use of selected supplements or finasteride (Proscar).
Cancer of the prostate in its early stages rarely produces symp-toms. The symptoms that develop from urinary obstruction occur late in the disease. This cancer tends to vary in its course. If the neoplasm is large enough to encroach on the bladder neck, signs and symptoms of urinary obstruction occur: difficulty and frequency of urination, urinary retention, and decreased size and force of the urinary stream. Other symptoms may include blood in the urine or semen and painful ejaculation. Hematuria may re-sult if the cancer invades the urethra or bladder, or both. Prostate cancer can metastasize to bone and lymph nodes. Symptoms re-lated to metastases include backache, hip pain, perineal and rectal discomfort, anemia, weight loss, weakness, nausea, and oliguria (decreased urine output). Unfortunately, these symptoms may be the first indications of prostate cancer.
When prostate cancer is detected early, the likelihood of cure is high. Every man older than 40 years of age should have a DRE as part of his regular health checkup. Routine repeated rectal palpa-tion of the gland (preferably by the same examiner) is important because early cancer may be detected as a nodule within the sub-stance of the gland or as an extensive hardening in the posterior lobe. The more advanced lesion is “stony hard” and fixed. DRE also provides useful clinical information about the rectum, anal sphincter, and quality of stool.
The diagnosis of prostate cancer is confirmed by a histologic examination of tissue removed surgically by transurethral re-section, open prostatectomy, or transrectal needle biopsy. Fine-needle aspiration is a quick, painless method of obtaining prostate cells for cytologic examination. The procedure is helpful for de-termining the stage of disease as well.
Most prostate cancers are diagnosed when a man seeks medical attention for symptoms of urinary obstruction or after abnor-malities are found by DRE. Incidentally detected cancer with trans-urethral resection of the prostate for clinically benign disease and prostatism occurs in 10% to 20% of patients. Rarely do patients have other signs and symptoms, such as azotemia (nitrogen com-pounds in the blood), weakness, anemia, or bone pain.
PSA, a neutral serine protease, is produced by the normal and neoplastic ductal epithelium of the prostate and secreted into the glandular lumen (Brawer, Cheli, Neaman et al., 2000; Kalish & McKinlay, 1999). A simple blood test can be used to measure PSA levels. The concentration of PSA in the blood is proportional to the total prostatic mass. Although the PSA level indicates the pres-ence of prostate tissue, it does not necessarily indicate malignancy. PSA testing is routinely used to monitor the patient’s response to cancer therapy and to detect local progression and early recurrence of prostate cancer. The combination of DRE and PSA testing ap-pears to be a cost-effective method for detecting prostate cancer. The American Cancer Society recommends that, beginning at age 50, an annual DRE and PSA measurement be offered to men who have a life expectancy of at least 10 years and to younger men (age 45 years or older) who are at high risk. Risk factors include strong familial predisposition (two or more affected primary relatives) and African American race (Smith et al., 2000).
Transrectal ultrasound (TRUS) studies are indicated for men who have elevated PSA levels and abnormal DRE findings. TRUS studies help in detecting nonpalpable prostate cancers and assist with staging localized prostate cancer. Needle biopsies of the prostate are commonly guided by TRUS.
Other tests include bone scans to detect metastatic bone dis-ease, skeletal x-rays to identify bone metastases, excretory urog-raphy to detect changes caused by ureteral obstruction, renal function tests, and computed tomography (CT) scans or lym-phangiography to identify metastases in the pelvic lymph nodes.
The radiolabeled monoclonal antibody Capromab Pendetide with Indium-111 (ProstaScint) is an antibody that is attracted to the prostate-specific membrane antigen found on prostate cancer cells (Narayan et al., 2000). The radioactive element attached to the antibody is then visible with scanning, allowing detection of disease spread. This study is used to detect spread of prostate can-cer in the lymph nodes or other parts of the body in newly diag-nosed men who have apparently localized prostate cancer and who are thought to be at high risk for metastasis. In addition, men who have undergone a prostatectomy and who develop a ris-ing PSA level may also be evaluated with this study.
Men with prostate cancer commonly experience sexual dysfunc-tion before the diagnosis is made. Each treatment (see discussion that follows) for prostate cancer further increases the incidence of sexual problems. With nerve-sparing radical prostatectomy, the chance of recovering erections is better for men who are younger and in whom both neurovascular bundles are spared. Hormonal therapy also affects the central nervous system mechanisms that mediate sexual desire and arousability.
Sildenafil (Viagra) has been found to be effective for treating erectile dysfunction in younger men after radical retropubic prostatectomy, especially if the neurovascular bundles were preserved (Zagaja, Mhoon, Aikens et al., 2000). In addition, sildenafil can improve erectile function in men with partial or moderate erec-tile dysfunction following radiation therapy for localized prostate cancer (Zelefsky, 1999).
Treatment is based on the stage of the disease and the patient’s age and symptoms. Partin and associates (1997) combined PSA level with the clinical stage and pathologic grade of the tumor to create a nomogram to predict the pathologic stage of localized prostate cancer. This nomogram can be useful in making treat-ment decisions and predicting treatment outcomes. Nursing care of the patient with cancer of the prostate is summarized in the Plan of Nursing Care.
A radical prostatectomy (removal of the prostate and seminal vesicles) remains the standard surgical procedure for patients who have early-stage, potentially curable disease and a life expectancy of 10 years or more (Carroll et al., 2001). Sexual impotence fol-lows radical prostatectomy, and 5% to 10% of patients have var-ious degrees of urinary incontinence (Bishoff, Motley, Optenberg et al., 1998).
If prostate cancer is detected in its early stage, the treatment may be curative radiation therapy: either teletherapy with a linear ac-celerator or interstitial irradiation (implantation of radioactive seeds of iodine or palladium), also referred to as brachytherapy (Carroll et al., 2001). Teletherapy involves about 6 to 7 weeks of daily (5 days/week) radiation treatments. Interstitial seed im-plantation is performed under anesthesia. About 80 to 100 seeds are placed with ultrasound guidance, and the patient returns home after the procedure. Exposure of others to radiation is min-imal, but close contact with pregnant women and infants should be avoided for up to 2 months. Radiation safety guidelines in-clude straining urine for seeds and using a condom during sexual intercourse for 2 weeks after implantation to catch seeds that may pass through the urethra.
Side effects, which usually are transitory, include inflamma-tion of the rectum, bowel, and bladder (proctitis, enteritis, and cystitis) due to their proximity to the prostate and the radiation doses (Horwitz & Hanks, 2000; Krumholtz et al., 2000; Ragde, Grado, Nadir et al., 2000). Irritation of the bladder and urethra from radiation therapy can cause pain with urination and during ejaculation until the irritation subsides. There is a greater preser-vation of sexual potency, however, with radiation therapy than with surgery. For locally advanced prostate cancer, hormonal treatments before and during radiation therapy are frequently used to improve local control and disease-free survival (Lue, 2000).
Hormonal therapy is one method used to control rather than cure prostate cancer (Carroll et al., 2001). In the early 1940s, it was determined that most prostate cancers were androgen-dependent and could be controlled by androgen withdrawal. Hormonal therapy for advanced prostate cancer suppresses androgenic stimuli to the prostate by decreasing the circulating plasma testosterone levels or interrupting the conversion to or binding of dihydrotestosterone. As a result, the prostatic epithe-lium atrophies (decreases). This effect is accomplished either by orchiectomy (removal of the testes) or by the administration ofmedications.
Orchiectomy lowers plasma testosterone levels because about 93% of circulating testosterone is of testicular origin (7% is from the adrenal glands). As a result, the testicular stimulus required for continued prostatic growth is removed, resulting prostatic at-rophy. Although orchiectomy does not cause the side effects as-sociated with other hormonal therapies, it carries a significant emotional impact.
Estrogen therapy, usually in the form of diethylstilbestrol (DES), has long been used to inhibit the gonadotropins respon-sible for testicular androgenic activity, thereby removing the an-drogenic hormone that promotes the growth of the malignancy. DES relieves symptoms of advanced prostate cancer, reduces tumor size, decreases pain from metastatic nodules, and promotes well-being. However, DES significantly increases the risk for thromboembolism, pulmonary embolism, myocardial infarc-tion, and stroke. Other side effects of estrogen therapy include impotence, decreased libido, difficulty in achieving orgasm, de-creased sperm production, and gynecomastia (enlargement of breasts in men).
Newer hormonal therapies include the luteinizing hormone– releasing hormone (LH-RH) agonists (leuprolide [Lupron] and goserelin [Zoladex]) and antiandrogen agents, such as flutamide (Eulexin). LH-RH suppresses testicular androgen, whereas flu-tamide causes adrenal androgen suppression (Carroll et al., 2001). Cyproterone acetate is a synthetic progesterone derivative that provides effective, competitive inhibition of androgens at the tar-get cells. In contrast to estrogen, the newer hormonal agents are associated with a lower incidence of cardiovascular side effects, gynecomastia, and decreased sexual function. Hot flushing can occur with orchiectomy or LH-RH agonist therapy because theseagents increase hypothalamic activity, which stimulates the ther-moregulatory centers of the body.
Cryosurgery of the prostate is used to ablate prostate cancer inpatients who could not physically tolerate surgery or in those with recurrent prostate cancer. Transperineal probes are inserted into the prostate under ultrasound guidance to freeze the tissue directly. Chemotherapy, such as doxorubicin, cisplatin, and cyclophos-phamide, may also be used.
Keeping the urethral passage patent may require repeated transurethral resections. When this is impractical, catheter drainage is instituted by way of the suprapubic or transurethral route.
For men with advanced prostate cancer, palliative measures are indicated. Although cure is unlikely with advanced prostate cancer, many men survive for long intervals apparently free of metastatic disease. If prostate cancer metastasizes to the bones, these bone lesions can be very painful. Opioid and nonopioid medications are used to control the pain. In addition, external-beam radiation therapy can be delivered to skeletal lesions to relieve pain. Radiopharmaceuticals, such as strontium-89 and samarium-153, can also be intravenously injected to treat multiple sites of bone metastases (Cherney, 2000). Antiandrogen therapies are used in an effort to reduce the circulating androgens. If anti-androgen therapies are not effective, medications such as pred-nisone and mitoxantrone have been effective in reducing pain and improving quality of life. With advanced prostate cancer, blood transfusions are administered to maintain adequate hemo-globin levels when bone marrow is replaced by tumor.
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