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The Prostate
The prostate is a walnut-sized gland located below a man’s bladder. It secretes
seminal fluid during ejaculation.
Prevalence and Incidence of Prostate Cancer
According to the American Cancer Society, prostate cancer is one of the most
common forms of cancer among American men.1 Prostate cancer is even
more common among African American men than white men, though the reason for
this difference is not known. European rates are lower than those in the United
States, and the lowest rates have been observed in Asia. These variations may
be partially due to use of different diagnostic techniques or to currently unknown
risk factors.2
As men age, their chance of developing prostate cancer increases. An estimated
8 out of 10 men diagnosed with prostate cancer are over age 65. In fact, a large
percentage of men who live long enough are likely to get prostate cancer. According
to the National Cancer Institute (NCI), one third of all American men over age
50 have microscopic signs of prostate cancer.3 Furthermore, by age
75, 50 to 75 percent of American men will have cancerous changes in the prostate.3
The apparent incidence of prostate cancer rose sharply after 1989, but then began
falling rapidly after 1992. In 1995, NCI researchers published a study that linked
the sharp rise in new cases from 1989 to 1991 to the increased use of the prostate-specific
antigen (PSA) blood test.4 Physicians increased their use of the PSA
test for men age 65 and older — the age group most susceptible to prostate cancer — from
1,430 tests per 100,000 men in 1988 to 18,000 per 100,000 men in 1991.4 Use
of the PSA test increased the detection of prostate cancer cases and enabled
detection at an earlier stage than had been possible previously.
Guidelines have been developed by the American Cancer Society for how often the
PSA test should be performed. Although the PSA test itself is not foolproof,
when combined with follow-up evaluation, it is highly reliable and likely the
best and most effective means to detect and follow prostate cancer. It is now
available in all major hospitals and in many physicians’ offices.
Age-adjusted rates of prostate cancer incidence rose 69 percent in U.S. men from
1989 to 1992, compared with 20 percent from 1985 to 1988, and 3 percent from
1981 to 1984.4
For white men, the incidence rate peaked in 1992 at 185 new cases per 100,000
men before dropping 27 percent to 135 new cases per 100,000 in 1994. Incidence
in African American men peaked in 1993 at 265 cases per 100,000 before declining
11 percent to 234 cases per 100,000 in 1994.4
Diagnosing Prostate Cancer
Increasingly, physicians are relying on the results from
the PSA blood test to diagnose prostate cancer. When the prostate
gland has a hint of cancer-producing cells, a detectable substance,
namely PSA, is produced in the blood. As the PSA blood test has
been refined and developed, it has given doctors an invaluable tool
in making an initial — and earlier — diagnosis, as well as providing
an accurate, noninvasive way to monitor any recurrence of the disease
after treatment. An abnormally high PSA level alerts the physician
to the possible presence of prostate cancer.
In conjunction with the blood test, the prostate cancer screening process
includes a digital rectal exam, in which the doctor feels the prostate through
the rectum, checking for a hardening or enlargement that would be suspicious
for tumor.
If cancer is suspected, the doctor may recommend a biopsy. Prostate tissue
is removed with a needle and examined under a microscope. If the biopsy shows
prostate cancer, other tests are done to determine the type of treatment needed.1
Early Detection
In the early stages of prostate cancer, the disease stays
in the prostate and is not life threatening. But without treatment,
cancer can spread to other
parts of the body and eventually cause death. Almost 40,000 men will die
this year alone from prostate cancer.
To increase the likelihood of early detection and — as with many cancers — the
best chance for a cure, men and their doctors are increasingly looking to prostate
cancer screening.
Experts recommend routine PSA testing and a rectal exam, beginning at age
40 for African American men or anyone with a family history of prostate cancer;
and at age 50 for all other men.
Prostate Cancer Treatment Options
There are several ways to treat prostate cancer. The choice
depends on many factors, such as whether or not the cancer has spread
beyond the prostate, tumor characteristics, the patient's age and
general health, and how the patient feels about the treatment options
and their side effects.
Localized prostate cancer — when the cancer is confined to the prostate and
has not metastasized to other areas of the body — is considered highly curable.
Approaches to treatment include: watchful waiting — which assumes that the cancer
will grow slowly rather than quickly, so perhaps no course of treatment may
ever be necessary. Watchful waiting is most likely to be suggested in older
men who appear to have small, less aggressive tumors with minimal or no symptoms
and for whom aggressive treatments such as surgery may pose higher risk.1
One course of action, if treatment is given, is the removal of the entire
prostate. Men often experience incontinence and impotence following this surgery.1 Another
option is external beam radiation therapy (radiation doses delivered from outside
the body, also known as XBRT).
A treatment option that has been shown to be as effective as surgery is brachytherapy,
namely, the implanting of radioactive seeds into the prostate.5
Combination therapy (seed implants in conjunction with external radiation)
may be used in some cases, particularly with more aggressive tumors. XBRT, brachytherapy,
and combination therapy offer the potential for cure in a less invasive way
than surgery.
Seed Implantation (Brachytherapy)
More and more, patients are electing the implantation of
therapeutic seeds, such as OncoSeed™ (iodine-125 seeds). New
studies comparing the efficacy of radical prostate surgery versus
OncoSeed implantation 10 years following the
surgery or treatment show these two options provide a similar disease-free
survival rate.5 However, treatment with OncoSeed
has a lower incidence of permanent impotence and incontinence.6-8
If a patient elects brachytherapy, he will undergo an outpatient procedure
in which radioactive seeds are inserted into the prostate, where they can attack
the tumor from inside the gland. Within days following the procedure, most patients
are back to normal activity; sexual activity is permitted after two weeks.9
Disease Progression
Once the patient has been diagnosed with prostate cancer,
experts recommend regular monitoring and testing for recurrences
or previously undetected metastases.
If the disease progresses or is diagnosed in a later stage, the urologist
may administer a hormone suppressive therapy (ie, Lupron Depot®* or
Zoladex®*) or perform an orchiectomy (surgical castration) to
stop the progression of the disease. If the patient still does not respond or
the cancer continues to spread, he will likely be referred to an oncologist,
who will select therapies to treat advanced disease.
Expert Recommendations for Treatment
As with most cancers, a course of treatment is a highly
personalized decision that the doctor and patient, with input from
his family and close friends, should determine. A special panel
convened under the auspices of the American Urological Association
(AUA) concluded that in the instance of prostate cancer that is
detected early, no definitive recommendation of one course of treatment
over another could be made. Comparisons of radical prostatectomy
and OncoSeed implants show equal life expectancy, as much as 10
years after the operation or procedure.5 As a consequence,
the AUA panel offered official treatment "options" rather
than
explicit practice "guidelines."10
*Lupron Depot® (leuprolide acetate for
depot suspension) is a registered trademark of TAP Pharmaceuticals Inc; Zoladex® (goserelin
acetate implant) is a registered trademark of Zeneca Pharmaceuticals.
References
1. American Cancer Society. The Prostate Cancer Resource Center:
Prostate cancer - overview. Accessed March 30, 1999.
2. Health Protection Branch – Laboratory Centre for Disease
Control. Chronic Diseases in Canada. Accessed July 19, 1999.
3. National Cancer Institute. Understanding
Prostate Changes: A Health Guide for All Men. Washington,
DC: Public Health Services; 1998. US Dept of Health and Human
Services. NIH publication 98-4303.
4. National
Cancer Institute. Cancer Facts: Recent Trends in Prostate Cancer
Incidence and Mortality. Accessed April 2, 1999.
5. Ragde H, Elgamal A-AA, Snow PB, et al. Ten-year disease free
survival after transperineal sonography-guided iodine-125 brachytherapy
with or without 45-gray external beam irradiation in the treatment
of patients with clinically localized, low to high Gleason grade
prostate carcinoma. Cancer. 1998;83:989-1001.
6. Strum SB, Scholz MC. Brachytherapy: implantation of prostate
cancer with radioactive isotopes: analysis of the Seattle experience:
May 1996 update.
7. Stock RG, Stone NN, DeWyngaert JK, Lavagnini P, Unger PD.
Prostate specific antigen findings and biopsy results following
interactive ultrasound guided transperineal brachytherapy for
early stage prostate carcinoma. Cancer. 1996;77:2386-2392.
8. Catalona WJ, Carvalhal GF, Mager DE, Smith DS. Potency, continence
and complication rates in 1,870 consecutive radical retropubic
prostatectomies. J Urol. 1999;162:433-438.
9. Abel LJ, Blatt HJ, Stipetich RL, et al. Nursing management
of patients receiving brachytherapy for early stage prostate cancer. Clin J Oncol Nurs. 1999;3:7-15.
10. Middleton RG, Thompson IM, Austenfeld MS, et al. Prostate
cancer clinical guidelines panel summary report on the management
of clinically localized prostate cancer. J
Urol. 1995;154:2144-2148.
Please note that this information is provided for
educational purposes only. It is not intended to substitute for informed
medical advice. The user of this site should not use this information
to diagnose or treat a health problem or disease without consulting with
a qualified health care provider.
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