Prostate cancer

Prostate cancer is a common type of cancer among men. The prostate gland is part of the male reproductive system. Treatment for prostate cancer works best when the disease is found early.

Epidemiology

Among men who died and were organ donors, the prevalence at prostate cancer at autopsy was:

• age <50: 0.5% had prostate cancer
• age 50–59: 23% had prostate cancer
• age 60-69: 35% had prostate cancer
• age 70 or more: 46% had prostate cancer

Diagnosis

Early prostate cancer does not usually cause symptoms. As the cancer grows, it may cause trouble urinating, and the need to urinate often, especially at night. Other symptoms can be pain or burning during urination, blood in the urine or semen, pain in the back, hips, or pelvis, and painful ejaculation.

To figure out if these symptoms are caused by prostate cancer, the doctor will ask the patient questions about past medical problems, and will perform a physical exam, putting a gloved finger into the rectum to feel the prostate through the wall. Hard or lumpy areas may be a sign of cancer.

The doctor may also do a test to check the prostate-specific antigen (PSA) level in the blood. PSA levels may be high in men who have an enlarged prostate gland or prostate cancer.

It may also need to have an ultrasound exam. In this procedure, a probe that produces sound waves is put into the rectum. Sound waves bounce off the tissues, and a computer uses the echoes to make a picture of the prostate.

A biopsy is almost always needed to diagnose prostate cancer for sure. This exam takes out tiny pieces of the prostate and sends them to a laboratory to be checked for cancer cells under a microscope.

Prognosis

5-Year Relative Survival Rates By Year Dx By Cancer Site All Ages, All Races, Male 1975-2000.

Gleason score

The Gleason score is the "sum of the numbers associated with the most common histologic pattern plus the secondary pattern." The two numbers are based on the histologic grade:

Gleason grade

Gleason histologic grade	prognosis
1 - 2	well differentiated
3	moderately differentiated
4	poorly differentiated
5	undifferentiated

Gleason score and prognosis

Gleason score (sum of the primary and secondary histologic grades)	prognosis
< 6	indolent
6 - 8	intermediate
> 8	aggressive

A clinical prediction rule is available at http://www.prostate-riskindicator.com/en/w6-intro.html.

Staging

Prostate cancer staging information from the National Cancer Institute's Physician Data Query

Treatment

Prostate cancer treatment information from the National Cancer Institute's Physician Data Query

The choice of treatment depends on the stage of the cancer (whether it affects part of the prostate, involves the whole prostate, or has spread to other parts of the body). It also depends on the patient age and general health. There are three treatment options for cancer that has not spread beyond the prostate; however, a systematic review for the Agency for Healthcare Research and Quality concluded that " Assessment of the comparative effectiveness and harms of localized prostate cancer treatments is difficult because of limitations in the evidence."

Watchful waiting

Watchful waiting may be appropriate if the cancer is growing slowly and not causing problems. In this strategy, the doctor will check regularly for changes in the patient condition. Older men with other medical problems often choose this option.

Surgery

The most common type of surgery is a radical prostatectomy. The surgeon takes out the whole prostate and some nearby tissues. Side effects may include loss of sexual function (impotence) or problems holding urine (incontinence), which can go away within a year of surgery. But some men continue to have problems and have to wear a pad.

An operation called nerve-sparing surgery gives some men a better chance of keeping their sexual function.

Robotic-assisted, minimally invasive radical prostatectomy may result in "shorter length of (hospital) stay, fewer respiratory and miscellaneous surgical complications and strictures, and similar postoperative use of additional cancer therapies but experienced more genitourinary complications, incontinence, and erectile dysfunction."

Radiation therapy

Radiation therapy uses high-energy x-rays to kill cancer cells and shrink tumors. There are two kinds of radiation therapy. External radiation therapy is beamed into the prostate from a machine outside the body. Internal radiation therapy uses radioactive “seeds” that are placed in the prostate, into or near the tumor itself. Like surgery, radiation therapy can cause problems with impotence, not as likely to cause urinary incontinence as surgery. But it can cause rectal problems such as pain and soreness, rectal urgency, and trouble controlling bowel movements.

Hormone therapy

After radiation therapy, some men are treated with hormone therapy. This is used when chances are high that the cancer will come back. Hormone therapy is also used for prostate cancer that has spread beyond the prostate. Side effects of hormone treatments include hot flashes, loss of sexual function, and loss of desire for sex.

Screening

Some doctors think that men should have regular prostate specific antigen (PSA) tests, and others do not. The reason is even knowing that this test can catch a cancer before it causes symptoms, it is not sure that PSA tests save lives. Also, PSA tests find small cancers that would never grow or spread. When that happens, a man may have surgery or other heavy treatments that are not needed. Researchers are studying ways to improve the PSA test so that it catches only cancers that need treatment.

Clinical practice guidelines

Clinical practice guidelines may help guide decisions to screen:

• U.S. Preventive Services Task Force (USPSTF):

"the evidence is insufficient to recommend for or against routine screening for prostate cancer using prostate-specific antigen (PSA) testing or digital rectal examination (DRE). This is a grade I recommendation"

• American Cancer Society, in 2001, recommended:

"The PSA test and the DRE should be offered annually beginning at age 50 to men who have a life expectancy of at least 10 years. Men at high risk should begin testing at age 45. Information should be provided to patients about benefits and limitations of testing."

Interpreting the results of screening tests

Two clinical prediction rules help predict the probability of cancer based on the level of the prostate-specific antigen and other clinical findings.

Evidence from trials

Randomized controlled trials of screening for prostate cancer

Study name	Patients	Intervention	Comparison	Outcome	Rates		Relative risk ratio	Comment
					Screening group	Control group
Göteborg: 2010	20,000 Swedish males • Age range: 50-64 years	Biennial screening	Usual care.	Prostate cancer mortality after 14 years	0.5%	0.9%	0.56†	76% followup. Benefit found, but overdiagnosis also occurred. Number needed to treat = 293.
PLCO: 2009	76,693 American males • Median age range: 60-64 years • 86% anglo	Annual screening	Usual care. 52% of subjects in usual care group received screening outside of the study	Prostate cancer mortality after 7 years	2%	1.7%	1.22	No benefit found
ERSPC: 2009	162,243 European males • Mean age: 61 years • Races not stated	Screening every four years	Usual care. Rate of screening in the control group not stated, but estimated to be 20% prior to the trial.	Prostate cancer mortality after 9 years	0.3%	0.4%	0.80†	Number needed to treat = 1410.
Quebec: 1999	46,486 Canadian males	Frequency not stated	Usual care	Prostate cancer mortality at 11 years	0.1%	0.5%	0.26	Did not use intention to treat analysis.
† p < 0.05