Prostate cancer

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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:[1]

  • 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

A clinical prediction rule has been validated for predicted an abnormal prostate biopsy.[2] The calculator is online.

The prostate specific antigen (PSA) velocity does not help detect prostate cancer.[3]

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."[4] The two numbers are based on the histologic grade:

Gleason grade[5]
Gleason histologic grade prognosis
1 - 2 well differentiated
3 moderately differentiated
4 poorly differentiated
5 undifferentiated
Gleason score and prognosis[5]
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."[6]

Watchful waiting / active surveillance

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. This strategy may be appropriate when:[7][8]

  • SA level of 10 ng/mL or lower
  • Gleason score of 6 or lower
  • Clinical stage of T1c or T2a

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.

Prostatectomy has a small benefit after eight[9], fifteen[10], and 23 years[11].

Minimally invasive radical prostatectomy

Minimally invasive radical prostatectomy, usually robotic-assisted, 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" according to a cohort study.[12]

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.

Radiosurgery

Radiosurgery, also called gamma knife radiotherapy, has only been reported in uncontrolled studies.[13][14][15]

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):
    • 2002 recommendations stated[16][17][18] "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"
    • 2012 recommendations stated[19][20] "The USPSTF recommends against PSA-based screening for prostate cancer (grade D recommendation)"
"asymptomatic men who have at least a 10-year life expectancy have an opportunity to make an informed decision with their health care provider about screening for prostate cancer after they receive information about the uncertainties, risks, and potential benefits associated with prostate cancer screening. Prostate cancer screening should not occur without an informed decision-making process. Men at average risk should receive this information beginning at age 50 years. Men in higher risk groups should receive this information before age 50 years"
"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.[25][26]

Evidence from trials

Randomized controlled trials of screening for prostate cancer[27][28][29][30][31][32]
Study name Patients Intervention Comparison Outcome Rates Relative risk ratio Comment
Screening group Control group
Norrköping:[27]
2011
9,000 Swedish males
• Age range: 50-69 years
Triennial screening (four screenings from 1987 to 1996) Usual care. Prostate cancer mortality after 20 years 2.0% (30/1494) 1.7% (130/7532) 1.16 PSA was only available for the last two screens.
PLCO:[28]
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:[29]
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.
Göteborg:[30]
2010
Subgroup of ERSPC
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.
Quebec:[31][32]
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

A meta-analysis of the trials has concluded there is no mortality benefit.[33]

References

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