Please note: In 2003, the CTF updated its Grades of Recommendations to include an "I Recommendation" for situations where insufficient evidence exists to allow a recommendation to be made. (Formerly, these situations were captured under a "C Recommendation".) This change is not retroactive, and all "C Recommendations" made prior to 2003 have not been reevaluated in light of the new "I" recommendation grade. For a discussion of these recommendation grades, please link to the 2003 article in the Canadian Medical Association Journal here.
One of the major challenges in dealing with the early detection of prostate
cancer is the lack of a clear understanding of its natural history. Autopsy
studies indicate a prevalence of histologic cancer in the range of 20%
of men of average age 50 and 43% of men aged 80. Hence, the often heard
expression "more men die with prostate cancer than from prostate cancer".
This is an indication that, particularly in older age groups, prostate
cancer is often an incidental finding and can exist without creating major
morbidity and mortality. Unfortunately, the natural history of this disease
has not been defined. Thus, there is no way of indicating for any individual
which cancer, particularly those found at an earlier stage, will progress
to be clinically significant in terms of potential morbidity and/or mortality.
Options
Options for screening include digital rectal examination, transrectal
ultrasound, and prostate specific antigen (PSA) measurement. Treatment
options include watchful waiting, radiation therapy, and radical prostatectomy.
Outcomes
Sensitivity and specificity of the tests and mortality and disease-free
survival for each of the therapies.
Evidence
MEDLINE and bibliographies of relevant articles were searched. No keywords
or details of inclusion criteria for studies were provided.
Values
The 13-member Task Force of experts in family medicine, geriatric medicine,
pediatrics, psychiatry and epidemiology used an evidence-based method for
evaluating the effectiveness of preventive health care interventions. Recommendations
were not based on cost-effectiveness of options. Patient preferences were
not discussed.
Background papers providing critical appraisal of the evidence and tentative
recommendations prepared by the chapter author were pre-circulated to the
members. Evidence for this topic was presented and deliberated upon in
1- to 2-day meetings, 2 to 3 times per year from January 1993 to June 1993.
Consensus was reached on final recommendations.
Benefits, Harms, and Costs
Digital rectal examination is easy to do and inexpensive but is limited
because only the posterior and lateral aspects of the prostate can be palpated.
Also, accuracy may depend on examiner skill level. Sensitivity ranges from
33% to 58% and specificity from 96% to 99%. One study showed increased
sensitivity and specificity with repeat testing. The positive predictive
value of DRE is 28%.
Transrectal ultrasound results are also somewhat operator dependent on the skill of the interpreter, and, for small lesions, the false positive rate is high. Sensitivity is approximately 97% and specificity is 82%.
The PSA level cut point for diagnosis of prostate cancer with PSA has not been firmly established and has ranged from 3 to 10 m g/L. The positive predictive value ranges from 8% to 33%. Some evidence shows that up 67% to 92% of men with a positive PSA test will have an unnecessary biopsy. Risks for of biopsy include prostatitis, epididymitis, and hematuria (up to 4%)
No studies have been done that show that screening will save lives and some evidence exists that for early prostate cancer, no therapy has beneficial effects. For higher grade cancer, cohort studies that show radiation or radical prostatectomy may provide benefit. No RCTs have been done to evaluate these approaches to treating prostate cancer although one RCT is underway in the United States.
A pooled analysis of 6 non-randomized controlled trials that evaluated observational plus delayed hormone therapy for clinically localized cancer, showed a 10-year disease-specific survival of 87% for men with grade 1 or 2 tumours.
Surgical adverse effects are mortality of just over 1%, complete incontinence 7%, any incontinence 27%, impotence 32%, stricture 12%, and bowel injury requiring colostomy or long-term treatment 1%. Radiation has related mortality of 0.2%, any incontinence 6%, complete incontinence 1%, stricture 5%, bowel injury 2%, and impotence 42%.
Cost data are limited.
Recommendations
Recommendation grade [A, B, C, D, E] and level of evidence
[I, II-1, II-2, II-3, III] are indicated after each recommendation. Citations
in support of individual recommendations are identified in the guideline
text.