CTF Structured Abstract: Screening for Prostate Cancer

Canadian Task Force on Preventive Health Care

Structured Abstract

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.

Screening for Prostate Cancer

Prepared by John W. Feightner, Professor of Family Medicine, University of Western Ontario, London

These recommendations were finalized by the Task Force in June 1994

Objective
Burden of Suffering
Options
Outcomes

Evidence
Values
Benefits, Harms, and Costs
Recommendations

Validation
Sponsors
Selected References

Objective

To make recommendations on routine screening for prostate cancer in asymptomatic Canadian men > 50 years of age.

Burden of Suffering

Prostate cancer and its early detection have received increasing attention during the early part of the 1990s. It is the second most frequent cause of death from cancer among men (an estimated 3,800 deaths in 1993), and ranks third in terms of potential years of life lost from cancer among Canadian men. Excluding congenital anomalies and perinatal causes of potential years of life lost, prostate cancer ranks ninth among all causes for males. The lifetime risk of dying from prostate cancer is 3%. There is a rapid rise in incidence over the age of 60.

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.

Recommendations were graded as:

A Good evidence to support the recommendation that the condition be specifically considered in a PHE.

B Fair evidence to support the recommendation that the condition be specifically considered in a PHE.

C Poor evidence regarding inclusion or exclusion of the condition in a PHE, but recommendations may be made on other grounds.

D Fair evidence to support the recommendation that the condition be specifically excluded from consideration in a PHE.

E Good evidence to support the recommendation that the condition be specifically excluded from consideration in a PHE.

Quality of evidence was rated according to 5 levels:

I Evidence from at least 1 properly randomized controlled trial (RCT).

II-1 Evidence from well-designed controlled trials without randomization.

II-2 Evidence from well-designed cohort or case-control analytic studies, preferably from more than 1 centre or research group.

II-3 Evidence from comparisons between times or places with or without the intervention. Dramatic results in uncontrolled experiments could also be included here.

III Opinions of respected authorities, based on clinical experience, descriptive studies or reports of expert committees.

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.

Poor evidence exists to include or exclude digital rectal examination from the PHE of men > 50 years of age [C, II-2, II-3]. Insufficient evidence exists to have physicians who presently do the procedure change their behaviour. (Digital rectal examination can be done for other reasons other than to detect prostate cancer.)
Fair evidence exists to exclude routine screening with PSA testing from the PHE of asymptomatic men > 50 years of age [D, II-3].
Fair evidence exists to exclude routine screening with transrectal ultrasound from the PHE of asymptomatic men > 50 years of age [D, II-3].

Validation

This report was externally peer reviewed. The 1989 U.S. Preventive Services Task Force found that insufficient evidence exists for or against the use of digital rectal examination and PSA and transrectal ultrasound are not recommended for routine screening. The U.S. National Cancer Institute concluded that there is insufficient evidence to recommend routine screening with transrectal ultrasound and serum tumour markers. The British Columbia Office of Technology Assessment and the Canadian Cancer Society recommend against the use of PSA for a routine screening test. The Canadian Urological Association and the American Urological Associate recommend annual screening for men between the ages of 50 and 70 years with both digital rectal examination and PSA. The American Cancer Society recommends annual PSA for men beginning at the age of 50 years.

Selected References

Source Document

Feightner J.W. Screening for prostate cancer. In: Canadian Task Force on the Periodic Health Examination. Canadian Guide to Clinical Preventive Health Care. Ottawa: Health Canada, 1994; 812-23.

Link to Full Text of this review

Link to Summary Table of Recommendations of this review

Link to Selected References list of this review

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A	Good evidence to support the recommendation that the condition be specifically considered in a PHE.
B	Fair evidence to support the recommendation that the condition be specifically considered in a PHE.
C	Poor evidence regarding inclusion or exclusion of the condition in a PHE, but recommendations may be made on other grounds.
D	Fair evidence to support the recommendation that the condition be specifically excluded from consideration in a PHE.
E	Good evidence to support the recommendation that the condition be specifically excluded from consideration in a PHE.

I	Evidence from at least 1 properly randomized controlled trial (RCT).
II-1	Evidence from well-designed controlled trials without randomization.
II-2	Evidence from well-designed cohort or case-control analytic studies, preferably from more than 1 centre or research group.
II-3	Evidence from comparisons between times or places with or without the intervention. Dramatic results in uncontrolled experiments could also be included here.
III	Opinions of respected authorities, based on clinical experience, descriptive studies or reports of expert committees.