BSE_abs

Canadian Task Force on Preventive Health Care

Structured Abstract
Link to Related CMAJ Editorial

Preventive health care, 2001 update: Should women be routinely taught breast self-examination to screen for breast cancer?

Prepared by N. Baxter, MD, PhD, FRCS (C), with the Canadian Task Force on Preventive Health Care

These recommendations were finalized by the Task Force in October 2000.

Objective
Burden of Suffering
Options
Outcomes

Evidence
Values
Benefits, Harms, and Costs

Recommendations
Validation
Sponsors
Selected References

Objective

(1) To evaluate the evidence relating to the effectiveness of breast self-examination to screen for breast cancer, and (2) to provide recommendations for teaching of breast self-examination to women as part of a periodic health examination.

In 1994, the Canadian Task Force on the Periodic Health Examination concluded that there was insufficient evidence to recommend for or against screening for breast cancer using breast self-examination (BSE) (C recommendation). Given that there is additional trial evidence available, a review was deemed warranted.

Burden of Suffering

Breast cancer is the most frequently diagnosed cancer among Canadian women and accounts for 30% of all new cancer cases each year. In Canada, 19,200 new diagnosed cases of breast cancer and 5,500 deaths from the disease were estimated for the year 2000. The current age-standardized incidence and mortality rates for Canada are 106 and 27 per 100,000 respectively. The lifetime risk of dying of breast cancer is one in 25.8. Breast cancer is the number one cause of person-years of life lost for women.

The most important risk factor for women is age, with most breast cancers occurring during the postmenopausal years. It is rare in women under 30. As most women diagnosed with breast cancer have no identifiable risk factor, the effectiveness of breast self-examination should be demonstrated in the general population if it is to impact on disease burden.

Options

This review considers the routine teaching to women, by health professionals, of breast self-examination. Breast self-examination is defined as a systematic method of palpation of the breast and axilla, not casual or ad hoc palpation.

For breast cancer screening generally, current evidence supports mammography and clinical breast examination for women 50-69. For women 40-49, the evidence is insufficient to recommend for or against routine screening. For women above the age of 70 there is limited evidence regarding the benefit of screening.

Outcomes

Prevention of breast cancer mortality was viewed as the most important outcome. Others outcomes included: breast cancer incidence, the stage of cancer detected, the benign biopsy rate, number of patient visits for breast complaints, and psychological benefits and/or morbidity.

Evidence

With the help of a reference librarian Medline, Premedline, CINAHL, HealthStar, Current Contents, and the Cochrane Library were searched from 1966- October 2000 using the terms: breast diseases, breast self-examination, palpation, mass screening and clinical trials.

The search was restricted to publications with English abstracts. Abstracts of all retrieved papers were read; those relevant to the review were critically appraised. Related articles and reference lists of key articles were searched and experts in the field were consulted to ensure that no significant studies were missed.

All evidence was systematically reviewed using the procedures of the Canadian Task Force on Preventive Health Care. The Task Force, comprising expert clinicians and methodologists from a variety of medical specialties, used a standardized evidence-based method for evaluating effectiveness.

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 10-member Task Force of experts in family medicine, geriatric medicine, paediatrics, 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 primary author were pre-circulated to the members. Evidence for this topic was presented and deliberated upon in 1- to 2-day meetings from Nov 1999 to October 2000. Consensus was reached on final recommendations.

Benefits, Harms, and Costs

Estimates derived from one study suggest that the overall sensitivity of BSE alone was 26% in screened women, assuming that all interval cancers were detected by BSE. Sensitivity varied with age from 41% for women aged 35-39 to 21% in women aged 60-74. Specificity was not estimated.

In studies of lump detection in silicone breast models, sensitivity ranged from 40% to 89%, while specificity ranged from 66% to 81%. The sensitivity of lump detection in silicone models has been shown to be lower in women over 60 as compared to younger women. While sensitivity improved with training, so did the rate of false positive detection.

None of the studies, including 2 large randomized controlled trials, a quasi-randomized trial, a large cohort and several case-control studies, showed a benefit for regular performance of BSE or BSE education, compared to no BSE. In randomised controlled trials with up to 9 years of follow-up, no significant differences were found in: the number of breast cancers detected, stage at diagnosis, or breast cancer deaths. The effect of BSE technique was evaluated in secondary analyses of case-control studies. While there was demonstration of benefit in some sub-groups no statistical adjustment was made for multiple comparisons.

There is good evidence of harm from BSE instruction, including significant increases in physician visits for the evaluation of benign breast lesions and significantly higher rates of benign breast biopsies. The teaching and reinforcement of BSE are costly and may divert resources from other preventive activities.

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.

Women aged 50 to 69: Because there is fair evidence of no benefit, and good evidence of harm, there is fair evidence to support the recommendation that routine teaching of BSE be excluded from the periodic health examination [D, I, II-1, II-3].
Women aged 40 to 49: Because there is fair evidence of no benefit, and good evidence of harm, there is fair evidence to support the recommendation that routine teaching of BSE be excluded from the periodic health examination [D, I, II-1, II-3]. While the evidence indicates no benefit from routine instruction, some women will request teaching in BSE. The pros and cons should be discussed with the woman, and if BSE is taught, care must be taken to ensure that BSE is conducted in a proficient manner.
There is insufficient evidence for effectiveness of the maneuver in women younger than 40 or older than 70 years, thus precluding making recommendations for teaching breast self-examination to women in these age groups. The following issues may be important to consider: Women younger than 40 years: There is little evidence for effectiveness specific to this group. As the incidence of breast cancer is low in this age group, the risk for net harm is even more likely. Women 70 years or older: Though the incidence of breast cancer is high in this group, there is insufficient evidence to make a recommendation for women over age 70 years.

Validation

The members of the Canadian Task Force on Preventive Health Care reviewed the findings of this analysis through an iterative process. Three external peer reviewers also reviewed the draft of the report. It was again peer reviewed as part of the journal publication process.

Selected References

Source Document:

N. Baxter with the Canadian Task Force on Preventive Health Care. Preventive health care, 2001 update: Should women be routinely taught breast self-examination to screen for breast cancer? CMAJ 2001; 164(13):1837-46.

Link to Full Text of this review

Link to Summary Table of Recommendations of this review

Link to Selected References list of this review

Link to 2001 Update: Screening mammography among women aged 40–49 years at average risk of breast cancer

Link to 1999 Update: Follow-up after breast cancer

Link to 1998 rewording of recommendation for screening women aged 50-59 for breast cancer

Link to 1994 Chapter: Screening for breast cancer

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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.