Early Detection

Early Detection: Screening for Breast Cancer

Implementation for screening for breast cancer requires several steps:

A program of health education is needed to raise awareness of the disease and the importance of early diagnosis for curability.
A policy is needed to restrict examination to women 40 years of age or over (see below). Then a practical and effective mechanism to identify women in the target age group of 40 years of age or over must be devised.
Female primary health workers are then trained to examine the breasts and to teach women how to do breast self-examination (BSE).They are also instructed on proper case finding and referral procedures.
If resources make mammography available for population screening beyond diagnosis of individual patients, radiologists and radiographers must be trained, stationary and/or mobile mammographic facilities established along with a quality control program for films and readings.
A policy is needed to use mammography to screen the group of 50-69 years.
A link is needed between identification of an abnormality and referral to be sure that all suspected lesions are properly diagnosed and treated, and that women receive proper follow-up.
An information system will also be needed to allow for monitoring and evaluation of the program, including measurement of the downstaging phenomenon.

The natural history of breast cancer is long. The disease process begins about age 25, and in situ cancer appears between the ages of 40 to 50. Screening in this age group with mammography remains controversial. Small invasive cancers begin about age 50 through age 60, when large invasive cancers are seen leading to death about age 65. Currently clinical trials show that population screening has maximum cost-effectiveness in this 50-60 through 69 year age group.

Process, impact and outcome measures are used to monitor and evaluate secondary prevention programs. For breast cancer screening, examples might include (WHO,1995):

Process Measures
More than 80% of women aged 40 and over are educated about breast cancer screening.
More than 80% of primary health workers are educated and trained in breast examination and teaching BSE, and about screening policies.

Impact Measures:
Over 80% of women in the target 40 or older age group are examined at least once, and taught BSE.
Over 70% of women aged 50-69 are screened using mammography.

Outcome Measures
Short Term: More than one-third of breast cancers are discovered by screening. In mammography programs, the ration of cancers detected at first screen is three times the expected incidence.
Medium Term There is a more than 15% reduction in cases presenting with advanced disease (stage II and beyond).
Long Term: There is more than 15% reduction in the mortality of breast cancer.

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