The effect of mammographic screening on invasive breast cancer in Western Australia.
OBJECTIVE
To determine whether mammographic screening has affected the presentation of invasive breast cancer in Western Australia.


METHODS
Population-based reviews of the presentation of all invasive breast cancers diagnosed in Western Australia in 1989 and 1994.


METHODS
Western Australia (population 1.8 million). Active recruitment of women aged 50-69 years for mammographic screening began in 1989.


METHODS
Size and stage of invasive breast cancers at diagnosis.


RESULTS
From 1989 to 1994, the age-standardised incidence rose from 109 to 123 per 100,000 woman-years, based on 584 and 750 cases, respectively. The proportion of all invasive breast cancers detected as a result of a mammogram increased from 9.2% in 1989 to 34.5% in 1994. Among the cases where relevant information was recorded, the proportion of "impalpable" tumours increased from 7.7% in 1989 to 27.6% in 1994, and the average size of palpable tumours fell. There was an unexpected increase in the proportion of tumors that were negative on assays for oestrogen and progesterone receptors.


CONCLUSIONS
A relatively simple and inexpensive clinical review has boosted confidence that the outlay of public monies required to establish and conduct screening in Australia appears likely to yield the reductions in mortality from breast cancer that would be predicted on the basis of the earlier controlled trials of mammography.
Jamrozik
K
K
Department of Public Health, University of Western Australia, Perth, WA.
Byrne
M J
MJ
Dewar
J M
JM
Harvey
J M
JM
Ingram
D M
DM
Parsons
R W
RW
Watson
N
N
D017677:Age Distribution; D000368:Aged; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000473:pathology / Q000517:prevention & control*; D018672:Community Health Planning; D005260:Female; D006801:Humans; D015994:Incidence; D008327:Mammography; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D009367:Neoplasm Staging; D010173:Palpation; D011159:Population Surveillance; D015397:Program Evaluation; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D012042:Registries; D016896:Treatment Outcome; D014904:Western Australia / Q000453:epidemiology
D011960:Receptors, Estrogen; D011980:Receptors, Progesterone