Assessing the effectiveness of a mammography screening service.
BACKGROUND
Trials have shown that mammography screening reduces mortality and probably decreases morbidity related to breast cancer.


METHODS
We assessed whether the major mammography service in Western Australia (BreastScreen WA) is likely to reduce mortality by comparing prognostic variables between screen-detected and other cases of breast cancer diagnosed in 1999. We assessed likely reductions in morbidity by comparing treatments received by these two groups. To confirm mortality and morbidity reduction, we also compared prognostic variables and treatments with targets. Information on demographic variables, tumour characteristics at presentation and treatments were collected from medical records for all incident cases of breast cancer in Western Australia in 1999. We matched cases with the Western Australian Cancer Registry records to determine which cases had been detected by BreastScreen WA.


RESULTS
BreastScreen WA achieved the targets for mortality reduction. Tumours detected by BreastScreen WA were smaller in size, less likely to have vascular invasion, of lower histological grade and were more likely to be ductal carcinoma in situ alone without invasive carcinoma. Oestrogen receptor status was more likely to be positive, the difference in progesterone status was not significant, and lymph node involvement tended to be lower. BreastScreen WA patients were treated more often with local therapy and less often with systemic therapy, and the proportion of patients treated with breast-conserving surgery was close to the target for minimizing morbidity in breast cancer.


CONCLUSIONS
Mammographic detection of breast cancer by BreastScreen WA is associated with reduced breast cancer morbidity and a more favourable prognosis.
Clayforth
Cassandra
C
School of Population Health, University of Western Australia, Perth, Australia. cassclay@dph.uwa.edu.au
Fritschi
Lin
L
McEvoy
Suzanne
S
Byrne
Michael J
MJ
Wylie
Elizabeth
E
Threlfall
Tim
T
Sterrett
Greg
G
Harvey
Jennet M
JM
Jamrozik
Konrad
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000737:chemistry / Q000000981:diagnostic imaging* / Q000473:pathology; D002277:Carcinoma / Q000737:chemistry / Q000000981:diagnostic imaging / Q000473:pathology; D002278:Carcinoma in Situ / Q000737:chemistry / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D008327:Mammography; D008403:Mass Screening; D008875:Middle Aged; D015397:Program Evaluation; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis
D011960:Receptors, Estrogen; D011980:Receptors, Progesterone