OBJECTIVE
The goal of this study was to compare findings on initial and subsequent screening mammograms to determine the prognostic significance of screening-detected abnormalities.
MATERIALS AND METHODS
All 3386 abnormal examinations from a 9-year mammographic screening program were studied. An initial examination was defined as one for which there were no prior films available for comparison (even if one or more prior examinations had been performed); the remainder were called subsequent examinations. The principal mammographic feature of each abnormality was recorded, as well as whether a biopsy was performed. For all screening-detected cancers, we also determined several surrogate markers of prognosis (tumor size, presence of axillary lymph node metastasis, and tumor stage). These various parameters were analyzed as a function of initial versus subsequent screening.
RESULTS
The frequency of abnormal examinations was more than 2 times greater for initial examinations (7%) than for subsequent examinations (3%). Only minor differences were noted between initial and subsequent screenings when comparing the principal mammographic features of the abnormalities. However, the number of cancers found per number of biopsies performed was significantly greater (p = .02) for subsequent screenings (41%) than for initial screenings (32%). Among the 333 cancers detected, tumor size was significantly smaller for subsequent screenings (p = .0076). Node-negative status and early tumor stage (stage 0 or 1) also were found more frequently for subsequently screened cancers, but these differences were not statistically significant.
CONCLUSION
Substantially fewer abnormal screening interpretations are made when mammography has been performed previously and when the prior films are available for comparison. This results in cost savings and reduced morbidity at subsequent screening (no further work-up, less patient anxiety, fewer benign biopsies). Surrogate markers of prognosis also appear to be more favorable for cancers detected at subsequent screening.
[1]
L W Bassett,et al.
Obtaining previous mammograms for comparison: usefulness and costs.
,
1994,
AJR. American journal of roentgenology.
[2]
B. Cady.
Duct Carcinoma In Situ
,
1993
.
[3]
D. Kopans,et al.
Breast cancer survival among women under age 50: is mammography detrimental?
,
1992,
The Lancet.
[4]
E A Sickles,et al.
Quality assurance. How to audit your own mammography practice.
,
1992,
Radiologic clinics of North America.
[5]
L. Tabár,et al.
Update of the Swedish two-county program of mammographic screening for breast cancer.
,
1992,
Radiologic clinics of North America.
[6]
E. Sickles.
Impact of low-cost mammography screening on nearby mammography practices.
,
1988,
Radiology.
[7]
E A Sickles.
The use of computers in mammography screening.
,
1987,
Radiologic clinics of North America.
[8]
E. Sickles,et al.
Mammographic screening: how to operate successfully at low cost.
,
1986,
Radiology.
[9]
L. Tabár,et al.
Significant reduction in advanced breast cancer. Results of the first seven years of mammography screening in Kopparberg, Sweden.
,
1985,
Diagnostic imaging in clinical medicine.
[10]
M Moskowitz,et al.
The predictive value of certain mammographic signs in screening for breast cancer
,
1983,
Cancer.