Edward A. Sickles, MD
Diana L. Miglioretti, PhD
Rachel Ballard-Barbash, MD
Berta M. Geller, EdD
Jessica W. T. Leung, MD
Robert D. Rosenberg, MD
Rebecca Smith-Bindman, MD
Bonnie C. Yankaskas, PhD
Published online
10.1148/radiol.2353040738
Radiology 2005; 235:775–790
Abbreviations:
BCSC ⫽ Breast Cancer Surveillance
Consortium
BI-RADS ⫽ Breast Imaging Reporting
and Data System
DCIS ⫽ ductal carcinoma in situ
PPV ⫽ positive predictive value
1
From the Departments of Radiology
(E.A.S., J.W.T.L., R.S.B.) and Epide-
miology/Biostatistics (R.S.B.), Uni-
versity of California San Francisco
School of Medicine, 1600 Divisadero
St, Rm H-2801, San Francisco, CA
94115; Center for Health Studies,
Group Health Cooperative, Seattle,
Wash (D.L.M.); Applied Research Pro-
gram, Division of Cancer Control and
Population Sciences, National Cancer
Institute, Bethesda, Md (R.B.B.); Office
of Health Promotion Research, Uni-
versity of Vermont, Burlington, Vt
(B.M.G.); Department of Radiology,
University of New Mexico-HSC, Al-
buquerque, NM (R.D.R.); and Depart-
ment of Radiology, University of North
Carolina, Chapel Hill, NC (B.C.Y.).
Received April 23, 2004; revision
requested July 2; revision received
July 20; accepted
August 18. Sup-
ported by grants U01CA63740 (E.A.S.),
U01CA86076 (D.L.M.), U01CA70013
(B.M.G.), U0169976 (R.D.R.), U01CA70040
(B.C.Y.), U01CA63731 (Group Health Co-
operative, Diana Buist principal investiga-
tor), and U01CA86082– 01 (New Hamp-
shire Mammography Network, Patricia
Carney principal investigator) from the
National Cancer Institute; K07CA86032
(R.S.B.) from the NIH. Address corre-
spondence to E.A.S. (e-mail: edward
.sickles@ucsfmedctr.org).
Authors stated no financial relation-
ship to disclose.
Author contributions:
Guarantors of integrity of entire study,
E.A.S., D.L.M.; study concepts and de-
sign, E.A.S.; literature research, E.A.S.;
data acquisition, D.L.M.; data analysis/in-
terpretation, all authors; statistical analysis,
D.L.M.; manuscript preparation, E.A.S.;
manuscript definition of intellectual con-
tent, editing, revision/review, and final
version approval, all authors
©
RSNA, 2005
Performance Benchmarks for
Diagnostic Mammography
1
PURPOSE: To evaluate a range of performance parameters pertinent to the
comprehensive auditing of diagnostic mammography examinations, and to derive
performance benchmarks therefrom, by pooling data collected from large numbers
of patients and radiologists that are likely to be representative of mammography
practice in the United States.
MATERIALS AND METHODS: Institutional review board approval was met, in-
formed consent was not required, and this study was Health Insurance Portability
and Accountability Act compliant. Six mammography registries contributed data to
the Breast Cancer Surveillance Consortium (BCSC), providing patient demographic
and clinical information, mammogram interpretation data, and biopsy results from
defined population-based catchment areas. The study involved 151 mammography
facilities and 646 interpreting radiologists. The study population included women
18 years of age or older who underwent at least one diagnostic mammography
examination between 1996 and 2001. Collected data were used to derive mean
performance parameter values, including abnormal interpretation rate, positive
predictive value (for abnormal interpretation, biopsy recommended, and biopsy
performed), cancer diagnosis rate, invasive cancer size, and the percentages of
minimal cancers, axillary node-negative invasive cancers, and stage 0 and I cancers.
Additional benchmarks were derived for these performance parameters, including
10th, 25th, 50th (median), 75th, and 90th percentile values.
RESULTS: The study involved 332 926 diagnostic mammography examinations.
Mean performance parameter values were abnormal interpretation rate, 8.0%;
positive predictive value for abnormal interpretation, 31.4%; positive predictive
value for biopsy recommended, 31.5%; positive predictive value for biopsy per-
formed, 39.5%; cancer diagnosis rate, 25.3 per 1000 examinations; invasive cancer
size, 20.2 mm; percentage of minimal cancers, 42.0%; percentage of axillary
node-negative invasive cancers, 73.6%; and percentage of stage 0 and I cancers,
62.4%.
CONCLUSION: The presented BCSC outcomes data and performance benchmarks
may be used by mammography facilities and individual radiologists to evaluate their
own performance for diagnostic mammography as determined by means of peri-
odic comprehensive audits.
©
RSNA, 2005
Within the United States, Food and Drug Administration regulation requires limited
auditing of clinical outcomes for all screening and diagnostic mammograms assessed as
either suspicious for malignancy or highly suggestive of malignancy (1). More compre-
hensive auditing is performed by many mammography facilities in both the United States
and other countries. It is generally accepted that auditing is a useful quality assurance
procedure that provides performance parameter feedback both to mammography facilities
and to individual interpreting radiologists (2–4). Outcomes have been extensively re-
ported for screening mammography, leading to the publication of several performance
benchmarks that are currently in widespread use (5– 8).
Recent reports indicate significantly different clinical outcomes for diagnostic compared
with screening mammography, the diagnostic examinations being defined as those per-
formed for indications other than the periodic screening of asymptomatic women (9,10).
Breast Imaging
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However, these reports involve only a
moderate number (approximately 10 000)
of examinations, performed at a single in-
stitution, which may limit generalization
of the observed findings. There also is evi-
dence of considerable variability in perfor-
mance parameters among interpreting ra-
diologists; this is probably related to a
complex interaction of experience and ex-
pertise (7,11–17). For diagnostic mammog-
raphy, the published reports on perfor-
mance variability are based on data from
only 10 interpreting radiologists (9) and
are described by investigators as likely be-
ing at the ends of the spectrum of perfor-
mance rather than representing average
performance (18,19). Clearly, there is need
for more robust data on the clinical out-
comes of diagnostic mammography exam-
inations.
The Breast Cancer Surveillance Con-
sortium (BCSC) is a group of mammog-
raphy registries from geographically di-
verse areas in the United States, funded
by the National Cancer Institute, that
collects patient demographic and clinical
information, mammogram interpreta-
tion data, and biopsy results in the de-
fined catchment areas of its participating
facilities (20). The primary purpose of the
BCSC is to collect data from diverse pop-
ulation-based settings to examine the
practice and performance of mammogra-
phy throughout the United States. Six BCSC
registries collect data on the full range of
clinical outcomes pertinent to the com-
prehensive auditing of mammography
performance parameters. Pooling of the
data from these registries provides by far
the largest reported experience involving
diagnostic mammography practice, from
which reasonable and realistic performance
benchmarks may be derived. Thus, the
purpose of our study was to evaluate a
range of performance parameters perti-
nent to the comprehensive auditing of
diagnostic mammography examinations,
and to derive performance benchmarks
therefrom, by pooling data collected
from large numbers of patients and radi-
ologists that are likely to be representa-
tive of mammography practice in the
United States.
MATERIALS AND METHODS
Data Sources
Data were collected from six BCSC reg-
istries: Carolina Mammography Registry
(Chapel Hill, NC), Group Health Cooper-
ative (Seattle, Wash), New Hampshire
Mammography Network (Lebanon, NH),
New Mexico Mammography Project (Al-
buquerque, NM), San Francisco Mam-
mography Registry (San Francisco, Calif),
and Vermont Breast Cancer Surveillance
System (Burlington, Vt). To determine
cancer outcomes, each registry links its
data to a state tumor registry or to the
Surveillance Epidemiology and End Re-
sults program. The North American Asso-
ciation of Cancer Registries maintains
statistics for each of the cancer registries.
All cancer registries were found to be at
least 94.3% complete, except for the Ver-
mont registry, which did not have statis-
tics available. To supplement cancer reg-
istry information, each registry is also
linked to pathology databases. Each reg-
istry obtains annual approval from its in-
stitutional review board to collect and
maintain registry data. Individual in-
formed consent has not been required by
the institutional review boards because of
the strict maintenance of anonymity and
the observational nature of the study.
Our study was compliant with the Health
Insurance Portability and Accountability
Act. Linkage procedures follow protocols
specifically designed to preserve patient
confidentiality (21).
Each registry and the BCSC Statistical
Coordinating Center, or SCC, have devel-
oped data management and quality con-
trol procedures that result in high-quality
data collection that is comparable across
registries. Prior to sending data to the
SCC, data quality checks are conducted
at each registry by using their own pro-
cedures, such as manual validation of a
random sample of records, double data
entry, monitoring of facility volume over
time, and comparing different sources
(eg, cancer registry and pathology data-
bases) for consistency. After each annual
data submission from the individual reg-
istries, the SCC performs additional qual-
ity checks of the pooled data by flagging
coding errors and by comparing informa-
tion across registries and over time for
consistency and outlying values. The
SCC also conducts biennial site visits to
each registry and annual meetings in-
volving data managers from the registries
to review data management and quality
control procedures, as well as to check
data quality.
Across the six BCSC registries, 151
mammography facilities contributed to
the pooled data. This represents 1.5% of
the approximately 10 000 Food and Drug
Administration–certified mammography
facilities in the United States in 2000. The
pool of data contains diagnostic mam-
mogram interpretations made by 646 ra-
diologists. We have been unable to find
reliable estimates of how many radiolo-
gists met Food and Drug Administration
requirements to read mammograms in
2000.
Two authors (E.A.S. and D.L.M., by
consensus) compared the demographic
makeup (rural-urban mix, race, ethnicity,
education level, and socioeconomic sta-
tus) of the population living in the catch-
ment areas of the six BCSC registries in-
cluded in our study with that of the
entire U.S. population by using 2000 cen-
sus data. To describe the BCSC popula-
tion, we included census data from all
counties in which there was a participat-
ing mammography facility.
Subjects
The study population included women
18 years of age or older who had under-
gone at least one diagnostic mammog-
raphy examination during the years
1996–2001. Mammography examinations
performed after December 2001 were ex-
cluded to ensure that there was a period
of at least 12 months following examina-
tion during which cancer could be diag-
nosed and a period of an additional 24
months for reporting cancer data to tu-
mor registries. Cancer reporting was at
least 95% complete.
Diagnostic examinations are designed
to solve specific problems and almost al-
ways include as many mammograms as
are necessary to make a Breast Imaging
Reporting and Data System (BI-RADS) fi-
nal assessment, as well as case manage-
ment recommendations. However, under
certain circumstances a diagnostic exam-
ination is occasionally assessed as “incom-
plete—needs additional imaging evalua-
tion” (BI-RADS assessment category 0). In
this study, 15 971 (4.6%) of 348 897 ex-
aminations were given a category 0 as-
sessment. For this study, when one or
more diagnostic examinations followed
an initial diagnostic examination that
was assessed as category 0, all examina-
tions up to and including the first exami-
nation with a non-zero assessment (within
180 days) were treated as a single obser-
vation. The date of and indication for
examination were considered to be those
from the initial examination (the first
one with a category 0 assessment). How-
ever, we used the assessment and man-
agement recommendations from the first
non-zero assessment and attributed the
observed clinical outcomes to the radiol-
ogist who made that first non-zero assess-
ment. If there was no non-zero assessment
within 180 days, all of the examinations
were excluded (10 662 of 348 897 exam-
inations, 3.1%).
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Data Collection Procedures
Across all BCSC registries, mammogra-
phy patients complete a questionnaire
that requests medical history and demo-
graphic data (including date of most re-
cent mammography examination, family
history of breast cancer, previous percu-
taneous or surgical biopsies, personal his-
tory of breast cancer, and description of
breast symptoms experienced within the
past 3 months). Women were considered
to have a family history of breast cancer
if they reported having at least one fe-
male first-degree relative (mother, sister,
or daughter) with breast cancer. Women
were considered to have a personal his-
tory of breast cancer if they self-reported
previous breast cancer or if there was ev-
idence of previous breast cancer in the
cancer registry or pathology database.
Each woman was considered to have un-
dergone a previous mammography ex-
amination if she self-reported a history of
prior mammography or there was data
from a prior mammography examination
in the BCSC database.
Diagnostic mammography is performed
for a variety of problem-solving indica-
tions, including work-up of abnormalities
detected at screening mammography, eval-
uation of abnormalities found at clinical
examination, and short-interval follow-up
examinations both for probably benign le-
sions and for cancer patients recently
treated by means of breast preservation
surgery. Other special breast problems,
such as the presence of implants or the
evaluation of extent of disease for a known
malignancy may also represent indications
for diagnostic mammography. Across all
BCSC registries, the interpreting radiologist
prospectively classifies each diagnostic
mammography examination into one of
three categories: additional work-up of an
abnormality detected at screening exami-
nation, short-interval follow-up, or evalua-
tion of a breast problem. We further sub-
divided the “evaluation of a breast
problem” category according to whether
the patient indicated the presence of a pal-
pable lump on the medical history ques-
tionnaire that she completed at the time of
her mammography examination, because
results in previous published reports have
shown substantially different clinical out-
comes based on this approach (9,10). If the
self-reported response concerning palpable
lump was missing for a given examination,
we used the first nonmissing response, if
any, within the previous 90 days.
The mammography registry also col-
lects data on image interpretation, in-
cluding management recommendations
and the BI-RADS assessment categories
assigned by the interpreting radiologist
for each mammography examination
(22,23). A separate assessment is recorded
for each breast. For purposes of this
study, we have reported an overall assess-
ment for the entire examination, if ap-
propriate, by using the more abnormal
BI-RADS assessment category according
to the following hierarchy: negative (cat-
egory 1), benign (category 2), probably
benign (category 3), suspicious (category
4), or highly suggestive of malignancy
(category 5). Published results of a previ-
ous investigation, as well as our own
data, show only very small, nonsignifi-
cant differences between woman-specific
and breast-specific outcomes data (24),
indicating that woman-specific data are
sufficiently accurate measures of inter-
pretive performance.
All BCSC registries record data on
whether or not breast ultrasonography
(US) is performed concurrently with di-
agnostic mammography. However, these
data do not include a separate BI-RADS
assessment category for US examina-
tions.
In a report on diagnostic mammogra-
phy from the BCSC, Geller et al (25)
showed that in 10%–15% of examina-
tions with positive (abnormal) findings,
there is discordance between the BI-
RADS assessment and subsequent man-
agement recommendations provided by
the interpreting radiologist. An example
of such discordance is a finding assessed
as suspicious, accompanied by the rec-
ommendation for anything other than
biopsy or surgical consultation. In this
study, we have chosen to analyze mam-
mography interpretation data by using
both BI-RADS assessments and manage-
ment recommendations to parallel the
BI-RADS auditing approaches that will be
discussed in the paragraph concerning
positive predictive value (PPV) calcula-
tions.
Mammography patients were consid-
ered to have breast cancer if a state tumor
registry, Surveillance Epidemiology and
End Results program registry, or pathol-
ogy database indicated the diagnosis of
invasive carcinoma or ductal carcinoma
in situ (DCIS) within 12 months after a
diagnostic mammography examination.
Additional data collected for breast can-
cer cases included tumor size (for inva-
sive cancers), axillary lymph node status
(for invasive cancers), and American
Joint Committee on Cancer stage (26).
Outcome Measures
A positive (abnormal) assessment at di-
agnostic mammography was defined as
an overall assessment of suspicious for or
highly suggestive of malignancy. Cancer
diagnosis rate was defined as the number
of cancer cases identified at mammogra-
phy (mammographically true-positive)
divided by the total number of diagnostic
mammography examinations. A true-
positive case is one that is followed by
the diagnosis of invasive breast cancer or
DCIS within 12 months of a positive as-
sessment at diagnostic mammography.
Conversely, a case was considered to be
false-positive if results at diagnostic
TABLE 1
Demographics for the Study Population Compared with Those for the Entire
U.S. Population
Demographic Study Population* U.S. Population
†
Total population in selected counties 11 874 535 281 421 906
Rural-urban mix (%)
Rural 23.0 21.0
Urban 77.0 79.0
Race (%)
‡
White 82.7 84.9
African American 9.7 10.8
Other 7.5 4.3
Hispanic ethnicity (%) 6.3 7.3
No high school degree (%)
§
16.0 19.6
Economic status
Living in poverty (%) 11.2 12.4
Unemployed (%) 3.7 4.0
Median family income ($) 53 933 51 197
* Based on 2000 census data for all counties in which there was a mammography facility that
contributed data to this study.
†
Based on 2000 census data for the entire U.S. population.
‡
For women age 40 years and older.
§
For women age 25 years and older.
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mammography were interpreted as posi-
tive and no breast cancer was diagnosed
within the next 12 months.
In this article, we do not report on
measures of sensitivity or specificity be-
cause such measures require the enumer-
ation of false-negative and true-negative
cases, respectively, involving tumor reg-
istry linkage data that are not generally
available to mammography facilities or
individual practicing radiologists. These
measures, as well as other data beyond
the scope of this article, are available to
interested readers on the BCSC Web
site (breastscreening.cancer.gov/benchmarks
/diagnostic).
Statistical Analysis
Calculations of PPV were made by di-
viding the number of true-positive cases
by the sum of true-positive and false-pos-
itive cases. Three separate PPV calcula-
tions were performed by using BI-RADS
methods: PPV
1
, probability of cancer af-
ter positive mammography interpreta-
tion; PPV
2
, probability of cancer after
recommendation for biopsy or surgical
consultation, following positive mam-
mography interpretation; and PPV
3
,
probability of cancer after biopsy, follow-
ing positive mammography interpreta-
tion and a recommendation for biopsy or
surgical consultation. “Biopsy” included
the performance of any type of biopsy
(fine-needle aspiration, core, or surgical
biopsy), whether or not imaging guid-
ance was used to perform the biopsy.
Because the principal aim of this study
was to provide outcomes data to be used
for the derivation of clinically relevant
performance benchmarks, we have cho-
sen to provide only descriptive statistics
such as those enumerated previously. Be-
cause benchmarks are more meaningful
if they indicate ranges of performance as
well as arithmetic means, we also have
calculated percentile values for selected
outcomes. For example, the combination
of 25th and 75th percentile values de-
fines the range within which the middle
50% of performance is found, and the
combination of 10th and 90th percentile
values defines the range within which
the middle 80% of performance is found.
To reduce the number of radiologists
with zero observed “events” (eg, no ab-
normal interpretations, no cancers diag-
nosed) in our percentile data, we report
outcomes from only those radiologists
who contributed at least a designated,
subjectively determined minimum num-
ber of cases for each outcome, because
radiologists with zero events do not con-
tribute useful or informative data. We
have used graphical presentations (fre-
quency distributions overlaid with per-
centile values) to display these data in an
easily understandable format. More com-
plex analytic methods, designed to eluci-
date statistically significant interactions
among the data variables collected, are
beyond the scope of our study.
RESULTS
During the 1996–2001 study period, on
the basis of the specific eligibility criteria
previously described, the six participat-
ing BCSC registries contributed data from
2 547 845 mammography examinations,
which included both screening and
diagnostic examinations. This study in-
volved data from 332 926 diagnostic mam-
mography examinations among 239 751
women, of which 101 147 (30.4%) ex-
aminations were performed as further
work-up of abnormalities detected at
screening mammography, 81 285 (24.4%)
were performed as short-interval follow-up
examinations, and 150 494 (45.2%) were
performed to evaluate a breast problem.
Among this latter group of examinations,
60 901 (18.3% of all examinations) in-
volved women who reported a palpable
breast lump.
Demographic Factors
The demographic makeup of the pop-
ulation living in the catchment areas of
the six BCSC sites in our study is com-
pared with that for the entire U.S. popu-
lation in Table 1. There were only slight
differences, none greater than five per-
TABLE 2
Clinical Demographics by Indication for Examination for 332 926 Diagnostic Mammography Examinations
Clinical Demographic
Abnormality
Detected at
Screening
Mammography
Short-Interval
Follow-up
Evaluation of Breast Problem
All Diagnostic
Examinations
No Lump or
Lump Unknown Palpable Lump
All examinations 101 147 81 285 89 593 60 901 332 926
Age (y)
Missing data 45 (0.0) 32 (0.0) 26 (0.0) 0 (0.0) 103 (0.0)
⬍30 167 (0.2) 122 (0.2) 1558 (1.7) 2750 (4.5) 4597 (1.4)
30–39 5420 (5.4) 4919 (6.1) 11 094 (12.4) 14 607 (24.0) 36 040 (10.8)
40–49 33 938 (33.6) 24 462 (30.1) 25 475 (28.4) 21 216 (34.8) 105 091 (31.6)
50–59 29 566 (29.2) 23 596 (29.0) 21 874 (24.4) 11 109 (18.2) 86 145 (25.9)
60–69 17 718 (17.5) 14 907 (18.3) 15 289 (17.1) 5980 (9.8) 53 894 (16.2)
70–79 11 207 (11.1) 10 217 (12.6) 10 783 (12.0) 3759 (6.2) 35 966 (10.8)
ⱖ80 3086 (3.1) 3030 (3.7) 3494 (3.9) 1480 (2.4) 11 090 (3.3)
Mean 54.7 55.6 53.9 47.9 53.5
Median 52.0 53.0 52.0 46.0 51.0
Family history of breast cancer
Yes 13 910 (13.8) 12 631 (15.5) 12 201 (13.6) 8035 (13.2) 46 777 (14.1)
No or unknown 87 237 (86.2) 68 654 (84.5) 77 392 (86.4) 52 866 (86.8) 286 149 (85.9)
Personal history of breast cancer
Yes 5450 (5.4) 11 313 (13.9) 17 630 (19.7) 3.663 (6.0) 38 056 (11.4)
No or unknown 95 697 (94.6) 69 972 (86.1) 71 963 (80.3) 57 238 (94.0) 294 870 (88.6)
Previous mammography performed
Yes 100 448 (99.3) 80 938 (99.6) 77 940 (87.0) 47 603 (78.2) 306 929 (92.2)
No or unknown 699 (0.7) 347 (0.4) 11 653 (13.0) 13 298 (21.8) 25 997 (7.8)
Note.—Data are numbers of examinations, and numbers in parentheses are percentages.
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centage points, between our study popu-
lation and the U.S. population. Our study
population was slightly more rural, con-
tained slightly fewer African American
and Hispanic women, was slightly more
educated, and had a slightly higher me-
dian family income than the entire U.S.
population.
Previous reports have shown that clin-
ical outcomes for screening mammogra-
phy are affected by several other demo-
graphic factors, specifically age, family
TABLE 3
Abnormal Interpretations by Indication for Examination for 332 926 Diagnostic Mammography Examinations
Abnormal Interpretation
Abnormality
Detected at
Screening
Mammography
Short-Interval
Follow-up
Evaluation of Breast Problem
All Diagnostic
Examinations
No Lump or
Lump Unknown Palpable Lump
Abnormal interpretation rate (%) 12.3 3.4 5.7 10.5 8.0
Abnormal interpretations 12 431 2804 5120 6421 26 776
All examinations 101 147 81 285 89 593 60 901 332 926
PPV
1
(abnormal interpretation) (%)* 25.1 24.4 31.7 46.5 31.4
Cancer 3120 685 1622 2984 8411
Abnormal interpretation 12 431 2804 5120 6421 26 776
PPV
2
(biopsy recommended) (%)
†
24.6 24.6 32.9 48.0 31.5
Cancer 2732 577 1357 2507 7173
Abnormal interpretation 11 099 2347 4130 5223 22 799
PPV
3
(biopsy performed) (%)
‡
30.3 32.3 43.2 59.4 39.5
Cancer 2724 576 1348 2495 7143
Abnormal interpretation 8976 1782 3120 4198 18 076
Note.—Except where indicated, data are numbers of examinations.
* At assessment, either suspicious or highly suggestive of malignancy (BI-RADS category 4 or 5).
†
Abnormal interpretation and recommendation for either biopsy or surgical consultation.
‡
Abnormal interpretation, biopsy recommended, and biopsy results available.
TABLE 4
Cancers by Indication for Examination for 332 926 Diagnostic Mammography Examinations
Cancer Data
Abnormality
Detected at
Screening
Mammography
(n ⫽ 101 147)
Short-Interval
Follow-up
(n ⫽ 81 285)
Evaluation of Breast Problem
All Diagnostic
Examinations
(n ⫽ 332 926)
No Lump or
Lump Unknown
(n ⫽ 89 593)
Palpable Lump
(n ⫽ 60 901)
All cancers 3120 685 1622 2984 8411
Cancer diagnosis rate (per 1000) 30.8 8.4 18.1 49.0 25.3
Histologic finding*
DCIS 840 (26.9) 210 (30.7) 260 (16.0) 163 (5.5) 1473 (17.5)
Invasive carcinoma 2280 (73.1) 475 (69.3) 1362 (84.0) 2821 (94.5) 6938 (82.5)
Invasive cancer size (mm)
†
1–5 275 (13.9) 62 (14.9) 80 (6.9) 89 (3.6) 506 (8.4)
6–10 635 (32.0) 133 (32.0) 189 (16.3) 204 (8.4) 1161 (19.4)
11–15 532 (26.8) 98 (23.6) 256 (22.0) 445 (18.2) 1331 (22.2)
16–20 246 (12.4) 57 (13.7) 194 (16.7) 463 (19.0) 960 (16.0)
⬎20 294 (14.8) 66 (15.9) 442 (38.1) 1238 (50.8) 2040 (34.0)
Unknown 298 59 201 382 940
Mean 14.3 14.4 20.9 25.6 20.2
Median 11 11 17 21 15
Minimal cancer
‡
1750 (62.0) 405 (64.7) 529 (37.2) 456 (17.5) 3140 (42.0)
Axillary lymph node status (invasive cancers)
§
Negative 1745 (84.2) 360 (86.7) 825 (68.3) 1724 (65.6) 4654 (73.6)
Positive 327 (15.8) 55 (13.3) 383 (31.7) 905 (34.4) 1670 (26.4)
Unknown 208 60 154 192 614
Cancer stage
㛳
0 840 (30.0) 210 (34.8) 260 (18.5) 163 (6.3) 1473 (20.0)
I 1448 (51.7) 285 (47.2) 536 (38.1) 865 (33.6) 3134 (42.5)
II 461 (16.5) 92 (15.2) 493 (35.1) 1272 (49.5) 2318 (31.4)
III 42 (1.5) 10 (1.7) 84 (6.0) 195 (7.6) 331 (4.5)
IV 10 (0.4) 7 (1.2) 32 (2.3) 76 (3.0) 125 (1.7)
Unknown 319 81 217 413 1030
* Numbers in parentheses are percentages of all cancers.
†
Numbers in parentheses are percentages of invasive cancers of known size.
‡
Defined as DCIS or invasive cancer 10 mm or smaller; numbers in parentheses are percentages of DCIS and invasive cancers of known size.
§
Numbers in parentheses are percentages of invasive cancers of known nodal status.
㛳
Numbers in parentheses are percentages of DCIS and invasive cancers of known stage.
Volume 235
䡠
Number 3 Performance Benchmarks for Diagnostic Mammography
䡠
779
R
adiology
