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Characteristics and Treatment of Metaplastic Breast Cancer:
Analysis of 892 Cases from the National Cancer Data Base
Christopher M. Pezzi, MD,
1
Lina Patel-Parekh, MHA, CHE,
2
Karin Cole, MD,
1
Jan Franko, MD, PhD,
1
V. Suzanne Klimberg, MD
3
and Kirby Bland, MD,
4
and the Breast
Disease Site Team*
1
Department of Surgery, Abington Memorial Hospital, 1200 Old York Road, Abington, Pennsylvania 19001, USA
2
American College of Surgeons, Commission on Cancer, 633 N. Saint Clair Street, Chicago, Illinois 60611, USA
3
Department of Surgery, University of Arkansas for Medical Sciences, 4301 West Markham, Little Rock, Arkansas 72205, USA
4
Department of Surgery, University of Alabama, 1530 Third Avenue South, Birmingham, Alabama 35294, USA
Background: Metaplastic breast cancer (MBC) is characterized by various combinations of
adenocarcinoma, mesenchymal, and other epithelial components. It was officially recognized
as a distinct pathologic diagnosis in 2000. With few published reports, we hypothesized that
MBC may have markedly different characteristics at presentation than typical infiltrating
ductal carcinoma (IDC) and may be managed differently.
Methods: Data from patients with MBC and IDC reported to the National Cancer Data-
base from January 2001 through December 2003 were reviewed for year of diagnosis, patient
age, race/ethnicity, tumor size, nodal status, American Joint Committee on Cancer (AJCC)
stage, tumor grade, hormone receptor status, and initial treatment, and were analyzed sta-
tistically by the Pearson v
2
test.
Results: A total of 892 patients with MBC and 255,164 patients with IDC were identified.
The group with MBC was older (mean age, 61.1 vs. 59.7 years; P = .001), had a significantly
increased proportion of African American (14.1%, 126 of 892, vs. 10.2%, 25,900 of 255,164;
odds ratio [OR], 1.455, P = .001) and Hispanic patients (5.5%, 49 of 892 vs. 3.9%, 9,947 of
255,164; OR, 1.817, P = .001), had fewer T1 tumors (29.5% vs. 65.2%), more N0 tumors
(78.1% vs. 65.7%, OR, .5, P = .001), more poorly or undifferentiated tumors (67.8% vs.
38.8%), and fewer estrogen receptor–positive tumors (11.3% vs. 74.1%, OR, 22.4, P = .001)
than the IDC group. Patients with MBC were treated with breast-conserving surgery less
frequently than patients with IDC (38.5% vs. 55.8%, OR, 2.0, P = .001) because of the larger
tumor size. Chemotherapy was used more often for patients with MBC (53.4% vs. 42.1%, OR,
1.6, P = .001) because of more advanced AJCC stage.
Conclusions: MBC is a rare tumor with different characteristics than IDC: it presents with
larger tumor size, less nodal involvement, higher tumor grade, and hormone receptor nega-
tivity. Patients with MBC are treated more aggressively than IDC (more often with mastec-
tomy and chemotherapy) because of a higher stage at presentation, but are being treated by
the same principles as IDC. Follow-up will determine the long-term results of the current
treatment.
Key Words:
Metaplastic—Breast cancer.
Traditionally, all patients with breast cancer have
been treated in a similar fashion, and breast cancer
was treated as a single disease. Increasingly, the het-
erogeneity of breast malignancies is being recognized
and encompasses many factors, including hormone
receptor expression, variable patterns of gene
Received March 24, 2006; accepted June 26, 2006
Address correspondence and reprint requests to: Christopher M.
Pezzi, MD; E-mail: cpezzi@amh.org
*Members of the Breast Disease Site Team are listed in
Appendix 1.
Published by Springer Science+Business Media, Inc. Ó 2006 The Society of
Surgical Oncology, Inc.
Annals of Surgical Oncology (Ó 2006)
DOI: 10.1245/s10434-006-9124-7
expression, and varying histologic appearance. The
optimal management of a patient who receives a
diagnosis of a malignant tumor of the breast depends
on both a tumor-specific and a patient-specific ap-
proach. This requires knowledge about the tumor
type, as well as its predicted behavior, and response
to various treatments. Data concerning subtypes of
breast malignancy, including extremely rare subtypes,
will aid in these therapeutic decisions.
Metaplastic breast cancer (MBC) is a rare malig-
nancy characterized by various combinations of
adenocarcinoma, mesenchymal, and other epithelial
components. Because MBC was not officially recog-
nized as a distinct pathologic diagnosis until 2000,
1
knowledge about the patient demographics, presen-
tation, tumor characteristics, and treatment patterns
is limited. To date, only small series and case reports
have atte mpted to delineate the factors that make
MBC different from more common malignan t breast
histologies.
2–17
We hypothesized that MBC has
markedly different characteristics at presentation and
is managed differently than infiltrat ing ductal carci-
noma (IDC).
MATERIALS AND METHODS
Malignant tumors are reported to the National
Cancer Data Base (NCDB) with the use of diagnosis
codes from the 3rd edition of the International
Classification of Diseases for Oncology (ICD-O-3),
which was implemented in 2001 and included a new
histologic code for MBC: 8575/3.
1
Data reported to
the NCDB for all women with a diagnosis of MBC
that used this code from January 2001 through
December 2003 were included in this study and
analyzed. To obtain a homogenous group of patients
with MBC, other overlapping or potentially related
histologic diagnoses were neither included nor com-
bined.
Specific data examined included the year of diag-
nosis, patient age at diagnosis, race/ethnicity, pri-
mary tumor size, lymph node status, overall
American Joint Committee on Cancer (AJCC) stage,
tumor grade, and estrogen and progesterone receptor
activity. Primary tumor s with diffuse breast involve-
ment or of unknown size, and patients who did not
undergo surgery at the site of the primary tumor were
not included in the analysis of primary tumor size.
Also analyzed were the following: data concerning
initial treatment, including surgery of the primary
site, and the use of radiotherapy and/or chemother-
apy; and information about the primary payer or
type of medical insurance to provide insight con-
cerning access to screening examinations, specifically
mammography, of the study group. For comparison,
the same data for all patients with a diagnosis of
infiltrating ductal carcinoma (ICD-O-3 code 8500/3)
for the same time period were also retrieved. The
Pearson v
2
test was used for statistical analysis. A
value of P<.05 was considered statistically signifi-
cant, and all P values are two-tailed.
RESULTS
Eight hundred ninety-two patients with a new
diagnosis of MBC were reported to the NCDB be-
tween 2001 and 2003 (Table 1). During this period,
data of 255,164 patients with IDC were entered . This
represents .24% and 69.8%, respectively, of the total
of 365,464 patients with a new diagnosis of breast
cancer whose data were entered into the NCDB
during the study period. The number of patients with
MBC reported to the NCDB increased during each
year of the study period, with 243 patients in 2001,
318 patients in 2002, and 331 patients in 2003,
whereas the number of patients reported with IDC
did not increase (85,559 in 2001, 87,891 in 2002, and
81,714 in 2003). The mean age of the group with
MBC was older, 61.1 years, compared with the mean
age of the group with IDC, 59.7 years (P = .001).
Patients with MBC were statistically significantly
more likely to be African American or Hispanic, 126
(14.1%) and 49 patients (5.5%), respect ively, com-
pared with patients with IDC, 25,900 (10.2%)and
9,947 patients (3.9%), respectively, (odds ratio [OR],
1.455, P<.001 for African American, and OR, 1.817,
P<.001 for Hispanic). Both groups had a similar
percentage of patients identified as Asian or Pacific
Islander (2.7% for MBC vs. 2.6% for IDC) or as other
or unknown (2.5% for MBC vs. 2.6% for IDC).
The size of the primary tumor was reported in 807
patients (90.5%) with MBC and 228,501 patients
(89.6%) with IDC who underwent surgery at the
primary site. The size of the primary tumors was
much larger for patients with MBC than for patients
with IDC (Fig. 1). Only 5.5% patients with MBC had
tumors <10 mm in size (T1a or T1b) compared with
26.9% patients with IDC (OR, 6.3, P<.001). Most
patients with MBC (70.5%) presented with tumors
larger than 20 mm (T2 and above), whereas most
patients with IDC (65.2%) presented with tumors
smaller than 20 mm (OR, .7, P<.01). Tum ors larger
than 5 cm in size accounted for 20.4% of MBC, and
only 5.2% of IDC.
C. M. PEZZI ET AL.
Ann. Surg. Oncol. (Ó 2006)
Lymph node involvement was reported in 21.9% of
patients with MBC for whom noda l status was
available. This compares with 34.3% of patients with
IDC with positive lymph nodes (Fig. 2). This differ-
ence in the percentage of patients with negative
lymph nodes (78.1% for MBC vs. 65.7% for IDC) was
statistically significant (OR, .538, P<.001). Of the
174 patients with positive lymph nodes in the MBC
group, data concerning the specific number of posi-
tive nodes were available in 140 patients. One to three
positive nodes were reported in 72.1% of patients
with MBC, four to nine nodes in 19.3%, and 10 or
more positive nodes in 8.6%. In the IDC group,
67.3% of patients had one to three nodes positive,
22.4% of patients had four to nine nodes positive, and
10.2% of patients had 10 or more nodes posit ive, of
the total of 71,255 patients with IDC with positive
5.5
24
50.1
20.4
26.9
38.3
29.6
5.2
0
10
20
30
40
50
60
<10mm (T1a/b) 11-20mm (T1c) 21-50mm (T2) >50mm (T3)
Size in mm
(
T
)
% of Tumors
MBC
(n=807)
IDC
(n=228, 501)
FIG. 1. Primary tumor size by histology.
TABLE 1. Demographics and tumor characteristics
Characteristic Metaplastic breast cancer Infiltrating ductal carcinoma Odds ratio P value
No. 892 255,164
Mean age (y) 61.1 59.7 <.001
Proportion <40 y old 70 (7.8%) 16,302 (6.4%)NS
Proportion >80 y old 120 (13.5%) 24,028 (9.4%) <.001
Ethnicity/race
White 671 (75.2%) 205,885 (80.7%)
African American 126 (14.1%) 25,900 (10.2%) 1.455 <.001
Hispanic 49 (5.5%) 9,947 (3.9%) 1.817 <.001
Asian/Pacific Islander 24 (2.7%) 6,746 (2.6%)NS
Unknown 22 (2.5%) 6,686 (2.6%)NS
Tumor size
a
<2 cm 238 (29.5%) 149,071 (65.2%) .7 <.01
2–5 cm 404 (49.6%) 67,536 (29.5%)
>5 cm 165 (20.4%) 11,894 (5.2%)
Nodal status
a
Negative 619 (78.1%) 156,308 (65.7%) 2.000 <.001
Positive 174 (21.9%) 81,698 (34.3%)
Estrogen receptor status
a
Positive 72 (11.3%) 137,050 (74.1%) 22.4 <.001
Negative 564 (88.7%) 47,887 (25.9%)
Progesterone receptor status
a
Positive 66 (10.4%) 114,061 (62.4%) 14.2 <.001
Negative 566 (89.6%) 68,875 (37.6%)
NS, not significant.
a
Totals may not add to 100% if data were reported as missing or unknown to National Cancer Data Base.
78.10%
21.90%
65.70%
34.30%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
N0 N1 or above
Lymph Node Status
% of Patients
MBC (n=793)
IDC (n=238,006)
FIG. 2. Lymph node status by histology.
METAPLASTIC BREAST CANCER
Ann. Surg. Oncol. (Ó 2006)
nodes for whom the sp ecific number of involved
nodes was known.
The AJCC stage (5th edition) grouping was avail-
able for 825 patients with MBC and 246,575 patients
with MBC, with the remainder unknown (Table 2).
Despite the lower frequency of lymph node involve-
ment, patients with MBC more commonly presented
with stage II disease (MBC 55 % vs. IDC 37.3 %,OR,
.4, P<.001) as a result of larger primary tumors.
Patients with MBC were also more likely to be
diagnosed with stage III (10.5%) or stage IV disease
(4.6%) at presentation compared with patients with
IDC (8.4% and 3.4%, respectively).
Tumor grade was classified as well differentiated,
moderately diff erentiated, or poorly/undifferentiated
in 2.7%, 7.1%, and 67.8% of patients with MBC,
respectively. Grade was not recorded or was un-
known for 22.5% of patients with MBC. Tumor
grade for patients with IDC was well differentiated ,
moderately diff erentiated, or poorly/undifferentiated
in 17.1%, 37.9%, and 38.8% of patients, respectively,
and was not recorded or was unknown in 6.3%.
Estrogen receptor (ER) and progesterone receptor
(PR) testing was not perfor med on 3.0% of MBC
specimens. It is unknown whether these tests had
been performed or whether the results were unknown
in 25.7% and 26.1% of cases, respectively. Of the
cases in which ER testing was performed and the
results were known, 72 (11.3%) of 636 patients with
MBC were ER positive compared with 137,050
(74.1%) of 184,937 patie nts with IDC (OR, 22.4, P<
.001). For PR testing, 66 (10.4%) of 632 patients with
MBC were positive compared with 114,061 (62.4%)
of 182,936 patients with IDC (OR, 14.2, P<.001).
Surgery was performed in 847 patients (95.0%)
with MBC as part of their primary treatment and
included a mastectomy in 471 (55.6 %). Breast-con-
serving surgery (BCS) was performed in 373 patients
(44.0%) with MBC. Three patients (.4%) underwent
an unspecified surgical procedure. Of the 241,192
patients with IDC (94.5%) who underwent surgery as
part of their primary treatment, mastectomy was
performed in 92,424 patients (38.3%), and BCS was
performed in 147,814 patients (61.3%). The more
common use of BCS for IDC was statistically sig-
nificant (OR, 2.0, P<.001). An unspecified surgical
procedure was performed in 954 patients (.4 %) in the
IDC g roup. Surgery was used as the sole treatment
modality for 263 patients (29.5 %) in the MBC group
and 58,639 patients (23%) in the IDC group, and was
otherwise used in combinat ion with radiotherapy,
chemotherapy, and/or hormonal therapy. An analy-
sis of the choice of surgical treatment by tumor size
shows that for a given tumor size, the rates of BCS
and mastectomy were similar for both patients with
MBC and IDC (Fig. 3).
Radiotherapy was delivered as part of the primary
treatment to 379 (42.5%) of 892 patients with MBC,
compared with 132,691 patients (52.0%) in the IDC
group. Radiotherapy was most commonly combined
with surgical treatment for both histologic types of
breast cancer in 368 (97.1%) of 379 patients with
MBC, and 129,168 (97.3%) of 132,691 patients with
IDC. Eleven patients with MBC (2.9%) underwent
radiotherapy without surgery, either alone (n = 2),
with chemotherapy (n = 8), or with a combination
of chemotherapy and hormonal therapy (n = 1).
Similarly, 3523 patients (2.7 %) with IDC underwent
radiotherapy without surgery, either alone
(n = 1072), with chemotherapy (n = 1193), with
hormonal therapy (n = 772), or with a combinat ion
of chemotherapy and hormonal therapy (n = 486).
Systemic chemotherapy was administered to 53.4%
patients with MBC and was provided in addition to
surgery (preoperatively or postoperatively) in all but
16 patients (3.4%). In comparison, 42.1% of patients
with IDC were treated with systemic chemotherapy,
again usually in addition to surgical treatment, in all
but 4.1 %. The increased use of chemotherapy for
patients with MBC compared with those with IDC
(53.4% vs. 42.1%, respectively) was statistically sig-
nificant (OR, 1.6, P = .001). Hormonal therapy was
provided in only 57 patients (6.4%) with MBC over-
all, compared with 83,485 patients (32.7%) with IDC.
An analysis of treatment with systemic chemotherapy
by AJCC stage (Fig. 4) shows that chemotherapy was
almost twice as likely to be administered to stage I
patients with MBC compared with identically staged
patients with IDC (39.7% vs. 21.7%), but that the
percentage of stage II and III patients treated with
chemotherapy was identical in both groups.
The most common primary payors or types of
medical insurance for the MBC group of patients (in
order of decreasing frequency) were managed care,
TABLE 2. American Joint Committee on Cancer stage by histology (%)
Cancer Stage I Stage II Stage III Stage IV Unknown Total
Metaplastic breast cancer 199 (22.3%) 491 (55.0%) 94 (10.5%) 41 (4.6%) 67 (7.5%) 892 (100%)
Infiltrating ductal carcinoma 121,162 (47.5%) 95,256 (37.3%) 21,513 (8.4%) 8,644 (3.4%) 8,589 (3.3%) 255,164 (100%)
C. M. PEZZI ET AL.
Ann. Surg. Oncol. (Ó 2006)
Medicare with supplement, unspecified insurance,
Medicare alone, and Medicaid, accounting for 35.5%,
24.3%, 17.2%, 9.6%, and 6.2%, respectively. Only
3.7% of patients with MBC were recorded as not
insured or as self-pay, and the insurance status of
2.7% was unknown. Tricare, military, Veterans
Administration, and Indian/Public Health Service
accounted for the remainder of patients. Similarly,
the patients with IDC had the same top five payors or
types of medical insurance accounting for 37.4%,
21.9%, 20.1%, 9.3%, and 4.4%, respectively, with
2.5% of patients recorded as not insured or self-pay,
and the insurance status unknown in 3.5%.
DISCUSSION
The NCDB, established in 1989, contains data
from the records of more than 18 million patients
treated at more than 1400 approved cancer programs
in the United States. Data from approximately 75%
of all new patients diagnosed with cancer in the
United States are entered into the NCDB. The size of
the NCDB allows the examination of extremely rare
tumors in relatively large numbers and can provide
valuable information that would otherwise not be
available from smaller sources of data about their
presentation, characteristics, treatment, and out-
comes. We examined the characteristics at pre senta-
tion, demographics, and patterns of treatment for
patients diagnosed with MBC and IDC between 2001
and 2003 and compared the two populations.
MBC is a rare breast malignancy accounting for
only one-quarter of 1% of all breast malignancies
reported to the NCDB during the study period. The
increasing number of patients with MBC reported
each year during the study period may represent an
actual increa se in incidence of the disease in the
United States. However, it is likely that the increase
seen in the number of cases is a result of increasing
recognition of and familiarity with the diagnosis of
MBC by both pathologists and the tumor registrars
who assign and report codes to the NCDB. Since
early reports more than 30 years ago,
18,19
MBC has
been increasingly recognized and reported as a dis-
tinct histologic type of breast cancer, but because of
its rarity, only relatively small series have been re-
ported. In the largest previous publications,
8–12
Wargotz et al. separately described five subgroups of
MBC, including matrix-producing carcinoma, spin-
dle cell carcinoma, carcinosarcoma, squamous cell
carcinoma of ductal origin, and metaplastic carci-
noma with osteoclastic giant cells, with 26, 100, 70,
22, and 29 patients, respectively. Oberman
16
reported
29 cases of MBC and concluded that the lack of a
correlation of the microscopic pattern of these tu-
mors with prognosis, as well as the presence of
0%
10%
20%
30%
40%
50%
60%
70%
80%
I II III
AJCC Sta
g
e
Treatment with Chemotherapy (%)
MBC-Chemo
IDC-Chemo
FIG. 4. Systemic chemotherapy by American Joint Committee on
Cancer (AJCC) stage and histology.
0%
10%
20%
30%
40%
50%
60%
70%
80%
T1a/T1b
(<10mm)
T1c (11-20mm) T2 (21-30mm) T2 (31-40mm) T2 (41-50mm) T3 (51-100mm
)
Tumor Size, T
(
mm
)
Breast-Conservation (%)
MBC
IDC
FIG. 3. Breast-conserving surgery by primary tu-
mor size and histology (%).
METAPLASTIC BREAST CANCER
Ann. Surg. Oncol. (Ó 2006)
apparent overlapping microscopic findings, sup-
ported the concept that the subgroups described by
Wargotz et al. are all variants of a single entity. There
is still no strong consensus on this issue. Cytokeratin
positivity in both the epithelial and mesenchymal
components of MBC has led many to conclude that it
is metaplasia of the epithe lial elements of a carcinoma
that gives these lesions their pseudosarcomatous
appearance.
17
With the recognition by ICD-O-3 of a specific code
for MBC, cancer registries began collecting data from
across the United States in 2001. The continued use
of other overlapping or potentially related diagnoses,
some more specific and some less so, is a confounding
factor in the effort to study MBC. These additional
diagnoses include squamous cell carcinoma, spindle
cell carcinoma, carcinosarcoma, sarcoma not other-
wise specified, pleomorphic carcinoma, spindle cell
sarcoma, spindle cell squamous cell carcinoma,
osteosarcoma, and others. Undoubtedly, some pa-
tients diagnosed with these alternatives would be
considered by many pathologists to have MBC. We
chose to limit our study only to the specific diagnosis
of MBC for this analysis, to maximize the likelihood
that our observations would be applicable to clini-
cians faced with a diagnosis of MBC in the future.
A difference was seen in the race/ethnicity of pa-
tients with MBC compared with IDC, with a higher
percentage of patients identified as African American
or Hispanic. The reasons for these differences are
unknown, but represent a small but increased risk for
MBC in these groups. The difference observed in the
age of patients diagnosed with MBC compared with
IDC, although statistically significant (mean age, 61.1
vs. 59.7 years, P=.001), is not likely of major
clinical importance.
Patients with MBC had larger primary tumors
than patients with IDC. This difference in size could
possibly be explained by a difference in the use of
screening mammography between the groups, or by
a failure of screening examinations to identify MBC
compared with IDC. With similar primary payor
and types of medical insurance in both groups, it is
unlikely that differences in access to or use of
screening mammography alone can explain the large
difference in size seen in this study. In addition,
several reports
13,14
have described the mammo-
graphic and sonographic findings in MBC, including
a roun d to ovoid, high-density mass with ill-defined
or obscured margins and with architectural distor-
tion. In one study, most patients presented with a
rapidly growing palpable mass, which was then
visible as a mammographic mass in 15 of 16
patients.
13
These studies suggest that MBC is not
mammographically occult.
It is most likely that the larger size at presentation
for MBC is the result of a more rapid growth rate.
Successful early detection of IDC by mammography
depends on a relatively long, detectable, preclinical
phase resulting from slower tumor growth, which
may not exist with MBC. Most patients with MBC
had poorly differentiated or undifferentiated tumors
compared with IDC, which would also support this
theory of more rapid growth for MBC.
The lower incidence of axillary lymph node
involvement compared with IDC (21.9% vs. 34.3%)
also represents an observed biological difference be-
tween these two tumors. The difference is even more
dramatic when the larger tumor size of the patients
with MBC is considered. If these tumors were bio-
logically similar, we would expect a higher incidence
of nodal involv ement for patients with MBC on the
basis of the larger tumor size. The presence of mes-
enchymal components and sarcomatous elements
seen in MBC may explain this different biologic
behavior and pattern of metastasis. Wargotz et al.
8–12
reported an incidence of axillary lymph node metas-
tasis ranging from 6% to 26%, depending on the
subtype of MBC, and was highest for carcinosar-
coma. Additionally, for patients with carcinosar-
coma, it was carcinoma that was the most frequent
component to metastasize.
The higher AJCC stage seen in the MBC group,
despite having more lymph node–negative tumors, is
strongly influenced by the larger tumor size. The
29.5% of patients with MBC having tumors <2 cm in
size (T1), compared with 65.2% of patients with IDC
with T1 tumors, explains the much higher incidence
of AJCC stage I disease in patients with IDC, and
AJCC stage II disease in patients with MBC.
The very low incidence of hormone receptor posi-
tivity in MBC compared with IDC represents another
biologic difference in these tumors and has obvious
implications for differences in their treatment . Hor-
monal therapy was rarely provided to patients with
MBC, consistent with this low incidence of hormone
receptor positivity in these patients. As would be
suspected, the use of hormonal therapy in the patients
in both groups in this study was directly related to the
number of cases with hormone receptor–positive tu-
mors.
The lack of hormonal therapy as a therapeutic
option for adjuvant treatment, combined with an
increased risk of systemic metastasis that would be
predicted given the larger tumor size, higher AJCC
stage, higher tumor grade, and hormone receptor
C. M. PEZZI ET AL.
Ann. Surg. Oncol. (Ó 2006)
negativity, explains the increased frequency of treat-
ment with systemic chemotherapy in the patients with
MBC. Data supporting the effectiveness of adjuvant
chemotherapy for patients with MBC are lacking,
and its use represents extrapolation from data related
to more common histologic varieties of breast cancer.
Given the apparent differences in tumor biology, the
benefit of adjuvant chemotherapy, as well as the most
effective drugs if it is to be administered, is unclear.
Rayson et al.
15
reported 27 patients over a 30-year
period from the Mayo Clinic, 13 of whom (50%)
developed distant metastasis. Ten different chemo-
therapy regimens were used to treat metastatic dis-
ease, and only one partial response was observed.
They concluded that systemic therapy seems to be less
effective.
Surgery was used to treat approximately 95% of
both patients with MBC and IDC, but mastectomy
was most common for patients with MBC (55.6%),
whereas BCS was most common for patients with
IDC (61.3%). This difference was related to the larger
tumor size of the patients with MBC, including 20.4%
of the MBC tumors >5 cm in size compared with
only 5.2% for IDC tumors. When corrected for tumor
size, the rates of BCS and mastectomy were similar
between the two groups, suggesting that the princi-
ples of breast cancer surgery used for more common
histologies are being applied to patients with MBC.
The use of radiotherapy parallels the use of BCS, as
would be anticipated. In both histologic groups,
however, fewer patients received radiation than were
treated with BCS . BCS was performed in 44.0% pa-
tients with MBC. The results of BCS and radiation in
this group of patients with MBC, including ipsilateral
breast recurrence rates, are being reported to the
NCDB and will require furth er follow-up.
In summary, MBC is a very rare tumor and is
different from IDC, with different presenting char-
acteristics, demographics, and tumor biology. It is
increasingly being reported to the NCDB since the
ICD-O-3 codes have been implemented. Patients with
MBC are more commonly African American or
Hispanic and present with larger tumor size, less
nodal involvement, higher AJCC stage, higher tumor
grade, and hormone receptor negativity. Because of
the larger tumor size and higher AJCC stage, patients
with MBC are treated more aggressively than IDC,
more often with mastectomy and systemic chemo-
therapy. In the absence of histology-specific data,
patients are treated by use of the same principles that
govern treatment of more common breast cancers.
Follow-up is needed to determine the long-term re-
sults of the current treatment.
APPENDIX 1
Members of the Breast Disease Site Team of the
Commission on Cancer, American College of Sur-
geons, are as follows: Kirby Bland, MD
(Leader)—Birmingham, AL; Robert Kuske, MD
(Associate Leader)—Scottsdale, AZ; George Sledge,
MD (Associate Leader)—Indianapolis, IN; Paul
Baron, MD—Charleston, SC; James Connolly,
MD—Boston, MA; Rosemary Duda, MD—Boston,
MA; Timothy Eberlein, MD—St. Louis, MO; Ste-
phen Edge, MD—Buffalo, NY; James Edney,
MD—Omaha, NE; Suzanne Klimberg, MD—Little
Rock, AR; A. Marilyn Leitch, MD—Dallas, TX;
Joseph Lipscomb, PhD—Atlanta, GA; Lisa New-
man, MD—Ann Arbor, MI; Geoffrey Robb,
MD—Houston, TX; Edward Sickles, MD—San
Francisco, CA; Sonj a Eva Singletary, MD—Hous-
ton, TX; David P. Winchester, MD—Chicago, IL.
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