2012 EDUCATIONAL BOOK - American Society of Clinical Oncology

advantage for mastectomy 17,18 in this patient subset at high
risk of distant relapse. In a retrospective study of the relationship
of the 21-gene recurrence score (OncotypeDx) to the risk
of LR, the use of appropriate systemic therapy as predicted
by the 21-gene recurrence score, significantly reduced LR
(p � 0.0001), and in a multivariate model, type of surgery
(lumpectomy compared with mastectomy) was not significantly
associated with LR after controlling for biologic variables. 16
In aggregate, these findings indicate that local control is a
complex interaction between disease burden, tumor biology,
and the effectiveness of systemic therapy. In the current era
where multimodality treatment is routinely employed, there
is little evidence that larger surgical resections improve
patient outcomes.
Axilla
The multidisciplinary nature of breast cancer therapy
today has also affected our approach to the axilla. Axillary
dissection has traditionally been performed for staging and
local control. Its role in contributing to the cure of breast
cancer has been controversial since the NSABP B04 trial
demonstrated no difference in survival in patients treated
with and without axillary dissection in the prechemotherapy
era. 19 Sentinel node biopsy is a reliable method of identifying
axillary node involvement with a lower morbidity than
axillary dissection, 20 and biologic tumor features, rather
than number of axillary lymph nodes involved with tumor,
are increasingly used to select systemic therapy. In patients
undergoing BCS, the tangent field RT, which is a standard
part of treatment, covers some of the axilla, 21 and systemic
therapy also contributes to locoregional control. 6-8 These
observations resulted in the American College of Surgeons
Group (ACOSOG) Z11 study in which clinically nodenegative
women with T1 and T2 breast cancers undergoing
BCS and found to have hematoxylin and eosin-detected
metastasis in � 3 sentinel nodes were randomized to completion
axillary dissection or no further axillary treatment.
22,23 All patients received tangent breast RT and
systemic therapy. After a median follow-up of 6.3 years, the
54
KEY POINTS
● Rates of local recurrence after breast-conserving surgery
and radiotherapy have decreased over time.
● Evidence that lumpectomy margins more widely
clear further reduce local recurrence than tumor not
touching ink is lacking.
● Local control can be achieved with removal of the
sentinel nodes and no further axillary treatment for
patients with involvement of one or two sentinel
nodes treated with whole-breast irradiation and systemic
therapy.
● The incidence of contralateral breast cancer has been
declining since the mid-1980s because of the increased
use of adjuvant systemic therapy.
● Systemic therapy has a major effect on local control,
offering the opportunity to decrease the extent and
morbidity of surgery as the effectiveness of systemic
therapy increases.
Table 1. Patient Groups for Whom Axillary Dissection Remains
Standard Management of a Positive Sentinel Node
● Palpable Node Disease
● Locally Advanced (Stage III) Breast Cancer
● Treatment with Mastectomy
● Treatment with Partial Breast Irradiation
● Treatment with Neoadjuvant Therapy
● Involvement of � 3 Sentinel Nodes with Metastases
● Gross Extranodal Tumor Extension in Sentinel Nodes
regional recurrence rate in the sentinel node only arm was
0.9% compared with 0.4% in the axillary dissection arm,
despite the fact that 27.4% of patients treated with axillary
dissection had additional positive nodes removed beyond the
sentinel node. 23 No survival differences were seen between
groups, 22 and morbidity was significantly lower in the sentinel
node-only group. 22,23 This study clearly indicates that
axillary dissection can be eliminated for patients meeting
the ACOSOG Z11 eligibility criteria, but does not apply to a
considerable number of women with breast cancer (Table 1).
There have been concerns expressed that because most of
the patients in Z11 were postmenopausal with ER-positive
tumors, these results cannot be extrapolated to younger
women and those with ER-negative tumors. However, large
studies of regional node recurrence do not identify age or ER
status as predictors, 24,25 suggesting that they should not be
used to exclude women from this approach. Implementing
the results of Z11 necessitates some changes in practice. For
example, the identification of a single metastatic axillary
node with ultrasound and fine-needle aspiration no longer
changes the operative approach because the sentinel node
still must be surgically removed, and it should be abandoned.
Frozen section of the sentinel node also is not necessary
or appropriate in these cases because the finding of tumor
in a single node will not lead to dissection, and because
examination of all nodal tissue is necessary to determine the
number of nodes involved and the presence of extranodal
extension. Finally, based on the results of ACOSOG Z10 and
NSABP B32 indicating that micrometastases in the sentinel
node have minimal prognostic impact, the routine use of
immunohistochemistry to look for small tumor deposits can
be abandoned.
Contralateral Breast
MONICA MORROW
The use of contralateral prophylactic mastectomy (CPM)
is increasing, 26 with the most notable increases seen in
women less than 50 years of age and those treated in
hospitals managing a higher volume of patients with breast
cancer. 27 This is somewhat surprising, considering that the
clinical incidence of contralateral breast cancer has been
declining since 1985 because of the widespread use of
adjuvant therapy. 28 This decrease is most evident among
women with ER-positive cancers, where even for those in
their 20s and 30s at initial diagnosis, 10-year rates of
contralateral cancer are 2.5%–4.5%. 28 With such a low
incidence rate, it is not surprising that evidence indicating
that CPM improves breast cancer mortality is lacking. 29
Evidence suggests that level of anxiety, regardless of the
presence or absence of risk factors for contralateral breast
cancer, is a major predictor of undergoing CPM. 30