Review - Haymarket Media Group

CaseStudy
Risk of Local Recurrence for Breast Cancer Subtypes
Defined by ER, PR, and HER2 Status
Paul L. Nguyen, MD 1,2 ; Alphonse G. Taghian, MD, PhD 2,3 ; Jay R. Harris, MD 2,4
1 Harvard Radiation Oncology Program; 2 Harvard Medical School; 3 Department of Radiation Oncology, Massachusetts
General Hospital; 4 Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women’s Hospital;
all Boston, Massachusetts
A60-year-old female had a routine screening
mammogram that showed a 1 cm density
with associated microcalcifications in the
upper outer quadrant of the patient’s left breast. A
core biopsy revealed an infiltrating ductal carcinoma
(IDC), grade 2, with associated ductal carcinoma in
situ (DCIS). The tumor was estrogen receptor (ER)
positive, progesterone receptor (PR) positive, and
HER2 negative. The patient elected breast-conserving
therapy and had a negative sentinel lymph node
biopsy. Pathology from the lumpectomy showed a
1.2 cm grade 2 IDC without evidence of extensive
intraductal component (EIC). There was no lymphovascular
invasion. There was a focally positive inferior
margin, but all other margins were >2 mm. The
Oncotype DX recurrence score was 11 (low risk). A
reexcision of the inferior margin was performed and
was negative except for a single 1 mm focus of DCIS
that came within 1 mm of the final inferior reexcision
margin. The issue of a second reexcision to achieve a
>2 mm inferior margin was discussed, but both the
patient and surgeon were concerned that this might
lead to a poor cosmetic result given the patient’s relatively
small breast size.
Discussion
Classic Predictors of Local Recurrence After Breast-
Conserving Therapy
For women who undergo breast-conserving therapy
for invasive breast cancer, the risk of local recurrence
has been shown in several studies to be based on factors
such as margin status, nodal status, young age,
and presence or absence of EIC (defined as an infiltrating
ductal cancer in which greater than 25% of
the tumor volume is DCIS, and DCIS extends beyond
the invasive cancer into surrounding breast
parenchyma). 1-3
While the exact relative importance of each of the
factors is not always consistent across studies, most
have agreed that margin status is one of the most
important predictors of local recurrence for women
undergoing breast-conserving therapy, and patients
are almost always advised to undergo reexcision if
the tumor involves an inked margin (ie, a positive
margin), unless that positive margin is at the skin or
is a deep margin that has already extended to the
pectoral fascia. The issue of whether a “close margin,”
as our patient has, is a risk factor for local recurrence
is less clear. Investigators have variably
. . . most have agreed that margin
status is one of the most important
predictors of local recurrence.
defined a close margin as having tumor within 1 or 2
mm of the inked surface, and while several studies
have found an association between increasing margin
width and lower local recurrence, only three published
studies have subdivided this width enough to
make finer comparisons. 2,4 One study from Tufts-
New England Medical Center showed a 12-year local
recurrence rate of 9% for margins 0.1 to 2.0 mm, 5%
for 2.1 to 5.0 mm, and 0% for >5 mm. 5 Also, the
Harvard Joint Center for Radiation Therapy found
that 8-year rates of local recurrence were 7% for margins
0.1 to 1.0 mm, 6% for 1.1 to 2.0 mm, and 4% for
November 2008 • Vol 7 • Supplement 5 23