Ductal Carcinoma
In Situ
401
in women with ER-positive DCIS.
423
In the randomized
NSABP B24 trial, the 7-year risk of breast recurrence was
7.7% with lumpectomy and radiation plus tamoxifen and
11.1% after lumpectomy and radiation alone.
387
From the foregoing review, it is clear that, as a group, pa-
tients with DCIS benefit from the addition of radiotherapy to
breast-conserving surgery because the breast recurrence rate
is reduced by about 50%. Radiotherapy is usually indicated
for any of the following circumstances: high-grade DCIS,
when margins are close (variously described as 10 mm or
less), and for patients younger than 50 years. Tamoxifen may
be added for hormone receptor–positive DCIS. Omitting ra-
diotherapy is a consideration for women older than 50 years
with a widely clear margin (variously defined as more than
10 mm) and low-grade histology without necrosis. This type
of DCIS is very likely to be hormone receptor positive and,
therefore, amenable to adjuvant tamoxifen treatment. How-
ever, this approach is not without risk as described by Wong
et al.,
378
who reported an in-breast recurrence rate of 2.4%
per patient-year of follow-up and a projected 5-year breast
recurrence rate of 12%.
Mammography is an essential component of the clinical
follow-up of women treated by breast-conserving surgery
with or without radiotherapy and/or tamoxifen.
248
In one se-
ries of 162 women, 33 (20%) developed recurrent ipsilateral
carcinoma 6 to 168 months (median, 26) after primary ther-
apy.
424
Review of mammograms from 20 patients with re-
current carcinoma revealed that 17 (85%) of the recurrences
were detected solely on the basis of calcifications, which had
a pattern similar to that of calcifications seen prior to the ini-
tial excision in 82% of cases. DCIS alone was present in 65%
of recurrences, whereas 35% also had invasive carcinoma.
Particular attention should be paid to the mammographic
follow-up of the contralateral breast in women with atypical
hyperplasia or LCIS coexisting with DCIS. The role of rou-
tine MRI screening in the follow-up of women with DCIS,
treated by breast conservation, remains to be determined.
Some patients may choose mastectomy, even if they are
candidates for breast conservation. Mastectomy is prefer-
able for the patient with such widespread DCIS that negative
margins cannot be achieved with a cosmetically acceptable
surgical procedure. Many but not all of these patients have
dispersed calcifications on mammography. Lumpectomy
with or without radiation will suffice for most women with
DCIS limited to a single focus on the basis of pathologic and
clinical findings, if the margins of excision are negative, if
the lesion is not comedo type with necrosis and high nuclear
grade, and if the lesion is small (variously defined as less than
1.0 cm or less than 2.5 cm). Radiation after lumpectomy is
recommended regardless of size if the DCIS has high nuclear
grade, necrosis, or is distinctively of the comedocarcinoma
type, and if the margins are indeterminate or are involved.
The assessment of margins is only a guide to and not a pre-
cise measurement of the completeness of excision for DCIS.
This was demonstrated by Silverstein et al.,
425
who compared
the findings in reexcision specimens from patients who had
positive and who had negative margins in their initial exci-
sional biopsy specimens. Although the chance of finding
routine screening in asymptomatic women. In such a situ-
ation, most patients have relatively limited disease and are
eligible for breast conservation (i.e., maximal preservation
of disease-free breast). The common breast conservation
treatment options include lumpectomy alone, lumpectomy
followed by radiation, or mastectomy. An SERM, such as
tamoxifen, is the main systemic treatment option. Typically,
most patients with DCIS do not require a mastectomy, and
the majority of patients in the United States and elsewhere
choose breast conservation.
420
Treatment recommendations for DCIS are made on the
basis of clinical and pathologic findings in consultation with
the patient. Important considerations include the manner of
clinical presentation (e.g., palpable, incidental, or mammo-
graphic), extent by mammography, size measured grossly or
microscopically when possible, margin status of the lumpec-
tomy, and histologic features of the DCIS such as nuclear
grade, growth pattern (e.g., cribriform, comedo, solid, or
papillary), and the presence or absence of necrosis. The issue
is complicated by the many different combinations of these
and other features that can occur in a given case.
Numerous studies cited indicate that margin status and
the biologic characteristics of DCIS represented histologi-
cally by nuclear grade and the presence or absence of necrosis
are the most important predictors of local recurrence in the
breast after breast conservation with or without radiotherapy.
Tumor size correlates well with the extent of the lesion and
thus influences margin status. For example, Cheng et al.
421
reported positive lumpectomy margins in 15%, 28%, and
69% of patients with DCIS lesions measured as less than 1.0
cm, 1.0 to 2.4 cm, and 2.5 cm or larger, respectively. Biologic
characteristics, at least partially reflected in the histologic ap-
pearance of DCIS, have a complex influence on the success of
treatment by affecting the rate of growth (and to some extent
the time to detection of clinical recurrences) and radiosen-
sitivity of residual DCIS after lumpectomy. Consequently, it
is possible for patients with comparable amounts of incom-
pletely excised residual high-grade (comedo) and low-grade
(cribriform) DCIS who receive the same treatment to have
similar absolute risks for breast recurrence, but they may
differ in time to clinical detection of recurrence, especially
of invasive lesions, and in responsiveness to radiotherapy or
antiestrogens. Follow-up for more than 10 years of large uni-
formly treated patient groups with diverse types of DCIS will
be needed to reliably assess the interplay of these factors.
Retrospective and prospective randomized studies re-
viewed in detail in this chapter have demonstrated that ra-
diotherapy after excisional surgery reduces the chance of
recurrence in the breast by about 50%. The degree to which a
reduced frequency of breast recurrence contributes to over-
all survival remains to be determined for patients with DCIS.
The possibility that there could be a survival advantage con-
ferred by reducing breast recurrences is suggested by a meta-
analysis of randomized studies of radiotherapy and breast
conservation in women with invasive breast carcinoma that
detected this beneficial effect.
422
The addition of a selective ER modulator such as tamoxi-
fen to breast conservation therapy reduces breast recurrences
