Important Studies

Question 1

Whole breast RT

Answer 1

EBCTCG: DCIS s/p lumpectomy→WBRT vs. obs. Meta-analysis of SweDCIS, EORTC, UK/ANZ, NSABP B17.” RT improved IBTR, but not BCM, all cause mortality, or other mortality 10-yr IBTR 28% vs. 13%
BCM: 4%, not different. Benefit with RT in all groups (age, size, grade, margin, TAM, etc) on subanalysis.

NSABP B-17: DCIS s/p resection with negative margin→50 Gy WBRT vs. obs. 9% received boost. Total IBTR 32% vs. 16%. WBRT after resection for DCIS reduces IBTR

SweDCIS: DCIS <1/4 of breast s/p WLE sector resection →50 Gy WBRT (no boost) vs. obs.
IBTR 27% vs. 12% RT. WBRT after WLE for DCIS reduces IBTR. There is less effect in younger age. IBTR continues to rise with f/u.

EORTC 10853: DCIS s/p WLE →50 Gy WBRT vs. obs. 5% received boost. WBRT after WLE for DCIS reduces IBTR.

Question 2

Observation(Omission of RT)

Answer 2

RTOG 9804: Mammogram detected, grade 1-2, size <2.5 cm, margins ≥3mm. Lumpectomy →50 or 42.5 Gy WBRT vs. obs. 7-yr LR 6.7% vs. 0.9%. 12-yr LR 11.4% vs. 2.8%. WBRT for low risk DCIS improves IBTR. IBTR continues to rise with f/u.

ECOG: Low or int grade, size ≤2.5cm or high grade, size ≤1cm both with margins ≥3mm after WLE. Prospective: No RT.
TAM optional (used in ~40%). Low and intermediate grade DCIS may be safe to observe after WBRT. IBTR in high risk DCIS seems elevated enough to benefit from WBRT.

Harvard: DCIS s/p WLE, Grade 1-2 DCIS and ≥1cm margins. Prospective:
No RT and no TAM. LR is substantial without RT and TAM even if wide margins taken.

Question 3

Evaluated Tamoxifen, RT, Observation

Answer 3

UKCCCR: DCIS s/p resection with negative margin→obs
vs. TAM x 5 yrs vs. RT 50 Gy (no boost) vs. RT + TAM. IBTR 22% obs, 18% T, 8% RT, 6% RT+T
10-yr IBTR 17% obs, 13% T, 2.6% RT, 2.4% RT+T

RT reduced both ipsi invasive and ipsi DCIS
When RT is given, TAM had no benefit on ipsi invasive or ipsi DCIS, or even contralateral tumors
RT and TAM do not interact

Question 4

Tamoxifen for DCIS

Answer 4

NSABP B-24: “S/p WLE for DCIS (including + margin)( ER± allowed at time of trial). →50 Gy + TAM x 5 yrs vs. 50 Gy alone. TAM added to RT reduces invasive breast cancer recurrence (among all patients before ER was assessed) in DCIS. When testing ER, ER+ tumors had reduced total invasive breast cancer events with TAM, although isolated effects were small.

Question 5

Tamoxifen vs Anastrozole

Answer 5

IBIS-II DCIS: Postmenopausal DCIS ER+ s/p resection and radiotherapy, negative margins→anastrozole vs. TAM x 5 yrs. There is no difference in efficacy between anastrozole and TAM in DCIS. The side effect profiles differ.

NSABP B-35: Postmenopausal DCIS ER+ s/p resection and radiotherapy, negative margins”→anastrozole vs. TAM x 5 yrs. “10-yr BCFI 93.1% vs.89.1%
BCFI Benefit of anastrozole in age <60 10-yr DFS 82.7% vs. 77.9%. 10-yr OS 92.5% vs. 92.1%.

Anastrozole improves BCFI over TAM in DCIS age <60.

Question 6

Boost in DCIS

Answer 6

Yale: Pure DCIS treated with WBRT with or without electron or photon boost with minimum 5 year follow-up. Boost provides LC benefit.
15-yr IBTR 91.6% vs. 88% boost
10-yr IBTR 94.1% vs. 92.5%
5-yr 97.1% vs. 96.3%. This large retrospective study supports boost in DCIS. Boost should be considered for DCIS patients with negative margins and 10-15 year life expectancy.

Question 7

Boost Hypofraction

Answer 7

BIG 3-07 TROG 07.01 (ongoing): DCIS→conventional vs. hypofrac →16 Gy boost vs.
no boost.

Question 8

Oncotype

Answer 8

DCIS s/p surgery without RT from ECOG trial. Recurrence score of DCIS patients without RT. Developed based on DCIS samples from ECOG cohorts. The DCIS score quantifies recurrence risk and provides a new tool for individualized treatment.