DCIS and LCIS

Question 1

What % of all breast malignancies are DCIS?

Answer 1

20%

Question 2

What are the 5 most common histologic subtypes of DCIS?

Answer 2

Cribiform, comedo, papillary, medullary, solid

“C2PMS”

Question 3

Which DCIS subtypes have the worst 2 prognoses?

Answer 3

Comedo is the worst

Solid is the second worst

Question 4

What percentage of DCIS are ER+?

Answer 4

75-85% of DCIS are ER+

Question 5

What is the most common clinical presentation of DCIS?

Answer 5

Microcalcifications on a mammogram

Question 6

What is the most common clinical presentation of LCIS?

Answer 6

Usually incidental finding, no mammographic or clinical abnormalities

Question 7

What percentage of DCIS will progress to invasive disease if left untreated?

Answer 7

15-50%, difficult to determine

Question 8

What is the risk of a patient with LCIS to be diagnosed with invasive breast cancer by 10yrs?

Answer 8

7% risk at 10 years but risk is equal in both breasts

Question 9

What % of patients with LCIS that progress to invasive disease will have invasive lobular carcinoma?

Answer 9

Only 25-50% of LCIS patients that progress will have ILC

Question 10

Which LCIS subtype has the worst prognosis?

Answer 10

Pleomorphic LCIS has the worst prognosis

Question 11

What is the T-stage for DCIS?

Answer 11

Tis

Question 12

What is the definition of DCIS with microinvasion?

Answer 12

Invasion <1mm in size, LN Bx is indicated and are found to be positive 4%-8% of the time

Question 13

What is the treatment paradigm for unifocal DCIS?

Answer 13

Lumpectomy + RT +/- tamoxifen
Lumpectomy alone +/- tamoxifen
Mastectomy + SLNBx

Question 14

Is axillary SLNBx indicated for DCIS?

Answer 14

No, but consider if patient undergoing mastectomy or if lumpectomy location may compromise future SLNBx

Question 15

For a patient with DCIS, what is the rate of LR after mastectomy alone?

Answer 15

1-5% at 10 years

Question 16

What are considered adequate surgical margins in patients receiving breast conservation surgery for DCIS?

Answer 16

2mm for patients undergoing postop RT

3mm if no postop RT

Question 17

Contraindications for BCT for DCIS?

Answer 17

Multicentric disease, persistently +margins, cosmetic limitations, inability to get RT (pregnancy, prior RT)

Question 18

Is there a benefit of mastectomy over BCT for DCIS?

Answer 18

Undetermined. No prostpective study

Question 19

What is the impact of post-lumpectomy RT on patients with DCIS based on ipsilateral breast tumor recurrence and overall survival?

Answer 19

PORT reduces LR by 50-85% but does not benefit OS

Question 20

What are 4 prospective studies that support the addition of RT after lumpectomy?

Answer 20

NSABP B-17
EORTC 10853
UKCCCR
SweDCIS

Question 21

Treatment arms and invasive/noninvasive LR outcomes in NSABP B17 and EORTC 10853

Answer 21

B17: 818 DCIS pts w/ lumpectomy, neg margins, randomized to RT 50Gy/25fx or no RT; RT reduced LF from 31% to 18%, half of recurrences were invasive

EORTC: 1010 DCIS pts treated with lumpectomy, neg margins, randomized to RT 50Gy/25fx or no RT; RT reduced LF from 31% to 18%, half of recurrences were invasive

Question 22

Traditional target, dose and fractionation for PORT for DCIS?

Answer 22

Whole breast 50 Gy in 25 fx

Question 23

Could hypofractionated RT to the whole breast be considered for DCIS?

Answer 23

Yes although RCTs for hypofractionation in breast cancer excluded women with DCIS

Question 24

Could APBI be considered for DCIS?

Answer 24

Yes - ASTRO consensus statement has low-risk DCIS as suitable for APBI. NSABP B39/RTOG 0413 assessing APBI includes patients with DCIS in addition to early stage invasive breast cancers

Question 25

Is there a benefit to tamoxifen for patients with ER+ DCIS?

Answer 25

Yes. NSABP B24 and UKCCCR studies both demonstrate improved incidence of breast events with tamoxifen (NSABP 8.2% vs. 13.4%; HR 0.49) (UKCCCR 12yr ovrall breast events HR 0.71)

Question 26

Is there evidence supporting the use of AIs for DCIS?

Answer 26

Yes. NSABP B35 and IBIS-III included tamoxifen or anastrozole in DCIS patients after lumpectomy and RT. B35 reported longer breast cancer free interval with anastrozole in women younger than 60y

Question 27

Is there a role for trastuzumab for DCIS?

Answer 27

Not currently. NSABP B43 is evaluating 2 cycles of concurrent trastuzumab with whole breast RT after lumpectomy for DCIS

Question 28

How does adjuvant tamoxifen effect contralateral breast tumor recurrence in patients with DCIS?

Answer 28

NSABP B24 showed significant reduction in CBTR as 1st site of recurrence from 4.9% to 2.3% at 7 years

Question 29

For ER+ DCIS, does RT add benefit beyond adjuvant tamoxifen?

Answer 29

Yes. UKCCCR was a 2x2 study that demonstrated reduced IBTR in women given RT and tamoxifen (6% vs. 18%)

Question 30

What are risk factors for LR in patients with DCIS?

Answer 30

Decreased margin width (most important), increased tumor size, high grade, young age, postmenopausal status, comedonecrosis, multifocality

Question 31

What is the purpose of the Van Nuys Prognostic Classification system?

Answer 31

To identify DCIS patients who are at low risk for recurrence after RT alone. Developed from retrospective data and not validated with prospective studies

Question 32

Do all DCIS patients require postop RT?

Answer 32

No. Some low-risk can be observed - grade 1-2 DCIS, no larger than 2.5 cm, margins of at least 3mm ECOG 5194 and RTOG 9804 both evaluate the omission of RT. 5194 showed 12 yr ipsilateral breast event rate 14.6% for G1-2, 24.6% for G3. 9804 showed 6.7% 7 year LF rate.

Question 33

What is the treatment paradigm for LCIS?

Answer 33

Observation following lumpectomy for pure LCIS

Question 34

What are options to reduce risk of developing invasive cancer in patients with LCIS?

Answer 34

``` Antiestrogen therapy (tamoxifen or raloxifene) - NSABP P1 trial Bilateral mastectomy ```

Question 35

What should follow if LCIS detected on percutaneous core needle biopsy?

Answer 35

Surgical excision to confirm pure LCIS

Question 36

If lumpectomy has invasive cancer and LCIS, can they still get BCT?

Answer 36

Yes. BCT is appropriate even with coexisting LCIS without special effort needed.

Question 37

What is the benefit of tamoxifen in patients with LCIS?

Answer 37

Halves the risk for invasive recurrence in either breast?

Question 38

What is the most common contraindication for adjuvant tamoxifen therapy?

Answer 38

History of stroke or other coagulopathy

Question 39

What is recommended follow up schedule after treatment for DCIS

Answer 39

interval H&P exam q6-12m with annual bilateral mammograms

Question 40

What is recommended observation strategy for a patient with LCIS?

Answer 40

H&P q6-12mo with annual bilateral mammogram

Question 41

What is the role of MRI screening in patients with previous LCIS or DCIS?

Answer 41

MRI indicated if there is a >20% chance for 2nd primary breast cancer based mostly on family history