DCIS and LCIS Flashcards
What % of all breast malignancies are DCIS?
20%
What are the 5 most common histologic subtypes of DCIS?
Cribiform, comedo, papillary, medullary, solid
“C2PMS”
Which DCIS subtypes have the worst 2 prognoses?
Comedo is the worst
Solid is the second worst
What percentage of DCIS are ER+?
75-85% of DCIS are ER+
What is the most common clinical presentation of DCIS?
Microcalcifications on a mammogram
What is the most common clinical presentation of LCIS?
Usually incidental finding, no mammographic or clinical abnormalities
What percentage of DCIS will progress to invasive disease if left untreated?
15-50%, difficult to determine
What is the risk of a patient with LCIS to be diagnosed with invasive breast cancer by 10yrs?
7% risk at 10 years but risk is equal in both breasts
What % of patients with LCIS that progress to invasive disease will have invasive lobular carcinoma?
Only 25-50% of LCIS patients that progress will have ILC
Which LCIS subtype has the worst prognosis?
Pleomorphic LCIS has the worst prognosis
What is the T-stage for DCIS?
Tis
What is the definition of DCIS with microinvasion?
Invasion <1mm in size, LN Bx is indicated and are found to be positive 4%-8% of the time
What is the treatment paradigm for unifocal DCIS?
Lumpectomy + RT +/- tamoxifen
Lumpectomy alone +/- tamoxifen
Mastectomy + SLNBx
Is axillary SLNBx indicated for DCIS?
No, but consider if patient undergoing mastectomy or if lumpectomy location may compromise future SLNBx
For a patient with DCIS, what is the rate of LR after mastectomy alone?
1-5% at 10 years
What are considered adequate surgical margins in patients receiving breast conservation surgery for DCIS?
2mm for patients undergoing postop RT
3mm if no postop RT
Contraindications for BCT for DCIS?
Multicentric disease, persistently +margins, cosmetic limitations, inability to get RT (pregnancy, prior RT)
Is there a benefit of mastectomy over BCT for DCIS?
Undetermined. No prostpective study
What is the impact of post-lumpectomy RT on patients with DCIS based on ipsilateral breast tumor recurrence and overall survival?
PORT reduces LR by 50-85% but does not benefit OS
What are 4 prospective studies that support the addition of RT after lumpectomy?
NSABP B-17
EORTC 10853
UKCCCR
SweDCIS
Treatment arms and invasive/noninvasive LR outcomes in NSABP B17 and EORTC 10853
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
Traditional target, dose and fractionation for PORT for DCIS?
Whole breast 50 Gy in 25 fx
Could hypofractionated RT to the whole breast be considered for DCIS?
Yes although RCTs for hypofractionation in breast cancer excluded women with DCIS
Could APBI be considered for DCIS?
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
Is there a benefit to tamoxifen for patients with ER+ DCIS?
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)
Is there evidence supporting the use of AIs for DCIS?
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
Is there a role for trastuzumab for DCIS?
Not currently. NSABP B43 is evaluating 2 cycles of concurrent trastuzumab with whole breast RT after lumpectomy for DCIS
How does adjuvant tamoxifen effect contralateral breast tumor recurrence in patients with DCIS?
NSABP B24 showed significant reduction in CBTR as 1st site of recurrence from 4.9% to 2.3% at 7 years
For ER+ DCIS, does RT add benefit beyond adjuvant tamoxifen?
Yes. UKCCCR was a 2x2 study that demonstrated reduced IBTR in women given RT and tamoxifen (6% vs. 18%)
What are risk factors for LR in patients with DCIS?
Decreased margin width (most important), increased tumor size, high grade, young age, postmenopausal status, comedonecrosis, multifocality
What is the purpose of the Van Nuys Prognostic Classification system?
To identify DCIS patients who are at low risk for recurrence after RT alone. Developed from retrospective data and not validated with prospective studies
Do all DCIS patients require postop RT?
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.
What is the treatment paradigm for LCIS?
Observation following lumpectomy for pure LCIS
What are options to reduce risk of developing invasive cancer in patients with LCIS?
Antiestrogen therapy (tamoxifen or raloxifene) - NSABP P1 trial Bilateral mastectomy
What should follow if LCIS detected on percutaneous core needle biopsy?
Surgical excision to confirm pure LCIS
If lumpectomy has invasive cancer and LCIS, can they still get BCT?
Yes. BCT is appropriate even with coexisting LCIS without special effort needed.
What is the benefit of tamoxifen in patients with LCIS?
Halves the risk for invasive recurrence in either breast?
What is the most common contraindication for adjuvant tamoxifen therapy?
History of stroke or other coagulopathy
What is recommended follow up schedule after treatment for DCIS
interval H&P exam q6-12m with annual bilateral mammograms
What is recommended observation strategy for a patient with LCIS?
H&P q6-12mo with annual bilateral mammogram
What is the role of MRI screening in patients with previous LCIS or DCIS?
MRI indicated if there is a >20% chance for 2nd primary breast cancer based mostly on family history
