Treatment/Prognosis

Question 1

What is the Tx paradigm for unifocal DCIS?

Answer 1

There are 3 Tx paradigms for unifocal DCIS: RT can be delivered to the whole breast using hypofractionation, standard fractionation or could be delivered using accelerated partial breast irradiation.

1. Lumpectomy + postop RT (PORT) +/− tamoxifen (if ER+)
2. Lumpectomy alone +/− tamoxifen (if ER+)
3. Mastectomy + SLNB

Question 2

Is an axillary sentinel node Bx needed for DCIS?

Answer 2

No. Surgical axillary evaluation is not needed for DCIS. However, per NCCN 2018, consider if (1) the pt is undergoing mastectomy for Tx or (2) if the location of lumpectomy will compromise future sentinel Bx should it be necessary.

Question 3

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

Answer 3

For a pt with DCIS, the rate of LR after mastectomy is ∼1%–5% at 10 yrs.

Question 4

What are considered adequate surgical margins in pts receiving breast conservation Sg for DCIS?

Answer 4

For pts who will undergo postop RT: 2 mm. For pts who will not rcv postop RT: 3 mm. A systematic review of published trials in DCIS with BCT involving 4,660 pts found that a 2-mm margin was sup to a margin <2 mm (ORR 0.53), without any LC benefit in margins >2 mm. (Dunne C et al., JCO 2009) RTOG 9804 (RCT of omission of RT) and ECOG 5194 (observational study of omission of RT) both required a min 3-mm margin. The 2018 NCCN guidelines accept no tumor on ink as negative margins (per Society of Surgical Oncology (SSO)/ASTRO/ASCO Consensus) but acknowledge lower rate of ipsilateral breast tumor recurrence (IBTR) with margins of at least 2 mm.

Question 5

What are the contraindications for BCT for DCIS?

Answer 5

Contraindications for BCT for DCIS: multicentric Dz, persistently +margins, cosmetic limitations, and, potentially, the inability to get PORT (pregnancy or prior RT).

Question 6

Is there a benefit of mastectomy over BCT for DCIS?

Answer 6

This is undetermined. No prospective study has directly compared mastectomy vs. BCT for DCIS. Indirect comparisons suggest that mastectomy results in lower LR than BCT. However, there is no expectation that mastectomy would improve OS compared to BCT, b/c the risk of breast cancer–related death after a Dx of DCIS is <2%.

Question 7

For a pt with DCIS treated with lumpectomy, what is the impact of PORT on ipsi breast recurrence (invasive and noninvasive) and OS?

Answer 7

For DCIS treated with lumpectomy, PORT reduces LR by 50%–85%, but there is no evidence for OS benefit.

Question 8

Name 4 prospective studies that support the addition of RT after lumpectomy in pts with DCIS.

Answer 8

1. NSABP B-17 (Fisher B et al., Semin Oncol 2001)
2. EORTC 10853 (Bijker N et al., JCO 2006)
3. UKCCCR (Houghton J et al., Lancet 2003)
4. SweDCIS (Holmber L et al., JCO 2008)

Question 9

Describe the Tx arms and the invasive and noninvasive LR outcomes in NSABP B-17 and EORTC 10853.

Answer 9

In NSABP B-17, 818 DCIS pts treated with lumpectomy with no tumor at inked margins were randomized to 50 Gy whole breast RT or no RT. At 10 yrs, the overall IBTR rate was 30.8% vs. 14.9% in favor of RT. Both the invasive and noninvasive recurrence rate was appx halved by RT.

In EORTC 10853, 1,010 DCIS pts treated with lumpectomy with no tumor at inked margins were randomized to 50 Gy whole breast RT or no RT. At 15 yrs, RT reduced LF from 31% to 18%. Half of all recurrences were invasive.

Question 10

What is the traditional target, dose, and fractionation for PORT for DCIS?

Answer 10

Target the whole breast to 50 Gy in 25 fx.

Question 11

Could hypofractionated RT to the whole breast be considered?

Answer 11

Yes. The RCTs that established the efficacy of hypofractionation excluded women with DCIS, and the ASTRO task force on hypofractionated whole breast RT (Smith BD et al., IJROBP 2011) chose not to offer recommendations for or against hypofractionation for DCIS as these pts were excluded from the randomized trials. However, subsequent completed and ongoing trials using hypofractionation (including Shaitelman SF et al., JAMA Onc 2015) have included women with DCIS. Caution should be used in pts with very large volume DCIS or very large breasts.

Question 12

Could accelerated partial breast irradiation be considered?

Answer 12

Yes. The updated ASTRO APBI consensus statement placed low-risk (as per RTOG 9804 criteria) DCIS in the “suitable” group for APBI (Correa C et al., PRO 2017). The NSABP B 39/RTOG 0413 trial to assess the role of APBI included pts with DCIS, as well as stage 1 or 2 breast cancer with tumors ≤3 cm and ≤3 +LNs.

Question 13

For a pt with ER+ DCIS, is there a benefit to tamoxifen? What studies support this?

Answer 13

Yes. 2 trials provide evidence to support the use of tamoxifen in DCIS: NSABP B-24 and United Kingdom Coordinating Committee on Cancer Research (UKCCCR).

NSABP B-24 compared lumpectomy + RT +/– tamoxifen. Pts were enrolled without respect to estrogen receptor (ER) status. At 5 yrs, the overall incidence of breast events (ipsi and contralat, invasive and noninvasive) was decreased with tamoxifen (8.2% vs. 13.4%) (Fisher B et al., Lancet 1999). A subsequent analysis of tamoxifen effect by ER status analyzed 732 of the 1,801 pts on NSABP B24 (Allred DC et al., JCO 2012). At 10 yrs, the HR for any breast event was 0.49 for ER+ pts who rcvd tamoxifen.

The UKCCCR was a 2 × 2 factorial trial of RT, tamoxifen, both, or neither after lumpectomy for DCIS or microinvasive Dz, without respect to ER status. At a median f/u of 52 mos, tamoxifen marginally reduced overall DCIS events only (UKCCCR Working Group, Lancet 2003). However, on 12-yr f/u analysis, tamoxifen significantly reduced overall breast events (HR 0.71). (Cuzick J et al., Lancet 2011)

To summarize, in current practice, ER+ DCIS pts are offered adj tamoxifen.

Question 14

Is there evidence supporting the use of AIs for DCIS?

Answer 14

Yes. NSABP B-35 and International Breast Cancer Intervention Study II (IBIS-II) both compared 5 yrs of either tamoxifen or anastrozole for pts with DCIS after lumpectomy and RT; NSABP B-35 (Margolese RG et al., Lancet 2016) reported a longer breast cancer–free interval with anastrozole mainly in women younger than 60. IBIS-II (Forbes JF et al., Lancet 2016) found no difference in overall recurrence rate.

AIs can be used in place of tamoxifen d/t differences in toxicity profiles.

Question 15

What about trastuzumab (Herceptin)?

Answer 15

There is currently no role for trastuzumab in the Tx of DCIS. NSABP B-43 is evaluating the use of 2 cycles of concurrent trastuzumab with whole breast RT after lumpectomy for DCIS.

Question 16

For a pt with DCIS, what is the effect of adj tamoxifen on contralateral breast tumor recurrence (CBTR)?

Answer 16

NSABP B-24 showed that the addition of tamoxifen to BCT in DCIS pts significantly reduced CBTR as the 1st site of recurrence from 4.9% to 2.3% at 7 yrs.

Question 17

For a pt with ER– DCIS, is there benefit to adj tamoxifen after lumpectomy + RT?

Answer 17

Probably not. Retrospective subset analysis of NSABP B-24 showed that the benefit of adj tamoxifen was limited to ER+ pts. (Allred DC et al., JCO 2012)

Question 18

For a pt with ER+ DCIS, does adj tamoxifen obviate the benefit of RT after lumpectomy? What study evaluated this?

Answer 18

RT is still beneficial for pts with DCIS treated with lumpectomy even with adj tamoxifen. UKCCCR was a 2 × 2 factorial study looking at the benefit of RT and tamoxifen in DCIS pts after lumpectomy. After a median f/u >4 yrs, RT reduced IBTR in women given adj tamoxifen (6% vs. 18%). (Houghton J et al., Lancet 2003)

Question 19

For a pt with DCIS, name some risk factors associated with LR and which is most important.

Answer 19

Risk factors for LR in a pt with DCIS:

1. Decreased margin width (most important)
2. Increased size of tumor
3. High grade
4. Young age (<50 yrs)
5. Postmenopausal status
6. Comedonecrosis
7. Multifocality

Question 20

What is the purpose of the Van Nuys Prognostic Classification system, and what are its limitations?

Answer 20

The Van Nuys Prognostic Classification system is meant to identify DCIS pts who are at low risk for recurrence after RT alone using width of margins, size, grade, and age. The system was developed retrospectively and has not been validated in prospective studies or in different retrospective datasets. (Silverstein MJ et al., Am J Surg 2003)

Question 21

Do all DCIS pts require PORT?

Answer 21

Some pts with low-risk DCIS can probably be safely observed. Pts can be considered for omission of RT if they have grade 1–2 DCIS no larger than 2.5 cm, with margins at least 3 mm. 2 studies provide the main evidence for omission of RT:

ECOG 5194 (Solin LJ et al., JCO 2015): prospective single-arm observational trial. 711 pts with nonpalpable DCIS measuring at least 3 mm and conservatively resected with ≥3 mm microscopic margins (606 with G1–2 Dz measuring up to 2.5 cm, 105 with G3 DCIS measuring up to 1 cm). Pts were followed without RT; 31% declared an intent to take tamoxifen. At a median f/u of 12.3 yrs, 12-yr ipsi breast event rate was 14.6% (G1–2) and 24.6% (G3). 12-yr invasive ipsi breast event rate was 7.5% (G1–2) and 13.4% (G3).

RTOG 9804 (McCormick B et al., JCO 2015): prospective randomized trial of whole breast RT (50 Gy, no boost) vs. no RT for G1–2 DCIS conservatively resected with ≥3 mm margins. 636 eligible pts enrolled (accrual target 1,790 pts); 62% took tamoxifen. At a median f/u of 7.17 yrs, the 7-yr LF rate was 0.9% with RT vs. 6.7% without RT (p < 0.001).

Question 22

What whole breast dose and boost dose are used for a pt with DCIS after lumpectomy?

Answer 22

For DCIS, the whole breast dose is 40–50 Gy with a 10–16 Gy lumpectomy bed boost. The role of a boost in DCIS is controversial. The practice is extrapolated from results of the EORTC and Lyon boost trials for invasive cancers, but there have been no prospective trials of the role of boost in DCIS pts. ∼44% of pts from B-24 were given a boost, mainly for +margins.

A recent population–based analysis showed that the addition of a boost was not associated with a lower risk of local or invasive recurrence unless pts had positive margins. (Nilsson C et al., Radiother Oncol 2015)

Question 23

What is the Tx paradigm for LCIS?

Answer 23

LCIS Tx paradigm: for pure LCIS after lumpectomy, pts can be observed +/– risk reduction procedures. Occurrence of invasive Dz after LCIS is low and is often in the contralat breast. In addition, invasive Dz after LCIS is generally relatively favorable, and deaths subsequently are rare. The exception may be pleomorphic LCIS, although data are limited.

Question 24

For a pt with LCIS, what are 2 options to reduce the risk of development of an invasive cancer?

Answer 24

Options to reduce the risk of development of an invasive cancer:

1. Antiestrogen therapy with tamoxifen or raloxifene (raloxifene only if postmenopausal) (NSABP P1 trial)
2. Bilat mastectomy

Question 25

What is the management for a woman with LCIS detected on percutaneous core needle Bx?

Answer 25

LCIS on core needle Bx should typically prompt a surgical excision to confirm pure LCIS.

Question 26

Is LCIS associated with invasive cancer a contraindication for BCT?

Answer 26

No. Current literature supports the safety of BCT in the presence of coexisting LCIS in the specimen, and no special effort needs to be made to obtain –margins on LCIS.

Question 27

For a pt with LCIS, what is the benefit of primary tamoxifen?

Answer 27

For a pt with LCIS, tamoxifen halves the risk of invasive recurrence in either breast. (Fisher B et al., Lancet 1999)

Question 28

In a pt with DCIS or invasive Dz, what is the most common contraindication for adj tamoxifen therapy?

Answer 28

In a pt with DCIS or invasive Dz, the most common contraindication for adj tamoxifen therapy is Hx of stroke or other coagulopathy.