DCIS – Are we cutting it?

Dr Alex Lemaigre

With thanks to:Mr Richard BoultonDr Elizabeth OsinibiMr Oladapo Fafemi

Introduction to DCIS

• Ductal carcinoma in situ• Non invasive neoplasm in the milk ducts of the

breast• Predisposes to invasive ductal carcinoma• 2900 cases of screen-detected DCIS per

annum (9)

DCIS - Treatment

• Usually wide local excision (lumpectomy) +- radiotherapy.

• Prognosis improved by greater resection margin, and the use of radiotherapy.(1,2,3)

• Sentinel node biopsy (SNLB) not recommended (incidence LN metastases <1%). (4,5)

Aims and Objectives

• To discover how many of DCIS cases on core biopsy will be found to have invasive cancer on excision histology.

• Can we predict which these will be?• Should we be doing SNLB on these patients?

• How successful are we at adequately excising the neoplasm with wide local excision?

Methods

• Analysed all new patients diagnosed with DCIS only on core biopsy in 2009, 2010 and 2011.– grade of initial DCIS– diagnosis on excision specimen

– closest resection margin– need for re-excision

• Inclusion criteria: all patients newly diagnosed with DCIS ONLY on core biopsy in 2009, 2010 or 2011, regardless of age, sex, or method of detection.

• Exclusion criteria: Recurrent breast cancer, DCIS + any other diagnosis on core biopsy.

• Where multiple grades of DCIS were present in a specimen, the highest grade was considered.

Results

• Total 36 patients with DCIS only in 3 years

High grade61% (22)

Interme-diate grade

22% (8)

Low grade17% (6)

Pie chart demonstrating the percentages of low, intermediate and high grade DCIS found on core biopsy for patients diagnosed with DCIS between 2009

and 2011

DCIS + microinvasion 19% (7)

DCIS + invasive cancer 19% (7)

DCIS - higher grade than on core biopsy

3% (1)

DCIS - same or lower grade than on core

biopsy 59% (21)

Pie chart demonstrating excision biopsy results for patients diagnosed with DCIS only on core biopsy between 2009 and 2011

High grade28% (2)

Intermediate grade43% (3)

Low grade29% (2)

Pie chart demonstrating the breakdown of DCIS grade on initial core biopsy for patients diagnosed with invasive cancer on excision histology

DCIS of same or lower grade59%

DCIS + microinvasion32%

DCIS + invasive cancer9%

Pie chart showing breakdown of excision histology for patients diagnosed with high grade DCIS on core biopsy

Conclusions

• 19% of patients with DCIS only on core biopsy were found to have invasive ductal carcinoma on excision histology.

• These patients cannot be predicted by the initial grade of the DCIS.

• High grade DCIS does not increase the risk of invasive cancer compared to lower grades.

Resection Margins

• Analysed the resection margins on excision specimens.

• 1 case was excluded as the patient had a mastectomy for multifocal DCIS

• 1 case was excluded as the biopsy appeared to have entirely excised the DCIS

• Total = 34 patients

• North Middlesex standard “safe” excision margin for DCIS = 5mm

• There is some variability between centres on this figure (1mm – 10mm).

involved <1mm <5mm > 5mm0

2

4

6

8

10

12

6

8

9

11

Bar Graph to show closest resection margins on excision histology

Size of excision margin

Tota

l num

ber o

f cas

es

Anterior Posterior Medial Lateral Superior Inferior0

2

4

6

8

10

12

14

9

12

8

6

2

8

Bar chart to show which margins are most commonly the closest on excision histology

Margin involved

Tota

l num

ber

NB – total number here = 45 as many specimens had >1 margin reported as close

Need for Re-excision?• According to these data 11 out of 34 cases had

wide enough resection margins.• Therefore 23/34 (67%) require re-excision to

improve margins. • However – improving the posterior margin

involves resecting the chest wall (including pectoralis major).

• There is no prognostic benefit to this, and it causes greater morbidity.

• Excluded those where the posterior margin was the only close margin <5mm (n=3)

Involved <1mm <5mm0

1

2

3

4

5

6

7

8

Bar chart to show distribution of close excision margin after exclusion of those cases with only the posterior margin deemed close

Size of excision margin

Tota

l num

ber

The Saga Continues...

• 20 cases still require re-excision• = 55% of our original population of 36 patients

• 2 had a mastectomy• 1 was referred to Royal Free• 2 lost to NMUH follow-up• 11 had successful re-excision• 4 had inadequate re-excision

Conclusions

• 55% of DCIS patients required more than one operation to adequately clear the DCIS

Discussion – Excision histology + SLNB

• SLNB used in invasive cancer to determine lymph node spread.

• SLNB cannot be performed after WLE due to disruption of lymphatic drainage.

• DCIS grade does not predict probability of invasive carcinoma.

• Therefore cannot guide us which patients to select for SLNB.

• No value in SLNB on DCIS patients as <1% will show LN involvement (4,5).

• Ductal carcinoma in situ • 1.4.5 Do not perform SLNB routinely in

patients with a preoperative diagnosis of DCIS who are having breast conserving surgery, unless they are considered to be at a high risk of invasive disease.

• 1.4.6 Offer SLNB to all patients who are having a mastectomy for DCIS.

Discussion – Excision Margins

• Surgery for DCIS aims to balance disease clearance (and risk of recurrence) and an acceptable cosmetic appearance.

• No prospective trials have assessed optimum excision width for in situ disease.

• Involved margins carry the worst prognosis (6)

• No consensus on standard acceptable margins• How do we decide?

• 1.3 Surgery to the breast • Ductal carcinoma in situ • 1.3.1 For all patients treated with breast conserving surgery

for DCIS a minimum of 2 mm radial margin of excision is recommended with pathological examination to NHSBSP reporting standards. Re-excision should be considered if the margin is less than 2 mm, after discussion of the risks and benefits with the patient.

• 1.3.2 Enter patients with screen-detected DCIS into the Sloane Project (UK DCIS audit)[5].

• 1.3.3 All breast units should audit their recurrence rates after treatment for DCIS.

Discussion – Re-excision rates

• 55% re-excision seems very high.• Wong et al stated a re-excision rate of 84% to

achieve margins of >10mm. (7)

• Holland et al stated a re-excision rate of 43% to achieve margins of >1mm. (8)

• Re-excision rates will depend on what distance the excision margin is considered safe.

Discussion - Radiotherapy• Post-operative radiotherapy significantly decreases risk of

disease recurrence (1,2,3).– Julien et al 2000: 4 year recurrence free = 84% vs 91% if

treated with radiotherapy (1)

– Chan et al 2001: Recurrence of 18.6% vs 11.1% if treated with radiotherapy (3)

– Wong et al 2006: abandoned trial of WLE only (10mm margin) due to high recurrence rate of 2.4% per patient year. (7)

• NMUH does not routinely offer radiotherapy to DCIS patients

• 1.11 Radiotherapy • Radiotherapy after breast conserving surgery • 1.11.1 Patients with early invasive breast cancer

who have had breast conserving surgery with clear margins should have breast radiotherapy.

• 1.11.2 Offer adjuvant radiotherapy to patients with DCIS following adequate breast conserving surgery and discuss with them the potential benefits and risks (see recommendation in section 1.3.1)

Further Work

• Audit recurrence rates in these patients.

• Compare our results with rates of re-excision data from other centres with similar choice of acceptable margins.

• Compare our data with previous data collected by Mr Fafemi some years ago.

Re-assess the treatment we offer for DCIS

References1. Julien J, Bijker et al. Radiotherapy in breast conserving treatment for ductal carcinoma in situ:

first results of EORTC randomized phase III trial 10853. Lancet 2000; 355:528-33.2. Fisher ER, Dignam J et al. Pathologic findings from the National Surgical Adjucant Breast Project

(NSABP) eight-year update of Protocol B-17 intraductal carcinoma. Cancer 1999;86:429-383. Chan KC, Knox WF et al. Extent of excision margin width required in breast conserving surgery for

ductal carcinoma in situ. Cancer 2001;91:9-164. Kitchen PR, Cawson JN et al. Axillary dissection and ductal carcinoma in situ of the breast: a

change in practice. Aust NZ J Surg 2000;70:419-225. Veronesi P, Intra M et al. Is sentinel node biopsy necessary in conservatively treated DCIS? Ann

Surg Oncol 2007;14(8):2202-86. Law, Tsz Ting MBBS; Kwong, Ava FRCS. Surgical Margins in Breast Conservation Therapy: How

Much Should We Excise? Southern Medical Journal: December 2009 - Volume 102 - Issue 12 - pp 1234-1237

7. Wong J, Kaelin CM et al. Prospective study of wide local excision alone for ductal carcinoma in situ of the breast. J clin oncol 2008;24(7):1031-1036

8. Holland PA, Gandi A, et al. The importance of complete excision in the prevention of local recurrence of ductal carcinoma in situ. Br J Cancer 1998; 77(1):110-114.

9. Dodwell D, Clements K, Lawrence G, Kearins O, Thomson C, Dewar J, Bishop H, on behalf of the Sloane Project Steering Group. Radiotherapy following breast-conserving surgery for screen-detected ductal carcinoma in situ: indications and utilisation in the UK. Interim findings from the Sloane Project. British Journal of Cancer 2007; 97: 725-729

10. NICE guidelines – Feb 2009 – Early and locally advanced breast cancer, diagnosis and treatement.

Any questions?