Breast Care A-Z · Condition · DCIS

Ductal carcinoma in situ (DCIS)

also: DCIS, intraductal carcinoma, stage 0 breast cancer, pre-invasive breast cancer · pronounced DCIS spelled out: D-C-I-S

Ductal carcinoma in situ (DCIS) is a non-invasive, very early breast cancer in which abnormal cells are confined inside the milk ducts and have not spread into surrounding tissue. You or someone close to you has probably had a mammogram, biopsy, or clinic letter mentioning DCIS; understanding what it is — and is not — helps the next conversation with your surgeon.

Quick answers

Is DCIS breast cancer?

DCIS is an early, non-invasive form of breast cancer. The cells are abnormal in the same way that cancer cells are abnormal, but they are contained within the milk duct and have not invaded the surrounding breast tissue. Some clinicians use the term pre-invasive or stage 0 cancer.

Can DCIS spread to other parts of the body?

No — while it remains in situ, DCIS cannot spread beyond the breast, because it has not crossed the duct wall into the surrounding tissue or into blood or lymph vessels. The concern with DCIS is that, if untreated, a proportion of cases would eventually develop an invasive component — which is why it is treated.

What is the difference between DCIS and invasive breast cancer?

DCIS is contained within the duct lining. Invasive breast cancer has grown beyond the duct into the surrounding breast tissue, and from there it can potentially spread to lymph nodes and to other parts of the body. DCIS and invasive breast cancer can occur separately or together in the same breast.

PLATE XL · ONCOLOGY · PRE-INVASIVE DISEASE ductal carcinoma in situ DCIS · NON-INVASIVE BREAST CANCER · INTRADUCTAL CARCINOMA malignant epithelial cells confined within the basement membrane of the breast ducts, without stromal invasion 1 FIG 01 — DUCT CROSS-SECTION: NORMAL vs DCIS lumen (open) Normal duct comedo necrosis DCIS (comedo type) i basement membrane (intact) ii malignant epithelial cells iii comedonecrosis iv uninvolved stroma v preserved duct architecture — no stromal invasion DCIS ARCHITECTURAL PATTERNS Comedo Central necrosis, high grade Cribriform Sieve-like spaces Micropapillary Finger-like projections into lumen Solid Sheets of cells, no spaces NUCLEAR GRADE CLASSIFICATION Grade 1 Low Small uniform nuclei Low mitoses Grade 2 Intermediate Moderate atypia Variable architecture Grade 3 High Large pleomorphic nuclei Frequent mitoses ± necrosis 2 FIG 02 — LOW-GRADE vs HIGH-GRADE DCIS Low-grade DCIS High-grade DCIS Nuclear grade Small, uniform nuclei Large, pleomorphic nuclei Mitotic rate Low (<2/10 HPF) High (>10/10 HPF) Necrosis Absent Comedonecrosis common Architecture Cribriform/micropapillary Comedo/solid ER status Usually ER+ Often ER− HER2 Usually HER2− Often HER2+ Recurrence risk Lower Higher Grade (Silverstein) Group 1 Group 3 Treatment Excision ± RT Excision + RT ± hormone Prognosis Excellent Good, higher local recurrence 3 FIG 03 — DCIS vs INVASIVE CANCER vs NORMAL Feature DCIS Invasive cancer Basement membrane Intact Breached Stromal invasion Absent Present Lymph node spread Not applicable Possible Metastatic risk Nil Present 5-yr survival >98% ~90% (stage I–II) Mammographic sign Calcifications Mass ± calcifications Surgical aim Clear margins Clear margins + staging Systemic therapy Hormone ± (if ER+) Full MDT plan Classification Stage 0 Stage I–IV 4 FIG 04 — CLINICAL PATHWAY Screening mammogram (calcifications) → Core biopsy image-guided → Histological diagnosis (B5a) ↓ MDT discussion multidisciplinary team ← Wide local excision + margins ← Adjuvant RT ± hormone therapy 5 FIG 05 — DCIS SUBTYPES OVERVIEW Comedo DCIS Central necrosis High grade · ER variable HER2 often + HIGH RISK Cribriform DCIS Sieve-like spaces Low–intermediate grade Usually ER+ LOWER RISK Micropapillary Finger-like projections Low–intermediate grade Often ER+ MODERATE RISK Solid DCIS Sheets of cells No intraluminal spaces Variable grade VARIABLE RISK Low nuclear grade Small uniform nuclei Low mitotic rate Favourable biology GOOD PROGNOSIS High nuclear grade Large pleomorphic nuclei Frequent mitoses Necrosis common HIGHER RISK 6 FIG 06 — KEY STATISTICS ~20% of all screen-detected breast cancers [1] >98% 5-yr survival with treatment [2] grade-dependent progression risk (14–53% by grade) [3] ~50% local recurrence reduction with RT [4] 7 FIG 07 — REFERENCES 1. NICE NG101. Early breast cancer guidelines 2023 2. Cancer Research UK. DCIS statistics 2024 3. Sanders ME et al. DCIS natural history. Cancer 2005;103:2316 4. Donker M et al. BIG 3-07 / TROG trial. Lancet Oncol 2013 5. Silverstein MJ. USC/Van Nuys Prognostic Index. Breast J 2003 Clinically authored by Dr Fiona Tsang-Wright , FRCS (Gen Surg) GMC 4549831 · ORCID 0000-0003-4801-026X
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Definition
Ductal carcinoma in situ, or DCIS, is an early, non-invasive breast cancer in which abnormal cells are contained within the lining of a milk duct and have not spread into the surrounding breast tissue.
≈ 100% 5-year breast-cancer-specific survival after treatment
≈ 50% Reduction in local recurrence with radiotherapy after BCS 1 3

Common questions The questions patients ask first

Is DCIS breast cancer?
DCIS is an early, non-invasive form of breast cancer. The cells are abnormal in the same way that cancer cells are abnormal, but they are contained within the milk duct and have not invaded the surrounding breast tissue. Some clinicians use the term pre-invasive or stage 0 cancer.
Can DCIS spread to other parts of the body?
No — while it remains in situ, DCIS cannot spread beyond the breast, because it has not crossed the duct wall into the surrounding tissue or into blood or lymph vessels2. The concern with DCIS is that, if untreated, a proportion of cases would eventually develop an invasive component — which is why it is treated3.
What is the difference between DCIS and invasive breast cancer?
DCIS is contained within the duct lining. Invasive breast cancer has grown beyond the duct into the surrounding breast tissue, and from there it can potentially spread to lymph nodes and to other parts of the body. DCIS and invasive breast cancer can occur separately or together in the same breast.
Do I need chemotherapy for DCIS?
Chemotherapy is not used for pure DCIS2, because chemotherapy is aimed at cancer that has spread beyond the breast, and DCIS has not. Treatment for DCIS focuses on surgery, radiotherapy where indicated3, and sometimes endocrine therapy5.

Ductal carcinoma in situ, or DCIS, is an early, non-invasive breast cancer in which abnormal cells are contained within the lining of a milk duct and have not spread into the surrounding breast tissue.

DCIS is sometimes called stage 0 breast cancer because it is confined to the ducts and has not become invasive. It is most often picked up on a screening mammogram as an area of tiny calcium deposits called microcalcifications, rather than as a lump. DCIS is treated, because a proportion of untreated cases would go on to become invasive breast cancer — but it is not the same as invasive cancer and is not expected to spread elsewhere in the body while it remains in situ.

Orientation Why you might be reading about this

You or someone close to you has probably had a mammogram result, a biopsy result, or a letter from a breast clinic that mentions DCIS. Understanding what it is — and what it is not — helps the next conversation with your surgeon. DCIS is a diagnosis that surprises many people because it is both early enough not to be immediately dangerous and serious enough to require treatment.

Related terms: Invasive ductal carcinoma · Lobular carcinoma in situ · Grade · Stage · Wide local excision · Mastectomy · Mammogram · Microcalcification

How it’s found How DCIS is found

The great majority of DCIS is found on screening mammograms4, where it usually shows as a cluster of microcalcifications — tiny specks of calcium in the duct wall. A smaller proportion of DCIS is found when investigating a lump, nipple discharge, or other symptoms. A biopsy — typically a vacuum-assisted biopsy guided by the mammogram — confirms the diagnosis.

Grading Grade: low, intermediate, or high

DCIS is given a grade based on how different the abnormal cells look from normal duct cells under the microscope. Low-grade DCIS grows slowly; intermediate-grade is in between; high-grade DCIS grows faster and is the most likely to progress to invasive cancer if untreated. The grade influences the treatment plan.

Treatment Treatment

Treatment for DCIS usually involves surgery, with one of two main options:

  • Wide local excision (also called breast-conserving surgery or lumpectomy) — removing the area of DCIS with a margin of healthy tissue around it (with 2 mm being the UK standard (Association of Breast Surgery) and widely accepted international consensus for BCS plus radiotherapy)1, and keeping the rest of the breast. This is the most common approach and is usually followed by radiotherapy3 to reduce the risk of recurrence.
  • Mastectomy — removing the whole breast2. This is recommended when the DCIS is extensive, when there are several separate areas in different parts of the breast, or when wide local excision cannot achieve clear margins. Mastectomy for DCIS can usually be combined with immediate reconstruction.

Some patients are also offered endocrine therapy (tablets that reduce the effect of oestrogen on breast tissue) after surgery, depending on whether the DCIS is oestrogen-receptor positive and on individual risk factors5.

Because DCIS is confined to the ducts and has not spread, sentinel lymph node biopsy is not routinely performed unless a mastectomy is planned, or unless there is a concern that an invasive component may also be present2.

Outlook Outlook

Outcomes after treatment for DCIS are very good. The five-year breast-cancer-specific survival figure for DCIS is close to 100%13. The main risk after treatment is local recurrence in the same breast — either as further DCIS or as invasive cancer — which is why follow-up with regular mammograms is important.

At consultation Questions to take to consultation

Questions worth asking your surgeon include: what grade is the DCIS; how extensive is it on the mammogram; can it be removed with a wide local excision or is mastectomy recommended; will I need radiotherapy; will I need endocrine therapy; what are my reconstruction options if mastectomy is recommended. See the breast cancer surgery services page for more on treatment options.


Resources Further reading

Sources & guidance

Every figure on this page is anchored to a published source. Tap a number in the text or below to jump to the reference.

  1. guideline Morrow M, Van Zee KJ, Solin LJ, et al. Society of Surgical Oncology – American Society for Radiation Oncology – American Society of Clinical Oncology consensus guideline on margins for breast-conserving surgery with whole-breast irradiation in ductal carcinoma in situ. Journal of Clinical Oncology. 2016 ;34(33):4040–4046 doi:10.1200/JCO.2016.68.3573 Cited for: Standard 2 mm margin for breast-conserving surgery in DCIS with whole-breast irradiation; influential international consensus.
  2. guideline National Institute for Health and Care Excellence (NICE). Early and locally advanced breast cancer: diagnosis and management (NG101). London: NICE. 2018 ;Last updated 2024 https://www.nice.org.uk/guidance/ng101 Cited for: UK pathway for surgery, radiotherapy, and endocrine-therapy decisions in DCIS; sentinel-node biopsy at mastectomy for DCIS.
  3. meta analysis Early Breast Cancer Trialists' Collaborative Group (EBCTCG). Overview of the randomised trials of radiotherapy in ductal carcinoma in situ of the breast. Journal of the National Cancer Institute Monographs. 2010 ;2010(41):162–177 doi:10.1093/jncimonographs/lgq039 Cited for: Whole-breast radiotherapy after BCS for DCIS roughly halves ipsilateral recurrence (both DCIS and invasive); does not affect breast-cancer-specific mortality.
  4. guidance Public Health England / NHS Breast Screening Programme. NHS Breast Screening Programme: how it works. London: gov.uk. 2024 https://www.gov.uk/guidance/breast-screening-programme-overview Cited for: Most DCIS in the UK is detected via screening mammography (microcalcifications) rather than as a symptomatic lump.
  5. cohort Cuzick J, Sestak I, Pinder SE, et al. (UK/ANZ DCIS Trial). Effect of tamoxifen and radiotherapy in women with locally excised ductal carcinoma in situ: long-term results from the UK/ANZ DCIS trial. The Lancet Oncology. 2011 ;12(1):21–29 doi:10.1016/S1470-2045(10)70266-7 Cited for: Tamoxifen reduces ipsilateral and contralateral new breast events in ER-positive DCIS after BCS; rationale for endocrine therapy discussion.