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Health condition · Clinically reviewed

DCIS, pre-invasive breast cancer - what it means and how it is treated.

Ductal carcinoma in situ is a stage 0 breast cancer picked up on screening. Most people are cured with surgery and radiotherapy, and there are real choices to make about how far to go.

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A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE NG101, the NHS Breast Screening Programme, ABS and RCR standards.

  • 03

    Current for 2026

    Reflects modern UK practice including hypofractionated radiotherapy, oncoplastic surgery and active-monitoring trials.

Key facts

DCIS at a glance.

The essentials, in plain English - what it is, how it is graded, and how it is treated in the UK today.

  • What it is

    Ductal carcinoma in situ - malignant cells confined to the breast duct that have not crossed the basement membrane. Stage 0 breast cancer.

  • How it is found

    Usually asymptomatic and picked up as microcalcifications on a screening mammogram - clusters, linear or branching patterns.

  • Grade matters

    Low, intermediate or high grade based on nuclei, necrosis and architecture - high grade behaves more aggressively.

  • Molecular profile

    Often ER positive and PR positive; a meaningful minority are HER2 positive. This shapes hormonal treatment decisions.

  • Risk of invasion

    If untreated, roughly 20 to 50 per cent may progress to invasive cancer over 20 to 30 years - highest for high-grade DCIS.

  • Treatment mainstay

    Breast-conserving surgery plus adjuvant radiotherapy for most, with mastectomy reserved for extensive or multifocal disease.

Why this guide matters

Pre-invasive, but real - and treatable.

DCIS sits between benign and invasive. The three points below shape everything that follows on this page.

  • Screening finds most cases

    Around a fifth to a quarter of screen-detected breast cancers are DCIS - most people have no symptoms at all.

  • Grade drives risk

    High-grade DCIS is more likely to progress to invasive cancer and needs more definitive treatment.

  • Choices matter

    Type of surgery, radiotherapy schedule and endocrine therapy are shared decisions - not one-size-fits-all.

How the diagnosis is made

From screening recall to a clear plan.

The steps a UK breast unit will normally follow, in order - so you know what to expect and why each test is done.

  1. 01

    Imaging

    Screening mammography

    Two-view digital mammography with magnification views and tomosynthesis to characterise microcalcifications using BI-RADS categories.

  2. 02

    Imaging

    Targeted ultrasound

    Used to look for a mass or duct correlate and to guide biopsy where a lesion is visible.

  3. 03

    Imaging

    Breast MRI in selected cases

    Considered for extent mapping in younger patients, high-grade disease, dense breasts and surgical planning.

  4. 04

    Confirming

    Stereotactic vacuum biopsy

    Vacuum-assisted biopsy (VAB) is standard for microcalcification; core biopsy is used when there is a discrete mass.

  5. 05

    Confirming

    Specialist pathology

    Grade, architecture, necrosis and ER, PR and HER2 status reported and reviewed at a specialist breast MDT.

  6. 06

    Planning

    Assess for hidden invasion

    Adequate sampling is essential - roughly 10 to 20 per cent of DCIS diagnoses are upgraded to invasive disease at surgery.

  7. 07

    Planning

    Breast MDT and shared decision

    A specialist breast MDT sets the plan with you - surgery, radiotherapy, endocrine therapy and, where relevant, genetics.

Typical timeline: from screening recall to a settled treatment plan in a matter of weeks.

Symptoms

What DCIS actually looks like.

Usually nothing to feel - and everything to see on a mammogram. Sometimes a lump, discharge or nipple change is the first sign.

  • Asymptomatic screen finding

    The most common presentation - no symptoms at all, picked up on a routine NHS screening mammogram.

  • Microcalcifications

    Clusters, linear or branching calcifications on mammography are the classic radiological signature.

  • Palpable lump

    Uncommon but possible - a firm area or lump that needs prompt triple assessment at a breast clinic.

  • Nipple discharge

    Spontaneous, single-duct or bloody discharge deserves urgent breast-clinic review to exclude DCIS or invasive disease.

  • Paget disease of the nipple

    Persistent eczematous or scaly change of the nipple can signal underlying DCIS and needs a punch biopsy.

  • Nipple or skin change

    New retraction, dimpling or eczematous change - especially unilateral - warrants urgent assessment.

  • Duct ectasia mimics

    Benign duct ectasia can present similarly; imaging and biopsy tell them apart.

  • Red flag - bloody nipple discharge

    Spontaneous bloody discharge from a single duct is a two-week-wait symptom - do not delay.

Treatment

How DCIS is treated in the UK.

Surgery is the backbone, with radiotherapy after breast-conserving surgery, endocrine therapy for ER-positive disease, and genetics where family history warrants it.

  • Breast-conserving surgery (WLE)

    Wide local excision with oncoplastic techniques is first-line for suitable disease - aim for clear margins of at least 2 mm.

  • Mastectomy

    For extensive or multifocal DCIS, where clear margins are not achievable, or by patient preference - with immediate reconstruction options.

  • Sentinel node biopsy

    Considered at mastectomy and for high-grade WLE where occult invasion is a real possibility.

  • Adjuvant radiotherapy

    After breast-conserving surgery - typically 40 Gy in 15 fractions, halving the risk of local recurrence.

  • Partial breast radiotherapy

    Selected low-risk cases in specialist centres; hypofractionated 5-fraction schedules (FAST-Forward style) are emerging.

  • Endocrine therapy

    For ER-positive DCIS - tamoxifen 20 mg for 5 years, or anastrozole after the menopause (IBIS-II evidence). Shared decision.

  • Active monitoring (trial-based)

    For carefully selected low-risk DCIS - the LORIS, LORD and COMET trials are testing surveillance rather than immediate surgery.

  • Genetics and risk reduction

    Testing for BRCA1, BRCA2, PALB2 and other genes where family history suggests - opens risk-reducing options.

Related surgical and diagnostic pages: breast-conserving surgery, breast reconstruction, vacuum-assisted breast biopsy, oncoplastic breast surgery and hereditary cancer panel.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your breast surgeon and oncologist know your case in detail and can tell you which parts apply to you. If in doubt, ask them.

  • NICE. Early and locally advanced breast cancer: diagnosis and management (NG101).

  • NHS Breast Screening Programme (BSP) clinical guidance and pathology reporting standards.

  • Association of Breast Surgery (ABS) consensus statements on margins and oncoplastic surgery.

  • Royal College of Radiologists (RCR) postoperative radiotherapy for breast cancer guidance.

  • National Cancer Registration and Analysis Service (NCRAS) DCIS outcome data.

Red flags

When breast changes need urgent attention.

Most breast symptoms turn out to be benign - but these features should trigger prompt review at a specialist breast clinic.

  • Bloody or single-duct nipple discharge

    Spontaneous, unilateral, blood-stained discharge from a single duct is a two-week-wait symptom and needs urgent breast-clinic assessment.

  • Persistent eczematous nipple change

    Suspect Paget disease - a punch biopsy of the nipple is required, even when eczema seems the more obvious explanation.

  • New palpable breast lump

    Any new discrete lump in a woman over 30 warrants urgent triple assessment - clinical exam, imaging and biopsy.

  • Suspicious microcalcifications

    Clustered, linear or branching calcifications on mammography should trigger recall, magnification views and vacuum biopsy.

  • Upgrade at surgery

    Around 10 to 20 per cent of DCIS diagnoses are found to have invasive disease at excision - the surgical plan must anticipate this.

  • Strong family history

    Multiple close relatives with breast, ovarian, pancreatic or prostate cancer should prompt referral to clinical genetics.

  • Contralateral breast changes

    DCIS increases risk in the other breast - any new symptom on either side deserves review.

  • Recurrence after treatment

    Any new lump, skin change or imaging abnormality during follow-up needs prompt specialist review, not watchful waiting.

  • Psychological distress

    A "stage 0" label can still feel like cancer - low mood, anxiety or intrusive worry deserves proper support.

Living with it

A treatable diagnosis, with real choices.

Four things that make the biggest difference day to day - understanding what stage 0 means, recovering well from surgery, getting through radiotherapy and settling into follow-up.

A quiet reminder

Support matters, and so does asking for it.

Breast Cancer Now, Macmillan and your specialist breast cancer nurse are there for the practical and the emotional. Use them.

  1. 01 Understanding

    Stage 0, but still cancer

    DCIS is a pre-invasive cancer - taking it seriously without catastrophising is the right balance. Ask questions until you feel clear.

  2. 02 Recovery

    After surgery

    Most patients recover well from breast-conserving surgery within a few weeks - your breast team will guide wound care, exercises and driving.

  3. 03 Radiotherapy

    Getting through 15 fractions

    Skin changes and fatigue are common and settle - moisturise as advised and pace your energy across the three weeks.

  4. 04 Follow-up

    Annual mammography

    Long-term surveillance with annual mammography and clinical review keeps a close eye on both breasts.

Frequently asked

Everything we get asked about DCIS.

Quick answers on progression, surgery, radiotherapy, endocrine therapy and active monitoring.

  • What is DCIS?

    Ductal carcinoma in situ is a pre-invasive breast cancer - malignant cells are confined to the milk ducts and have not crossed the basement membrane. It is classified as stage 0 breast cancer and now accounts for around 20 to 25 per cent of screen-detected breast cancers in the UK.

  • Will DCIS turn into invasive breast cancer?

    Not always, but the risk is real. If left untreated, roughly 20 to 50 per cent of DCIS lesions may progress to invasive cancer over 20 to 30 years - the risk is highest for high-grade disease. Predicting who will progress is not yet possible with confidence, which is why treatment is usually recommended.

  • Do I need a mastectomy for DCIS?

    Usually not. Most people with DCIS are offered breast-conserving surgery (a wide local excision) followed by radiotherapy. Mastectomy is reserved for extensive or multifocal disease, when clear margins cannot be achieved, or by patient choice - with immediate reconstruction offered where suitable.

  • What is the point of radiotherapy after surgery?

    Radiotherapy after breast-conserving surgery roughly halves the risk of the DCIS coming back in the same breast, including as invasive cancer. The standard UK schedule is 40 Gy in 15 fractions; partial-breast and 5-fraction regimens are used in selected cases.

  • Do I need tamoxifen or anastrozole?

    For ER-positive DCIS, endocrine therapy for 5 years reduces the risk of recurrence and of a new cancer in the other breast. Tamoxifen suits pre- and post-menopausal women; anastrozole is an option after the menopause. It is a shared decision - your team will weigh benefits against side effects.

  • Can I just watch and wait?

    Active monitoring is being tested for carefully selected low-risk DCIS in trials such as LORIS, LORD and COMET, and results are still awaited. Outside a trial, standard NHS practice remains treatment. Ask your breast team whether a trial is open and appropriate for you.

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