Stage 0 DCIS — understanding your diagnosis

Public education

A clear starting place after a stage 0 (DCIS) diagnosis

Ductal carcinoma in situ (DCIS) is often called stage 0 breast cancer. Abnormal cells are still inside a milk duct and have not been shown to invade surrounding breast tissue on biopsy. Outlook for treated DCIS is excellent in population data — but the best path for you depends on pathology, imaging, personal values, and a care team you trust.

This site is education only — not a diagnosis, care plan, or second opinion. Clinicians treat; people decide with them. Do not put personal health details in public feedback.

Learn · explore · decide

Learn What DCIS is, in plain language The name, what it is not, and the words you will hear. Explore Usual care and alternatives Surgery, radiation, endocrine therapy, and the optional deeper track. Decide Questions to take to a visit What to ask so the next conversation is yours.

What is DCIS?

In plain language

DCIS means abnormal cells are confined to a milk duct (in situ = “in place”).
It is not the same as invasive breast cancer, where cells have crossed into surrounding tissue.
Many cases are found on screening mammograms (often as calcifications), before there is a lump.
Not all DCIS behaves the same: grade, size/extent, hormone receptors, and features like necrosis affect risk discussions.
Core biopsy can miss a small area of invasion; surgery (when done) also completes staging of the area that was sampled.

Words you may hear

Stage 0 — another name for pure DCIS (no invasive component identified).
Grade (low / intermediate / high) — how abnormal the cells look under the microscope.
ER / PR — estrogen and progesterone receptors; if positive, hormone (endocrine) therapy is often discussed.
HER2 — a receptor test; status can matter if invasion is found or in research settings.
Margins — after lumpectomy, how close cells were to the edge of removed tissue.
Comedonecrosis — a pattern of cell death inside the duct; often discussed as a higher-risk feature when present.
Ipsilateral / contralateral — same breast vs opposite breast.
Absolute risk — chance stated in plain numbers (prefer this over “50% less risk” alone).

Full glossary (searchable) →

What DCIS is not

Not a guarantee that invasive cancer would have developed — many lesions never would — but we cannot always know which ones.
Not “nothing.” It is a real diagnosis that deserves a plan and follow-up.
Not the same for everyone: age, family history, density, extent, and pathology all change the conversation.
Not something this website can individualize. Your path report and imaging belong in discussion with your team.

Aspects of the diagnosis teams review

Decisions usually rest on several layers — not a single label. Ask for plain-language explanations of each. Unfamiliar words? Check the glossary.

Pathology Type (DCIS vs invasive), nuclear grade, architecture (e.g. solid, cribriform), necrosis, calcifications, receptors (ER/PR/HER2 when reported).

Imaging Mammogram findings, ultrasound, sometimes MRI — extent of disease, other areas of concern, breast density.

Clinical context Age, menopausal status, prior breast disease, family history, germline genetics when indicated, other health conditions, medications (including hormones).

Values & logistics Preferences about breast conservation vs mastectomy, radiation travel/burden, fertility or hormone goals, anxiety about surveillance, support system.

Standard of care — paths & considerations

What “standard of care” means here: The approaches most widely recommended in guidelines and practice for many people with DCIS — typically local treatment (surgery ± radiation) and, when hormone receptors are positive, a discussion of endocrine (hormone-blocking) therapy. Your team adapts this to your case. Guidelines evolve; ask what applies to you.

1. Surgery — local control

Breast-conserving surgery (lumpectomy) removes the area of DCIS with a margin of normal tissue when extent allows. Mastectomy removes more or all breast tissue and is considered when disease is widespread, margins cannot be cleared, risk is high, or by preference (including reconstruction planning).

Surgery treats known disease and can reveal upgrade to invasive cancer not seen on core biopsy.
Clear margins are a common goal after lumpectomy; re-excision is sometimes needed.
Lymph-node surgery is not routine for pure DCIS but may be discussed if invasion is found or mastectomy is planned.

2. Radiation — after lumpectomy

Radiation to the breast (or part of the breast in selected cases) is often offered after lumpectomy to lower the chance of DCIS or invasive cancer returning in that breast.

Benefit is mainly local control (fewer ipsilateral events), not a large change in overall survival for typical DCIS.
Absolute benefit varies with age, grade, size, margins, and biology.
Genomic tools (e.g. DCISionRT in some centers) may inform shared decisions — ask radiation oncology.

3. Endocrine therapy — if ER/PR+

For hormone-receptor–positive DCIS, medicines such as tamoxifen or an aromatase inhibitor (depending on menopausal status) are often discussed for several years.

Main goal: lower risk of future breast events in either breast (not usually framed as “life-saving” for stage 0).
Side effects can include hot flashes, sexual/sleep changes, bone or joint effects (especially AIs), and rare serious risks (e.g. clots or uterine cancer with tamoxifen).
Tradeoffs with quality of life and any hormone replacement goals belong in the conversation — with oncology and your other clinicians.

4. Surveillance & support

After (or alongside) treatment, ongoing mammograms and clinical follow-up look for new or residual disease. Supportive care covers symptoms, bones, mental health, and rehabilitation.

Imaging schedule is individualized (often annual mammography at minimum after breast conservation).
Genetic counseling/testing may be appropriate based on age, family history, or guidelines — not only “strong family history.”
Second opinions are reasonable, especially before major irreversible choices.

How the pieces fit together (not always “all three”)

Historically many people heard about a package: lumpectomy + radiation + endocrine therapy. Modern care is increasingly risk-adapted and shared: each layer has its own benefits, burdens, and eligibility. You can ask for absolute (percentage-point) risks with and without each component for your pathology.

Building block	Often addresses	Common considerations
Surgery	Remove / fully assess the lesion	Extent, margins, reconstruction, recovery
Radiation (after BCS)	Ipsilateral local recurrence risk	Travel, skin/fatigue effects, modest absolute benefit for some
Endocrine therapy	Future ipsilateral & contralateral events (HR+)	Side effects, duration, bone/heart/QoL tradeoffs
Surveillance	Catch new events early	Anxiety vs reassurance; imaging access

Questions worth bringing to early visits

What exactly does my pathology report say (grade, necrosis, receptors, size/extent estimates)?
What is my chance of upgrade to invasive disease if I have surgery?
Is breast conservation realistic for me, or is mastectomy on the table — and why?
If I have a lumpectomy, what is the approximate absolute reduction in local events from radiation for my profile?
If I am ER/PR+, what are the 5–10 year event rates with and without endocrine therapy, and what side effects should I plan for?
Should we discuss germline genetic testing or additional imaging (e.g. MRI)?
What is the follow-up schedule if I choose each main option?
Who coordinates my care (navigator, surgeon, radiation oncologist, medical oncologist, PCP)?

Reputable starting sources (standard care)

NCI — Breast cancer treatment (PDQ) Patient-friendly overview including DCIS concepts American Cancer Society — DCIS What DCIS is and how it is often treated NCCN Guidelines for Patients Patient versions of major oncology guidelines Breastcancer.org — DCIS Accessible explanations and community context

Looking beyond the usual package?

Some people explore de-escalation (omitting radiation or endocrine therapy after shared decision), active monitoring for carefully selected low-risk DCIS, or clinical trials. Those paths are real areas of research and practice change — and they are not risk-free or appropriate for everyone.

The alternatives track explains options, known risks, eligibility caveats, and where to read primary sources. Unfamiliar trial names (COMET, RECAST, RTOG)? See the glossary research section.

Open alternatives track →