DCIS (Ductal Carcinoma In Situ)
The earliest, non-invasive form of breast cancer
Quick Facts
- Type: Non-invasive (stage 0) breast cancer
- Location: Inside a breast milk duct
- Often found by: Mammogram screening
- Outlook: Generally very good with treatment
Overview
DCIS stands for ductal carcinoma in situ. It is the earliest form of breast cancer, sometimes called stage 0, in which abnormal cells are found inside a milk duct of the breast. The phrase in situ means "in place," because the abnormal cells have not broken through the duct wall to invade the surrounding breast tissue.
Because it is non-invasive, DCIS does not spread to other parts of the body. However, if left untreated, some cases of DCIS can over time progress to invasive breast cancer, which can spread. For this reason DCIS is taken seriously and treated. Most cases are found through routine mammogram screening, before any lump can be felt, and the outlook after treatment is generally very good.
Symptoms
DCIS usually causes no symptoms and is most often discovered on a screening mammogram. When signs do appear, they may include:
- A breast lump (uncommon with DCIS)
- Bloody or unusual discharge from the nipple
- An area of skin change on the breast
Most cases are detected as tiny specks of calcium (microcalcifications) seen on a mammogram. Because symptoms are rare, regular screening as recommended for your age and risk is the main way DCIS is found early.
Causes
The exact cause of DCIS is not fully understood. It begins when cells lining a milk duct develop genetic changes that cause them to grow and look abnormal, while still staying inside the duct.
- Genetic changes in duct cells: Mutations occur that allow abnormal cells to multiply.
- Inherited and hormonal factors: Family history, inherited gene changes, and lifetime exposure to estrogen can play a role.
As with other breast cancers, DCIS develops from a combination of genetic, hormonal, and lifestyle factors rather than a single cause. Having risk factors does not mean a person will definitely develop it.
Risk Factors
- Increasing age
- A personal or family history of breast cancer
- Inherited gene changes such as BRCA1 or BRCA2
- Older age at first pregnancy or never having been pregnant
- Early start of periods or late menopause
- Dense breast tissue
- Long-term use of certain hormone therapies after menopause
Diagnosis
DCIS is usually suspected on a mammogram and confirmed with further tests:
- Mammogram: Often shows clusters of tiny calcium deposits (microcalcifications).
- Additional imaging: Further mammogram views, ultrasound, or sometimes MRI to assess the area.
- Biopsy: A small tissue sample is removed and examined under a microscope to confirm DCIS and look at how the cells appear (the grade).
The biopsy results, including the grade and the extent of the abnormal area, help guide treatment decisions.
Treatment
Treatment aims to remove the abnormal cells and lower the chance of cancer returning or becoming invasive. Options depend on the size, grade, and location of the DCIS.
- Breast-conserving surgery (lumpectomy): Removal of the DCIS and a margin of normal tissue, usually followed by radiation therapy.
- Mastectomy: Removal of the whole breast, sometimes recommended when the area is large or there are several sites.
- Radiation therapy: Often given after lumpectomy to reduce the risk of recurrence.
- Hormone therapy: If the DCIS is hormone-receptor positive, medication may be advised to lower future risk.
Because DCIS is non-invasive, chemotherapy is not usually needed. Treatment decisions are individualized and made together with the care team.
Prevention
- Attend recommended breast cancer screening for your age and risk level
- Be aware of your breasts and report any new lump, skin change, or nipple discharge
- Maintain a healthy weight and stay physically active
- Limit alcohol
- Discuss your family history and inherited risk with your doctor
- Talk with your doctor about the risks and benefits of hormone therapy after menopause
When to See a Doctor
See a doctor if you notice any change in your breasts, including:
- A new lump or thickening in the breast or underarm
- Bloody or unusual nipple discharge
- Changes in the size, shape, or skin of the breast
Also keep up with recommended screening mammograms, since DCIS is most often found before any symptoms appear. If you have been told a mammogram shows an abnormal area, follow up promptly for further evaluation.
Frequently Asked Questions
Is DCIS really cancer?
DCIS is the earliest, non-invasive form of breast cancer, sometimes called stage 0. The abnormal cells are confined within a milk duct and have not spread, but because some cases can become invasive over time, DCIS is treated.
Can DCIS spread to other parts of the body?
No. By definition DCIS has not broken through the duct wall, so it cannot spread elsewhere. The concern is that, if untreated, it can sometimes develop into invasive cancer that can spread.
How is DCIS usually found?
Most cases are found on a routine screening mammogram, often as tiny clusters of calcium deposits, before any lump can be felt. A biopsy then confirms the diagnosis.
What treatment does DCIS need?
Common options are breast-conserving surgery (lumpectomy) usually with radiation, or sometimes mastectomy. Hormone therapy may be added if the cells are hormone-receptor positive. Chemotherapy is generally not required.
What is the outlook for DCIS?
The outlook is generally very good because DCIS is caught early and is non-invasive. Treatment greatly reduces the chance of it returning or becoming invasive, and most people do well.
References
- American Cancer Society. Ductal Carcinoma In Situ (DCIS).
- Mayo Clinic. Ductal carcinoma in situ (DCIS) — Symptoms and causes.
- National Cancer Institute (NCI). Breast Cancer Treatment.
- MedlinePlus, U.S. National Library of Medicine. Breast cancer.