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Ductal Carcinoma In Situ (DCIS) Treatment in Los Angeles
Reviewed by Elizabeth Arena, MD, FACS.
Dr. Elizabeth Arena, a breast surgical oncologist in Los Angeles, treats women whose biopsy has shown ductal carcinoma in situ (DCIS): abnormal cells inside a milk duct that have not grown through the duct wall. She removes DCIS with a lumpectomy or a mastectomy. When radiation or hormone therapy is part of your treatment, she sets up your appointments with a radiation oncologist or a medical oncologist.
Is DCIS cancer?
DCIS is the earliest form of breast cancer, also called stage 0, non-invasive breast cancer or intraductal carcinoma. The cells lining one of your milk ducts look like cancer cells under the microscope, but they have not grown through the duct wall into the breast tissue around it. On their own, they cannot spread to your lymph nodes or other organs. DCIS makes up 20% to 25% of new breast cancer diagnoses in the United States. [1]
The National Cancer Institute calls DCIS a precancer, while the American Cancer Society calls it non-invasive or pre-invasive breast cancer; both names describe the same diagnosis. Doctors still treat DCIS, because an estimated 10% to 50% of DCIS cases left untreated may become invasive breast cancer over time. [2] If your biopsy also shows invasive cancer, Dr. Arena recommends an operation and any lymph node surgery for the invasive cancer, as described under breast cancer treatment.
What are the signs of DCIS?
Most women with DCIS have no symptoms and most cases are found on a screening mammogram. [1] When there is a sign, it is one of these:
- Calcifications on a mammogram: tiny white specks that lead to a callback and a biopsy, as described in what happens after an abnormal mammogram.
- A lump: occasionally DCIS forms a lump that you or your doctor can feel.
- Nipple discharge: fluid from the nipple that is not breast milk.
What does your biopsy report say about your DCIS?
Your pathology report lists the grade of your DCIS, its hormone receptors and the size of the area it covers. At your consultation Dr. Arena goes through each line with you and shows you the same area on your mammogram and ultrasound images. HER2, a protein measured in invasive breast cancer, is usually not tested in DCIS, so your report may not mention it. [1]
| On your report | What it means | How it affects your treatment |
|---|---|---|
| Ductal carcinoma in situ, no invasion | All the abnormal cells are inside the duct | Lymph nodes are usually left in place during a lumpectomy |
| Grade: low (1), intermediate (2) or high (3) | How abnormal the cells look; low- and intermediate-grade DCIS grows more slowly than high-grade | High-grade DCIS is more likely to come back after treatment, which affects whether radiation is recommended |
| Estrogen or progesterone receptor-positive | The cells use these hormones to grow, as most DCIS does | Hormone therapy may be offered after a lumpectomy |
| Size or extent | How large an area of your breast the DCIS covers | A large area, or DCIS in several separate areas, can mean a mastectomy |
When your mammogram does not show how far the DCIS extends, Dr. Arena may order a breast MRI before surgery.
Does DCIS need surgery?
Surgery is the standard treatment for DCIS. Active monitoring, meaning regular breast imaging in place of an operation, is being tested in clinical trials for DCIS that looks low risk. The American Cancer Society does not yet count it as a standard treatment. [3]
The largest US trial so far, COMET, enrolled 995 women whose DCIS was:
- Low or intermediate grade: grade 1 or 2.
- Hormone receptor-positive: the cells use estrogen or progesterone to grow.
- HER2-negative: no extra HER2 protein.
After two years, invasive cancer had been found in the same breast in 4.2% of the women assigned to active monitoring and 5.9% of the women assigned to surgery, with or without radiation. Results beyond two years have not yet been published. [4] If your report shows low- or intermediate-grade, hormone receptor-positive DCIS, Dr. Arena checks your report against the trial's criteria with you and explains what active monitoring would involve.
Lumpectomy or mastectomy for DCIS?
In the United States, most women with DCIS have a lumpectomy followed by radiation. A mastectomy is usually recommended when the DCIS covers a large area of your breast, is present in several separate areas, or cannot be removed with clear margins (a rim of healthy tissue all around it) even after a second operation. [3]
| Compared | Lumpectomy | Mastectomy |
|---|---|---|
| What Dr. Arena removes | The DCIS and a rim of healthy tissue around it | All your breast tissue; in a nipple-sparing mastectomy, your skin and nipple stay |
| Radiation afterward | Usually: daily for 3 to 4 weeks, or 5 treatments for some women | Rarely needed |
| Lymph nodes | Usually none removed | Often a sentinel lymph node biopsy, removing the first few lymph nodes under your arm, in the same operation |
| Chance of DCIS or invasive cancer returning in your treated breast | Higher | Very low |
| Survival | Same as after a mastectomy | Same as after a lumpectomy |
| Reconstruction | Usually not needed; an oncoplastic lumpectomy reshapes the remaining tissue in the same operation | Optional, at the same time or later, performed by the plastic surgeon you choose |
At your consultation Dr. Arena measures the DCIS on your images against the size of your breast and explains which operations would remove it with clear margins. If your age or family history suggests an inherited gene change, she offers genetic testing in the office, so the result is back before you choose. For the reasons women choose one operation over the other, see lumpectomy or mastectomy: how to decide.
What happens during DCIS surgery?
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Marking the DCIS
Most DCIS cannot be felt, so a radiologist uses a mammogram or ultrasound to place a small marker in the area and Dr. Arena uses the marker to find the area during the operation.
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Removing the DCIS
Dr. Arena removes the area with a rim of healthy tissue, aiming for at least 2 mm of healthy tissue between the DCIS and the edge, the current standard for lowering the chance of it coming back. [3] She places the incision where it will be least visible, such as along the edge of the areola or in the fold beneath your breast.
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Checking the margins
A pathologist examines the tissue under a microscope. If DCIS reaches too close to an edge, Dr. Arena removes more tissue from that area in a second operation.
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Checking for invasive cancer
Occasionally the removed tissue shows a small invasive cancer that the biopsy missed. The chance is higher with larger and higher-grade DCIS. If invasive cancer turns up in tissue removed at a mastectomy, a sentinel lymph node biopsy can no longer be done, so Dr. Arena may remove the first few lymph nodes under your arm during a mastectomy for DCIS.
Will you need radiation or hormone therapy after surgery?
Most women have radiation after a lumpectomy for DCIS, planned by a radiation oncologist. A medical oncologist prescribes hormone therapy if your DCIS is hormone receptor-positive.
| Treatment | What it does for DCIS | Who usually has it |
|---|---|---|
| Whole-breast radiation | Lowers the chance of DCIS or invasive cancer coming back in your treated breast by about half, in a study combining 4 clinical trials; given daily, 5 days a week, for 3 to 4 weeks | Most women after a lumpectomy |
| Partial-breast radiation | Treats only the area where the DCIS was | Some women with small, low- or intermediate-grade DCIS and clear margins |
| No radiation | Avoids radiation; DCIS is more likely to come back than with radiation | Older women, women with other serious health problems, or small low-grade DCIS removed with wide clear margins |
| Hormone therapy: tamoxifen (a pill that blocks estrogen), or an aromatase inhibitor (a pill that lowers estrogen) after menopause | Lowers the chance of a new DCIS or invasive cancer in either breast, taken for 5 years | Women with hormone receptor-positive DCIS after a lumpectomy; usually not after a mastectomy |
Radiation does not change survival after a lumpectomy. Your radiation oncologist bases the recommendation on your grade, the width of your margins, your age and what you prefer. [2]
Why choose Dr. Arena for DCIS treatment in Los Angeles?
- Double board certification: Dr. Arena is double board-certified in general surgery and complex general surgical oncology.
- Fellow of the American College of Surgeons (FACS): the College grants Fellowship after reviewing a surgeon's training, surgical case log and ethical conduct. [5]
- In-office tests: breast ultrasound and genetic test samples, without a separate imaging or lab appointment.
- Same surgeon throughout: Dr. Arena reviews your biopsy report, performs your operation and sees you at your follow-up visits.
Dr. Elizabeth Arena is surgical oncologist who brings both advanced surgical expertise and a compassionate approach to treating DCIS for patients in Los Angeles and surrounding areas.
Frequently asked questions
Can DCIS come back after treatment?
Yes, in a small number of women, as DCIS or as invasive cancer in the same breast. It happens more often after a lumpectomy with radiation than after a mastectomy. With close follow-up, an invasive cancer after DCIS is usually found early.
What is the best treatment for high-grade DCIS?
High-grade DCIS is treated with a lumpectomy, usually followed by radiation, or a mastectomy. It is more likely than low-grade DCIS to come back after treatment and it was not eligible for the COMET active monitoring trial.
How urgent is surgery for DCIS?
Surgery for DCIS is not usually needed within days of the diagnosis. Dr. Arena schedules surgery after she has reviewed your imaging, any genetic test result has come back and you have chosen a lumpectomy or a mastectomy.
Should you get a second opinion for DCIS?
You can get a second opinion at any point before or during treatment. Dr. Arena reviews your pathology report, your imaging and the operation you have been offered. She tells you whether she would recommend the same treatment. See breast cancer second opinion.
Sources
- National Cancer Institute. What Is Ductal Carcinoma in Situ (DCIS)? Posted December 2, 2025. https://www.cancer.gov/types/breast/breast-cancer-types/dcis
- Susan G. Komen. Treatment for DCIS. https://www.komen.org/breast-cancer/treatment/by-diagnosis/dcis/
- American Cancer Society. Treatment of Ductal Carcinoma in Situ (DCIS). Last revised July 9, 2026. https://www.cancer.org/cancer/types/breast-cancer/treatment/treatment-of-breast-cancer-by-stage/treatment-of-ductal-carcinoma-in-situ-dcis.html
- American Association for Cancer Research. COMET Trial Finds Active Monitoring Is a Viable Option for Some Patients With Low-risk DCIS (results presented at the San Antonio Breast Cancer Symposium and published in JAMA, December 2024). https://www.aacr.org/about-the-aacr/newsroom/news-releases/comet-trial-finds-active-monitoring-is-a-viable-option-for-some-patients-with-low-risk-dcis/
- American College of Surgeons. Surgeon Qualifications and Certifications. https://www.facs.org/for-patients/preparing-for-surgery/qualifications/
Speak with Dr Arena about your next step
Whether you have a new diagnosis, want another opinion, are weighing surgical options or need a concerning finding assessed, the first step is a consultation focused on your specific situation.
After you submit the request, the office will contact you to confirm the appropriate consultation and the records or information needed.
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