Ductal carcinoma in situ (DCIS) is a very early form of breast cancer that starts in the breast’s milk ducts and hasn’t spread outside the ducts. DCIS is usually highly treatable with surgery. Some people have breast-conserving surgery, such as a lumpectomy (surgery to remove cancer or abnormal tissue from the breast), often followed by radiation therapy.

However, an increasing number of people are deciding to treat their DCIS with a mastectomy (surgery to remove the entire breast) or bilateral mastectomy (surgery to remove both breasts). Some people may prefer mastectomy over more common DCIS treatments, while in other cases, their doctor may recommend it for medical reasons.

In this article, we take a closer look at common reasons why people decide to have a mastectomy to treat DCIS so you can have a more informed conversation with your breast cancer specialist.

Reasons To Consider Mastectomy for DCIS

Some people prefer breast-conserving surgeries, such as a lumpectomy, to treat DCIS because it preserves more breast tissue. However, there are reasons why a mastectomy might be the safer or more preferable option.

DCIS Is Widespread

Some DCIS is large or widespread enough to affect a large portion of the breast. In cases like these, a lumpectomy might not lead to desirable cosmetic results.

If your DCIS affects a large percentage of your breast and is widespread throughout the milk ducts, your breast cancer specialist might recommend removing the entire breast instead of having a lumpectomy.

They may also remove some lymph nodes during surgery. Lymph nodes are small, bean-shaped organs that are part of the immune system. Although DCIS is usually noninvasive, doctors may sometimes check nearby lymph nodes during surgery to look for signs that cancer has spread.

There Are Multiple Areas of DCIS

If your breast has several separate areas of DCIS in the milk ducts (called multifocal DCIS), then your doctor might advise a mastectomy instead of breast-conserving surgery. This is because it can be difficult to remove multiple areas of DCIS with a lumpectomy, especially if those areas are far apart within the breast.

Cancer Cells Are Found in the Margins

A lumpectomy involves removing the DCIS and a margin of healthy tissue surrounding the lump. Sometimes, the cancer cells extend farther into the tissue than expected, because DCIS can have a “skip pattern.” This means there may be small areas of DCIS between areas of normal tissue.

Your breast cancer specialist might recommend a mastectomy if they find cancer cells in areas that were thought to be healthy tissue. It may be safest to remove all breast tissue rather than perform additional surgeries to try to achieve clear margins.

You’re Not a Candidate for Radiation Therapy

Not everyone can safely undergo radiation therapy, which usually follows a lumpectomy for DCIS. Your doctor might advise a mastectomy if you’re not a candidate for radiation therapy due to:

• Having had previous radiation therapy to the breast or chest area
• Being in the first trimester of pregnancy
• Having a connective tissue disease that makes you more sensitive to radiation side effects, such as lupus or scleroderma
• Being unable to commit to daily radiation therapy for any reason

You Don’t Want To Have Radiation Therapy

Some people would prefer not to have radiation therapy, either because of the time commitment or the risk of side effects.

Side effects of radiation therapy after a lumpectomy can include:

• Skin irritation on the breast or chest area
• Fatigue (extreme tiredness)
• Hardening of the breast tissue
• Lymphedema (swelling, especially in the arms and upper body)
• An increased risk of heart disease and inflammation of the heart

If you have any concerns about radiation therapy after a lumpectomy for DCIS, talk to your doctor about the pros and cons.

You Want a Lower Risk of Recurrence

Overall survival rates are similar for people who have a mastectomy for DCIS and those who have a lumpectomy with radiation therapy. However, there is a slight difference in recurrence rates (the risk of DCIS coming back) between the two treatment options.

Radiation therapy can reduce the risk of DCIS recurrence after a lumpectomy. Even with radiation therapy, however, a lumpectomy carries a higher risk of recurrence than a mastectomy. In both cases, DCIS is most likely to recur if it was diagnosed at a higher grade.

With a nipple-sparing mastectomy (a mastectomy that keeps the nipple intact), the risk of DCIS recurrence is under 3 percent. DCIS rarely involves the nipple or areola (the darker area of skin around the nipple). Because some breast tissue may remain under the nipple, your doctor may recommend follow-up imaging or exams after surgery.

You Want To Lower Your Overall Breast Cancer Risk

Some people decide to get a bilateral mastectomy because they know they have a high risk of developing invasive breast cancer in the future. This is called a risk-reducing bilateral mastectomy, and it can lower the risk of future breast cancer in women who are at high risk by at least 90 percent.

Your doctor or breast cancer specialist might evaluate you for specific inherited gene mutations (changes) that increase your risk of developing invasive breast cancer.

You might be interested in a risk-reducing bilateral mastectomy if you have any of these gene changes:

• BRCA1
• BRCA2
• CDH1
• PALB2
• PTEN
• STK11
• TP53

Talk to your doctor about your genetic breast cancer risk. They can help you decide if risk-reducing surgery is the right option and discuss options for breast reconstruction after a mastectomy.

Talk to Your Breast Cancer Specialist About DCIS Treatment

Shared decision-making between you and your cancer care team is essential for choosing your best option for DCIS treatment. Be sure to share your preferences and treatment goals with your breast specialist so they can make recommendations that align with your needs.

If you’re leaning toward getting a mastectomy for DCIS, bear in mind that the procedure comes with its own emotional and surgical risks. Your breast specialist can help you weigh the benefits and potential risks of each DCIS treatment option. Once you’ve decided on a path forward, they can help you prepare for treatment and follow-up care.

Join the Conversation

On MyBCTeam, people share their experiences with breast cancer, get advice, and find support from others who understand.

Why might you prefer a mastectomy over a lumpectomy for DCIS? Let others know in the comments below.