Stage 0 Breast Cancer Overview
Stage 0 breast cancer might sound a little confusing: Is it even cancer? What does Stage 0 actually mean?
Stage 0 Breast Cancer Explained
The earliest stage of breast cancer, Stage 0 is non-invasive, meaning it hasn’t spread outside of its original location in the breast tissue, and is highly treatable when detected early. If left undetected or untreated, however, it can spread into surrounding breast tissue.
No matter what the stage, it is important to know about the type of breast cancer, diagnosis, and potential treatments. Learn more about all breast cancer stages.
What is Stage 0 Breast Cancer?
Stage 0 breast cancer, or “carcinoma in situ,” is a non-invasive cancer where abnormal cells have been found in the lining of the breast milk duct but have not spread. It is called “non-invasive” because the cancer cells have not invaded, or spread, beyond the original site of the cancerous growth. Stage 0 breast cancer accounts for 20% of all newly diagnosed breast cancers. DCIS, ductal carcinoma in situ, is the earliest form of breast cancer that can be detected.
People with breast cancer that has not spread beyond the breast tissue, such as Stage 0, have a five-year relative survival rate of 99%, according to the American Cancer Society.
Even though Stage 0 is the earliest stage of breast cancer, it is important to talk with your healthcare team about treatment options and what to expect.
What does the term “in situ” mean?
Stage 0 cancers are called “carcinoma in situ.” The term carcinoma means cancer and in situ means “in the original place.” Therefore, Stage 0 breast cancer is cancer that is in its original location, which indicates that it has not spread.
Types of Stage 0 Breast Cancer
There are three possible types of “carcinoma in situ” of the breast tissue. They are:
- Ductal carcinoma in situ (DCIS)
- Lobular carcinoma in situ (LCIS)- It should be noted that LCIS is not breast cancer, despite being called “carcinoma in situ.” Instead, it is a risk factor for developing breast cancer.
- Paget disease of the nipple
What is DCIS Stage 0 Breast Cancer?
Stage 0 ductal carcinoma in situ (DCIS) is a non-invasive or pre-invasive cancer where abnormal cells have been found in the lining of the breast milk ducts but have not spread to the lymph nodes, bloodstream, or surrounding tissue.
DCIS is very early cancer that is highly treatable, but it can spread into surrounding breast tissue if left untreated or undetected.
Staging of DCIS
DCIS is considered Stage 0 breast cancer because it is localized and has not spread, or metastasized, to other areas of the body, such as lymph nodes or other organs. Learn more about breast cancer stages and how they are determined.
What is LCIS Stage 0?
Although it has carcinoma in the name, lobular carcinoma in situ (LCIS) is not breast cancer; it is a breast condition or breast change. LCIS is a collection of abnormal but non-invasive cells that form in the lobules (milk glands) of the breast.
While LCIS is not cancer, it may indicate a woman has an increased risk of developing breast cancer in one or both breasts and may require additional breast screenings.
Often no treatment is required for LCIS. However, your doctor may recommend regular clinical breast exams and mammograms to stay vigilant. Sometimes, surgery to remove the abnormal cells may be recommended. Additionally, hormone therapy medications that help prevent cancer cells from growing may be prescribed.
Stage 0 Breast Cancer Symptoms
Stage 0 breast cancer often has no symptoms at all and is typically discovered during a routine screening mammogram or other imaging test.
If symptoms are present, they can include a lump or abnormal nipple discharge, including blood. To learn more about breast cancer signs and symptoms, download NBCF’s free Know the Symptoms Guide.
Stage 0 Breast Cancer Diagnosis
Mammogram & Ultrasound for Stage 0 Breast Cancer
Early-stage breast cancer is often found through a routine mammogram or testing following the discovery of a lump.
A mammogram, or low-dose breast x-ray, is often the best option for detecting breast cancer in its earliest stages. Mammograms can find breast cancer or other issues even before symptoms develop. Mammograms are performed with a machine that has two plates that flatten the breast and spread the tissue apart, providing a clearer picture of the breast.
Following the discovery of a lump, abnormal nipple discharge, or other abnormal symptom, doctors will advise further testing to get to the bottom of the issue. These tests may include a diagnostic mammogram and/or ultrasound to test for Stage 0 breast cancer. Learn more about mammograms and how to prepare for one with NBCF’s free Mammogram 101 eBook.
After an initial mammogram, doctors might also recommend a breast ultrasound, which uses sound waves to view the inside of the breasts. The ultrasound generates a picture called a sonogram, which can help measure the size and location of a lump and determine if it is a cyst, which is not typically cancerous, or breast cancer.
DCIS Grades
When abnormal cells are detected on a mammogram, your doctor will order a follow-up needle biopsy that removes cells from the area of concern for further testing in order to determine if the cells are cancerous or not. A pathologist examines the cells under a microscope to make a diagnosis and grade the cancer.
DCIS or Stage 0 breast cancer is classified into 3 grades, sometimes called nuclear grades, which can help inform treatment decisions. The lower the grade, the less aggressive the cancer.
| Grade | Indication |
| Grade 1 | • Cancer cells look much like normal breast cells • Cancer cells tend to grow slowly |
| Grade 2 | • Cancer cells look much like normal breast cells • Cancer cells tend to grow at a moderate pace (faster than Grade 1) |
| Grade 3 | • Cancer cells look distinctly different from normal breast cells • Cancer cells tend to grow quickly and rapidly (faster than Grade 2) • Presents a higher chance of invasive breast cancer diagnosis or recurrence in the future |
Following an early-stage breast cancer diagnosis, some people opt for genetic testing to learn more about their cancer, their genetic risks, and the likelihood that the cancer will return. The information uncovered through genetic testing can help determine the best treatment plan for Stage 0 breast cancer.
Stage 0 Breast Cancer Treatment
Not all Stage 0 breast cancers require treatment. Sometimes active monitoring or a watch-and-wait approach is recommended to see if the cancer will remain stable or if it will progress. However, DCIS is often treated because the cancerous cells can undergo additional changes that later become invasive breast cancer. Research is underway to help determine which types of DCIS cells will progress into invasive breast cancer and which ones likely will not. That research will directly impact which cancers get treated, and how, in the future.
Treatments such as surgery, radiation, hormone therapy, or a combination of these treatments, may be recommended. Chemotherapy is not part of the treatment regimen for Stage 0 breast cancer.
The best treatment plan for Stage 0 breast cancer will vary from person to person based on:
- Age at diagnosis. Women who are diagnosed with Stage 0 breast cancer at a younger age are at greater risk of recurrence, which may encourage more immediate treatment, according to research. If diagnosed at an early age, women hoping to become pregnant may choose to freeze their eggs ahead of treatment.
- Estrogen receptors. Cancer cells with estrogen receptors (ER+) may progress more slowly, allowing more time for a treatment decision to be made.
- Genetic risk: Breast cancer is sometimes caused by inherited gene mutations, such as BRCA mutations. Based on family history and genetic risk, women may choose to proceed with treatment sooner than later.
- Health history. Based on other health factors, women may choose a particular course of treatment that makes sense for their entire health picture.
- Personal preference: Some women are comfortable with a “wait-and-watch” approach while others want to address Stage 0 immediately. The recommendations of your healthcare team can also play into this decision.
Treatment Options
Stage 0 breast cancer typically covers a small area of tissue and there are a variety of treatment options, with many patients opting for a combination of Stage 0 treatments. Chemotherapy is not used to treat Stage 0 breast cancer. Side effects vary by treatment.
Lumpectomy
Lumpectomy, also known as breast-conserving surgery, is the most common treatment for Stage 0 DCIS breast cancer. Rather than removing all of the breast tissue, a lumpectomy removes only the cancerous tissue and a small margin of normal tissue around it. Lymph node removal is not usually needed. Lumpectomy for Stage 0 breast cancer is often followed by radiation to reduce the chance of the cancer coming back.
Mastectomy
While mastectomy was once the gold-standard for Stage 0 DCIS breast cancer treatment, breast-conserving surgery (lumpectomy) is now more common. However, if the Stage 0 cancer is widespread, occurs in multiple areas of the breast, or a lumpectomy cannot remove the cancer completely, then a mastectomy will likely be recommended. If a mastectomy is performed, a sentinel node biopsy will also be performed to determine if any of the tissue that contains DCIS cells also contains areas of invasive cancer.
A double mastectomy to treat Stage 0 breast cancer is rare, but may be discussed with your healthcare team and surgeon. Women who have a mastectomy for Stage 0 breast cancer typically do not require radiation after surgery.Read more about breast surgery options by downloading NBCF’s free Breast Cancer Surgery eBook.
Radiation
Radiation, which is used to destroy any remaining cancer cells post-surgery, may be used after a lumpectomy for Stage 0 DCIS. Radiation reduces the chance of cancer recurrence. Most radiation is administered at a radiation center and usually begins three to four weeks after surgery.
If the cancerous area is small or low-grade, then radiation may not be needed following a lumpectomy.
Wait-and-Watch Approach
Some women with Stage 0 breast cancer opt for a wait-and-watch approach, sometimes called active surveillance, in lieu of immediate treatment. They will undergo more frequent screening to ensure that the abnormal cells haven’t spread, but won’t have a lumpectomy, mastectomy, radiation, or other treatments in the meantime.
Hormone Therapy
Hormone therapy may be given to women with hormone receptor-positive (HR+) breast cancer after radiation or surgery to decrease the risk of recurrence. Drugs, including tamoxifen or aromatase inhibitor (for post-menopausal women), can be taken as a pill for up to five years post-surgery.
Targeted Cancer Therapy
In addition to other treatments for Stage 0 breast cancer, newer targeted therapies can attack specific breast cancer cells without harming normal cells and with fewer side effects. Targeted cancer therapy, which uses drugs to block the growth of cancer cells, may be used in conjunction with other treatment options for DCIS.
Bone Strengthening Treatment
Bone-density medications are sometimes given to help prevent bone loss during breast cancer treatment. Known as bisphosphonates, bone-strengthening treatments may also reduce the risk of recurrence or invasive breast cancer for those with DCIS. Risks, however, can include heart disease and kidney issues.
Breast cancer survivors have a significantly higher risk of osteoporosis and osteopenia, according to research, and hormonal therapy can also increase the risk of fractures. It is important to talk with your doctor about overall bone health.
Stage 0 Breast Cancer Survival Rate
People with breast cancer that has not spread beyond the breast tissue, such as Stage 0, have a five-year survival rate of 99%, according to the American Cancer Society. When caught and treated early, the prognosis for recovery from Stage 0 breast cancer is excellent.
Life After Stage 0 Breast Cancer
Stage 0 breast cancer is very treatable and very survivable. With a variety of treatment options and an excellent survival rate, Stage 0 may still create stress and anxiety, but there is far more reason for hope as patients with DCIS have normal life expectancy.
You can enjoy a full, healthy life after stage 0 breast cancer. You will likely receive additional screenings and diagnostic mammograms, and it is important to maintain contact with your healthcare provider. Many Stage 0 cancer survivors also decide to devote greater time to their mental and emotional health and well-being. To learn how to live fully present in the moment, download NBCF’s free 10 Prompts to Mindfulness eBook.
If you would like additional support no matter where you are in your breast cancer journey, NBCF is here to help. We can provide encouragement and comfort in the form of a patient navigator to help you manage the journey, a support group, a HOPE Kit, and more—all reminders that you are never alone.
Sources: National Cancer Institute