Anyone receiving a diagnosis of ductal carcinoma in situ, or DCIS, will probably feel both confused and frightened by the diagnosis. After all, it’s always scary to hear you have cancer even if it’s the tiniest of tumors. But DCIS breast disease isn’t your ordinary cancer.
In fact, DCIS carries with it such a low risk that the National Cancer Institute no longer even refers to it as cancer, preferring to call it a non-invasive “condition” instead.
That being said, we know anyone who’s recently been given the diagnosis of DCIS has questions, and we want you to have answers. So with that in mind, we'd like you to read on to discover 10 things you need to know about DCIS, including its prognosis and treatment.
What Is DCIS Breast Disease?
Each breast has approximately 15 to 20 ducts, which serve (in women) as a system for transporting milk to a nursing baby. Sometimes cells within these ducts begin to proliferate and take on the appearance of cancer cells. When this happens, a diagnosis of DCIS is made.
Because DCIS is confined to the milk ducts of the breast, it's classified as an intraductal carcinoma and is considered a non-invasive breast cancer. The non-invasive nature of DCIS is also why it’s often referred to as stage 0 cancer.
And because it stays in its “original place” (meaning it doesn’t spread to other areas of the body, including the lymph nodes) within the ducts, it’s referred to as in situ.
While it’s still unclear what causes ductal cells to mutate and grow abnormally, it’s thought that genetics, environmental factors, toxins, and general habits all play a role.
Risk factors that may affect your chances of developing DCIS include:
- Family history of breast cancer
- Increasing age
- History of benign breast disease
- Genetic mutations
Keeping all this in mind, here are 10 things you need to know about stage 0 breast cancer.
1. DCIS Is Not Actually Cancer
While having “carcinoma” in the name makes you think it has to be cancer, DCIS is not actually classified as such. Typically, the designation “cancer” is reserved for abnormal cells that spread from their original location to other areas of the body. DCIS, by its very nature, does not spread to surrounding tissues.
However, if cells do begin to migrate from the breast ducts to other parts of the body, a diagnosis of invasive ductal carcinoma (IDC) is made. In fact, IDC is the most common type of breast cancer, accounting for between 70% and 80% of all cases. If left untreated, approximately 20% to 50% of cases of DCIS may progress to invasive cancer.
Interestingly, while DCIS typically presents with no symptoms and is found on breast imaging only, it sometimes grows large enough that a breast lump can be felt. Nipple discharge may be present in some cases as well.
2. A Mammogram Can Reveal DCIS
A routine mammogram is usually the way DCIS is discovered and diagnosed. When DCIS is present, it will typically show up as a cluster of calcifications of varying shapes and sizes within a breast duct (or ducts).
These calcifications are the result of tiny specks of calcium that form in the cells of old cancer cells that have died off and piled up. If calcifications are seen on a mammogram, a biopsy will then be performed to confirm the diagnosis of DCIS.
While the incidence of DCIS has risen sharply since the 1970s, this increase has been attributed primarily to the increased use of screening mammograms.
3. Size, Grade, and Hormone Receptor Status Matter
When assessing the risk of recurrence after surgical removal of DCIS, the size of the lesion is very important. If the total size of the DCIS is determined to be greater than 20 to 25 millimeters, additional treatment—including radiation and hormone therapy—will generally be recommended.
Likewise, your health care provider will consider the hormone status of your lesion. If your tumor’s cells are found on biopsy to have hormone receptors (special proteins that grow in response to signals from hormones) for estrogen or progesterone, hormone therapy may be recommended.
In addition, your health care provider will also consider the nuclear grade of your DCIS, which is determined using a biopsy as well. To establish the grade, the nuclei (hence the term “nuclear”) of the cells are examined to see how closely they resemble the nuclei of normal breast cells.
There are currently three grades used to classify DCIS:
- Grade 1 (low, most like normal cells)
- Grade 2 (moderate)
- Grade 3 (high, most abnormal)
4. DCIS Accounts for 1 in 5 Breast Cancer Diagnoses
Studies have shown that 20% of breast cancer diagnoses (or one in five) are classified as DCIS. With lifespans getting longer and more women getting regular mammograms and access to better technology, DCIS detection rates have increased.
Earlier detection also means more people are getting diagnosed and treated sooner, and there’s less chance of the condition turning into invasive breast cancer.
5. New Tools Can Predict Your Risk of Recurrence or Progression
Sometimes your health care provider may decide to perform what’s called an Oncotype DX test.
Using a tissue sample taken from your DCIS lesion, this genomic test analyzes the 12 different genes that can affect how your DCIS is likely to behave and respond to treatment. The test then uses a scale of 0 to 100 to determine your risk of recurrence or development of an invasive cancer within the next 10 years.
Your health care provider will then combine this score with other factors, such as the size and nuclear grade of the DCIS, to help guide your DCIS treatment, including whether you’re a candidate for hormone or radiation therapy after surgery.
A recent study has affirmed the ability of the Oncotype DX test to help reduce overtreatment of those at low risk and undertreatment of those with a significant risk of recurrence.
The National Cancer Institute and Memorial Sloan Kettering Cancer Center also offer assessment tools that allow both patients and health care providers to assess the risk of developing another cancer in the future.
6. Men Can Get DCIS Too
Many of us naturally think of women when discussing breast (or milk) ducts, but did you know that men actually have these structures too? And while it doesn’t happen very often, men can also develop DCIS. In fact, when men develop breast cancer, it’s usually ductal carcinoma.
But since men don’t normally have mammograms, DCIS is often not detected in them until the tumor has increased in size or progressed to a later stage. Because of this, the presence of a breast lump may be the only sign that something’s wrong.
However, once discovered, DCIS in men is treated based on the same factors governing treatment in women.
7. DCIS Can Be Removed Surgically
Treatment for DCIS begins (and often ends) with surgery. Depending on the size of the tumor and how far it has spread within the breast ducts, this can mean either a lumpectomy or mastectomy.
In lumpectomy, which is also known as breast-conserving surgery, partial mastectomy, and wide local excision, only the tumor and a small rim of healthy tissue (the margin) are removed.
However, if the tumor has spread to many ducts within the breast, your surgeon will most likely decide to perform a mastectomy. In this surgery, the entire breast is removed.
If there’s any suspicion your DCIS has become invasive cancer, your surgeon may choose to remove some lymph nodes from under your arm as well. This additional lymph node excision will then be used to help determine the extent of your cancer (and treatment).
8. Chemotherapy Isn’t Necessary
Because DCIS is a non-invasive cancer, chemotherapy isn’t typically part of the treatment plan. While chemotherapy is effective at attacking cancer cells, its list of side effects—from vomiting, fatigue, and hair loss to infections, anemia, and fertility issues—can be long and difficult to endure.
In an extremely small number of cases (less than 1%), some of the DCIS cancer cells may begin to break through the wall of the breast duct. When this happens, chemotherapy may be recommended in some patients. However, research on the effectiveness of this intervention is still ongoing.
9. Long-Term Prognosis Is Excellent
Because DCIS is not invasive, long-term prognosis is considered excellent, with survival rates calculated at almost 100%. In fact, a recent study from the Netherlands found that women diagnosed with DCIS are as likely to be alive 10 years after diagnosis as people in the general population.
And in patients older than 50, the news is even better, as they were found to actually have a lower risk of dying than the general population!
Researchers speculated that the reason for this unexpected finding may actually have to do with the DCIS diagnosis itself, as patients diagnosed with the condition are likely to be more health conscious than the average individual.
Another recent study also confirmed this finding, showing that although recurrence rates remain low across all groups, risk of recurrence only declines as you get older.
10. After DCIS, Your Cancer Risk Rises
Stage 0 breast cancer is certainly not a death sentence, and we’ve seen that treatment is also very effective. However, if you’ve been diagnosed with DCIS, you are at a higher risk of both recurrence and developing a new cancer than someone who’s never had breast cancer before.
According to breastcancer.org, your chance of recurrence is highest within the first 5 to 10 years after initial diagnosis but decreases if radiation therapy has been included as part of your treatment plan.
However, as stated earlier, whether your health care provider recommends radiation or hormone therapy will depend on several factors, including the size of your lesion, grade, and hormone status.
Regardless, when it comes to breast health, prevention and early detection are key. So keep up with your breast self-exams, see your health care provider regularly, and have your breasts imaged on a regular basis.
And if you have nipple discharge, feel a lump in one of your breasts, or notice an area of skin that appears abnormal, be sure to make an appointment with your health care provider as soon as possible.
Being diagnosed with breast cancer can be scary, but a diagnosis of DCIS comes with an excellent prognosis. And remember that your health care provider will also be there to offer you the reassurance, appropriate education, and information you need to decide on the best DCIS treatment options for you.