An Overview of Stage Zero Breast Cancer

Is it cancer or not?

In This Article

female radiologist looking at breast
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Stage 0 breast cancer is often a confusing diagnosis. It means you have abnormal cells in the lining of the milk ducts of your breast but are contained to the ducts or lobules and haven't invaded the surrounding breast tissues.


Many people who have been diagnosed with stage 0 breast cancer find it frustrating when they talk to others. Some people may say "it's not really cancer" or "you aren't in danger at all," and these messages can be very painful. That's because this diagnosis often means surgery and radiation plus five or more years of hormone therapy. Such comments then are invalidating, and leave women feeling that their diagnosis has been belittled and their emotions dismissed.

Any diagnosis involving the word "cancer," including pre-cancer, is terrifying to the person receiving it and should be taken seriously by others. Studies have found that the emotions people experience when diagnosed are similar whether it's an early, highly curable tumor or advanced cancer with no chance of a cure.

This confusion over this diagnosis is common. To understand why, it helps to learn the facts about stage 0 breast cancer, which includes two types:

  • Ductal carcinoma in situ DCIS
  • Lobular carcinoma in situ LCIS

Cancer In Situ

In situ means that the cancer cells are all "in place" and not invasive. Carcinoma in situ, whether it is found in the lining of your milk ducts or inside the lobes where breast milk is produced, is a contained clump of abnormal cells. Oncologists call it stage 0 because it hasn't broken out of place (has not spread beyond something called the basement membrane) or invaded other tissues. The cells in carcinoma in situ look identical to the cancer cells in invasive cancer. The only difference is whether they've spread.

Invasive breast cancers are assigned a stage number from one to four and it is important to remember that the lower stages are easier to treat, resulting in higher survival rates.


The American Joint Committee on Cancer (AJCC) publishes the standards by which cancers are staged. Breast cancer is staged by the TNM system, with numbers assigned to a score for the Tumor (Tis), Nodes (N), and Metastasis (M). DCIS and LCIS are described as Tis N0 M0 (as is Paget's disease of the nipple if no tumor is detected.)

  • Tis means that no tumor was found, but abnormal cells are present.
  • N0 means no lymph nodes are involved.
  • M0 confirms that no metastasis (spreading to other parts of the body) has occurred.

That is what an oncologist means by stage 0 breast cancer.

Precancer or Noninvasive Cancer?

Some physicians use the terms precancerous and noninvasive cancer interchangeably whereas others simply refer to stage 0 breast cancer as "cancer." Regardless of their terminology, they're talking about the same thing.

However, when you hear the term "precancerous," you may worry that you've got a condition that will inevitably progress to cancer and must be treated as such. Then again, if you're told that your diagnosis is "noninvasive cancer," you may freeze with fear upon hearing the "C" word! Let's face it: No one likes either term.

Both DCIS and LCIS are worrisome because they have the potential to invade beyond their well-contained sites. Both carcinomas have the cellular appearance of cancer and both might eventually grow and spread beyond their original clumps, or they might not. So far, doctors can't say which direction any particular case will go.

So, is stage zero really breast cancer, or not? Doctors still don't agree on this. Generally, DCIS is considered cancer while LCIS isn't. Some doctors prefer the term "lobular neoplasia" because it's less frightening. Remember, though, that those delineations are just a matter of terminology. Don't get hung up on the words when deciding on treatments.

As with any cancer diagnosis, you should consider getting a second opinion to make sure you get the best and most effective treatment for you.


Not all stage 0 breast cancers require treatment. Some oncologists may tell you to "watch and wait" to see if the carcinoma will resolve on its own or if it will progress. Others recommend standard cancer treatments. Some people "just want it out" if there is a chance that stage 0 could become invasive cancer, whereas other people are more comfortable with a conservative approach of waiting along with careful follow-up.

Numerous factors will affect your treatment plan. Some of these include:

  • Hormone status
  • Genetic risk
  • Menopausal status
  • Personal preferences

Treatments options may include a lumpectomy followed by radiation, or mastectomy if there's a concern that there may be other regions of DCIS or LCIS in the breast or if a woman has a strong family history of breast cancer. Hormone therapy may follow for at least 5 years, with tamoxifen often used for premenopausal women and aromatase inhibitors for those who are postmenopausal.

Either way, you will face uncomfortable decisions and a range of emotions. To be supportive of you, people need to respect that regardless of your specific diagnosis.

Survival Rates

The outlook is good for people diagnosed with stage 0 cancers. When detected early and treated, the 5-year relative survival rate is 100 percent.

The 5-year survival rate drops to 93 percent for stage 2 cancer and 73 percent for stage 3 diagnoses. That shows you how important it is to catch breast cancer early.

Follow-Up Care

After treatment for stage 0 breast cancer, you face a small risk of recurrence or the future development of invasive breast cancer. Your doctor may recommend more frequent exams and/or tests so any future cancers can be caught and treated early.


Any diagnosis of cancer is scary, and no one has the right to criticize or belittle you for being upset over your diagnosis.

While you may feel helpless at first, know that the more you educate yourself about treatment options and the emotional aspect of the diagnosis, the better prepared you'll be to deal with the difficult decisions ahead.

To make sure you get the care you deserve, you'll want to learn how to advocate for yourself.

A Word From Verywell

No one wants their doctor to say the "C word," but with a stage-0 diagnosis, you're facing the best-case scenario by catching it early. Work closely with your doctor to formulate the treatment plan that's best for you and move forward with the knowledge that what you have is not only treatable but highly curable.

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