One of the women in my breast cancer support group was diagnosed with DCIS -- ductal carcinoma in situ. She was upset because a well-meaning but thoughtless friend said, "Oh, that's not really cancer, that's Stage Zero! You aren't in danger at all." This woman had been treated with surgery and radiation, and was looking at five years of hormone therapy. She didn't need to have her diagnosis belittled and her emotions dismissed. Those of us with invasive breast cancer continued to support her, not to snub her or treat her like a second-class cancer patient.
This confusion over a diagnosis of in-situ breast cancer is common. Let's take a look at the reasons for the confusion and find out what the facts are about DCIS and its cousin LCIS -- lobular carcinoma in situ.
Cancer In Situ
A diagnosis of carcinoma in situ has a specific meaning -- 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 cells. Oncologists call this type of diagnosis Stage Zero because it has not broken out of place, nor has it invaded other tissues. 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, Nodes, and Metastasis. Tis N0 M0 describes DCIS and LCIS as well as 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, and M0 confirms that no metastasis has occurred. That is what an oncologist is saying when they tell you that you have Stage Zero breast cancer.
Precancer or Noninvasive Cancer?
Dr. Susan Love discusses DCIS and LCIS in Chapter 13 of her Breast Book. She uses the terms precancerous and noninvasive cancer interchangeably when referring to these two in situ diagnoses. It's kind of like saying that you have six eggs in a basket or half a dozen eggs in a basket -- either way, you're talking about the same thing with a slightly different term.
But 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: We don't like either term, especially when it is referring to our breasts.
Stage Zero - Cancer or Not?
Both ductal and lobular carcinoma in situ are worrisome because they have the potential to invade beyond their well-contained sites. Scientists can't tell exactly which patients will be more at risk for developing invasive breast cancer, if their DCIS or LCIS is left untreated. Both carcinomas have the cellular appearance of cancer and both might eventually grow and spread beyond their original clumps, or they might not.
Many other factors affect your treatment plan: hormone status, genetic risk, and menopausal status. Treatments can include lumpectomy or mastectomy, radiation, and hormone therapy. Some oncologists may tell you to "watch and wait" to see if the carcinoma will resolve on its own or if it will progress. Other doctors will proceed to recommend standard cancer treatments.
Either way, you will face uncomfortable decisions and a range of emotions. People who will be supportive of you must respect that regardless of your specific diagnosis. So: is Stage Zero really breast cancer -- or not? Doctors still don't agree on this, but that is a matter of terminology. Don't get hung up on the words, but do get a second opinion, to make sure that you get the best and most effective treatment for your health.
AJCC Cancer Staging Manual 6th Edition. Springer Verlag, New York, NY. 2002, pp. 223-240.
Special Situations and Populations. Pp. 363-401. Dr. Susan Love's Breast Book. Susan M. Love, M.D. Fifth Edition, 2010.