DCIS

I realized I kinda glazed over my diagnosis of DCIS (Ductal Carcinoma in Situ) and thought I’d provide a bit more info.

DCIS can only exist in the Ductal glands which lead to the nipple.  If it is contained, it cannot spread to the body and is considered Stage 0.  There is a ‘sister’ diagnosis of LCIS (lobular carcinoma in Situ) which exists in the lobes attaching to the ducts.  This may be more benign (benign being used very loosely in that doing nothing will result in invasive cancer for ANY of the pre-cancer conditions). The risk of a pre-cancer condition becoming invasive (Intra Ductal Carcinoma) is about 2-3% per year.

Typically women opt for lumpectomy with radiation or a mastectomy.  I opted for the mastectomy and was surprised by a ‘quiet’ undetected large area of dcis adjacent to a defined one that resulted in an unclean (<2mm) margin.  Having an unclean margin increases the odds of recurrence from 1-2% up to 10-16%.  And that is why I’m taking Tamoxifen (or could have opted for radiation).

Typically, DCIS does not invade the lymph nodes..however, because my grade (there are grades and cancer stages…we try not to confuse the two). was high (2-3), there was a concern.  Turned out after the Sentinel node biopsy to still be clean!

Some studies that describe risks follow:

Here’s some info on DCIS recurrence rates after a mastectomy:

  • http://www.scienceblog.com/community/older/2004/4/20043379.shtml  “Of the 1,136 patients, 286 had had a lumpectomy and radiotherapy, 444 had had a lumpectomy only, and 406 had had a mastectomy. After ten years, cancer had recurred in the same breast (local recurrence) in 18 per cent (lumpectomy and radiotherapy), 30 per cent (lumpectomy only) and 1.8 per cent (mastectomy) of the women. “
  • http://www.ajsfulltextonline.com/article/S0002-9610(06)00447-8/abstractClinical, pathologic, and outcome data were collected prospectively for 1236 patients with pure DCIS accrued from 1972 through 2005.  There were 150 recurrences (87 DCIS and 63 invasive). Invasive local recurrence after mastectomy was rare (0.5% of patients) and after breast preservation was more frequent (12.0% of patients).
  • http://www.aafp.org/afp/20070101/tips/4.html “For the 430 women treated with mastectomy, the 12-year probability of local invasive recurrence was 0.5 percent
  • http://www.annalssurgicaloncology.org/cgi/content/abstract/15/1/235 “The 8-yearoverall local recurrence rate was 12% after breast-conservingtreatment (BCT) [15.6% after WLE and 8.8% after WLE+RT (P =0.161)] and 0.9% after mastectomy (P < 0.0001). “
  • http://cme.medscape.com/viewarticle/447028  – % loco-regional recurrence: 1.6%First, DCIS carries an excellent overall prognosis, with only 1% of patients developing metastatic breast cancer. There is no substantial difference in survival expected for any of these local treatment choices. Second, mastectomy provides excellent local control in DCIS. Lumpectomy is associated with a roughly 1 in 4 risk of local tumor recurrence. By contrast, the addition of radiation therapy to lumpectomy reduces the risk of local recurrence by half, to approximately 1 in 8.
  • http://www.dcis.info/treatment-options.html  “The recurrence rate and overall chance of dying from (DCIS) after simple mastectomy is between 0 and 2%. “.

When DCIS recurs, there is approx. a 50% – 60% chance that it will recur as DCIS and a 40% – 50% chance that it will recur as invasive cancer.  Pure DCIS cannot recur as mets, as least not without one step in-between.  The step in-between is that first the DCIS would have to recur as invasive cancer.  It could happen that if DCIS recurs as invasive cancer and this recurrence isn’t found until it has progressed to become mets, it might appear that DCIS has recurred as mets, but in fact this isn’t true – there was that step in-between.  For someone who had a mastectomy for DCIS, the likelihood of the DCIS recurring as IDC and then progressing to mets is extremely small.  For all women who have DCIS, including the approx. 60% who have lumpectomies (who generally have a higher recurrence risk), the risk of having an invasive recurrence that then progresses to mets is only 1% – 2%.  What this means is that the long-term survival rate for DCIS is 98% – 99%.  So for the 40% of DCIS women who have mastectomies, the risk would be significantly lower than 1%.

DCIS, because it is non-invasive, cannot recur in the other breast.  Of course, anyone diagnosed with BC one time is at higher risk to get BC again, and this includes those who were diagnosed with DCIS.  So someone could be diagnosed with a new occurrence of BC in the other breast but this would be a new cancer, not a recurrence of the original DCIS.

DCIS is Stage 0, non-invasive breast cancer.  Anyone diagnosed as being Stage I, Stage II or Stage III does not have DCIS.  Because so many women have DCIS along with their invasive cancer (DCIS and IDC are often found together), this can be confusing because the term “DCIS” is included in the pathology report.  But any staging other than Stage 0 means that there is invasive cancer present.  And what happens then is that the invasive cancer “trumps” the DCIS and the diagnosis and treatment is based on the invasive cancer, not the DCIS.  In these cases, the DCIS in effect becomes irrelevant, except that it needs to be removed.  So there is no such thing as DCIS Stage I or DCIS Stage II or DCIS Stage III.  There is only DCIS Stage 0.

Similarly, because DCIS by definition is confined to the breast and cannot travel outside of the breast, and because chemo is given to address the risk that cancer cells have escaped the breast and moved into the body, chemo should never be required for DCIS.  So it’s pretty safe to say that anyone who is given chemo does not have DCIS (although there may be a DCIS component to their cancer, along with the invasive component).

Breast cancer is very complicated.  It’s not one disease; it’s many diseases.  And even one tiny difference in pathology can make a significant difference in the diagnosis or treatment.  While DCIS is very commonly found together with invasive cancer, pure DCIS is distinct in it’s treatment and prognosis.

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