DCIS Diagnosis

[fooddiva]

I had a core biopsy about two months ago.  DCIS was confirmed and at the time the doctor told me it was preliminary and surgery should remove it just fine.  I had the surgery and after removing the mass, I was told it was aggressive DCIS.  The margins weren't clear. I'm awaiting copies of the pathology report so I can't include specifics right now.  Anyway, my question is why was the biopsy report so different from after the surgery. My doctor told me the good news is that I don't have invasive breast cancer but it is aggressive DCIS.  He said he wants to remove more at the second surgery to prevent it from spreading. If after the second surgery it is still not gone, he may recommend a mastectomy. I asked about the percentage of getting it all the second time and he said 75%. Is it worth getting a second opinion on the pathology report? Since DCIS spreads through the ducts, how can a pathologist say it has spread if they are only looking at the actual mass that was removed? Can xrays see the DCIS? Would doing radiation treatment after the second surgery be an alternative to the mastectomy? And how fast does aggressive DCIS progress? I appreciate any info you can give.

[CCF-RN,MSN-rf]

Dear fooddiva:  The reason that the two pathology reports are different is because a needle biopsy only removes a very small fragment of tissue.  Once the lumpectomy is done, the remaining tissue can be evaluated pathologically. Unfortunately, it is often impossible to differentiate malignant cells from benign cells with the naked eye.  Therefore, a surgeon, wanting to take the least amount of tissue possible, makes his/her best guess as to where the edges are.  Only the pathologist can make the final determination - thus the margins are sometimes positive.  One of the defining characteristics of DCIS vs invasive cancer is that DCIS does not "spread."  However, it is believed that DCIS left in the breast will, at some point, become invasive cancer.  This is the reason to remove all evidence of the DCIS.  When the DCIS is an aggressive subtype, additional treatment, such as radiation therapy may be recommended.  The decision to to lumpectomy vs mastectomy depends upon the amount of breast tissue and the amount of tissue needing to be removed and whether the cosmetic result will be acceptable.  Sometimes a mastectomy with reconstruction will leave a better result than a disfigured breast from the removal of too much tissue.  X-rays are not a tool to diagnose DCIS.  Mammograms may help but are not independently conclusive.  The rate of growth of DCIS is not known.  It appears to be different in different people.

[surgeon]

the difference between the two reports likely has to do with the fact that a core biopsy is a much smaller sample; when the larger area was removed, they could see more, and get a better idea of certain patterns as well. It's generally considered necessary to do enough surgery that the edges of the tissue removed are free of any cancer cells. If they are still at those margins, and if wider surgery isn't possible without distorting the breast, then mastectomy is considered the next option. Data show that when the margins aren't clear, recurrance is higher than when they are, with or without radiation. xrays might show DCIS, but generally only if it's associated with a particular pattern of calcifications. No one can say what's going on in the rest of the breast; if no invasive cancer is found, then the chance of spread outside the breast is near zero. The more extensive the DCIS within the material removed, the more likely it is to be elsewhere in the breast; but it's basically an assumption. Finally, the term "aggressive" is a pretty vague and subjective term. There are certain more specific criteria that are somewhat predictive of local recurrance if lumpectomy alone is performed; but "aggressive" per se doesn't say much about how fast it grows.