Sentinal node biopsy with DCIS?

[lu1952]

I was diagnosed one month ago with DCIS (comedo with necrosis) tumor 2.2 cm.  There was at least a 1.6 mm clear margin and I am going to start radiation soon. My surgeon brought up the subject of sentinal node biopsy but said he wouldn't push it since only 3-5% of tumors this size may have lymph node involvement.  My oncologist stated that it would be appropriate to have the biopsy just to make sure since a small number of tumors this size could have microinvasion.  Is the sentinal node biopsy something I should consider?

[CCF-RN,MSN-rf]

Dear lu1952:  By definition, DCIS is not invasive, making node biopsy unnecessary.  However, if any part of this was invasive cancer - not DCIS, then a sentinel lymph node biopsy would be necessary. Some types of DCIS are considered more "aggressive" than others.  Comedo is one of them.  In these cases, additional local control (such as radiation therapy) is usually recommended in addition to lumpectomy (if that were the procedure).  In most cases, sentinel lymph node biopsies are well tolerated.  However, if you have already had the lump removed, this means another surgery, which, may not be necessary at all.

[surgeon]

As you can see from the fact that you've already gotten differing opinions, it's not carved in stone. In general, node sampling is not felt necessary for DCIS, because by definition it's not yet invasive, and it's only by invasion beyond the walls of the ducts that cancer can spread out of the breast. On the other hand, we know not all DCIS is alike, and that when there's DCIS there's some possibility, since we can't look at every last cell under the microscope, that there could be areas of invasion that went undetected. Of the various characteristics of DCIS to which we pay attention, the comedo form with necrosis implies it's further along the spectrum toward invasion. There's a higher incidence of local recurrance with comedonecrosis than there is with garden-variety of DCIS, which is why most everyone recommends aggressive local treatment. (In some cases of DCIS, local excision alone is considered enough. With comedo necrosis, most people recommend treating the entire breast in some way or another.) So, if checking the sentinal node in DCIS ever makes sense, it's probably in the setting of comedonecrosis. However, since the chance of spread is still very low, and the cure rate with breast treatment alone is very high, it's not routine to check sentinal nodes with any form of DCIS. Long answer, short on specifics. Sentinal node biopsy, for what it's worth, adds very little morbidity to the procedure, other than signifcant cost, and a few minutes more of anesthesia time.