DCIS and HER2+

The reason that a number of clinical studies are underway or planned for HER2+ DCIS is because at this point, doctors really don't understand what role, if any, HER2 status has for DCIS.  So there is interest in knowing more.  So far this has not been studied much and the information to-date has been inconclusive and conflicting.  For example, one small study concluded that HER2+ DCIS was more aggressive while another small study concluded that HER2+ DCIS was less aggressive.  What is known is that at least double the % of women who have DCIS are HER2+ vs. women who have IDC, so this either means that HER2+ DCIS is less likely to become invasive, or that HER2+ DCIS may convert to become HER2- IDC if the cancer does become invasive.

Because the impact of HER2 status on DCIS is unknown, HER2 status for DCIS is, for now, considered irrelevant.  Unless you are part of a clinical study on this issue, there is no difference in treatment if your DCIS is HER2+ or HER2-.  Additionally, Herceptin is not approved for women who have DCIS only (again, except for those who participate in one of the clinical studies).  For these reasons, often HER2 status isn't determined for women who have DCIS only or these women may not be told their HER2 status (because it would only lead to questions that can't be answered).

Here's some information about HER2 status and DCIS.  Basically it says that at this point, we don't know what, if any, affect HER2+ status has on the likelihood that DCIS will recur.  http://www.oncology-times.com/pt/re/oncotimes/fulltext.00130989-200704250-00016.htm;jsessionid=JKKH71373ycMXDQKwQRgTp0vPMfjpqGS6JQvGszJgwGBlnn3TDGj!-256325120!181195629!8091!-1

And here is information about NSABP Trial B-43:  http://www.grcop.org/Attachments%5CB-43%20FastFacts.pdf  What's significant about this trial is that it appears that patients only receive two doses of Herceptin.  This is quite different than the treatment given to patients with invasive breast cancer that is HER2+.  They receive Herceptin for every week (or every 3 weeks) for 1 year.  This is a very important difference because Herceptin is a serious drug with the possibility of very serious side effects.  So for someone with pure DCIS who does not have the risk of mets, it would not make since to risk a full regime of Herceptin.  On the other hand, it would be interesting to see if a small dose of Herceptin has any effect on reducing recurrence rates for those are have HER2+ DCIS.

I just signed my consent form to have my tissue tested re: HER2, to see if I can enter the clinical trial...now I just have to get my surgery scheduled! My med onc was very excited to be able to tell me about the trial - she's a very enthusiastic and supportive person and she has high hopes re: Herceptin therapy for DCIS with HER2+. If I get qualify, I will report anything useful that I learn.

I  don;t  understand someone's  sig line here!!!   How in the world  does someone have DCIS  with  lymph node of 1/1? I presume that  means the sentinal node was +?   If so,  isn't  that automatically  stage 1????

Please enlighten me!

Beesie,

Beesie,

What  would we do  without  you?   Thanks so much for all you do for this group. 

to radiate  or not radiate---that  is the question. 

  It's now into March and still I've had no surgery  BUT now the time has come. I  am trying to  make arrangements  for lumpectomy.   My 1.8 cm  DCIS is Her2+ but  the  suspicious for 2-mm tubular cancer is HER2  negative  I'm wondering whether having radiation is really necessary.   It's my understanding that  Tubular cancer  is in a  special class that doesn't require  as much treatment as regular IDC.  That's what  i was told.   As  for Her2+, this is the only part of my  diagnosis that  still dogs  me.  

peppopat,  

Good luck with your lumpectomy!  And how interesting that your DCIS is HER2+ but the "suspicious for tubular" is HER2-.  That supports the hypothesis that the HER2 status of DCIS may change if a cancer becomes invasive.  And that in and of itself is a reason why we shouldn't worry about the HER2 status of DCIS.... at least until medical science tells us something different.

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From Dr. Susan Love: Should I have my DCIS tested to see if it is HER2-positive?

HER2 status is not useful in guiding treatment for ductal carcinoma in situ (DCIS) because it is more common for DCIS to be HER2-positive than it is for invasive cancer to be HER2-positive (we don't yet know why this is).

Also, we have no data on treating women with DCIS with trastuzumab (brand name Herceptin), which is the treatment used for HER2-positive tumors. This is, though, an area of active research. http://www.dslrf.org/breastcancer/content.asp?CATID=15&L2=3&L3=7&L4=0&PID=&sid=132&cid=842

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And from a presentation at the 2010 San Antonio conference:  Does HER2 Status Influence Outcomes in DCIS?

As it turned out, all of the patients in the study, including those with HER2-positive disease, were recurrence free at a median follow-up of 58 months.

With no recurrences to analyze, Dr. Halasz and colleagues could not say whether HER2 status puts patients at more or less risk for recurrence.

"It's still an interesting question - whether HER2 status influences outcome in DCIS," she said. "It doesn't seem to influence recurrence when patients are treated with radiation and surgery," she concluded.  http://www.medscape.com/viewarticle/734028

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Daisy6/Erica31/Janewell/etc., how delightful to see you crawl out from under your rock as sammysmom.  I'm so glad to know that you are not attacking me or anyone else (or at least, that you had the sense to delete whatever attacks you'd written). I hope - and I'm sure that others share my hope - that you live up to your words, whatever screenname you happen to be using. 

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Edited to try to fix the links (don't know why they are being so problematic today!).  The Susan Love link seems to still not be working.  Try instead just googling the exact words to the question and the correct page will pop to the top of the search list.  As for the Medscape link, if you aren't registered with Medscape (patients can register; you don't have to be a doctor), you won't be able to see it. 

lmr1963,  I don't know much about different radiation methods.  I had a single mastectomy and didn't require radiation so I've never done much reading on it.  I am aware of the radioactive seeds that are used for prostate cancer but I don't know if has been tested for breast cancer.  Have you posted this question in the Radiation Forum on this board?