Tamoxifin or no Tamoxifin????

Abby, I have to admit that I am completely confused by what your doctor told you.

When someone is diagnosed with both IDC and DCIS together - and that's very common - it is always the case that the DCIS is ignored.  The DCIS needs to be surgically removed, but other than that, because the IDC is the more serious condition, any treatment that is done for the IDC will be more than adequate to treat the DCIS.  So what this really means is that by treating the IDC, you have already treated the DCIS - in fact you've hit it over the head with a sledgehammer, having had some treatments (chemo and Herceptin) that those with pure DCIS will never get.

When it comes to hormone therapy such as Tamoxifen, there are actually much more compelling reasons why you might want to consider it based on the fact that you had IDC, rather than to treat the DCIS.  Tamoxifen proves three benefits:

1) It reduces the risk of a local (in the breast area) recurrence.  Reducing this risk is important for anyone who's had either DCIS or IDC.  But an invasive recurrence is more serious than a DCIS recurrence, so I'd say that for you, the more compelling argument for Tamoxifen is to reduce risk of a recurrence that could result from your having had IDC.

2) It reduces the risk of a new primary breast cancer in either breast.  This benefit is the same whether one has had DCIS or IDC.

3) It reduces the risk of a distant recurrence, i.e. mets.  DCIS cannot develop into mets so there is no benefit here for those who've had only DCIS.  This benefit is exclusively for those who've had IDC and I think most doctors (and patients) would argue that this is the most critical and significant benefit of Tamoxifen.  So having had DCIS doesn't even factor in here.

I really don't understand why your doctor has brought up the DCIS in the context of the Tamoxifen decision.  You need to decide on whether or not you should take Tamoxifen, but your DCIS isn't what should drive this decision.  Not as far as I can tell.

If you have a BMX for DCIS that is ER and PR+, is there a reason to take Tamoxifen?

The three situations here are very different.

Abby and pammer, you have both had invasive cancer, so unlike someone who's had pure DCIS, you face a risk of distant recurrence, i.e. metastasis.  This is the most serious and concerning risk that anyone diagnosed with breast cancer faces.

Abby, you were given chemo and Herceptin to address this risk. Tamoxifen is also often given to address this risk but because your invasive cancer was ER-, Tamoxifen will not provide any benefit for you in this area. So for you, the primary benefit of Tamoxifen is that it will reduce your risk to develop a new ER+ primary breast cancer in either breast; it is, as you said, preventative.  redsox, I would agree with you that Abby's "oncologist is making recommendations consistent with the evidence" if not for the fact that Abby has already had an ER- invasive breast cancer.  So her situation is not the same as someone who is merely high risk.  She had a history of ER- breast cancer and it seems to me that this contraindicates Tamoxifen, because it's known that Tamoxifen increases the risk of ER- cancers. But I say that as a patient, not as a doctor, so perhaps I am putting more weight on this risk than I should.  But it certainly would raise a red flag with me.

pammer, your diagnosis appears to have been early stage enough that it did not warrant chemo. Tamoxifen then becomes your only treatment to reduce your risk of a distant recurrence.  Whether it is worth it or not depends on what your risk of mets is.  Since Tamoxifen is being recommended to you, I am assuming that your cancer was ER+. Did you have the Oncotype test? Your Oncotype score provides information about your risk of mets, and that in turn can help you decide if the risk and sides effects from Tamoxifen are worth it for you.

Anne, I'm not sure if your question was about Abby's situation or your own but I'm assuming that you were asking for yourself.   If your diagnosis was pure DCIS, then you do not face a risk of mets. So you will not get any benefit from Tamoxifen in this area because you have no risk in this areas.  Having had a BMX, your risk of local recurrence or a new primary breast cancer is in the range of 1% - 2% (assuming that the MX on the cancer side left you with acceptable surgical margins and assuming that you are not extremely high risk, such as being BRCA+).  So this means that the best that Tamoxifen can do for you is reduce your local breast cancer risk from at most 2% to around 1%.  The risk of serious side effects from Tamoxifen is in the range of 2% - 3% (or could be higher if you have other health conditions that already put you at risk for conditions such as uterine cancer, DVT, stroke, etc.). Personally I don't think that there are very many black and white situations in the world of breast cancer, and knowing that we all see risk differently, I rarely will say anything as definitively as I will say this. But from my understanding, someone who's had a BMX for pure DCIS, and who has acceptable surgical margins and no extreme risk factors, actually puts themselves at greater health risk by taking Tamoxifen than by not taking it.  I think any oncologist who recommends Tamoxifen in this type of situation is irresponsible. 

Abby,



Tamoxifen for you would primarily be for prevention of new primaries. It would also help with prevention of recurrence from the DCIS which could be another DCIS or could be IDC. The estimate of 2% reduction from tam seems a little low to me but I don't think your risk is very high. The fact that you are so young is a big risk factor.



The studies showing more recurrences after tamoxifen to be hormone receptor negative are unclear. They show a higher proportion to be negative - not surprising since tam is known to reduce only hormone positive cancers which then leads to a higher proportion of hormone negative. But whether they show a higher absolute rate of hormone negative recurrences depends on the underlying risk levels for the study.
These results from observational studies need to be confirmed and remain an open question, but one well worth discussing with your doctors.