Aug 5, 2020 01:05PM Beesie wrote:
LL, from reading your other posts, it appears that you are leaning towards a BMX. If you go that route, then with pure DCIS, or even DCIS with a microinvasion (as I had), endocrine therapy will not be required. After a MX for DCIS, your recurrence risk is low enough that the risk reduction benefit from Tamoxifen or an AI will be less than the risk of serious side effects from these meds. In other words, with this diagnosis and a BMX, you would put yourself at greater health risk by taking endocrine therapy than not taking it.
If you have a UMX (a single mastectomy), then you have a decision to make on whether to take endocrine therapy as a preventative against a new primary breast cancer in your contralateral breast. And if you have a lumpectomy, then endocrine therapy can provide risk reduction benefit both relative to a recurrence of this cancer (DCIS recurrences are DCIS ~50% of the time and invasive cancer ~50% of the time) and as a preventative against a new cancer. With such low ER and PR, how much benefit would you get? I'd guess not much but there has been studies done to suggest that even 1% ER/PR positive provides some benefit and warrants taking endocrine therapy.
It's important to note however than these studies have been done on patients with invasive cancer. For these patients, the most significant benefit of endocrine therapy is a reduction in the risk of distant metastasis - in other words, these meds can be be life saving. With pure DCIS, since it is non-invasive, this direct benefit does not exist. So whether endocrine therapy is warranted for low ER/PR DCIS remains a question. And ultimately it depends on your risk level after surgery. If you have a 15% risk of recurrence and rather than reduce your risk by ~50%, with low ER/PR, your risk might be reduced by 20% (I pulled that out of the air), would that be worth it to you? Would it be worth it to you if your starting recurrence risk after surgery was 30%?
Some light reading: