Tuesday, November 19, 2013

DCIS Study Does NOT Mean TNBC Recurrence Is More Likely

I am very careful about what I put on this page.  If I think a research report is weak and could cause unnecessary worrying without adding to our knowledge in any meaningful way, I do not share it.    The internet, however, is a wild and wooly place, without gatekeepers and perspective.  So I often hear from readers about a study that "proves" things that are counter to what the broader body of research has told us about triple-negative breast cancer.

One recent study, published in BMC Cancer,  has caused readers to believe that the recurrence of TNBC after five years is greater than that of other forms of breast cancer.  This runs counter to several other studies that have shown the opposite--that TNBC tends to recur within three years if it is going to recur, and that the incidence after five years is significantly lower than for other forms of breast cancer.

Here's the deal.  This new research studied DCIS and found that those cases of DCIS that were TNBC tended to recur after five years at a higher rate than other types of breast cancer.  The researchers, though, warned that only 27 women in the study had TNBC, far too small a sample for any generalization.  In addition,  it does not appear, from the report, that any of the women with DCIS had chemotherapy—the treatments mentioned were surgery and radiation. This is not unusual, as few docs give chemo for DCIS.  So the small group of TNBC women studied did not have the insurance most women now have against TNBC—chemo.  And most research on long-term survival of invasive breast cancer deals with women who have had chemo.  And it shows that chemo often works better for estrogen-negative breast cancer than for estrogen-positive.

A few things this might tell us  (although, again, with such a small sample it is difficult to generalize):  Chemo works.  And DCIS perhaps should be treated more aggressively if it is TNBC.

It does NOT tell us that those of us with TNBC have more cause to worry about long-term recurrence.

• Read more about TNBC in my book, Surviving Triple-Negative Breast Cancer.

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Anonymous said...

My oncologist does not classify DCIS as cancer. He considers it precancerous. It is no big surprise that more aggressive forms of dcis indicate a greater risk for developing breast cancer. This is a completely different kind of claim than one looking at the risk of recurrence after a diagnosis of and treatment for invasive tnbc. Everything I have read indicates that after systemic treatment invasive tnbc has the highest risk of recurrence in the first few years and then drops significantly after that.

Jo Entwistle said...

Hi patricia, thanks for this -I had already found this study. My concern is that I had new DCIS after invasive ducal (for such I did chemo) in 2011-I also had DCIS around the tumour. I just had a mastectomy for the new DCIS. So now I'm wondering about my chances of a third bout of DCIS and thinking 'quite likely' , even with the mastectomy which leaves 5% risk in any case. So unfortunately I'm not reassured by your post, but that isn't your fault of course! Will raise with oncologist when I see her in the spring though having chemo for this would be ridiculous and won't don't prevent another local recurrance in 10 years. Any reassuring words welcome!

Patricia Prijatel said...

Jo: While I don't want you to have a recurrence of any type at any time, a local recurrence is treatable and manageable. And a 5 percent risk is really, really small, so you are at minimal risk of even that. I see that as a pretty positive prognosis.

The chemo, I hope, protects you from a distant metastases, which is what is deadly.

Anonymous said...

I posted the original comment. I also had dcis and triple negative invasive breast cancer at my initial diagnosis. I had a single mastectomy at that time. Later, I had a prophylactic mastectomy over a year after my first. I had microscopic dcis, some high grade, but not triple negative. The study seems to be saying that people with triple negative dcis have a higher risk of developing invasive breast cancer after 10 years. Presumably, I have already developed and been treated for idc, so the risk associated with dcis takes aback seat to this. It is unclear to me whether the women in the study had lumpectomis or mastectomies. DCIS itself is low risk, even triple negative, and having a mastectomy for dcis puts people at pretty low risk for breast cancer, though it does not eliminate the risk. I understand the anxiety of a breast cancer diagnosis, but I have realized as I get farther away my diagnosis that there are mortality risks everywhere, and dcis itself is not life a threatening. Ultimately, why worry excessively about dcis when you are probably at greater risk from things you don't even worry about.

Patricia Prijatel said...

So true. We have control over our worries and reducing them could make our lives much easier. I agree that DCIS is something to watch, but not stew about.