Faith, I don’t have answers for you. I hope you don’t mind my saying how much that sucks that you are dealing with mbc at such a young age. Your questioning is very normal. I think the mind goes through a process, trying in some ways, to make sense of it.

Because of your age and because you initially were diagnosed with dcis, your doctors probably thought “no way” your prognosis would develop into anything further. I mean, I’ve read numerous articles where some in the medical field feel dcis is often dealt with too aggressively and that those diagnosed with dcis and go through with surgery and chemotherapy are going overboard.

Consider the fact that it’s possible that you or your medical team could have done nothing different to prevent the progession to mbc from happening. There is a wild card element to breast cancer, and no one can say with any certainty which women will eventually become metastatic and which ones will have the bc eradicated forever.

I am not Stage IV, so my apologies for intruding on the Stage IV forum.

Faith123, I am so sorry about your Stage IV diagnosis.

It is very rare for this to happen as you describe, although there are a few possibilities that might have led to this. The first and most likely scenario is that your original diagnosis did in fact include a small amount of invasive cancer that was not discovered by the pathologist. The fact that you presented with a lump when you were diagnosed with DCIS is unusual - DCIS does not usually present as a lump and when it does, it is much more likely that there will also be some invasive cancer present. While on average approx. 20% of preliminary DCIS diagnoses (via a needle biopsy) are upgraded to invasive cancer once the final pathology is done, according to the following study, 49% of those who presented with palpable DCIS ended up with an invasive cancer diagnosis:

Should palpable DCIS be treated as IDC? A retrospective audit.

You also mentioned that you had widespread DCIS; this too is more likely to indicate the presence of a microinvasion or a larger invasive cancer. The following study shows the significance of both size of the DCIS and palpability as being key factors that significantly increase the risk that invasive cancer will be present:

A Simple Model to Assess the Probability of Invasion in Ductal Carcinoma In Situ of the Breast Diagnosed by Needle Biopsy

Another possibility is that you may have had an occult invasive cancer somewhere else in your breast, separate from the DCIS. Although the pathologist should look thoroughly at all the breast tissue removed, it is possible that the areas of tissue not directly involved with the DCIS might not have been checked quite so carefully.

Did you have a BMX or a UMX? If you had a UMX, the question is whether you might have an occult invasion in your other breast. If you still have a remaining breast, I trust you've had an MRI? If you had a BMX, here again it's possible that the breast tissue in the non-cancer breast was not as thoroughly checked through by the pathologist, and a small invasive cancer could have been missed. Not likely, of course, but it is certainly more likely that the mets sourced from an invasive cancer rather than from the DCIS, so all the possibilities for where an occult invasion might have been hiding should be considered. With a BMX, there is a lot of breast tissue to look at under the microscope, and missing a tiny 1mm or 2mm invasive cancer is certainly possible.

Is your current diagnosis HER2+? I ask because if you did have an occult invasion and it was HER2+, that would have been a small but aggressive invasive cancer, which could lead to your current diagnosis.

Unfortunately, occult invasions happen with DCIS. Not common, but common enough. Most of the time there is no negative impact but sometimes women are found to have positive nodes despite finding only DCIS in the breast, and sometimes, as happened with you, mets develops despite finding only DCIS in the breast.

Again, I am so sorry that you are dealing with this at such a young age, and with two young babies. I wish you every luck with your treatment.

Nicole, your case is a bit different than Faith's because you had a local recurrence, which included invasive cancer and DCIS, at the same time that you had the metastatic recurrence. So while the development of mets in your situation is just as devastating, it followed a more expected and understood route, DCIS --> IDC (in breast recurrence) --> Metastatic recurrence. When DCIS recurs locally, in about 50% of cases the recurrence is not found until after the cells have already evolved to become invasive cancer. And in an extremely small number of those cases, the invasive cancer has spread and metastasized before even the local recurrence is diagnosed.

To your point, because you had a fairly large area of high grade DCIS and almost involved surgical margins after your original DCIS surgery, it's quite likely that some DCIS remained in your breast. No one can know when those cells evolved into IDC, but it could have been anytime time after your first DCIS diagnosis. As soon as those cells became IDC, they had the ability to spread/metastasize, so you may have had a small area of IDC for in your breast for years before it became large enough to be found as a local recurrence. A more understandable sequence of events that Faith's, but equally shocking.

Again, my apologies for posting in the Stage IV forum.

Beesie, once again you are awesome in your explanation!!! I miss chatting with you!!! I too would never mind you being here to chat in Stage IV