DCIS & Neoadjuvant treatment - moving discussion to a new thread

['lizbeth]

This information is provided by AussieGirl. Since more and more studies and patient treatments will involve neoadjuvant treatment - it is a good topic for us to explore.

Here's one article http://www.ncbi.nlm.nih.gov/pubmed/21667238

and here's a recent book chapter of interest which suggests that Herceptin added to neo-adjuvant chemo helps get rid of HER2 DCIS providing more complete responses. http://books.google.com.au/books?id=...0chemo&f=false

In the pathology literature, it is well known that DCIS is the last thing to go when we have to assess specimens for complete pathological response. The DCIS cells often looks "sick", like they are ill and dying, but we don't call it complete response unless the bad cells have disappeared.

So the neo-adjuvant therapy has an impact on DCIS but if it is incomplete, what does it mean?

I found this study http://jco.ascopubs.org/content/25/19/2650.full
which suggests the residual DCIS doesn't affect disease free survival.

Then this one showing that residual DCIS post-neoadjuvant Rx is bad. (my translations in red)
http://jco.ascopubs.org/content/30/15/1796.full
"We conclude that pCR defined as ypT0 ypN0 (=no residual tumor) is associated with highly favorable outcome. ypTis (=residual DCIS), ypT1mic (=residual microinvasion), and ypN+ (=residual positive node)residuals only are associated with increased relapse risk and should therefore no longer be considered as pCR. Extent of residual disease and evidence of regression provide helpful additional prognostic information. pCR is a suitable surrogate end point for patients with HER2-positive (nonluminal), TN, and luminal B/HER2-negative tumors but not for luminal B/HER2-positive and luminal A tumors. "

Also earlier in this article:
"We further demonstrate that in subgroups considered to have slowly proliferating tumors, pCR is not associated with prognosis, whereas in subgroups with highly proliferating tumors, pCR can discriminate between patients with good and poor prognosis accurately. The recently proposed clinicopathologic definition of the St Gallen panel nicely recognizes these subgroups. In fact, prognostic impact of pCR is highest in HER2-positive (nonluminal) and TN tumors, where patients achieving pCR show a prognosis comparable to that of patients with luminal A tumors.
Surprisingly, pCR was not prognostic in the luminal B/HER2-positive subgroup irrespective of trastuzumab treatment. In this subgroup, pCR rates were low, despite concomitant anti-HER2 therapies,11,28,29 but similar outcomes were observed in the adjuvant trastuzumab studies.30"

SO...
I think treatment of DCIS with neo-adjuvant chemo is a work in progress - the residual DCIS gets cut out anyway, or at least zapped with radiation, so it wouldn't be a big surprise if eventually residual DCIS is shown not to be so important if a mastectomy is performed.

However, it'd be good to know if you could have neo-adjuvant chemo followed by Limited surgery (or perhaps No surgery, on the basis of core biopsies as an assessment of response. )

And how will neoadjuvant Perjeta work on DCIS?? So much to learn!