NIH Consensus Conference DCIS

This conference was only 15 months ago.  Most of the speakers are involved in the ongoing research and were able to give the latest available info on ongoing studies, plus they could update before the manuscripts went to press.  This is as current as you are likely to find.  There have been publications since then but the most relevant ones were anticipated by the conference.

There is considerable controversy along the overtreatment and undertreatment lines without a clear right answer, but if two or more doctors make different recommendations the reasons may include:

1. they disagree on the diagnosis or interpretation of the pathology

2. they are considering a somewhat different set of factors or putting different degrees of importance on particular factors

3. they are willing to accept different levels of risk

It is important to try to get a clear understanding of the reasons behind the different recommendations -- to be sure it is consistent with your own goals and risk tolerance. 

My hope lies in the biomarker work.  I think they will identify biological factors of the tumors that predict which patients are likely to recur and which are not, but they did not have the answers in time for us.

Another important article published since this conference reported extended follow-up for two key clinical trials on DCIS in the Journal of the National Cancer Institute, Vol. 103, Issue 6 , March 16, 2011:

http://jnci.oxfordjournals.org/content/103/6/478.full.pdf+html

It was entitled:

Long-Term Outcomes of Invasive Ipsilateral Breast Tumor Recurrences After Lumpectomy in NSABP B-17 and B-24 Randomized Clinical Trials for DCIS

Irene L. Wapnir, James J. Dignam, Bernard Fisher, Eleftherios P. Mamounas, Stewart J. Anderson, Thomas B. Julian, Stephanie R. Land, Richard G. Margolese, Sandra M. Swain, Joseph P. Costantino, Norman Wolmark

It reports on extended follow-up for the two NSABP clinical trials B-17 and B-24 which have both been reported earlier and are key studies for DCIS. B-17 looked at the question of lumpectomy alone vs. lumpectomy + radiation therapy while B-24 looked at the question of lumpectomy + radiation therapy with or without tamoxifen. The primary endpoint reported in this paper is recurrence of invasive breast cancer in the same breast as the original tumor, but it also reports many other endpoints and breaks down the data by other factors. The follow-up is longer than for earlier reports of these studies, ~15 years (for B-17 median follow-up is 207 months or about 17 years and for B-24 median follow-up is 163 months or about 13.6 years).

The results show that in B-17 radiation therapy reduced the risk of invasive same-breast recurrences by 52% while B-24 showed that tamoxifen in combination with radiation therapy showed a 32% reduction in the risk of invasive same-breast recurrences. (The 32% reduction is for tamoxifen. All patients in this trial had radiation.) The cumulative incidence of invasive
same-breast recurrences at 15 years was 19.4% for lumpectomy alone, 8.9% for lumpectomy + radiation therapy in B-17 and 10% in B-24, and 8.5% for lumpectomy + radiation therapy + tamoxifen.

The article shows numerous survival curves with four groups displayed on each graph. I found it a little confusing until I realized that it is not a single trial with 4 study arms but rather two separate trials each with two study arms. Patients were randomized for the two arms of the first trial and then other patients were randomized for the two arms of the second trial but arms of different trials are not randomized with each other. The eligibility criteria were looser for the second trial, especially with regards to margin status, presumably because all patients in the second trial received radiation therapy, so the absolute values of the numbers across the two trials are not
exactly comparable.

Still, each trial did not include all DCIS cases but tried to define a group likely to have a relatively favorable prognosis. The criteria for defining a favorable group once again do not work well -- the criteria seem to relate to speed of recurrence at least as much as ultimate rate of recurrence.

The article reported other endpoints in addition to invasive same-breast recurrence. Among them were DCIS same-breast recurrence and cancers in the other breast. Of all same-breast occurrences 46.3% were noninvasive or DCIS while 53.7% were invasive (the ones I talked about in my previous post). 1.3% had other local, regional, or distant recurrences without documented breast recurrence. In the B-17 trial lumpectomy + radiation therapy resulted in 47% lower rate of DCIS recurrence compared to lumpectomy alone.

Breast cancer in the other breast was the first event for 7.2% of patients. In the B-24 trial patients who received lumpectomy + radiation therapy + tamoxifen had a 32% reduction in other breast cancers compared to those who had lumpectomy + radiation therapy with no tamoxifen.