Treatment outcomes in patients with invasive breast cancer treated with neoadjuvant systemic therapy and breast MR imaging

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Published: 15 Dec 2015
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Prof Jennifer De Los Santos - University of Alabama, Birmingham, USA

Prof Los Santos talks to ecancertv at SABCS 2015 about updated results of a study looking at the treatment outcomes of women with invasive breast cancer who had been treated with neoadjuvant therapy and then underwent lumpectomy or mastectomy.

The trial included more than 1000 women aged a median of 50 years from nine institutions in the USA who were retrospectively identified as having undergone neoadjuvant chemotherapy and who had magnetic resonance imaging (MRI) data available both before and after systemic treatment.

After a median follow-up of 4.2 years, the rate of loco-regional recurrence among women who achieved a pathological or a radiological complete response was similar among women regardless of the surgical procedure used. There were also no differences in terms of survival (disease-free or overall), or time to progression.

A subset analysis showed that there may be an advantage for some women with triple negative breast cancer to undergo neoadjuvant chemotherapy then breast conservation, but this did not lead to an improved disease-free survival rate.

Dr De Los Santos observes in the interview that these results confirm the “outstanding outcomes” that can be achieved with neo-adjuvant chemotherapy and that for some women mastectomy may not be necessary as great results can be achieved with breast conservation approaches.

ecancer's filming at SABCS 2015 has been kindly supported by Novartis through the ECMS Foundation. ecancer is editorially independent and there is no influence over content.

You have been looking at the outcomes of treatment and this is in patients who have invasive breast cancer that has been treated with neoadjuvant therapy and also breast imaging comes into it, doesn’t it? What were you trying to investigate here, what was the big issue?

Well, the original study was looking at women who had MR imaging before and after neoadjuvant systemic therapy. When we originally created the study we were interested in seeing if MRI correlated with pathologic CR.

So basically with MRI you can really be on top of whether your neoadjuvant therapy is achieving what you’d like?

Correct. We were interested in finding out if the complete response in imaging translated into a pathologic complete response and we published that approximately two years ago. This was an update of that data and it looked at outcome analyses among patients that had been treated. In particular this was a more advanced cohort of patients, they were generally younger age, the median age was 50 and they all had systemic therapy. What we have found in this contemporarily treated cohort of patients is that overall survival and disease free survival was similar in patients that received breast conserving surgery as compared with mastectomy.

There has been something of a resurgence of popularity of mastectomy in the United States, hasn’t there?

Yes, there has been.

And now you’re saying that you’re finding these are equivalent. What can you say about that choice between lumpectomy and mastectomy?

We’ve noted over the past decade that there have been trends towards increasing use of mastectomy. These are multifactorial in terms of factors that are driving decisions in women but in general people have used mastectomy in settings where breast conservation would be a very reasonable option. This study is reinforcing what we already knew in that women who have breast conservation have excellent outcomes.

I’m trying to work out where the imaging comes into this, how important was it to use MRI?

The MR portion of the study wasn’t focussed on as much in these outcomes but what we basically found was patients on univaried analysis who had radiographic complete response had a statistically significant improvement in overall survival and in disease free survival. However, when we put it into a multivariable model that included pathologic complete response, radiographic complete response lost significance. That’s not too surprising, there’s no imaging that we have that can detect microscopic disease.

But what you are finding is this very interesting comparison between conservative therapy and mastectomy. You say they’ve become equivalent, what are the numbers in things like disease free survival, overall survival and time to progression?

They were excellent. I think it’s really important to remember that this was a retrospective study and so we can’t compare groups directly. There were selection biases so patients that did have breast conservation in general had earlier stage disease and patients that had mastectomy tended to have more advanced presentations. However, what we found overall was an extremely low rate of local regional recurrence so in this cohort of almost 1,100 patients we had only 32 local regional recurrences. The majority of the failures were distant but, despite that, 85% of these patients with more advanced presentations were doing quite well or NED, they had no evidence of disease.

And this is over what period of time?

The median follow-up was only 4.2 years but the range of the follow-up went back over 13 years.

What do you think, then, this might be telling doctors about the effectiveness of, on the one hand, conservative therapy and, on the other hand, mastectomy?

I think that many of us feel that mastectomy is being over-utilised nowadays. We’re doing a wonderful job individualising therapy based on systemic treatments but we’re not doing as good a job individualising therapy with surgery. This data, again, reinforces that we can achieve excellent outcomes in patients that are treated with neoadjuvant therapy and go on for breast conservation.

There has been evidence that lumpectomy is pretty good for a long time so what do you think is driving this tendency to continue to do mastectomy?

Again I think it’s multifactorial but certainly social media, personalities on TV such as Angelina Jolie who have gone on for bilateral mastectomies in the setting of BRCA positivity. I think general fear of not only the cancer the patient has but another cancer forming are some of the variables that have been looked at that are driving these selections.

So it’s patient fears, not necessarily the data.

Well, that’s true, however, I think in general we can do a better job educating patients. One of the things that we’ve noted in our own practice at UAB is that patients come in and when we explain to them that mastectomy does not reduce their chance to zero of having a recurrence, nor does prophylactic mastectomy reduce their chance to zero of having a new cancer, they’re often surprised and sometimes they change their mind.

So could you give me a bottom line to take home for doctors listening?

In many patients neoadjuvant chemotherapy is resulting in outstanding outcomes and we are over-utilising mastectomy in a subset of patients that could have great outcomes with less surgery by doing breast conservation. This data really reinforces that.