ASCO 2015: No change in metastatic breast cancer survival found at one Canadian institution, 1970 – 2013

This in itself is bad news, but the investigators also noted some alarming trends in the aggressiveness of metastatic disease once it emerged in later years.

The purpose of this study, not formally presented at the 2015 ASCO Annual Meeting but published in conjunction with the meeting,  was to look at survival of metastatic breast cancer patients from 1970 through 2013 at a hospital in Montreal.  Using a tumor registry, investigators found 1079 patients who had developed metastatic disease, and divided them into 4 cohorts according to the diagnosis of the metastatic disease (cohort 1: 1970-1995 (339 patients), 2: 1996-2000 (292), 3: 2001-2005 (249) and 4: 2006 plus (199)).

The median age of diagnosis of metastatic disease increased over time, from 54 to 58 years of age, and the time until metastatic diagnosis was significantly delayed, from 4.2 years to 5.7 years after initial diagnosis.  However, overall survival did not change, from cohort 1 to cohort 4 (initial diagnosis until death). So while the appearance of metastatic disease was delayed, this did not result in increasing survival.

The investigators hypothesize that a parallel increase in the use of adjuvant hormonal therapy, such as tamoxifen, might explain the delay in the development of the metastatic disease, but that perhaps this therapy was also leading to a drug resistance, making the metastatic disease harder to control.  A disturbing trend was that the aggressiveness of the disease when it appeared increased between cohort 1 and 4: the percentage of patients with visceral disease (metastatic disease appearing in organs such as the lung and liver) when first diagnosed with metastases increased from 33% to 45% between cohort 1 and 4.

The investigators conclude ” In our institution, no increase in overall survival was noted between the initial diagnosis and death throughout cohorts 1 to 4, but the significant increase in time to progression from initial diagnosis may reflect that adjuvant therapy delays disease progression.”

It’s been awhile since I’ve posted a blog entry.  I’ve been learning a lot about the trends in research and treatment directed at many other tumor types beyond breast cancer, as part of my job as an oncology news editor.  Now I’m hoping to occasionally stop by to share information and insights I’m gathering along the way that might be helpful for breast cancer advocates. I’m particularly interested in sharing developments in immunotherapy, or therapy aimed at boosting an individual’s unique defense against cancer development and spread.  When these therapies work – so far only in a subset of patients, particularly those with melanoma, lung cancer, or bladder cancer – they often work for the long haul, not just for a month or two.  These developments are causing a buzz in the oncology world, and I think offer the most promise for making meaningful differences in women’s lives, changing these dismal numbers for those who develop metastatic disease.  Several studies are currently underway to look at these therapies in breast cancer.

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  • Deborah Laxague  On June 28, 2015 at 2:24 pm

    Good to see you back blogging here, Laura! And thanks for drawing our attention to this publication, disheartening as it is. It does make sense that, as they surmise, improved adjuvant treatments may be picking the lowhanging (less aggressive and/or more susceptible) fruit, leaving the cancers that do recur being more aggressive and/or resistant. It doesn’t seem to have a full text publication yet? I’d like to see if they looked at subtypes, for example. And I’m with you, re: watching with cautious enthusiasm both for the immunotherapy approach to have success in breast cancer, and for us to learn enough to know why it works so spectacularly for a few (so we can make it do the same for more cancers).

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