Defining the Survival Benchmark for Breast Cancer Patients with Systemic Relapse
the ONA take:
In patients with breast cancer, the new benchmark for median survival from first systemic relapse (MSFSR) approaches 3 years, according to a review published in the journal Breast Cancer: Basic and Clinical Research.
In 1992, researchers reported a median overall survival after first relapse of 26 months in patients with breast cancer, and most clinicians cite a median survival for metastatic breast of about 2 years. Now, researchers have found that median overall survival has improved by 7 months over the past 20 years.
For the study, researchers analyzed the records of 5,168 patients from an oncology practice that mostly treats breast cancer. Researchers identified 189 patients that were first seen within 2 months of diagnosis of metastasis. Results showed that the MSFSR for the 189 patients was 33 months. Subgroup analysis demonstrated an MSFSR of 39 months for estrogen receptor (ER)-positive patients and 23 months for ER-negative patients.
Furthermore, researchers found that HER2 negativity, ER negativity, disease-free interval (DFI) less than 24 months, higher number of metastatic sites, and age greater than 50 years were associated with a significantly poorer prognosis.
The authors suggest that that the improvement in median survival is likely due to increased use of taxanes, aromatase inhibitors, trastuzumab, and other novel agents.
Breast Cancer Basic and Clinical Research
Our original paper, published in 1992, reported a median overall survival after first relapse in breast cancer of 26 months. The current retrospective review concentrates more specifically on patients with first systemic relapse, recognizing that subsets of patients with local recurrence are potentially curable.
Records of 5,168 patients from a largely breast-cancer-specific oncology practice were reviewed to identify breast cancer patients with their first relapse between 1996 and 2006 after primary treatment. There were 189 patients diagnosed with metastatic disease within 2 months of being seen by our therapeutic team and 101 patients diagnosed with metastatic disease greater than 2 months. The patients were divided in order to account for lead-time bias than could potentially confound the analysis of the latter 101 patients.
Median survival for our primary study population of 189 patients was 33 months. As expected, the median survival from first systemic relapse (MSFSR) for the 101 patients excluded because of the potential for lead-time bias was better at 46 months. Factors influencing prognosis included estrogen receptor (ER) status, disease-free interval (DFI), and dominant site of metastasis. Compared with our original series, even with elimination of local-regional recurrences in our present series, the median survival from first relapse has improved by 7 months over the past two decades.
The new benchmark for MSFSR approaches 3 years.
Keywords: breast cancer, median survival, estrogen receptor positive, disease-free interval, HER2 positive, systemic relapse, metastatic breast cancer
Breast cancer is the most prevalent cancer among women in the United States, and remains the second leading cause of cancer-related mortality. In 2013, approximately 232,340 women were diagnosed, and 39,620 women died of breast cancer.1 Although most patients with early stage disease will be cured, the 10-year risk of distant recurrence at 5 and 10 years is approximately 14% and 36%, respectively.2,3 The prognosis of patients with metastatic breast cancer (mBC) is rather heterogeneous, ranging from several months to many years, depending on numerous factors including original tumor stage (tumor size and number of metastatic lymph nodes involved), age at relapse, estrogen receptor (ER) status, human epidermal growth factor receptor 2 (HER2) receptor status, sites and number of sites of relapse, disease-free interval (DFI), and prior exposure to adjuvant or neo-adjuvant chemotherapy.4–24
Our original paper, published over 20 years ago, reported a median survival after first relapse (MSFR) of 26 months (range: 15–90 months) among a population of patients diagnosed with relapse between 1976 and 1982 treated at the University of Miami.4 In the intervening time since the initial publication, there have been significant advances in the treatment of mBC, including new surgical and radiation techniques, and the addition of novel systemic agents, including aromatase inhibitors (AI), taxanes, and the advent of HER2 targeted agents. One of the critical elements of our original paper was accounting for lead-time bias. Lead-time bias has been discussed extensively as a potential confounding variable in the reduction of overall mortality of newly diagnosed breast cancer due to the potential impact of early detection through screening.1 Our original publication would have overestimated median survival results if we had not adjusted for lead-time bias.4
The purpose of this study was to define a new benchmark for survival in patients with systemic breast cancer excluding the potentially curable subset of loco-regional relapse. Most still cite a median survival for metastatic breast cancer of approximately 2 years.2,13 However, there remains significant controversy regarding this number.6,8,18,25 The current retrospective review was undertaken in an attempt to clarify the median survival for those subsets of metastatic breast cancer that are considered “incurable”.