Purpose Given the clinical relevance of ESR1 mutations as potential drivers of resistance to endocrine therapy, this study used sensitive detection methods to determine the frequency of ESR1 mutations in primary and metastatic breast cancer, and in cell free DNA (cfDNA). Patients and Methods Six ESR1 mutations (K303R, S463P, Y537C, Y537N, Y537S, D538G) were assessed by digital droplet PCR (ddPCR), with lower limits of detection of 0.05% to 0.16%, in primary tumors (n=43), bone (n=12) and brain metastases (n=38), and cfDNA (n=29). Correlations between ESR1 mutations in metastatic lesions and single (1 patient) or serial blood draws (4 patients) were assessed. Results ESR1 mutations were detected for D538G (n=13), Y537S (n=3) and Y537C (n=1), and not for K303R, S463P or Y537N. Mutation rates were 7.0% (3/43 primary tumors), 9.1% (1/11 bone metastases), 12.5% (3/24 brain metastases), and 24.1% (7/29 cfDNA). Two patients showed polyclonal disease with more than one ESR1 mutation. Mutation allele frequencies were 0.07% to 0.2% in primary tumors, 1.4% in bone metastases, 34.3 to 44.9% in brain metastases, and 0.2% to 13.7% in cfDNA. In cases with both cfDNA and metastatic samples (n=5), mutations were detected in both (n=3) or in cfDNA only (n=2). Treatment was associated with changes in ESR1 mutation detection and allele frequency. Conclusions ESR1 mutations were detected at very low allele frequencies in some primary breast cancers, and at high allele frequency in metastases, suggesting that in some tumors rare ESR1 mutant clones are enriched by endocrine therapy. Further studies should address if sensitive detection of ESR1 mutations in primary breast cancer and in serial blood draws may be predictive for development of resistant disease.

Approximately 6 % of patients with breast cancer are diagnosed with de-novo distant metastases. We set out to look at two cohorts of patients seen at breast cancer-specific practices, compare the results to other reports and larger databases, and see how advances in treatment have impacted overall survival (OS). The records from a large breast cancer oncology private practice and a second data set from the University of Miami/Sylvester Comprehensive Cancer Center (UM/SCCC) tumor database were, retrospectively, reviewed to identify patients with de-novo metastases. We included those patients identified to have metastatic disease within 3 months of diagnosis of a breast primary cancer. Patients diagnosed between 1996 and 2006 were chosen for our study population. The OS for the private practice was 41.0 months (46.0 for ER positive and 26.0 for ER negative) and 36.0 months for UM/SCCC (52 months for ER positive and 36 months for ER negative). ER negativity and CNS- or visceral-dominant disease were associated with a significantly worse prognosis within the private practice. Dominant site was associated with a significantly worse prognosis within the UM/SCCC database but with a trend also for ER negativity. Age and ethnicity did not contribute significantly to the survival of patients within either cohort. The median survival in both cohorts and most other reported series was larger than that seen in the surveillance, epidemiology, and end results program and the National Cancer Database. The median OS among patients with de-novo metastatic breast cancer treated within two breast-specific oncology practices was over 3 years, which appears better than larger, more inclusive databases and publications from earlier decades.

BACKGROUNDOur 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.METHODSRecords 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.RESULTSMedian 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.CONCLUSIONThe new benchmark for MSFSR approaches 3 years.

To determine if a low fixed dosing strategy of capecitabine would produce comparable clinical activity with less adverse toxicities compared to published data with higher doses in the setting of metastatic breast cancer (mBC). We retrospectively analyzed patients treated with a low fixed dose of capecitabine (CAPE-L) at 1,000 mg twice daily for 14 days every 21 days. Outcomes included clinical benefit rate (CBR), overall response rates (ORR), time to progression (TTP), and overall survival (OS). A historical comparison group of mBC patients treated on 12 prior trials at the package-insert dose of capecitabine (n = 1,949) was utilized. Eighty-six patients were analyzed in our cohort. Positive hormone receptor status (79.1 vs. 50.6 %), and capecitabine as first-line chemotherapy (44.2 vs. 16.5 %) were more frequent in our cohort relative to the historical comparison. The median starting dose in our cohort was 633.5 mg/m(2). The CBR was similar between the CAPE-L and the standard dose cohorts (55.8 vs. 49.5 %), as was ORR (24.3 vs. 24 %), and median TTP (7 mo, 95 % CI 5.5-8.5 vs. 5.1 mo, 95 % CI 4.5-5.7). Median OS was longer in our cohort (24 mo, 95 % CI 16.8-31.2) than the historic standard dose cohort (12.1 mo, 95 % CI 9.6-14.4), a difference that was likely explained by the higher proportion of patients in the CAPE-L cohort who received capecitabine as first-line chemotherapy and who had hormone receptor positive disease. As expected, adverse events were less frequent with CAPE-L. We found that CAPE-L, which translates into a dose of 600-650 mg/m(2), appeared to have good clinical efficacy and acceptable toxicity.

Women with advanced breast carcinomas have few therapeutic options. Recent advances in genomic profiling represent a new paradigm of cancer classification and treatment, but experience with genomic testing in a clinical setting remains limited. We retrospectively determined the genomic variants and correlate these with histology [histomorphologic subtype, nuclear grade, standard immunohistochemistry (IHC)] and clinical utilization (ordering, turnaround time, report review, and targeted therapy). Among 48 patients, 2 showed no genetic alterations, 11 (23%) showed variants of unclear significance only and 35 (73%) showed variant(s) affecting function (VaF) and/or variants of unclear significance. Overall, 119 variants were observed in 20 of 50 tested genes. Each patient had a unique molecular profile, with numerous (n=58) variants not previously reported in breast cancer. VaF detected in more than 2 patients included: TP53 (n=21), PIK3CA (n=20), and FGFR1 (n=3). VaF comprised 46 single nucleotide variants (79%), 7 amplifications (12%), 3 frameshifts (5%), 1 insertion (2%), and 1 deletion (2%). The tested samples had very high Ki67 index (average 57%±23%) and approximately half were hormone receptor and HER2 negative (25/46, 54%). Metastatic breast carcinomas showed a higher average VaF versus breast-localized tumors (1.3±0.99 vs. 0.18±0.60, P<0.05). Next-generation sequencing reports were promptly reported and reviewed (average 1 to 2 d) and 7 (∼25%) of potentially eligible patients received targeted therapy. Advanced breast cancers show unique landscapes of genetic variants. Most testing was done in late disease, often in metastatic and receptor-negative carcinomas. Next-generation sequencing results were promptly reported and reviewed, but the utilization of targeted therapies was limited.