Tamoxifen metabolism predicts drug concentrations and outcome in premenopausal patients with early breast cancer

Tamoxifen is the standard-of-care treatment for estrogen receptor-positive premenopausal breast cancer. We examined tamoxifen metabolism via blood metabolite concentrations and germline variations of CYP3A5, CYP2C9, CYP2C19 and CYP2D6 in 587 premenopausal patients (Asians, Middle Eastern Arabs, Caucasian-UK; median age 39 years) and clinical outcome in 306 patients. N-desmethyltamoxifen (DM-Tam)/(Z)-endoxifen and CYP2D6 phenotype significantly correlated across ethnicities (R2: 53%, P<10?77). CYP2C19 and CYP2C9 correlated with norendoxifen and (Z)-4-hydroxytamoxifen concentrations, respectively (P<0.001). DM-Tam was influenced by body mass index (P<0.001). Improved distant relapse-free survival (DRFS) was associated with decreasing DM-Tam/(Z)-endoxifen (P=0.036) and increasing CYP2D6 activity score (hazard ratio (HR)=0.62; 95% confidence interval (CI), 0.43–0.91; P=0.013). Low (<14?nM) compared with high (>35?nM) endoxifen concentrations were associated with shorter DRFS (univariate P=0.03; multivariate HR=1.94; 95% CI, 1.04–4.14; P=0.064). Our data indicate that endoxifen formation in premenopausal women depends on CYP2D6 irrespective of ethnicity. Low endoxifen concentration/formation and decreased CYP2D6 activity predict shorter DRFS

Breast cancer and aging: results of the U13 conference breast cancer panel

Breast cancer is predominantly a disease of older women, yet there is a knowledge gap due to the persisting misalignment between the age distribution of women with breast cancer and the age distribution of participants in clinical trials. The purpose of this report is to state the U13 conference breast cancer panel’s recommendations regarding therapeutic clinical trials that will fill gaps in knowledge regarding the care of older patients with breast cancer. The U13 conference was a collaboration between the Cancer and Aging Research Group and the National Institute on Aging and the National Cancer Institute (NCI). Clinical trials should be developed for frail and vulnerable patients who would not enroll on the standard phase III trials, as well as efforts need to be made to increase enrollment of fit older patients on standard phase III trials. As a result of this conference, panel members are working with the NCI and cooperative groups to address these knowledge gaps. With the aging population and increasing incidence of breast cancer with age, it is essential to study the feasibility, toxicity, and efficacy of cancer therapy in this at-risk population

Using ePrognosis to estimate 2-year all-cause mortality in older women with breast cancer: Cancer and Leukemia Group B (CALGB) 49907 and 369901 (Alliance A151503)

Tools to estimate survival, such as ePrognosis (http://eprognosis.ucsf.edu/carey2.php), were developed for general, not cancer, populations. In older patients with breast cancer, accurate overall survival estimates would facilitate discussions about adjuvant therapies

Importance of highly selective LC–MS/MS analysis for the accurate quantification of tamoxifen and its metabolites: focus on endoxifen and 4-hydroxytamoxifen

The antiestrogenic effect of tamoxifen is mainly attributable to the active metabolites endoxifen and 4-hydroxytamoxifen. This effect is assumed to be concentration-dependent and therefore quantitative analysis of tamoxifen and metabolites for clinical studies and therapeutic drug monitoring is increasing. We investigated the large discrepancies in reported mean endoxifen and 4-hydroxytamoxifen concentrations. Two published LC–MS/MS methods are used to analyse a set of 75 serum samples from patients treated with tamoxifen. The method from Teunissen et al. (J Chrom B, 879:1677–1685, 2011) separates endoxifen and 4-hydroxytamoxifen from other tamoxifen metabolites with similar masses and fragmentation patterns. The second method, published by Gjerde et al. (J Chrom A, 1082:6–14, 2005) however lacks selectivity, resulting in a factor 2–3 overestimation of the endoxifen and 4-hydroxytamoxifen levels, respectively. We emphasize the use of highly selective LC–MS/MS methods for the quantification of tamoxifen and its metabolites in biological samples

Abstract P5-10-13: Pre-surgical plasma microRNA pattern defines a biologically distinct triple negative breast cancer (TNBC) occuring in black (B) compared to white (W) women.

Abstract Background: Black women with triple negative breast cancer have 46% lower survival rates; this may be due to differences in tumor biology. We analyzed presurgical plasma microRNA of white (W) and black (B) women with TNBC enrolled in the breast ovarian tissue bank to detect if differences in the pre-surgical plasma microRNA could be detected in B patients relative to W patients relative to healthy controls. Aims: MicroRNA in pre-surgical plasma of TNBC W or B was compared to plasma from controls race and age matched controls to assess if differences in plasma and tumor microRNA may explain the survival disparity observed in B. We addressed 2 questions 1) are the patterns in the pre-surgical miRNA profiles different between W and B patients, differences that could explain outcomes discrepancy? 2) What are the miRs changes in patients W or B relative to healthy controls? Methods: Between 2004 and 2011 plasma miRNAs was measured before, after surgery, during and after chemotherapy in 73 surgical breast cancer patients and 11 age and race matched controls. We also analized miRs in the tumor and benign adjacent breast in 5 specimes. Samples were analyzed using qRT-PCR in the ABI's TaqMan OpenArray Panel for 750 miRs. Samples were spiked with ath-miR-159a and hsa-miR-320 most strongly correlated in its expression to ath-miR-159a through the Pearson correlation coefficient. 2-sample t-test was used for comparisons between means and ANOVA followed by post-hoc test to compare the mean response between subject factors of interest. All tests were 2-tailed; statistical significance was set at p &amp;lt; 0.05. Results: 44 W and 23 B, mean age at surgery 48 years (range 35–78) and 11 controls – mean age 44 years (range 35–67). Black TNBC patients did not express over 70 % of pre-surgical plasma miRs present in the W pre-surgical plasma. B over-expressed high levels of miR-1244, -190 and -638, which were not detected in any of the W patients (p &amp;lt; 0.005). W patients and controls expressed miRs10a, -190, -502-3p, -548, and -9* not detected in B TNBC patients. White patients over-expressed over 80% of plasma miRs present in controls, while black patients over-expressed only 30% of miRs present in controls (P &amp;lt; 0.005). Conclusions: Patterns of pre-surgical miR expression are different in B versus W patients with TNBC. In B the presence of TNBC leads to silence in circulating plasma miRs in comparison to W and controls. In W the presence of the tumor increases the miR “chatter”. Black patients have a different “communication” style between host-TNBC when analyzed by the response of plasma microRNA. This difference may call for different treatment protocols for patients. Specific treatment interventions, such as administration of chemotherapy before surgery, in an attempt to increase the microRNA levels in plasma may improve the outcomes of black patients with TNBC. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-10-13.</jats:p