Tamoxifen Metabolism and Efficacy in Breast Cancer: A Prospective Multicenter Trial.

Purpose: Levels of endoxifen, the most active metabolite of tamoxifen, vary by the highly polymorphic cytochrome P450 (CYP) 2D6 enzyme. We prospectively investigated tamoxifen efficacy by serum endoxifen levels and the tamoxifen activity score (TAS).Experimental Design: A prospective observational multicenter study included postmenopausal women with an estrogen receptor-positive breast cancer receiving first-line tamoxifen, 20 mg daily in the neoadjuvant or metastatic setting, recruited between February 2009 and May 2014. The primary endpoint was the objective response rate (ORR) using RECIST criteria 1.0. Secondary endpoints were clinical benefit (CB), progression-free survival (PFS), and tolerability of tamoxifen. The main analysis used logistic regression to relate ORR to serum endoxifen levels after 3 months. Endpoints were also related to other tamoxifen metabolites and to TAS.Results: Endoxifen levels were available for 247 of all 297 patients (83%), of which 209 with target lesions (85%). Median follow-up time for PFS was 32.5 months, and 62% progressed. ORR and CB were 45% and 84%, respectively. ORR was not related to endoxifen, and the OR of ORR was 1.008 per µg/L increase in endoxifen (95% confidence interval, 0.971-1.046; P = 0.56). In general, none of the endpoints was associated with endoxifen levels, tamoxifen metabolites, or TAS.Conclusions: Under the prespecified assumptions, the results from this prospective clinical trial do not suggest therapeutic drug monitoring of endoxifen to be of clinical value in postmenopausal women treated with tamoxifen for breast cancer in the neoadjuvant or metastatic setting. Clin Cancer Res; 24(10); 2312-8. ©2018 AACR.

Clinical and genetic risk factors for epirubicin-induced cardiac toxicity in early breast cancer patients.

Anthracycline-induced cardiotoxicity (ACT) is a well-known serious adverse drug reaction leading to substantial morbidity. The purpose of this study was to assess ACT occurrence and clinical and genetic risk factors in early breast cancer patients. In 6 genes of interest (ABCC1, ABCC2, CYBA, NCF4, RAC2, SLC28A3), 10 single nucleotide polymorphisms (SNPs) involved in ACT were selected based on a literature search. Eight hundred and seventy-seven patients treated between 2000 and 2010 with 3-6 cycles of (neo) adjuvant 5-fluorouracil, epirubicin and cyclophosphamide (FEC) were genotyped for these SNPs using Sequenom MassARRAY. Main outcome measures were asymptomatic decrease of left ventricular ejection fraction (LVEF) > 10 % and cardiac failure grade 3-5 (CTCAE 4.0). To evaluate the impact of these 10 SNPs as well as clinical factors (age, relative dose intensity of epirubicin, left-sided radiotherapy, occurrence of febrile neutropenia, and planned and received cycles of epirubicin) on decrease of LVEF and cardiac failure, we performed uni- and multivariable logistic regression analysis. Additionally, exploratory analyses including 11 additional SNPs related to the metabolism of anthracyclines were performed. After a median follow-up of 3.62 years (range 0.40-9.60), a LVEF decline of > 10 % occurred in 153 patients (17.5 %) and cardiac failure in 16 patients (1.8 %). In multivariable analysis, six cycles of FEC compared to three cycles received and heterozygous carriers of the rs246221 T-allele in ABCC1 relative to homozygous carriers of the T-allele were significantly associated with LVEF decline of > 10 % (OR 1.3, 95 % CI 1.1-1.4, p < 0.001 and OR 1.6, 95 % CI 1.1-2.3, p = 0.02). Radiotherapy for left-sided breast cancer was associated with cardiac failure (OR 3.7, 95 % CI 1.2-11.5, p 0.026). The other 9 SNPs and clinical factors tested were not significantly associated. In our exploratory analysis, no other SNPs related to anthracycline metabolism were retained in the multivariate model for prediction of LVEF decline. ACT in breast cancer patients is related to number of received cycles of epirubicin and left-sided radiotherapy. Additional studies should be performed to independently confirm the potential association between rs246221 in ABCC1 and LVEF.

Multivariable regression analysis of febrile neutropenia occurrence in early breast cancer patients receiving chemotherapy assessing patient-related, chemotherapy-related and genetic risk factors.

BACKGROUND: Febrile neutropenia (FN) is common in breast cancer patients undergoing chemotherapy. Risk factors for FN have been reported, but risk models that include genetic variability have yet to be described. This study aimed to evaluate the predictive value of patient-related, chemotherapy-related, and genetic risk factors. METHODS: Data from consecutive breast cancer patients receiving chemotherapy with 4-6 cycles of fluorouracil, epirubicin, and cyclophosphamide (FEC) or three cycles of FEC and docetaxel were retrospectively recorded. Multivariable logistic regression was carried out to assess risk of FN during FEC chemotherapy cycles. RESULTS: Overall, 166 (16.7%) out of 994 patients developed FN. Significant risk factors for FN in any cycle and the first cycle were lower platelet count (OR = 0.78 [0.65; 0.93]) and haemoglobin (OR = 0.81 [0.67; 0.98]) and homozygous carriers of the rs4148350 variant T-allele (OR = 6.7 [1.04; 43.17]) in MRP1. Other significant factors for FN in any cycle were higher alanine aminotransferase (OR = 1.02 [1.01; 1.03]), carriers of the rs246221 variant C-allele (OR = 2.0 [1.03; 3.86]) in MRP1 and the rs351855 variant C-allele (OR = 2.48 [1.13; 5.44]) in FGFR4. Lower height (OR = 0.62 [0.41; 0.92]) increased risk of FN in the first cycle. CONCLUSIONS: Both established clinical risk factors and genetic factors predicted FN in breast cancer patients. Prediction was improved by adding genetic information but overall remained limited. Internal validity was satisfactory. Further independent validation is required to confirm these findings.

Vitamin D status at breast cancer diagnosis: correlation with tumor characteristics, disease outcome, and genetic determinants of vitamin D insufficiency.

We correlated serum 25-hydroxyvitamin D(3) (25OHD) levels with tumor characteristics and clinical disease outcome in breast cancer patients and assessed the impact of genetic determinants of vitamin D insufficiency. We collected serum from 1800 early breast cancer patients at diagnosis, measured 25OHD by radioimmunoassay (RIA), and determined genetic variants in vitamin D-related genes by Sequenom. Multivariable regression models were used to correlate 25OHD levels with tumor characteristics. Cox proportional hazard models were used to assess overall survival (OS), disease-specific survival (DSS), and disease-free interval (DFI). Lower 25OHD serum levels significantly correlated with larger tumor size at diagnosis (P = 0.0063) but not with lymph node invasion, receptor status, or tumor grade. Genetic variants in 25-hydroxylase (CYP2R1) and vitamin D-binding (DBP) protein significantly determined serum 25OHD levels but did not affect the observed association between serum 25OHD and tumor size. High serum 25OHD (>30 ng/mL) at diagnosis significantly correlated with improved OS (P = 0.0101) and DSS (P = 0.0192) and additionally had a modest effect on DFI, which only became apparent after at least 3 years of follow-up. When considering menopausal status, serum 25OHD had a strong impact on breast cancer-specific outcome in postmenopausal patients [hazards ratios for 25OHD >30 ng/mL versus ≤30 ng/mL were 0.15 (P = 0.0097) and 0.43 (P = 0.0172) for DSS and DFI, respectively], whereas no association could be demonstrated in premenopausal patients. In conclusion, high vitamin D levels at early breast cancer diagnosis correlate with lower tumor size and better OS, and improve breast cancer-specific outcome, especially in postmenopausal patients.

A Novel Method (CiMON) for Continuous Intra-Abdominal Pressure Monitoring: Pilot Test in a Pig Model.

Background. Intravesical pressure (IAP(ivp)) measurement is considered to be the gold standard for assessment of intra-abdominal pressure (IAP). This study evaluated a new minimally invasive IAP monitoring device (CiMON) against three other devices in a wide range of clinically relevant IAP and in different body positions in healthy pigs. Methods. The CiMON catheter (IAP(CiM)) and another balloon-tipped catheter (IAP(spie)) were positioned into the stomach. Fluid-filled catheters were used for direct intraperitoneal (IAP(dir)) and IAP(ivp) measurement. Both in supine and 25° head-of-bed positions, IAP was increased from baseline to 30 mmHg. At every IAP level, 4 IAP measurements were recorded simultaneously. Mean differences and the limits of agreement were calculated. Results. Bias between IAP(CiM) and IAP(spie) was nearly zero with very good agreement, both in supine and 25° position. In supine position, IAP(CiM) slightly overestimated IAP(ivp) and IAP(dir) by 1.5 and 2.1 mmHg with reasonable agreement. In 25° position, IAP(CiM) underestimated IAP(ivp) and IAP(dir) by 1.0 and 0.5 mmHg, again with reasonable agreement. Conclusions. Agreement between IAP(CiM) and IAP(spie) was very good, while good-to-moderate agreement exists between IAP(CiM) and IAP(dir) or IAP(ivp). Simplicity, continuous monitoring, and the combination with a feeding tube should lead to further clinical studies, evaluating this new CiMON device.

Undetectable antimüllerian hormone levels and recovery of chemotherapy-induced ovarian failure in women with breast cancer on an oral aromatase inhibitor.

OBJECTIVE: Knowledge of the menopause status of a woman with breast cancer is important for good clinical practice. Long-lasting amenorrhea is frequent in this population, often for reasons other than definitive menopause. Antiestrogens like tamoxifen or oral aromatase inhibitors (AIs) may reactivate the ovary causing vaginal bleeding, menstruation, pregnancy, and unopposed endometrial stimulation. In contrast to tamoxifen, AIs are not active against breast cancer in the presence of functional ovaries. Antimüllerian hormone (AMH) is a potential marker of residual ovarian function that can predict not only the onset of menopause but also chemotherapy-induced amenorrhea (CIA) and fertility. We assess the value of AMH in women who recovered from CIA on an AI. METHODS: This is a series of six women with clinical and biochemical evidence of ovarian recovery during AI treatment. All six were premenopausal at breast cancer diagnosis and developed CIA. AMH, follicle-stimulating hormone, and estradiol levels were measured when patients developed clinical signs of ovarian recovery and/or when a gynecological procedure showed evidence of this. RESULTS: In all six AI-treated women, AMH levels were undetectable despite clinical, biochemical, or pathological evidence of ovarian reactivation after a long period of amenorrhea and sensitive biochemical markers indicating definitive menopause status. CONCLUSIONS: Repeated biochemical monitoring of ovarian function remains important in women with breast cancer undergoing AI treatment because ovarian function can recover, AIs are not active with functional ovaries, and amenorrhea does not, by itself, confirm definitive menopause. Undetectable AMH levels do not exclude residual ovarian function in women with breast cancer on an AI.

The impact of resuscitated fecal peritonitis on the expression of the hepatic bile salt transporters in a porcine model.

Sepsis is often associated with cholestatic liver dysfunction caused by changes in the expression profile of hepatic bile salt transporters. However, in rodent endotoxin models, the role of ischemic hepatitis caused by liver hypoperfusion cannot be delineated. We hypothesized that hepatocytes change their expression pattern of bile salt transporters during early severe sepsis despite adequate resuscitation. Fifteen anesthetized and instrumented pigs were randomized to either fecal peritonitis (n = 8) or control (n = 7). Resuscitation was performed by hydroxyethyl starch and norepinephrine infusion. Hemodynamic parameters and markers of cholestatic and ischemic hepatic dysfunction were recorded. At baseline and after 21 h, messenger RNA (mRNA) and protein expression of bile salt transporters was determined by quantitative real-time polymerase chain reaction and immunohistochemistry, respectively, on in vivo liver biopsies. All resuscitated septic pigs developed a normotensive hyperdynamic circulation with increased portal flow. After 21 h of peritonitis, no signs of biochemical or histological cholestasis were present. Na-taurocholate cotransporting polypeptide and bile salt export pump mRNA were downregulated by 83% (P = 0.001) and 67% (P = 0.001), respectively, in comparison with controls, whereas multidrug resistance-associated protein 4 (MRP4) mRNA was upregulated by 85% (P = 0.02). Bile salt export pump and MRP2 staining were downregulated in septic pigs. During early porcine fluid-resuscitated sepsis, hepatic basolateral influx (Na-taurocholate cotransporting polypeptide) and canalicular efflux (bile salt export pump) of bile salts were downregulated without hemodynamic signs of hepatic hypoperfusion or biochemical signs of cholestasis. In parallel, the basolateral escape transport (MRP4) was markedly upregulated, possibly as an early adaptive response to counteract hepatocellular accumulation of toxic bile acids.