Abstract P5-05-04: Relationship between plasma estradiol levels and estrogen-regulated gene expressions in premenopausal estrogen receptor-positive breast cancers

Background: Estrogen receptor (ER) and progesterone receptor (PgR) expression status in breast cancer are important factors in determining the use of adjuvant therapy. Plasma estradiol (E2) and progesterone vary markedly through the menstrual cycle. Recently, the levels of PgR expression were reported to be correlated with E2 at the time of surgery in Caucasian premenopausal breast cancer patients. Materials and methods: In this study, plasma E2 levels at surgery were examined for correlations with expressions of estrogen-regulated genes (ERGs), including PgR, and proliferation genes in 147 Japanese premenopausal ER-positive breast cancers. Plasma E2 and progesterone, FSH, and LH were measured on the day of surgery by ECLIA and mRNA expressions were analyzed for 4 ERGs (PgR, GREB1, TFF1, PDZK1), 2 progesterone-regulated (RANKL, cyclin D1) and 2 proliferation genes (MKI67, BIRC5) by RT-PCR using the TaqMan system. ER and PgR protein expression levels were estimated by immunohistochemistry. Results: Our results revealed that expressions of PgR mRNA and protein in breast cancer tissues were significantly correlated with plasma E2 levels at surgery (p = 0.005, p = 0.0165, respectively). Other ERGs were also significantly correlated with plasma E2 levels. However, there were no correlations between mRNA expressions of proliferation genes, MKI67 and BIRC5, and plasma E2 levels. Furthermore, mRNA expressions of the progesterone-regulated genes, RANKL and cyclin D1, were significantly correlated with PgR mRNA expression (p<0.0001, p<0.0001, respectively). Discussion: Significant correlations were seen in the expression of ERGs in Japanese ER-positive breast cancers according to the plasma E2 levels, which vary markedly through the menstrual cycle. Our results supported the previous report in Caucasian patients by other group. This variability may affect the interpretation of gene expression profiles incorporating ERGs such as the 21-gene recurrence score.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-05-04.

Abstract P1-14-01: Randomized controlled trial of toremifene 120 mg compared with exemestane 25 mg after prior non-steroidal aromatase inhibitor treatment in postmenopausal women with hormone receptor-positive metastatic breast cancer (Hi-FAIR ex study)

(Background) After the failure of a non-steroidal aromatase inhibitor (nsAI) for postmenopausal patients with metastatic breast cancer (mBC), it is uncertain which of endocrine therapy is the most appropriate.

(Methods) A randomized, open-label, multicenter phase II study was conducted to compare the efficacy and safety of daily toremifene 120 mg (TOR120), a selective estrogen receptor modulator, with exemestane 25 mg (EXE), a steroidal aromatase inhibitor. After disease progressed with assigned drug, the patients were subsequently treated with the other drug if patients were suitable for continuation with endocrine treatment. The primary endpoint was clinical benefit rate (CBR). The secondary end points were objective response rate (ORR), progression-free survival (PFS), overall survival (OS), toxicity and antitumor effect of subsequent endocrine treatment. To prove a probability of 90% that TOR120 was superior to EXE, 41 patients were required for each group. To account for dropouts and protocol violation, we planned to recruit 90 patients (45 in each group).

(Results) Initially, a total of 91women was registered in the study and randomly assigned to either TOR120 (n = 46) or EXE (n = 45) from October 2008 to November 2011. Three of the 46 patients in the TOR120 arm were not received treatment, 2 patients having withdrawn from the trial by their preference and one having been dropped due to administration of another SERM. When analyzed after a median observation period of 16.9 months, the intention-to-treat analysis showed that there was no statistical difference between TOR120 (n = 46) and EXE (n = 45) in terms of CBR (41.3% vs. 26.7%, p = 0.14), ORR (10.8% vs. 2.2%, p = 0.083), and OS (Hazard ratio (HR) 0.60, p = 0.22). The PFS of TOR120 was longer than that of EXE, the difference being statistically significant (HR 0.61, p = 0.045). Both treatments were well-tolerated with no severe adverse events, although the treatment of 3 of 43 women with TOR120 was stopped after a few days because of nausea, general fatigue, hot flash and night sweating. Twenty-four patients received subsequent TOR120 after failure of initial EXE treatment. Of these patients, ORR and CBR were 4.2% (1/24) and 33.3% (8/24), respectively. In 23 patients who received EXE after TOR120, ORR and CBR were 17.4% (4/23) and 30.4% (7/23), respectively.

(Conclusion) TOR120, as a subsequent endocrine therapy for mBC patients who failed non-steroidal AI treatment, could be equal to or potentially be more beneficial than EXE. In addition, about one third of patients who progress on either TOR120 or EXE could obtain clinical benefit from subsequent EXE or TOR120.

Trial registration number: UMIN000001841.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-14-01.

Ultrasound image-based endoscope localization for minimally invasive fetoscopic surgery

The purpose of this work is to introduce an ultrasound image-based intraoperative scheme for rigid endoscope localization during minimally invasive fetoscopic surgery. Positional information of surgical instruments with respect to anatomical features is important for the development of computer-aided surgery applications. While most surgical navigation systems use optical tracking systems with satisfactory accuracy, there are several operation limitations in such systems. We propose an elegant framework for intraoperative instrument localization that does not require any external tracking system but uses an ultrasound imaging system and a computation scheme based on constrained kinematics of minimally invasive fetoscopic surgery. Our proposed algorithm simultaneously estimates endoscope and port positions in an online sequential fashion with standard deviation of 1.28 mm for port estimation. Robustness of the port estimation algorithm against external disturbance was demonstrated by intentionally introducing artificial errors to measurement data. The estimation converges within eight iterations under disturbance magnitude of 30 mm.

Abstract P3-12-03: Combined targeting of HER2 and VEGFR2 for effective treatment of HER2-amplified breast cancer brain metastases

Brain metastases remain a serious obstacle in the treatment of patients with human epidermal growth factor receptor-2 (HER2)-amplified breast cancer. Unlike HER2-amplified breast tumors growing in extra-cranial locations, brain metastases do not respond well to HER2 inhibitors and are often the reason for treatment failure. One of the major challenges in studying brain metastases is the lack of preclinical models. We developed a HER2-amplified mouse model of brain metastasis using an orthotopic xenograft of BT474 cells in mice. As seen in patients, the HER2 inhibitors trastuzumab and lapatinib failed to contain brain metastatic tumor growth.

Based on previous findings from our laboratory suggesting a role of vascular endothelial growth factor (VEGF) in the resistance of HER2-overexpressing breast cancer brain metastases to trastuzumab, we combined HER2 inhibitors with the anti-VEGFR2 antibody DC101. The combination of either trastuzumab and DC101 or lapatinib and DC101 significantly slowed metastatic tumor growth in the brain, and resulted in a striking improvement in overall survival. The benefit is due largely to an anti-angiogenic effect. The combination of anti-HER2 and anti-VEGFR2 therapy reduced both the total and functional microvascular density in the brain metastatic tumors. Moreover, tumor tissues under combination therapy showed a marked increase in necrosis.

Preclinical and clinical evidence suggest that the combination of trastuzumab and lapatinib is superior to either agent alone – though this has never been tested in the brain metastatic setting. We consistently observed increased phosphorylation of HER2 in breast tumor cells growing in the brain compared with the mammary fat pad. In addition, while short-term lapatinib treatment significantly reduced HER2 activation in the brain, it could do so only to the level of that observed in the untreated mammary fat pad - and this effect disappeared over time. We hypothesized that more pronounced HER2 inhibition would be beneficial to these brain metastases with increased HER2 activation. We show here a significant growth delay with the combination of the two HER2 inhibitors compared with monotherapy. Moreover, we found a dramatic brain metastatic tumor growth delay in mice treated with both HER2 inhibitors, trastuzumab and lapatinib, and DC101. The triple combination prolonged overall survival 5 times longer than control-treated mice.

Brain metastasis from breast cancer is considered the “final frontier” of breast cancer research and treatment. Our findings support the clinical development of a three-drug regimen of trastuzumab, lapatinib and a VEGF pathway inhibitor for the treatment of HER2-amplified breast cancer brain metastases. While the anti-VEGF antibody bevacizumab in combination with trastuzumab and chemotherapy has shown some promise in HER2-positive metastatic breast cancer patient, there are no data on its efficacy in the context of brain metastases. A clinical trial is now recruiting patients to evaluate the efficacy of bevacizumab in breast cancer patients with active brain metastases, including its combination with trastuzumab in patients with HER2-positive disease. This trial may provide clinical evidence for the approach presented here.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-12-03.

Abstract P3-06-18: Increase of serum androgen and its metabolites in postmenopausal primary breast cancer patients with disease progression during neo-adjuvant exemestane treatment; JFMC 34–0601 TR

BACKGROUND: We reported a positive correlation between body mass index (BMI) and clinical response to neo-adjuvant hormonal therapy (NAH) with steroidal aromatase inhibitor, exemestane, in post-menopausal breast cancer patients (Takada M et al. Breast 2012). Here, we examined the relationship between serum concentrations of sex steroids and BMI, and explored their predictive value for clinical response.

PATIENTS AND METHODS: Among the 116 post-menopausal patients enrolled in the JFMC 34–0601 clinical trial of 24 weeks (wks) of NAH with exemestane, serums from 60 patients at pre-treatment, at 4wks and end of the treatment (24wks) were subjected to this study. Estradiol (E2), estrone (E1), dehydroepiandrosterone (DHEA), androstenedione (A-dione), 5-androstene-3β, 17β-diol (Aenediol), 5α-androstane-3β, 17β-diol (Aanediol) were measured using LC-MS/MS analysis and E1- sulfate (E1S) was by RIA.

RESULTS: There were no significant correlations between pre-treatment concentrations of sex steroids and BMI, except for moderate correlation of E2 and BMI (p = 0.004). In multivariate analysis, E1 was an independent predictive factor for objective response [odds 6.0, 95% confidence interval (CI) 1.5 — 34.6, p = 0.011], as well as BMI. All of the estrogens decreased to under-detection levels (0.5 for E1 and E2, 5 pg/assay for E1S) at 4 wks of treatment, and maintained through to the end of treatment in almost all patients independently of clinical response. The geometric mean percentage changes in androgens after NAH were: DHEA −0.2% (95%CI −15.3% — +17.6%) for patients without progressive disease (non-PD) and +44.8% (95%CI +22.1% — +71.8%) for patients with progressive disease (PD); A-dione −2.3% (95%CI −17.3% — +15.4%) for non-PD and +45.6% (95%CI +28.3% — +65.3%) for PD; Aenediol −11.5% (95%CI −20.6% — −1.4%) for non-PD and +24.9% (95%CI +1.9% — +53.0%) for PD; Aanediol +21.3% (95%CI −5.5% — +55.8%) for non-PD and +56.3% (95%CI +5.3% — +132.0%) for PD, respectively. The changes in the concentrations of both DHEA and A-dione in patients with PD were statistically significant (p = 0.008 and p = 0.002, respectively). In all of the PD patients, the serum concentrations of DHEA and A-dione were increased after NAH.

CONCLUSION: Pretreatment serum concentration of E1 was an independent predictive factor for clinical response to NAH with exemestane. Measurement of dynamics of the serum androgen concentrations might be helpful for monitoring treatment response, and mechanism of increase of androgens has a value for further investigation. Our results should be validated using a larger dataset. (UMIN ID; C000000345)

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-06-18.

Abstract P1-14-02: Preoperative docetaxel (T) with or without capecitabine (X) following epirubicin, 5-fluorouracil and cyclophosphamide (FEC) in patients with operable breast cancer (OOTR N003): Results of comparative study and predictive marker analysis

Objective: This preoperative study aimed to evaluate the efficacy of 4 cycles of TX compared with 4 cycles of T, following 4 cycles of FEC in operable breast cancer patients.

Methods: Women with operable breast cancer (T1C-3N0M0/T1-3N1M0) were randomly assigned to receive either T (75 mg/m2, q3) plus X (825 mg/m2 bid, days 1 to 14) or T alone (75 mg/m2, q3) after completion of FEC (5-fluorouracil 500 mg/m2, epirubicin 100 mg/m2, cyclophosphamide 500 mg/m2, q3). Patients who had disease progression on FEC were excluded from randomization. The primary endpoint was pathological complete response (pCR). Predictive factor analysis was conducted using clinicopathological markers such as hormone receptors, Ki67 labeling index (Ki67LI) and thymidine phosphorylase (TP).

Results: From November 2005 to October 2009, 504 patients were enrolled and 239 and 238 patients were assigned to TX and T group, respectively (median age 49 years, median tumor size 3.5 cm and node positive rate 56%). Treatment discontinuation was observed in 22% of TX group and 5% in T group (p < 0.0001). The major reasons for discontinuation were toxicity, refusal/ consent withdrawal and several others. No significant difference in pCR rate was shown between the two groups (TX 23% and T 24%, p = 0.748). Neither clinical response nor surgical outcome differed between TX and T. The pCR rate in patients who had therapy discontinuation or dose-reduction on TX was 23%, whereas pCR rate in those on T was 11%. A subpopulation treatment effect pattern plots method indicated a trend that TX may improve the pCR rate in patients having a middle range of pretreatment Ki67LI, such as 10%–20%. In the median follow-up time of 3.7 years, disease-free survival (DFS) was not different between TX and T (3-year DFS: 92% in TX and 91% in T; hazard ratio 0.907, 95%CI 0.528–1.557, p = 0.723). The frequency of major grade 3 or greater adverse events of TX and T were leukopenia, 36% and 34%, febrile neutropenia 8% and 5%, and hand-foot syndrome 15% and 2%, respectively.

According to the analysis for evaluating predictive values of biomarkers, a multivariate logistic regression analysis showed that HER2 (+/−: odds ratio 4.107, p < 0.0001), Ki67LI (continuous variables: 1.029, p = 0.003), hormone receptor status (+/−: 0.457, p = 0.009), stroma TP status (0.523, p = 0.02) and grade (1/3: 0.387, 2/3: 0.532, p = 0.047) had statistical significant values for predicting pCR. A multiple Cox model in landmark analysis showed that tumor size (p < 0.0001), cancer cell TP status (p = 0.005), pCR and posttreatment Ki67LI (p = 0.016), and age (p = 0.049) were associated with DFS significantly.

Conclusions: Addition of X to T showed no superiority to T alone following FEC in neoadjuvant treatment of these patients with operable breast cancer. Treatment discontinuation rate was significantly higher in TX than T group, however the pCR rate in patients in TX group who required treatment discontinuation or dose-reduction was similar to that in patients who completed as scheduled, which was different from T group. Determination of pre-/ post-treatment Ki67LI looks useful for predicting pCR and DFS.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-14-02.

Abstract P4-12-06: A mammographic density prediction model using environmental factors, endogenous hormones and growth factors in Japanese women

The incidence of breast cancer in Japanese women has doubled in all age groups over the past two decades, making it important to evaluate breast cancer risk factors in Japanese women. It is well known that mammographic density is positively associated with breast cancer risk in Western countries, and mammographic density is known to be affected by some environmental factors, serum hormones, and growth factors. We performed stepwise variable selection in a multiple regression model with fifteen independent variables as described below, based on the Akaike information criteria (AIC) to build a mammographic density prediction model using a dataset of 1191 women (913 women with breast cancer and 278 disease-free controls). The variables included were: environmental risk factors (body-mass index (BMI), age at menarche, pregnancy, age at first birth, breastfeeding, family history of breast cancer, age at menopause, use of hormone replacement therapy, alcohol intake and smoking), serum hormones and growth factors (estradiol, testosterone, prolactin, insulin-like growth factor 1 (IGF1) and IGF binding protein 3 (IGFBP3)) and mammographic density. The resulting prediction model is:

Mammographic density = + 0.000476 (IGF1) −0.0605 (testosterone) − 0.0508 (IGFBP3) − 0.00683 (age) − 0.0175 (BMI) + 0.00883 (age at menarche) − 0.0153 (breast feeding), (R2 = 0.336).

In this model, IGF1, testosterone, IGFBP3, age, BMI, age at menarche, and breastfeeding were considered to be important factors. IGF1 and age at menarche were positively associated with mammographic density, while on the other hand testosterone, IGFBP3, age, BMI, and breast feeding were negatively associated with mammographic density. Further studies are required to build a modified model incorporating serial measurements of serum hormones and growth factors to take into account time-dependent changes of serum hormones and growth factors, and to assess its accuracy.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-12-06.