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 Three of the 46 patients in the TOR120 arm were not received treatment, 2 patients having withdrawn from the trial by their preference and one having been dropped due to administration of another SERM.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.

Intestinal absorption and biliary elimination of glycyrrhizic acid diethyl ester in rats

Background

The purpose of this study was to evaluate absorption and elimination from the gastrointestinal tract of glycyrrhizic acid diethyl ester (GZ-DE) which was prepared as a prodrug of glycyrrhizic acid (a poorly absorbed compound) in rats.

Methods

After the GZ-DE solution was administered via the intravenous, intraduodenal, intraileal, and stomach routes, GZ-DE and GZ concentrations in bile were determined by high-performance liquid chromatography. The stability of GZ-DE was estimated from residual GZ-DE and GZ produced in GZ-DE solutions prepared with distilled water, a pH 1.2 solution, 0.9% NaCl solution, and phosphate-buffered solution (pH 7.4) at 37°C.

Results

GZ-DE was eliminated into bile by the pharmacokinetic parameters of apparent distribution rate constant (4.56 ± 0.36 per hour) and apparent elimination rate constant (0.245 ± 0.042 per hour). After intravenous and intraduodenal administration of GZ-DE, the concentration ratio of GZ-DE to GZ in bile was approximately 4:1, and the bioavailability of GZ containing GZ-DE was three-fold higher compared with the bioavailability of GZ after intraduodenal administration. GZ-DE was immediately precipitated in pH 1.2 solution and was converted to GZ by hydrolysis in pH 7.4 solution.

Conclusion

Improvement of intestinal absorption of GZ was made possible by administration of GZ-DE into the intestine where absorption of GZ is lower than in the strong acidic environment of the stomach. However, because the elimination rate in bile simulated from kinetic parameters of GZ-DE was higher than the conversion rate from GZ-DE to GZ by hydrolysis, it is thought that the availability of GZ as a revolutionary prodrug was not high from the viewpoint of bioavailability of GZ in the liver by intestinal administration of GZ-DE.

[Features of PHITS and its application to medical physics]

PHITS is a general purpose Monte Carlo particle transport simulation code to analyze the transport in three-dimensional phase space and collisions of nearly all particles, including heavy ions, over wide energy range up to 100 GeV/u. Various quantities, such as particle fluence and deposition energies in materials, can be deduced using estimator functions "tally". Recently, a microdosimetric tally function was also developed to apply PHITS to medical physics. Owing to these features, PHITS has been used for medical applications, such as radiation therapy and protection.

Abstract P2-14-03: “Ethinylestradiol” is beneficial for postmenopausal advanced breast cancer patients heavily pre-treated with endocrine agents

Purpose and Methods: Estrogen deprivation therapy using aromatase inhibitors is a standard therapy in postmenopausal hormone-dependent breast cancer. Paradoxically, low-dose estradiol was reported to be beneficial for the postmenopausal patients who have been heavily pre-treated with long-term sequential anti-estrogen therapies. To determine efficacy and safety of ethinylestradiol (3mg/day oral), a phase 2 study has been performed for the postmenopausal patients with advanced or recurrent breast cancer who became resistant to sequential endocrine treatments. The primary endpoint was clinical benefit rate, secondary were safety, objective response rate and time to progression. The interim data will be reported because of the extremely beneficial results.

Results: Eighteen cases with ER-positive tumor which showed resistance to previous sequential-endocrine therapies including SERMs and/or aromatase inhibitors were registered from Oct 2010 to May 2012. Their mean age was 62 years-old and the mean observation time was 9.2 months. Nine cases were evaluated as partial response, 1 case as long NC, 3 cases as stable disease, and another 2 cases as progressive disease. In three cases of all 18 cases, the estradiol administration was withdrawn within 1 week with their early endocrine-related symptoms, such as nausea, general fatigue and fever. Duration of effect in the case of the PR (including the 4 ongoing cases) was more than 24 weeks. All of 9 responders had high ER expression in the primary or metastatic tumor and had a history of long-term endocrine therapies in metastatic setting and had response to previous endocrine therapies. Serum estradiol levels elevated as 30–100pg/mL, and FSH was suppressed below premenopausal levels in 4 weeks later administration. Although the weight gain, irregular vaginal bleeding, or endometrial thickening was observed in patients treated with long-term treatment, there was no severe adverse event, such as deep venous thrombosis or other malignancies in this series.

Discussion: The mechanism of low-dose estrogen treatment can be considered the estrogen-induced apoptosis. The high ER expression and the response to previous endocrine therapies might be recognized as predictive factor of this treatment. This low-dose estrogen therapy may contribute to overturn the common sense of the endocrine therapy for breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-14-03.

Abstract P1-12-01: Evaluation on efficacy and safety of capecitabine plus docetaxel versus docetaxel monotherapy in metastatic breast cancer patients pretreated with anthracycline: Results from a randomized phase III study (JO21095)

Introduction: A previous large-scale phase III study demonstrated that, compared with docetaxel (T) alone, capecitabine (X) and T in combination (XT) offered significantly superior progression free survival (PFS) and overall survival (OS) in metastatic breast cancer (MBC). However, XT increased Grade 3/4 adverse events (AEs) which led to more frequent dose reductions than with T alone. Optimal dose of XT in Japanese was examined in a phase Ib study. Based on the background, we conducted a phase III randomized study in Japanese HER2 negative MBC patients pre-treated with anthracycline to compare efficacy and safety of XT therapy and T therapy.

Methods: Eligible pts were HER2-negative MBC pts with anthracycline-pretreatment, a measurable tumor, and ECOG performance status of 0 or 1. Pts were randomly assigned to the XT group or the T→X group. The XT group received concurrent therapy of X (1650 mg/m2/day from day 1 to 14) and T (60 mg/m2) in 3-week cycle. The T→X group received sequential therapy of T (70 mg/m2) in 3-week cycle followed at disease progression by X (2500 mg/m2/day from day 1 to 14 followed by 1-week rest). Primary endpoint was PFS. Secondary endpoints were OS, overall response rate (ORR), time to treatment failure (TTF), safety, and quality of life. The XT group and the T phase of the T→X group (T group) were compared in our evaluation.

Results: Of 163 pts enrolled, 156 were eligible. Baseline characteristics of all pts in each group were well balanced. The median delivered dose was 79.0% and 95.1% of the planned dose respectively for X and T in the XT group, and it was 97.2% in the T group. Median PFS in the XT group was 10.5 months compared to 9.8 months in the T group (hazard ratio [HR], 0.62; 95% confidence interval [CI], 0.40–0.97). The ORR was 70% and 61%; the median TTF was 9.6 months and 7.0 months in the XT group and the T group, respectively. Median OS has not been reached yet. Subgroup analysis showed PFS was longer in pts with liver metastasis (HR, 0.39; 95% CI, 0.19–0.84) and in pts with lung metastasis (HR, 0.43; 95% CI, 0.21–0.90) in the XT group. Incidence of treatment related AEs (TR-AEs) ≥Grade 3 was 74.4% (61 pts) in the XT group and 76.3% (61 pts) in the T group. Frequently reported TR-AEs ≥Grade 3 were; decrease in neutrophil count (XT, 57.3%; T, 60.0%), neutropenia (XT, 8.5%; T, 12.5%) and febrile neutropenia (XT, 6.1%; T, 10.0%). TR-AE ≥Grade 3 in the XT group with incidence at least 5% higher than the T group was hand-foot syndrome (XT, 7.3%; T, 0%). On the other hand, TR-AEs ≥Grade 3 in the T group with incidence at least 5% higher than the XT group were fatigue (XT, 2.4%; T, 8.8%) and peripheral edema (XT, 1.2%; T, 6.3%).

Conclusion: The concurrent therapy of XT demonstrated significant improvement of PFS compared with T alone. Superior efficacy of XT therapy was reported as same as the previously reported study on XT versus T although the dose was lower in our study. Considering the efficacy and tolerability, we consider concurrent Japanease dose XT therapy is a preferable treatment for MBC pts with liver or lung metastasis.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-12-01.

Abstract P6-05-06: Serum estradiol levels in postmenopausal ER+/PR- breast cancer are lower than those in postmenopausal ER+/PR+

(Background) Activation of growth factor receptor (GFR) signaling is related with ER+/PR- breast cancer (BC). Proportion of ER+/PR- phenotype in ER+ BC in postmenopausal patients is higher than that in premenopausal. However, this phenomenon cannot be explained by only GFR signaling activation. We hypothesized that ER+/PR- phenotype in postmenopausal patients has at least two subtypes, one is related with activation of GFR signaling and the other is related with suppression of PR expression due to low estrogenic stimulation.

(Purpose) The aim of this study is to clarify out hypothesis.

(Patients and methods) We measured serum E2 levels with radioimmuno assay (range of E2 levels: 1.3 to 50 pg/ml) in 154 postmenopausal ER+ BC patients. Cut-off levels of ER and PR were used 10% or more expression in tumor cells. We analyzed the correlation between serum levels of E2 and clinicopathological factors including PR expression. We also examined the relationship between HER2 expression levels and ki67 labeling index in ER+/PR- BC. In addition, we analysed the difference in ki67 LI between in premenopausal patients (n = 65) and in postmenopausal patients.

(Results) Median serum levels of E2 in ER+/PR+ phenotype (6.7 pg/ml) were significantly higher than in ER+/PR- phenotype (4.5 pg/ml)(p = 0.036). Serum levels of E2 was positively associated with body mass index (p = 0.01). However, there was no significant difference between serum E2 levels and other clinicopathological factors including tumor size, nodal status, nuclear grade, levels of ER expression and ki67 LI. In ER+/PR- phenotype, ki67 LI were varied (Median: 7.5%, range: 0.5 to 85%). Ki67 LI in Postmenopausal patients with ER+/PR- phenotype was significantly lower than that in premenopausal patients with ER+/PR- phenotype (p = 0.0022). Expression levels of HER2 was positively associated with ki67 LI(p = 0.002).

(Conclusions) ER+/PR- cancer in postmenopausal patients may have two types of phenotype. One is highly proliferative phenotype that is stimulated with GFR signaling. The other is low proliferative one that PR expression is suppressed by without sufficient estrogen supply. Serum levels of E2 might affect development of ER+ BC in postmenopausal women, especially in case of no activation of GFR signaling.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-05-06.

Three-dimensional visualization of composite fillings for dental identification using CT images

OBJECTIVES

This study aimed to discriminate between enamel and composite resins by differences in Hounsfield units shown on 16 section multidetector CT (MDCT) images taken of unidentified bodies.

METHODS

First, we determined the Hounsfield units of composite resins in 15 extracted human teeth. We then filled a single cavity prepared in each of the teeth with one of five different types of composite resins, and scanned the teeth using our routine post-mortem CT protocol for the head and neck. Obtained data were transferred to a radiological workstation and reconstructed. Furthermore, post-mortem CT images of the head of three unidentified bodies were reconstructed in the same manner.

RESULTS

Four types of composite resins containing radio-opaque fillers showed a constant value of 4000 HU, and one radiolucent composite resin showed values in the range of 660-800 HU in the extracted teeth. Pixels at 4000 HU indicated that the composite resins were selected and visualized as three-dimensional colour images. Composite resins could be visualized on reconstructed images of the three unidentified bodies, and the sites visualized matched those noted on the forensic dental charts.

CONCLUSIONS

Discriminating enamel and composite resins containing radio-opaque materials was difficult because of their similar Hounsfield unit values. However, we did succeed in visualizing the composite resins despite limitations of the CT scale. CT reconstructed images can contribute to dental identification, particularly in cases where it is difficult to detect composite resins on external investigation, and these images can be prepared during routine dental identification work.

Systematic measurement of lineal energy distributions for proton, He and Si ion beams over a wide energy range using a wall-less tissue equivalent proportional counter

The frequency distributions of the lineal energy, y, of 160 MeV proton, 150 MeV/u helium, and 490 MeV/u silicon ion beams were measured using a wall-less tissue equivalent proportional counter (TEPC) with a site size of 0.72 µm. The measured frequency distributions of y as well as the dose-mean values, y(D), agree with the corresponding data calculated using the microdosimetric function of the particle and heavy ion transport code system PHITS. The values of y(D) increase in the range of LET below ~10 keV µm(-1) because of discrete energy deposition by delta rays, while the relation is reversed above ~10 keV µm(-1) as the amount of energy escaping via delta rays increases. These results indicate that care should be taken with the difference between y(D) and LET when estimating the ionization density that usually relates to relative biological effectiveness (RBE) of energetic heavy ions.

P1-09-04: A Genetic Predictor for Breast Cancer Risk in a Japanese Population

Objective Genome-wide association studies (GWASs) have identified genetic variants associated with breast cancer. Most GWASs to data were conducted in women with European background and the extent to which these variants contribute as predictors of breast cancer among Japanese population is unknown.

Methods We analyzed 24 genetic variants that have been identified in previous GWASs and conducted a case-control study with 697 cases and age- and menopausal status- matched 1394 controls in the framework of the Hospital-based Epidemiologic Study at Aichi Cancer Center (HERPACC). All subjects were asked to provide information on lifestyle factors and blood samples for genetic studies. We fit conditional regression models with genetic variants and conventional risk factors including age, age at menarche, menopausal status, current body-mass-index, age at first live birth, regular exercise, family history of breast cancer, and referral pattern to our hospital. In addition, we created a polygenetic risk score, using the single nucleotide polymorphisms (SNPs) with statistically significant association with the breast cancer risk to measure the cumulative effect of multiple genetic risk variants. Furthermore, we evaluated the prediction model that included conventional risk factors by comparing with and without the genetic risk score, using c statistic.

Results Eleven SNPs (FGFR2-rs2981579, rs2981578, rs1219648, rs2420946, rs2981582, TOX3/TNRC9-rs8051542, rs3803662, LOC643714-rs4784227, C6orf97-rs2046210, 8q24-rs13281615, SLC4A7-rs4973768) revealed significant associations with breast cancer risk (each P < 0.05 in either per allele, dominant, or recessive model). A dose-dependent association was observed between the risk of breast cancer and the genetic risk score, which is an aggregate measure of the alleles in 7 selected variants; rs2981579, rs3803662, rs2046210, rs13281615, rs4973768, rs3817198 and rs10931936. Compared to women with scores of 3 or less, odds ratios (ORs) for women with scores of 4–5, 6–7, 8–9 and 10 or more were 1.33 (95% confidence interval, 1.00 - 1.80), 1.71 (1.26 - 2.30), 3.01 (1.97 - 4.58) and 8.69 (2.74 - 27.5), respectively (Ptrend < 0.001). The ORs for premenopausal women with the corresponding risk scores were 1.71 (1.12 - 2.63), 1.79 (1.15 - 2.78), 3.70 (1.98 - 6.93), and 14.0 (3.30–59.5), respectively, and those for postmenopausal women with the corresponding risk scores were 1.09 (0.72 - 1.66), 1.71 (1.12 - 2.61), 2.60 (1.44 - 4.71), 3.75 (0.57 - 24.4), respectively, compared to those with scores of 3 or less (each Ptrend < 0.001). The c statistic for a model including the genetic risk score in addition to the conventional risk factors was 0.633, whereas 0.602 without it (P < 0.001). Population-attributable fraction of the risk score was 33.8%.

Conclusion we identified a genetic predictor of breast cancer in a Japanese population. A risk model including genetic risk score may be useful to distinguish women at high-risk of breast cancer from those at low-risk, particularly in the context of targeted prevention.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-09-04.

P3-03-01: Low Expression of microRNA-210 Is an Independent Good Prognostic Factor in Japanese Triple-Negative Breast Cancer Patients

Background: microRNAs (miRNAs) have emerged as a new class of non-coding genes involved in regulating cell proliferation, differentiation, and viability. Recent studies have identified miR-210 among a set of hypoxia-regulated miRNAs and demonstrated a direct regulatory role of hypoxia-inducible factor-1 alpha (HIF-1 a) in its transcription. High expression of miR-210 has been reported to be a poor prognostic factor in several types of cancers including breast.

Materials and Methods: TaqMan MicroRNA assays for miR-210 expression were performed in 219 breast cancers (58 triple-negative (TNBCs), and 161 ER-positive and HER2−negative). Correlations between miR-210 expression and clinicopathological factors were analyzed. The effects of several variables on survival were tested by Cox proportional hazards regression analysis.

Results: miR-210 expression in TNBCs was significantly higher than in ER-positive and HER2−negative breast cancers (p<0.001). Patients whose TNBCs had low miR-210 expression experienced significantly better disease-free and overall survival compared with high miR-210 expressors (p=0.02 and p=0.05, respectively). Notably, among 40 node-negative TNBCs, 5-year disease-free survival was approximately 60% in patients whose tumors had high or intermediate miR-210 expression (n=26), while no patients with low miR-210 expression (n=14) suffered recurrent disease. Cox univariate and multivariate analyses demonstrated that low expression of miR-210 was an independent good prognostic factor in TNBCs.

Evidence-based therapy according to the guideline for gastric ulcers is cost-effective in Japan

Helicobacter pylori (H. pylori) infection is a major cause of gastric ulcers (GU) and eradication of the infection controls the ulcer with no requirement for maintenance therapy. In Japan, an evidence-based guideline (GL) was first published in 2003 (1(st) version) and then again in 2007 (2(nd) version) with a minor revision under support of the Japanese Ministry of Health, Labor and Welfare (GUGLJ). Adherence to its standards is high, estimated at 80%. GU patients aged 18 or older with active ulcers at the time of diagnosis by an endoscopic examination at National Hospital Organization (NHO) hospitals of Japan were enrolled between September 2004 and April 2005. Subjective and endoscopic outcome, medical treatments and medical costs during the following nine months were analyzed, retrospectively. As a result, 935 patients and 270 doctors in charge from 62 NHO hospitals were analyzed. Among H. pylori-positive GU patients, the endoscopic recurrence rate of 24 patients with failure of eradication was 29.2%, which was significantly higher than 8.8% of 194 patients with successful eradication. Successful eradication of H. pylori resulted in significantly lower endoscopic recurrence rates for GU patients either with or without administration of non-steroidal anti-inflammatory drugs (NSAID). GUGLJ adherence scores were significantly related to the specialty or knowledge on the GUGLJ of doctors in charge, and the total medical cost consumed. These results suggest that the therapy of GU along with an evidence-based GL is essential to implement cost-effective treatment and the GI experts or the doctors that understand the GUGLJ very well should perform it.

A phase II multi-center study of triple therapy with paclitaxel, S-1 and cisplatin in patients with advanced gastric cancer

OBJECTIVES

To carry out a phase II multi-center study on the efficacy and safety of triple combination therapy with paclitaxel, S-1, and cisplatin in patients with unresectable/metastatic gastric cancer.

METHODS

A total of 63 patients from 8 institutions were included in this study. Paclitaxel (160 mg/m²) was administered by infusion for 3 h on the first day. S-1 (70 mg/m²/day) was administered orally for 14 consecutive days from the first day. Cisplatin (60 mg/m²) was administered intravenously over 24 h on day 14 of every 28-day cycle.

RESULTS

All 63 patients were assessed for clinical efficacy and safety. A total of 259 cycles of treatment were administered (median 4, range 1-10). Grade 3-4 toxicities included neutropenia in 30.2%, thrombocytopenia in 12.7%, and anemia in 11.1%. There was no grade 3-4 non-hematological toxicity or treatment-related death. Complete response was observed in 6 patients and partial response in 34 patients. The overall response rate was 63.5%. The median progression-free survival and response duration were 8.0 and 8.8 months, respectively, and median survival time was 15 months.

CONCLUSIONS

Triple combination therapy with paclitaxel, S-1, and cisplatin showed promising safety and efficacy profiles with the potential to become a standard regimen for unresectable/metastatic gastric cancer.

Analysis of the effect of structural materials in a wall-less tissue-equivalent proportional counter irradiated by 290 MeV u(-1) carbon beam

Effects of structural materials in a wall-less tissue-equivalent proportional counter were evaluated based on the calculation of energy deposits by EGS5 and the measurement of lineal energy distributions using 290 MeV u(-1) carbon beams. It is found that the correction of measured data based on simulation is necessary for understanding the energy deposition spectra in the homogeneous condition in tissues.