The Japanese Breast Cancer Society Clinical Practice Guideline for systemic treatment of breast cancer, 2015 edition

Comparison of neoadjuvant and adjuvant chemotherapy for operable triple-negative breast cancer before the era of immune checkpoint inhibitors: A retrospective study from the Japanese National Clinical Database-Breast Cancer Registry

BACKGROUND

While neoadjuvant chemotherapy (NAC) is recommended for stage II-III triple-negative breast cancer (TNBC), its equivalence to adjuvant chemotherapy (AdjC) has been questioned based on a retrospective study using the National Cancer Database in the United States, which lacked adjustment for important covariates. Given the unlikelihood of new randomized trials being conducted, well-designed, large-scale, retrospective studies are needed.

PATIENTS AND METHODS

We retrospectively analyzed operable TNBC patients from the Japanese National Clinical Database- Breast Cancer Registry (2012-2016). Inclusion criteria were clinical stage I-IIIB, estrogen receptor (ER) < 10 %, progesterone receptor (PgR) < 10 %, and HER2-negative. We excluded patients with carcinoma in situ, cT4a/T4c/T4d, cN3, cM1, bilateral breast cancer, male, non-epithelial tumor, no chemotherapy, no surgery and no follow-up. Primary and secondary outcomes of overall survival (OS) and recurrence-free survival (RFS) were compared between NAC and AdjC using Cox proportional Hazard regression among the exact matched cohort based on age, BMI, cT, cN, histology, ER/PgR positivity, chemotherapy regimen, breast operative technique, radiotherapy, and institution size.

RESULTS

Among 9,000 AdjC and 5,520 NAC patients, 3,256 matched cases were compared. OS and RFS were significantly worse for patients with NAC (Hazard Ratio 1.45 (95 % confidence interval 1.26-1.68) and 1.33 (1.19-1.49), respectively), particularly in patients <65 years, with stage II-IIIB, and with invasive ductal carcinoma.

CONCLUSION

Patients with NAC had worse prognosis, possibly due to unadjusted confounders. Although the availability of immune checkpoint inhibitors (ICIs) limits the clinical impact, the result could provide supplemental insights for treatment decisions in patients who are not candidates for ICIs.

Retrospective study on the effectiveness of medroxyprogesterone acetate in the treatment of ER-positive/HER2-negative post-menopausal advanced breast cancer: an additional analysis of the JBCRG-C06 Safari study

BACKGROUND

Only old evidence exists to back up the use of medroxyprogesterone acetate. Therefore, this study aimed to explore the factors that influence the time to treatment failure of medroxyprogesterone acetate in real-world settings as late-line treatment.

METHODS

This was a cohort study that used the database of the Safari study on oestrogen receptor-positive post-menopausal advanced breast cancer (UMIN000015168). We created Kaplan-Meier curves for time to treatment failure with medroxyprogesterone acetate. Further, univariate and multivariate analyses were performed using a Cox hazard model of the clinicopathological factors involved in the time to treatment failure of medroxyprogesterone acetate.

RESULTS

From the 1031 patients in the Safari study, 279 patients were selected as the population for the analysis of effectiveness of medroxyprogesterone acetate monotherapy. In the analysis of medroxyprogesterone acetate by treatment line, the median time to treatment failure was 3.0 months for third-line treatment and 4.1 months for fourth and subsequent treatment lines. In cases where medroxyprogesterone acetate was used as a third-line or later endocrine treatment, multivariate analysis showed that the length of the disease-free interval was correlated with the length of time to treatment failure of medroxyprogesterone acetate (P = 0.004). With medroxyprogesterone acetate monotherapy as the fourth-line or later treatment, 20% of the patients achieved a time to treatment failure of 12 months or longer.

CONCLUSION

In actual clinical practice, patients treated with medroxyprogesterone acetate alone as the fourth or subsequent treatment lines showed a time to treatment failure of 4 months, suggesting that there is merit in using medroxyprogesterone acetate even in late treatment lines, especially in patients with long disease-free interval and those who are difficult to treat using other antineoplastic agents.

Pertuzumab retreatment for HER2-positive advanced breast cancer: a randomized, open-label phase III study (PRECIOUS)

No standard options existed for human epidermal growth factor receptor 2 (HER2)‐positive advanced breast cancer that progresses after second‐line trastuzumab emtansine therapy before 2020. The purpose of this study was to examine the efficacy of pertuzumab retreatment after disease progression following pertuzumab‐containing therapy for HER2‐positive locally advanced or metastatic breast cancer for the first time. This randomized, open‐label, multicenter phase III trial was undertaken in 93 sites in Japan. Eligible patients with HER2‐positive breast cancer who had received pertuzumab, trastuzumab, and chemotherapy as first‐ and/or second‐line therapy were randomly assigned (1:1) to: (i) pertuzumab, trastuzumab, and physician's choice chemotherapy (PTC), or (ii) trastuzumab and physician's choice chemotherapy (TC). The primary end‐point was investigator‐assessed progression‐free survival (PFS). Between August 1, 2015 and December 31, 2018, 219 patients were randomized to PTC (n = 110) or TC (n = 109). Median follow‐up was 14.2 months (interquartile range, 9.0–22.2), and median PFS was 5.3 months (95% confidence interval [CI], 4.0–6.6) with PTC and 4.2 months (95% CI, 3.2–4.8) with TC (stratified hazard ratio 0.76 [95% CI upper limit 0.967]; p = 0.022). Progression‐free survival was improved by adding pertuzumab in all prespecified subgroups. The PTC arm showed a trend towards better overall survival and duration of response, but similar objective response and health‐related quality of life. The incidence of treatment‐related adverse events was similar between groups except for diarrhea. Pertuzumab retreatment contributes to disease control for HER2‐positive locally advanced or metastatic breast cancer previously treated with pertuzumab‐containing regimens.

Factors associated with overall survival after recurrence in patients with ER-positive/HER2-negative postmenopausal breast cancer: an ad hoc analysis of the JBCRG-C06 Safari study

BACKGROUND

The Safari study (UMIN000015168) was a retrospective, multicenter study in which 1072 consecutive cases of estrogen receptor-positive advanced breast cancer treated using 500 mg fulvestrant were registered. We previously reported the relationship between the patient factors and overall survival after the diagnosis using the same cases and the same factors for the analysis of time to treatment failure in patients with estrogen receptor-positive advanced breast cancer. The current study is an ad hoc analysis that focused on the relationship between the patient factors and overall survival after recurrence by adding factors generally associated with overall survival after recurrence.

METHODS

The overall survival after recurrence in patients with estrogen receptor-positive human epidermal growth factor receptor 2 negative recurrent breast cancer was analyzed via univariate and multivariate analyses with a Cox proportional hazards model.

RESULTS

A total of 598 cases were used for the analysis of overall survival after recurrence. Multivariate analysis revealed that favorable overall survival (median, 6.4 years) was significantly correlated with long time from recurrence to fulvestrant use (≥3 years), low nuclear or histological grade (G3 vs. G1), long time to treatment failure of initial palliative endocrine therapy (≥12 months) and long time to initial palliative chemotherapy (≥2 years).

CONCLUSION

The results of this study indicate that sequential endocrine monotherapy may be a useful treatment option for patients with estrogen receptor-positive/human epidermal growth factor receptor 2 negative recurrent breast cancer who have been successfully treated with initial long-term palliative endocrine therapy.

A Nationwide Study on the Incidence of Breast Cancer in Korean Women with Osteoporosis Receiving Raloxifene Treatment

Purpose

Raloxifene is a selective estrogen receptor modulator (SERM), and raloxifene treatment for osteoporosis is reimbursable under the Korean National Health Insurance. Evidence suggests that SERMs use reduces the risk of breast cancer in Asian population. Herein, we retrospectively investigated the protective effect of raloxifene on breast cancer rates in Korean population.

Methods

Using the Health Insurance Review and Assessment Service database, we selected women with osteoporosis aged 50 years and above. Patients treated for at least 2 years with raloxifene were assigned to the user group, whereas the remaining patients were assigned to the non-user group. The effect on breast cancer risk was assessed using the Cox proportional-hazards model with a time-dependent covariate to adjust for immortal time bias.

Results

A total of 322,870 women who were registered between 2010 and 2011 were included. The user group comprised 0.7% (n = 2,307) of the total population. The mean age was 65.7 ± 8.0 years and 67.2 ± 8.6 years in the user and non-user groups, respectively (p < 0.001). There was no difference in the previous use of estrogen replacement between the 2 groups (p = 0.087). The incidence of breast cancer per 1,000 person-years was 0.49 (n = 8) and 0.68 (n = 1,714) in the user and non-user groups, respectively (hazard ratio [HR], 0.63, 95% confidence interval [CI], 0.32–1.27). HR decreased with increase in the treatment duration, but this change was not statistically significant (HR, 1.00, 95% CI, 0.32–3.11 in 2–3 years; HR, 0.63, 95% CI, 0.20–1.94 in 3–4 years; and HR, 0.41, 95% CI, 0.10–1.65 in 4–5 years).

Conclusion

Long-term treatment with raloxifene in women with osteoporosis was not significantly associated with a reduction in breast cancer rates. However, further investigation is required for a conclusive proof.

Trastuzumab deruxtecan in HER2-positive metastatic breast cancer and beyond

INTRODUCTION

Despite the substantial improvements made in human epidermal growth factor receptor 2 (HER2)-targeted therapies since the approval of trastuzumab more than 20 years ago, there is still considerable unmet need in patients with HER2-expressing breast cancer (BC) and other solid tumors. Trastuzumab deruxtecan (T-DXd) is a newer antibody-drug conjugate approved for the treatment of metastatic breast cancer (BC) and gastric cancer (GC) and is under active investigation in other solid tumors, including non-small cell lung cancer, colorectal cancer, and HER2-low tumors.

AREAS COVERED

The current treatment and investigational landscape of HER2-positive and HER2-low metastatic BC (mBC) and the preclinical and clinical trials investigating T-DXd. To identify relevant literature, a search was performed on English-language publications and congress abstracts.

EXPERT OPINION

T-DXd is likely to become the standard of care for second-line treatment of HER2-positive mBC, and it may play a role in the treatment of hormone receptor-positive and triple-negative mBC with HER2-low expression. Because it was recently approved in the United States and Japan to treat HER2-positive metastatic GC, it holds promise for the treatment of other HER2-positive solid tumors, including colorectal cancer, non-small cell lung cancer, and HER2-low BC.

The efficacy and safety of pertuzumab plus trastuzumab and docetaxel as a first-line therapy in Japanese patients with inoperable or recurrent HER2-positive breast cancer: the COMACHI study

PURPOSE

In the CLEOPATRA study of patients with human epidermal growth factor receptor 2 (HER2)-positive recurrent or metastatic breast cancer, the Japanese patient subgroup did not demonstrate the improved progression-free survival (PFS) of pertuzumab plus trastuzumab and docetaxel vs. placebo that was seen in the overall population. Therefore, COMACHI was conducted to confirm the efficacy and safety of this treatment regimen in this patient subgroup.

METHODS

This was a phase IV study of pertuzumab plus trastuzumab and docetaxel in Japanese patients with histologically/cytologically confirmed inoperable or recurrent HER2-positive breast cancer. All patients received pertuzumab, trastuzumab, and docetaxel intravenously every 3 weeks until disease progression/unacceptable toxicity. The primary endpoint was investigator-assessed PFS. Secondary endpoints were overall survival (OS), investigator-assessed objective response rate, and duration of response (DoR). Safety was also assessed.

RESULTS

At final analysis, median investigator-assessed PFS was 22.8 months (95% CI 16.9-37.5). From first dose, OS rate at 1 year was 97.7%; and at 2 and 3 years were 88.5% and 79.1%, respectively. Of the 118 patients with measurable disease at baseline, response rate was 83.9% (95% CI 77.3-90.5) and median investigator-assessed DoR was 26.3 months (95% CI 17.1-not evaluable). Treatment was well tolerated, with no new safety signals detected.

CONCLUSIONS

Our results suggest similar efficacy and safety for pertuzumab plus trastuzumab and docetaxel in Japanese patients compared with the overall population of CLEOPATRA, providing further support for this combination therapy as standard of care for Japanese patients with inoperable or recurrent HER2-positive breast cancer.

A Case of Pure Mucinous Breast Carcinoma in a 25-Year-Old Female Who Showed Complete Pathological Response to Neoadjuvant Chemotherapy despite Poor Clinical Response

Introduction

Mucinous breast carcinoma is a rare histologic subtype of primary breast cancers accounting for 1-6%. It is a rare histological variant in young patients and usually presents without lymph node involvement, and its pathological response to neoadjuvant chemotherapy is rarely reported.

Case Presentation

Pure mucinous breast carcinoma in a 25-year-old female was treated with neoadjuvant chemotherapy every 3 weeks for 8 cycles. After the fifth cycle, the mass size showed no change. We performed modified radical mastectomy in the left breast and axillary lymph node clearance. However, the pathological report showed a complete elimination of both the breast tumor and axillary lymph nodes, which were filled with mucus but did not contain malignant cells.

Discussion

Chemotherapy was profoundly effective against the tumor cells, but ineffective against large amounts of extracellular mucus. Even though the cancer cells were sensitive to chemotherapy, the volume of mucinous cancer couldnot be reduced.

Conclusion

In summary, the evaluation criteria of tumor response to chemotherapy based on maximum diameter only should be considered insufficient for mucinous carcinoma.

Population Pharmacokinetics of Trastuzumab Deruxtecan in Patients With HER2-Positive Breast Cancer and Other Solid Tumors

Trastuzumab deruxtecan (DS‐8201) is a human epidermal growth factor receptor 2 (HER2)–targeting antibody–drug conjugate with a novel enzyme‐cleavable linker, a topoisomerase I inhibitor payload, and a drug‐to‐antibody ratio of ≈ 8. We have characterized the population pharmacokinetics (PK) of trastuzumab deruxtecan and released drug (topoisomerase I inhibitor) in patients with HER2‐positive breast cancer or other solid tumor malignancies. This analysis includes pooled data from five clinical studies with 639 patients. Trastuzumab deruxtecan doses ranged from 0.8 to 8.0 mg/kg every 3 weeks. Serum concentrations of trastuzumab deruxtecan and released drug were analyzed using a sequential two‐step approach, with the nonlinear mixed‐effects modeling methods. Covariate assessment was based upon stepwise forward‐addition and backward‐elimination process, followed by both univariate and multivariate analysis quantifying their impact on steady‐state exposure of trastuzumab deruxtecan and released drug. A two‐compartment model with linear elimination best described PK profiles of intact trastuzumab deruxtecan, while a one‐compartment model with time‐varying release‐rate constant and linear elimination described released‐drug PK profiles. Statistically significant covariates (country, tumor size, sex, formulation, age, body weight, albumin, total bilirubin, and aspartate aminotransferase) resulted in < 20% change in steady‐state area under the concentration‐time curve of trastuzumab deruxtecan and released drug, except for increased body weight (95th percentile, 86 kg) and decreased albumin (5th percentile, 31 g/L). Analysis of patients stratified by country, race, renal function, and hepatic function found no clinically meaningful differences in steady‐state exposure of intact trastuzumab deruxtecan or released drug. Overall, results suggest that no dose adjustment based on tested covariates or in specific patient populations is warranted.

Multi-omics analyses identify HSD17B4 methylation-silencing as a predictive and response marker of HER2-positive breast cancer to HER2-directed therapy

HER2-positive breast cancers that achieve pathological complete response (pCR) after HER2-directed therapy consistently have good survival. We previously identified HSD17B4 methylation as a marker for pCR by methylation screening. Here, we aimed to identify a new marker by conducting a multi-omics analysis of materials prepared by laser capture microdissection, and adding 71 new samples. In the screening set (n = 36), mutations, methylation, and expression were analyzed by targeted sequencing, Infinium 450 K, and expression microarray, respectively, and 15 genes were identified as differentially expressed and eight genomic regions as differentially methylated between cancer samples with and without pCR. In a validation set (n = 47), one gene showed differential expression, and one region had differential methylation. Further, in the re-validation set (n = 55), all new samples, only HSD17B4 methylation was significantly different. The HSD17B4 methylation was at the transcriptional start site of its major variant, and was associated with its silencing. HSD17B4 was highly expressed in the vast majority of human cancers, and its methylation was present only in breast cancers and one lymphoblastic leukemia cell line. A combination of estrogen receptor-negative status and HSD17B4 methylation showed a positive predictive value of 80.0%. During HER2-directed neoadjuvant therapy, HSD17B4 methylation was the most reliable marker to monitor response to the therapy. These results showed that HSD17B4 methylation is a candidate predictive and response marker of HER2-positive breast cancer to HER2-directed therapy.

The Japanese Breast Cancer Society Clinical Practice Guidelines for systemic treatment of breast cancer, 2018 edition

Purpose

We present the English version of The Japanese Breast Cancer Society (JBCS) Clinical Practice Guidelines for systemic treatment of breast cancer, 2018 edition.

Methods

The JBCS formed a task force to update the JBCS Clinical Practice Guidelines, 2015 edition, according to Minds Handbook for Clinical Practice Guideline Development 2014. First, we set multiple outcomes for each clinical question (CQ). Next, quantitative or qualitative systematic review was conducted for each of the multiple outcomes, and the strength of recommendation for the CQ was taken into consideration during meetings, with the aim of finding a balance between benefit and harm. Finalized recommendations from each session were confirmed through discussion and voting at the recommendation decision meeting.

Results

The recommendations, the strength of recommendation and the strength of evidence were determined based on systemic literature reviews and the meta-analyses for each CQ.

Conclusion

The JBCS updated the Clinical Practice Guidelines for systemic treatment of breast cancer.

Electronic supplementary material

The online version of this article (10.1007/s12282-020-01085-0) contains supplementary material, which is available to authorized users.

Radiogenomics of magnetic resonance imaging and a new multi-gene classifier for predicting recurrence prognosis in estrogen receptor-positive breast cancer: A preliminary study

To examine the correlation of qualitative and quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) results with 95-gene classifier or Curebest 95-gene classifier Breast (95GC) results for recurrence prediction in estrogen receptor-positive breast cancer (ERPBC).This retrospective study included 78 ERPBC patients (age range, 24-74 years) classified into high- (n = 33) and low- (n = 45) risk groups for recurrence based on 95GC and who underwent DCE-MRI between July 2006 and November 2012. For qualitative evaluation, mass shape, margin, and internal enhancement based on BI-RADS MRI lexicon and multiplicity were determined by consensus interpretation by 2 breast radiologists. For quantitative evaluation, mass size, volume ratios of the DCE-MRI kinetics, and both the kurtosis and the skewness of the intensity histogram for the whole mass in the initial and delayed phases were determined. Differences between the 2 risk-groups were analyzed using univariate logistic regression analyses and multiple logistic regression analyses. Receiver-operating characteristic curve cut-off values were used to define the groups.As for the qualitative findings, the difference between the 2 groups was not significant. For the quantitative data, the volume ratio of "medium" in the initial phase differed significantly between the 2 groups (P = .049). The volume ratio of "medium" (P = .006) and of "slow-persistent" (P = .005), and the delayed phase kurtosis (P = .012) in the univariate logistic regression analyses, and in the multiple logistic regression, volume ratio of "medium" >38.9% and delayed phase kurtosis >3.31 were identified as significant high-risk indicators (odds ratio, 5.83 and 3.55; 95% confidence interval, 1.58 to 21.42 and 1.24 to 10.15; P = .008 and P = .018, respectively).A high volume ratio of "medium" in the initial phase and/or high kurtosis in the delayed phase for quantitative evaluation could predict high ERPBC recurrence risk based on 95GC.

Detection of Nonpalpable Tiny Axillary Lymph Nodes Surrounded by Adipose Tissue Using a Near-Infrared Camera

Background: It is not always possible to detect nonpalpable small lymph nodes (LNs) surrounded by adipose tissue under the wavelength of visible light. A newly developed near-infrared camera with InGaAs element was able to capture photographs using light at >1000-nm wavelength, at which the difference in absorbance between water and lipids is large. This study investigated the ability to detect nonvisible small LNs using light at 1300-nm wavelength. Methods and Results: Following retrieval of LNs through axillary LN dissection from 20 patients with breast cancer, residual specimens were simultaneously photographed using light at 970-, 1070-, 1200-, 1300-, 1450-, and 1600-nm wavelengths. A total of 45 specimens were observed pathologically at the selected portions in which the 1300-nm light was absorbed (high absorbance group [HA group], n = 25) and those in which the 970-nm light was absorbed instead (low absorbance group [LA group], n = 20). All specimens categorized in the HA group detected the LNs, whereas none of those categorized in the LA group detected an LN. The sensitivity and specificity in the identification of an LN were 1.0. The LNs detected using this camera were significantly smaller than those detected by surgeons (3.00 ± 2.93 mm vs. 5.90 ± 3.91 mm, p < 0.01). Discussion: The light at 1300-nm wavelength was absorbed by axillary LNs. This camera detected LNs that were undetectable by surgeons. This novel technology may be applied to lymphatic microsurgery and contribute to the development of a minimally invasive LN dissection method.

Oncoplastic breast-conserving surgery using chest wall perforator flaps: Three-dimensional quantitative analysis of the percentage of breast volume excised and changes over time in flap volume

BACKGROUND AND OBJECTIVES

We investigated the effects of oncoplastic breast-conserving surgery (BCS) using chest wall perforator flaps (CWPFs) on the subsequent expected deformity and evaluated the longevity of flap volume.

METHODS

We retrospectively reviewed oncological and cosmetic outcomes of 33 women who had undergone the above procedure. We calculated the percentage of breast volume excised (PBVE) from computed tomography volumetry and compared it between a historical BCS alone and the study (flap) group. We also sequentially evaluated flap volumes by magnetic resonance imaging volumetry.

RESULTS

Oncoplastic BCS using 25 lateral flaps and eight inferior flaps, depending on the site of the defect, was performed; mean PBVEs were 31.1% and 19.0%, respectively. No local and two distant recurrences occurred in a median follow-up of 61 months. PBVE was 2.6 times larger in the flap than in the BCS alone group. Over half the patients in the BCS alone group had poor cosmetic results when PBVE exceeded 15%, whereas patients in the flap group achieved good cosmetic results with PBVE >25%. In most patients, 80% of flap volume was maintained 5 years after surgery.

CONCLUSIONS

CWPF improves cosmetic outcomes in patients with predicted deformity after BCS alone and maintains its volume for at least 5 years.

Ovarian hyperstimulation closely associated with resumption of follicular growth after chemotherapy during tamoxifen treatment in premenopausal women with breast cancer: a multicenter retrospective cohort study

Background

We previously reported that tamoxifen (TAM)-induced ovarian hyperstimulation (OHS) is associated with high serum concentrations of estradiol in premenopausal women with breast cancer. To investigate risk factors for TAM-induced OHS, we performed a retrospective multicenter study.

Methods

Premenopausal patients who received surgical therapy for endocrine-dependent breast cancer (n = 235) were recruited in this study and classified into 4 groups: group A, treated with TAM alone; group B, TAM treatment after 2-year-combined therapy with a gonadotropin-releasing hormone (Gn-RH) agonist; group C, TAM treatment after chemotherapy; group D, 5-year-combined therapy with TAM and a Gn-RH agonist. A serum estradiol value of more than 300 pg/mL or mean follicular diameter of more than 30 mm was defined as OHS.

Results

The incidence of OHS in group A (n = 13/26, 50.0%) was significantly higher than those in group B (n = 17/63, 27.0%), group C (n = 20/110, 18.2%), and group D (n = 0/36, 0%). The incidence of OHS was significantly correlated with aging, and the median serum concentration of estradiol in the presence of OHS was 823.0 pg/mL. The incidence of OHS (less than 47 years old) was 62.5% in group A, 48.6% in group B, and 28.2% in group C, respectively. Notably, the incidence rate of OHS following amenorrhea in group C (n = 13/20, 65.0%) was significantly higher than that in group B (n = 1/17, 5.9%).

Conclusions

These findings indicate that the onset of OHS following amenorrhea was common in the post-chemotherapeutic group, while its ratio was low in the group after Gn-RH analog treatment, suggesting that combined treatment-based management involving TAM therapy is necessary for premenopausal patients with breast cancer.

Avoidance and Period-Shortening of Neoadjuvant Chemotherapy Against Triple-Negative Breast Cancer in Stages I and II: Importance of Ki-67 Labeling Index and the Recognition of Apocrine-Type Lesions

BACKGROUND

Triple-negative breast cancer encompasses heterogeneous subtypes. Neoadjuvant chemotherapy is ineffective against some triple-negative breast cancers, while others show a favorable prognosis despite chemoresistance.

METHODS

A total of 51 cases with stages I and II triple-negative breast cancer were analyzed; 34 triple-negative breast cancers treated with neoadjuvant chemotherapy were divided into "good responders" (n = 22), showing therapeutic effect G2b or G3 in surgical specimens, and "poor responders" with therapeutic effect G0, G1a, G1b, and G2a (n = 12). Neoadjuvant chemotherapy was spared in 17 cases (non-neoadjuvant chemotherapy group). Apocrine-type triple-negative breast cancer was defined as triple-negative breast cancer immunoreactive for both androgen receptor and forkhead-box protein A1. Triple-negative breast cancer other than apocrine-type (n = 16) and special types (myoepithelial, medullary, adenoid cystic, and spindle cell carcinomas, n = 6) was categorized as basal-like subtype (n = 29). Prognosis was evaluated in each category.

RESULTS

Neoadjuvant chemotherapy provoked significant effects against basal-like triple-negative breast cancer with high Ki-67 labeling (≧50%), and tumor-infiltrating lymphocytes predicted high chemosensitivity. Neoadjuvant chemotherapy was avoidable in triple-negative breast cancer of apocrine- and special types showing low (<50%) Ki-67 labeling. Ten (59%) lesions in the non-neoadjuvant chemotherapy group belonged to the apocrine-type. When clinical complete remission shown by contrast-enhanced magnetic resonance imaging was reached in the course of neoadjuvant chemotherapy against basal-like triple-negative breast cancer, the neoadjuvant chemotherapy period was shortened in 14 (64%) of 22 good responders. Disease-free and overall survival rates were excellent in all groups.

CONCLUSIONS

The following 2 hypothetical proposals should be proven by large-scale clinical trials. Immunohistochemical recognition of apocrine-type triple-negative breast cancer with low Ki-67 labeling is important for avoiding ineffective/unnecessary neoadjuvant chemotherapy. By employing appropriate clinical imaging, period-shortening is achievable in basal-like triple-negative breast cancer with high Ki-67 labeling.

Multicentre, phase II study of eribulin in combination with S-1 in patients with advanced breast cancer

Background

We previously reported the synergistic effect of S-1 and eribulin in preclinical models. In addition, our phase I study revealed the recommended dose for the phase II study of the combination therapy in advanced breast cancer (ABC) patients pre-treated with anthracycline and taxane. Our current study reports on the efficacy and safety of the combined use of eribulin and S-1 in patients with ABC and poor prognosis.

Methods

Patients with breast cancer who received prior anthracycline- and/or taxane-based therapy were assigned to receive a combination therapy of eribulin (1.4 mg/m² on days 1 and 8, every 21 days) and S-1 (65 mg/m², on days 1 to 14, every 21 days) for advanced/metastatic disease. All patients had at least one clinicopathological factor such as being oestrogen receptor negative, Human Epidermal Growth Factor Receptor 2 (HER2) receptor negative, presence of visceral involvement, presence of three or more metastatic sites, or having a disease-free interval shorter than 2 years. The primary endpoint was the independent-reviewer assessed objective response rate (ORR). Secondary endpoints were clinical benefit rate, disease control rate, progression-free survival (PFS), and overall survival (OS).

Results

This study enrolled 33 patients. Confirmed ORR was 33.3% (95% CI: 17.3 to 52.8). Median PFS was 7.5 months (95% CI: 4.0 to 14.3). Median OS time was not reached during the current experimental periods. The most common grade 3/4 adverse event was neutropenia (68.8%).

Conclusions

The combination of eribulin and S-1 is safe and effective for treatment in patients with ABC and poor prognosis.

Trial registration

Current Controlled Trials UMIN000015049, date of registration: September 5th 2014.

Progesterone receptor expression in proliferating cancer cells of hormone-receptor-positive breast cancer

Breast cancer has been suggested to have two distinct driving mechanisms: the hormone receptor and the growth factor receptor pathways. We hypothesized that each driving system produces a different expression pattern of estrogen-regulated genes, such as progesterone receptor, in proliferating cells. Progesterone receptor and Ki67 expressions were assessed by dual-fluorescence immunohistochemistry in estrogen-receptor-positive breast cancer tissues. Two distinct proliferating cell populations were observed: progesterone-receptor-positive and progesterone-receptor-negative. In the training cohort, tissues with progesterone-receptor-positive proliferating cells were associated with lower grade and better disease-free survival (p = 0.0055 and 0.0026, respectively). These associations were confirmed in the validation cohort from the neoadjuvant endocrine trial JFMC34 (p = 0.033 and 0.0003, respectively). In the validation cohort, patients with progesterone-receptor-positive proliferating cells responded better to endocrine therapy and had a lower Oncotype DX Recurrence Score. In the multivariate analysis, progesterone receptor status of proliferating cells, but not progesterone receptor or Ki67 alone, was an independent predictor of disease-free survival in both cohorts (p = 0.0043 and 0.0026). In conclusion, the progesterone receptor status of proliferating cancer cells was associated with histological grade and Recurrence Score, and a potent prognostic factor in estrogen-receptor-positive breast cancers. Results suggest that different driving systems generate different expression patterns of progesterone receptor in proliferating cancer cells. Further studies are warranted to validate the findings.

Palbociclib in combination with letrozole in patients with estrogen receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer: PALOMA-2 subgroup analysis of Japanese patients

Background

In PALOMA-2, palbociclib–letrozole significantly improved progression-free survival (PFS) vs placebo–letrozole in women with estrogen receptor–positive, human epidermal growth factor receptor 2–negative (ER+/HER2–) advanced breast cancer (ABC) in the first-line setting. We evaluated the efficacy, safety, and pharmacokinetics of palbociclib in Japanese women in PALOMA-2.

Methods

In this phase 3 study, 666 postmenopausal women with ER+/HER2– ABC were randomized 2:1 to palbociclib (125 mg/day [3 weeks on/1 week off]) plus letrozole (2.5 mg daily) or placebo plus letrozole. A prespecified, exploratory, subgroup analysis of Japanese patients (n = 46) was conducted to compare results with those of the overall population.

Results

At the February 26, 2016 cutoff, median PFS among the 46 Japanese patients was 22.2 months (95%CI, 13.6‒not estimable) with palbociclib–letrozole vs 13.8 months (5.6‒22.2) with placebo–letrozole (hazard ratio, 0.59 [95%CI, 0.26−1.34]). The most common adverse events (AEs) were hematologic and more frequent among Japanese patients than the overall population (neutropenia: 93.8% [87.5% grade 3/4] vs 79.5% [66.4%]; leukopenia: 62.5% [43.8%] vs 39.0% [24.8%]); no Japanese patients had febrile neutropenia. Palbociclib dose reductions due to toxicity (mainly neutropenia) were more common in Japanese patients (62.5% vs 36.0%); few permanently discontinued due to AEs. Although mean palbociclib trough concentration was higher in Japanese patients vs non-Asians (95.4 vs 61.7 ng/mL), the range of individual values of the Japanese patients was within that of non-Asians.

Conclusions

These results from PALOMA-2 suggest that palbociclib–letrozole merits consideration as a first-line treatment option for postmenopausal Japanese patients with ER+/HER2‒ ABC. ClinicalTrials.gov: NCT01740427.

Electronic supplementary material

The online version of this article (10.1007/s10147-018-1353-9) contains supplementary material, which is available to authorized users.

Cost-Effectiveness of Second-Line Endocrine Therapies in Postmenopausal Women with Hormone Receptor-positive and Human Epidermal Growth Factor Receptor 2-negative Metastatic Breast Cancer in Japan

BACKGROUND

Exemestane (EXE), exemestane + everolimus (EXE + EVE), toremifene (TOR), and fulvestrant (FUL) are second-line endocrine therapies for postmenopausal hormone receptor-positive (HR +)/human epidermal growth factor receptor 2-negative (HER2 -) metastatic breast cancer (mBC) in Japan. Although the efficacy of these therapies has been shown in recent studies, cost-effectiveness has not yet been determined in Japan.

OBJECTIVE

This study aimed to examine the cost-effectiveness of second-line endocrine therapies for the treatment of postmenopausal women with HR + and HER2 - mBC.

METHODS

A Markov model was developed to analyze the cost-effectiveness of the therapies over a 15-year time horizon from a public healthcare payer's perspective. The efficacy and utility parameters were determined via a systematic search of the literature. Direct medical care costs were used. A discount rate of 2% was applied for costs and outcomes. Subgroup analysis was performed for non-visceral metastasis. A series of sensitivity analyses, including probabilistic sensitivity analysis (PSA) and threshold analysis were performed.

RESULTS

Base-case analyses estimated incremental cost-effectiveness ratios (ICERs) of 3 million and 6 million Japanese yen (JPY)/quality-adjusted life year (QALY) gained for TOR and FUL 500 mg relative to EXE, respectively. FUL 250 mg and EXE + EVE were dominated. The overall survival (OS) highly influenced the ICER. With a willingness-to-pay (WTP) threshold of 5 million JPY/QALY, the probability of TOR being cost-effective was the highest. Subgroup analysis in non-visceral metastasis revealed 0.4 and 10% reduction in ICER from the base-case results of FUL5 500 mg versus EXE and TOR versus EXE, respectively, while threshold analysis indicated EVE and FUL prices should be reduced 73 and 30%, respectively.

CONCLUSION

As a second-line therapy for postmenopausal women with HR +/HER2 - mBC, TOR may be cost-effective relative to other alternatives and seems to be the most favorable choice, based on a WTP threshold of 5 million JPY/QALY. FUL 250 mg is expected to be as costly and effective as EXE. The cost-effectiveness of EXE + EVE and FUL 500 mg could be improved by a large price reduction. However, the results are highly sensitive to the hazard ratio of OS. Policy makers should carefully interpret and utilize these findings.

APOBEC3B gene expression as a novel predictive factor for pathological complete response to neoadjuvant chemotherapy in breast cancer

Background

Apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3B (APOBEC3B) is a gene editing enzyme with cytidine deaminase activity and high expression of its mRNA in breast tumors have been shown to be associated with progressive cases and poor prognosis. In this study, we aimed to examine the relationship between the expression of APOBEC3B and the effect of neoadjuvant chemotherapy (NAC) using pretreatment biopsy tissue, and examined whether the expression of APOBEC3B influenced chemotherapy efficacy.

Methods

We retrospectively selected a total of 274 patients with primary breast cancer who received NAC in more than 4 courses and underwent surgery at our institute. We assessed the expression of APOBEC3B mRNA using pretreatment biopsy specimens of NAC by quantitative real-time PCR (qRT-PCR) and examined the relationship between APOBEC3B mRNA expression and sensitivity to chemotherapy using pathological complete response (pCR) as an indicator. Further, we assessed the prognostic value of APOBEC3B in the patients receiving NAC.

Results

APOBEC3B mRNA expression levels were successfully assessed in 173 (63.1%) of the 274 specimens. The total pCR rate was 36.4% (n = 63). An association between APOBEC3B expression levels and pCR was observed (Wilcoxon test, P ≤ 0.0001). The patients were divided into two groups, low (n = 66) and high (n = 107), according to the APOBEC3B expression levels, using the cut-off value calculated by the receiver operating characteristics (ROC) curve for pCR. The rate of pCR was significantly higher among the patients in the high group than among those in the low group (47.7% vs 18.2%, P ≤ 0.0001). High APOBEC3B expression was significantly associated with high nuclear grade (P = 0.0078), high Ki-67 labeling index (P = 0.0087), estrogen receptor (ER) negativity (P ≤ 0.0001) and human epidermal growth factor receptor 2 (HER2) negativity (P = 0.032). Tumor size (P = 0.011), ER (P ≤ 0.0001), HER2 (P = 0.0013) and APOBEC3B expression (P = 0.037) were independent predictive factors for pCR in multivariate analysis. However, there was no association between APOBEC3B expression and prognosis.

Conclusions

Our study showed that APOBEC3B mRNA expression correlated with sensitivity to NAC in breast cancer patients. In contrast to previous studies, APOBEC3B mRNA expression was not associated with breast cancer prognosis in patients receiving NAC.

Interleukin-6 receptor inhibitor suppresses bone metastases in a breast cancer cell line

BACKGROUND

Interleukin-6 (IL-6) is a potent inflammatory cytokine that appears to play a key role in cancer growth and metastasis. In the present study, the effects of IL-6 receptor (IL-6R) on breast cancer aggressiveness and bone metastases were investigated.

METHODS

MDA-MB-231 (MDA-231) cells were treated in the presence or absence of anti-human IL-6 receptor (IL-6R) monoclonal antibody and examined with respect to cell survival. The expressions of signal transducer and activator of transcription 3 (Stat3), vascular endothelial growth factor (VEGF), and receptor activator of NF-κB (RANK) were analyzed by SDS-PAGE and immunoblotting. MDA-231 cells were injected into the left ventricle of mice, and then anti-human IL-6R monoclonal antibody or saline was administered intraperitoneally for 28 days. After 28 days, the incidence of bone metastases was evaluated in the hind limbs by radiography and histology.

RESULTS

Anti-human IL-6R monoclonal antibody reduced bone metastases in an animal model injected with MDA-231 cells on radiological and histomorphometric analyses. The mechanism of bone metastasis inhibition involved inhibited cell proliferation and decreased expressions of phospho-Stat3, VEGF, and RANK in MDA-231 cells.

CONCLUSIONS

The results of the present study suggest that inhibition of IL-6 signaling may become a preventive therapeutic option for breast cancer and bone metastases.

Palbociclib in combination with letrozole as first-line treatment for advanced breast cancer: A Japanese phase II study

This single-arm, open-label, phase II study in 42 Japanese postmenopausal patients with estrogen receptor-positive/human epidermal growth factor receptor 2-negative (ER+/HER2-) advanced breast cancer evaluated the efficacy, safety, and pharmacokinetics of first-line palbociclib (125 mg once daily, 3 weeks on/1 week off) coadministered with letrozole (2.5 mg once daily). Primary endpoint of investigator-assessed 1-year progression-free survival (PFS) probability was 75.0% (90% CI, 61.3%-84.4%), far surpassing the 40% lower limit of the 90% CI supporting efficacy. Median duration of treatment was 438 days. Among secondary efficacy measures, median PFS was not reached (95% CI, 16.7: not estimable), 17/42 patients (40.5%) had an objective response, 36/42 (85.7%) maintained disease control, and 27/42 (64.3%) remained in follow-up. Median overall survival was not reached, and 1-year survival probability was 92.9% (95% CI, 79.5%-97.6%). Results of intensive pharmacokinetics in a subset of 6 patients showed palbociclib steady-state mean area under the plasma concentration-time curve over the dosing interval [τ] and mean maximum plasma concentration were 1979 ng·h/mL and 124.7 ng/mL, respectively. For day 15 plasma samples from cycles 1 and 2, geometric mean of the within-patient mean trough concentration was 90.1 ng/mL. The most common treatment-related adverse events were neutropenia (100%) and stomatitis (73.8%). There was 1 case of treatment-related febrile neutropenia. Toxicities were generally tolerated and manageable by dose modifications and/or medical care. Efficacy and safety of first-line palbociclib plus letrozole therapy is supported in Japanese postmenopausal patients with treatment-naive ER+/HER2- advanced breast cancer.

Cost-effectiveness analysis of the introduction of S-1 therapy for first-line metastatic breast cancer treatment in Japan: results from the randomized phase III SELECT BC trial

Background

This study evaluated the cost-effectiveness of replacing standard intravenous therapy (taxane) with oral S-1 therapy for first-line metastatic breast cancer treatment.

Methods

This cost-effectiveness analysis was based on data from a randomized phase III trial (SELECT BC). As cost-effectiveness was a secondary endpoint of the SELECT BC trial, some of the randomized patients participated in an EQ-5D survey (N = 391) and health economic survey (N = 146). The EQ-5D responses, claims, and prescription data were collected for as long as possible until death. The expected quality-adjusted life years (QALY) obtained from each treatment were calculated using patient-level EQ-5D data, and the expected cost was calculated using patient-level claim data. The analysis was performed from the perspective of public healthcare payers.

Results

The estimated EQ-5D least-square means and 95% CI up to 48 months were 0.764 (95% CI, 0.741–0.782) and 0.742 (95% CI, 0.720–0.764) in the S-1 and taxane arms, respectively. The expected QALY was 2.11 for the S-1 arm and 2.04 for the taxane arm, with expected costs of JPY 5.13 million (USD 46,600) and JPY 5.56 million (USD 50,500), respectively. These results show that S-1 is cost-saving. According to probabilistic sensitivity analysis, S-1 was dominant with a probability of 63%. When the willingness to pay (WTP) value was JPY 5 million (USD 45,500) per QALY, the probability of being cost-effective was 92%.

Conclusions

Our results show that the introduction of oral S-1 therapy for metastatic breast cancer is highly likely to be cost-effective.

Trial registration

UMIN CTR C000000416. Registered on May 10, 2006.

Pathological complete response of HER2-positive breast cancer to trastuzumab and chemotherapy can be predicted by HSD17B4 methylation

Human epidermal growth factor (HER) 2-directed therapy is the standard treatment for HER2-positive breast cancer. Patients who achieved a pathological complete response (pCR) to the therapy are associated with excellent disease-free survival. However, few molecular markers are available to predict pCR. Here, we aimed to establish a DNA methylation marker to predict the response to trastuzumab and chemotherapy. A total of 67 patients were divided into screening (n = 21) and validation (n = 46) sets. Genome-wide DNA methylation analysis of the screening set identified eight genomic regions specifically methylated in patients with pCR. Among these, HSD17B4 encoding type 4 17β-hydroxysteroid dehydrogenase was most significantly differentially methylated. The differential methylation was confirmed by pyrosequencing (P = 0.03), and a cutoff value was determined. This association was successfully validated in the validation set (P < 0.001), and patients with pCR were predicted with a high specificity (79%). Multivariate analysis, including tumor stage and hormone receptor status, showed that HSD17B4 methylation was an independent predictive factor (odds ratio: 10.0, 95% confidence interval 2.54–39.50, P = 0.001). Combination with ER status and HSD17B4 methylation improved the specificity up to 91%. Identification of HER2-positive breast cancer patients who would achieve pCR only by trastuzumab and chemotherapy may lead to surgery-free treatment for this group of breast cancer patients.

The Impact of Treatment Preferences in Second-Line Chemotherapy on the Prognosis of HER2-Negative Metastatic Breast Cancer

OBJECTIVE

We assessed the impact of treatment preferences in second-line chemotherapy on breast cancer prognosis using the SELECT BC study.

METHODS

The SELECT BC study was performed in patients with HER2-negative metastatic breast cancer treated with initial chemotherapy. From these patients, 618 were assigned to 2 groups (S-1 group, 309; taxane group, 309). The S-1 and taxane groups were each subdivided into 3 groups: crossover group, protocol-recommended group, and other group, and the analysis of overall survival (OS) was performed using Cox regression with inverse probability weighting, to adjust for postrandomization confounding.

RESULTS

In the taxane group, the OS of the crossover group (39.6 months) was better than that of the protocol-recommended group (35.7 months) and the other chemotherapy group (36.9 months) (vs. the protocol-recommended group, HR 0.72 [95% CI 0.52-0.98], p = 0.037; vs. the other chemotherapy group, HR 0.71 [95% CI 0.43-1.18], p = 0.183). In the S-1 group, there was no statistically significant difference in OS between the 3 groups.

CONCLUSION

The study of the combination of first-line chemotherapy and second-line chemotherapy showed that S-1 might be recommended as a second-line chemotherapy in patients in whom taxane was the primary chemotherapy.

A phase 1, dose-finding and pharmacokinetic study of gemcitabine with nab-paclitaxel in patients with metastatic breast cancer

PURPOSE

Gemcitabine (Gem) with paclitaxel (Pac) is used for patients with metastatic breast cancer who require cytoreduction with manageable toxicities. Nanoparticle albumin-bound (nab)-Pac exhibits better efficacy and reduces the risk of hypersensitivity reactions associated with solvent-based Pac. Therefore, Gem plus nab-Pac (GA) therapy may be effective for metastatic breast cancer. The purpose of this study was to determine the maximum tolerated dose for GA therapy.

METHODS

The subjects were patients with metastatic breast cancer with performance status 0 or 1 and normal hepatic, renal and marrow function. Leukopenia, neutropenia or thrombocytopenia of grade 4, neutropenic fever, or non-hematological toxicity of grade 3 or higher during the 1st cycle, and chemotherapy-induced peripheral neurotoxicity of grade 2 or higher at the end of the 1st cycle were defined as dose-limiting toxicities (DLTs). Gem (1250 mg/m(2)) was administered on days 1 and 8. nab-Pac was administered at a starting dose of 180 mg/m(2) (cohort 1) and escalated to 220 mg/m(2) (cohort 2) and 260 mg/m(2) (cohort 3) on day 1 of the 21-day cycle, using a 3 + 3 design.

RESULTS

Nine patients (n = 3, 3, and 3 in cohorts 1, 2, and 3, respectively) were included in the study (median age 56 years; range 43-75 years). DLTs did not occur in any cohorts.

CONCLUSIONS

The initial recommend dose in GA therapy is 1250 mg/m(2) Gem and 260 mg/m(2) nab-Pac. It is well known that nab-Pac has cumulative toxicities, and thus the efficacy and safety of GA therapy require validation in a phase 2 study.