Breast cancer survival among Japanese individuals and US residents of Japanese and other origins: a comparative registry-based study.

BACKGROUND: Breast cancer survival outcomes vary across different ethnic groups. We clarified the differences in clinicopathological and survival characteristics of breast cancer among Japanese, US residents with Japanese origin (USJ), and US residents with other origins (USO). METHOD: Using Surveillance, Epidemiology, and End Results (SEER) 18 dataset and Japanese Breast Cancer Society (JBCS) registry, we included patients first diagnosed with breast cancer between 2004 and 2015. We categorized the patients into three groups based on the database and the recorded ethnicity: Japanese (all those from the JBCS registry), USJ (those from SEER with ethnicity: Japanese), and USO (those from SEER with ethnicity other than Japanese). Excluding patients diagnosed after 2012, stage 0, and 4 patients, we examined the overall survival (OS) and breast cancer-specific survival (BCSS) using the Kaplan-Meier method and Cox proportional hazards models, adjusting for age, sex, cancer stage, and hormone receptor (HR) status. RESULTS: We identified 7362 USJ, 701,751 USO, and 503,013 Japanese breast cancer patients. The proportion of HR-positive breast cancer was the highest among USJ (71%). OS was significantly longer among Japanese and USJ than USO (Hazard ratio 0.46; 95% Confidence Interval [CI] 0.45-0.47 for Japanese and 0.66 [95% CI 0.59-0.74] for USJ) after adjusting for baseline covariates. BCSS was also significantly higher in the two groups (HR 0.53 [95% CI 0.51-0.55] for Japanese and 0.53 [95% CI 0.52-0.74] for USJ). CONCLUSIONS: In stage I-III breast cancer, Japanese and US residents with Japanese origin experienced significantly longer survival than US residents with non-Japanese origins.

Role of Postmastectomy Radiotherapy After Neoadjuvant Chemotherapy in Breast Cancer Patients: A Study from the Japanese Breast Cancer Registry.

BACKGROUND: The role of postmastectomy radiotherapy (PMRT) in breast cancer patients receiving neoadjuvant chemotherapy (NAC) is controversial. We aimed to evaluate the effectiveness of radiotherapy in patients treated with NAC and mastectomy in the Japanese Breast Cancer Registry. METHODS: We enrolled patients who received NAC and mastectomy for cT1-4 cN0-2 M0 breast cancer. We evaluated the association between radiotherapy and outcomes, locoregional recurrence (LRR), distant disease-free survival (DDFS), and overall survival (OS) based on ypN status by multivariable analysis. RESULTS: Of the 145,530 patients, we identified 3226 who met the inclusion criteria. Among ypN1 patients, no differences were found in LRR, DDFS, or OS between groups with and without radiotherapy (p = 0.72, p = 0.29, and p = 0.36, respectively). Radiotherapy was associated with improved LRR-free survival (p < 0.001), DDFS (p = 0.01), and OS (p < 0.001) in patients with ypN2-3. Multivariable analysis demonstrated that use of radiotherapy was independently associated with improved LRR [hazard ratio (HR) 0.61, 95% confidence interval (CI) 0.45-0.82, p = 0.001] and OS [HR 0.69, 95% CI 0.53-0.89, p = 0.004) for ypN2-3 patients only. The association between radiotherapy and OS was not statistically significant among ypN0 (p = 0.22) and ypN1 patients (p = 0.51). CONCLUSIONS: The results from this nationwide database study did not show significant associations between PMRT and improved survival among ypN0 and ypN1 patients. Radiotherapy may be beneficial only for ypN2-3 breast cancer patients who receive NAC and mastectomy in the modern era.

Distinct breast cancer characteristics between screen- and self-detected breast cancers recorded in the Japanese Breast Cancer Registry.

The rate of breast cancer screening for women of all ages in Japan is increasing. However, little is known about the biological differences between screen- and self-detected tumors. We used data from the Japanese Breast Cancer Registry (JBCR), a nationwide registry of newly diagnosed breast cancer cases in Japan, to investigate patients diagnosed between January 1, 2004 and December 31, 2011. We compared the clinicopathological features of tumors and assessed yearly trends regarding the proportion of screen-detected cases during the study period. We found that 31.8 % (65,358/205,544) of cancers were detected by screening. Asymptomatic tumors detected by screening (asymptomatic) were more likely to have favorable prognostic features than those that were self-detected (ductal carcinoma in situ [DCIS]: 19.8 versus 4.1 %, node-negative: 77.0 versus 61.6 %, and estrogen receptor-positive [ER+]: 82.0 versus 72.9 %, respectively). All these findings were statistically significant (p < .001). The proportion of breast cancers detected by screening among all cases increased from 21.7 % in 2004 to 37.1 % in 2011. During the same time period, the proportion of screen-detected DCIS increased from 41.5 to 66.0 % and that of ER+ cancers increased from 23.2 to 39.7 %. This study demonstrated that low-risk tumors, including DCIS, ER+, and lower TNM stage, account for a substantial proportion of clinical screening-detected cancers. The differences in biological characteristics between screen- and self-detected cancers may account in part for the limited efficacy of breast cancer screening programs aimed at improving breast cancer mortality.

Young adult breast cancer patients have a poor prognosis independent of prognostic clinicopathological factors: a study from the Japanese Breast Cancer Registry.

PURPOSE: The aim of this study was to investigate whether young age at onset of breast cancer is an independent prognostic factor in patients from the Japanese Breast Cancer Registry, after adjustment of known clinicopathological prognostic factors. METHODS: Of the 53,670 patients registered between 2004 and 2006 and surveyed after a 5-year follow-up prognosis, 25,898 breast cancer patients (48.3 %), who were obtained prognostic data, were examined. Clinicopathological factors were compared between young adult (YA; <35 years), middle-aged adult (MA; 35-50 years), and older adult (OA; >50 years) patients. Five-year disease-free survival (DFS) and overall survival (OS) rates were studied. RESULTS: YA patients were associated with an advanced TNM stage and aggressive characteristics (e.g. human epidermal growth factor receptor 2 (HER2)-positive or oestrogen receptor (ER)-negative breast cancers) compared to MA and OA patients (P < 0.001). The 5-year DFS and OS rates were 79.4 % and 90.8, 88.5 and 95.0 %, and 87.8 % and 91.6 % for YA, MA, and OA patients, respectively. From the multivariable regression analysis, young age at onset was confirmed as an independent prognostic factor for both DFS (hazard ratio 1.73, 95 % confidence interval 1.42-2.10; P < 0.001) and OS (hazard ratio 1.58, 95 % confidence interval 1.16-2.15; P = 0.004). CONCLUSIONS: Young age at onset is an independent negative prognostic factor in breast cancer. Further studies are required to develop new therapeutic strategies for YA breast cancer patients.

A phase I study of combination therapy with nanoparticle albumin-bound paclitaxel and cyclophosphamide in patients with metastatic or recurrent breast cancer.

BACKGROUND: The objective of the present clinical study is to determine the maximum tolerated dose (MTD)/recommended dose (RD) of combination therapy with nanoparticle albumin-bound paclitaxel (nab-PTX) and cyclophosphamide (CPA) in patients with metastatic or recurrent breast cancer. METHODS: nab-PTX and CPA were administered on the first day of each 21-day treatment cycle. The dose of CPA was fixed at 600 mg/m(2), while the dose of nab-PTX was increased from 180 mg/m(2) (Level 1) to 220 mg/m(2) (Level 2) and then to 260 mg/m(2) (Level 3). RESULTS: A total of 11 patients from two institutions were enrolled in the present study. At Level 3, a dose-limiting toxicity (DLT) was observed in 1 patient. Considering treatment continuity and the risk of adverse events in Cycle 2 and thereafter at this level, further subject enrollment at Level 3 was discontinued after two patients had been enrolled. Since the doses used at Level 3 were considered the MTD of nab-PTX and CPA and the doses used at Level 2 were considered the RD of nab-PTX and CPA, three additional subjects were enrolled at Level 2. No DLTs were observed at Level 2. CONCLUSION: The RD of combination therapy with nab-PTX and CPA was 220 mg/m(2) and 600 mg/m(2), respectively, in patients with metastatic or recurrent breast cancer.

[Adjuvant hormonal treatment for estrogen receptor-positive breast cancer-a questionnaire survey conducted by Japanese breast cancer society-authorized facilities in Hokkaido].

According to the Japanese Breast Cancer Society national breast cancer registration, 71.8%of breast cancer cases reported in 2004 and 79.8% of cases reported in 2010 were estrogen receptor(ER)positive. The frequency of ER-positive breast cancer is increasing annually in Japan. Many clinical trials have proven that adjuvant hormonal treatment affects both progression- free survival and overall survival in ER-positive breast cancer cases. However, some clinical questions remain, including those regarding the definition of preoperative hormonal treatment, appropriate dosage period, and therapeutic drug choice. In January 2013, we conducted a questionnaire survey of 53 medical doctors engaged in breast cancer treatment at 15 Japanese Breast Cancer Society-authorized facilities in Hokkaido. This survey included 6 clinical questions about preoperative hormonal treatment, 5 clinical questions about postoperative hormonal treatment for premenopausal breast cancer, and 4 clinical questions about postoperative hormonal treatment for postmenopausal breast cancer. We obtained replies from 35 medical doctors at 27 facilities. The response rate was 66%. We accumulated and analyzed these data. The discussion of questionnaire results in the medical administration field facilitates the sharing of information regarding differences in the approaches of different facilities to breast cancer patients. As a result, standardization of the breast cancer medical treatment system in this area has been accomplished.

Positional advantages of supine MRI for diagnosis prior to breast­conserving surgery.

The present study aimed to evaluate the rate of positive surgical margins for magnetic resonance imaging (MRI) performed in the supine position prior to breast-conserving surgery (BCS). The rate of positive surgical margins and the clinicopathological factors were examined in consecutive patients with BCS who underwent preoperative MRI performed in the supine position at Sapporo Medical University Hospital (Sapporo, Japan) and related hospitals and clinics between January 2012 and December 2013. Of 1,175 eligible patients, 1,150 were included after excluding 25 patients with either bilateral breast cancer or stage IV disease. Positive margin was defined as no cancer seen on the resected margin. The primary endpoint was the rate of positive surgical margins when preoperative MRI was performed in the supine position and the secondary endpoint was identification of the factors that predict positive margins. Of the 1,150 female patients (median age, 55 years; range, 29-97 years) who underwent BCS for breast cancer following MRI performed in the supine position, 215 (18.8%) had positive margins, which is similar to the rate with MRI in the prone position, and 930 (81.2%) had negative margins. The rate of positive surgical margins in patients of the human epidermal growth factor receptor 2 (HER2) type was significantly higher than that in the non-HER2 type group (6.5 and 2.9%; χ2 P=0.0103). There was no increase in the rate of positive margins in breast cancers with a diameter of >T2. The rate of positive surgical margins following MRI performed in the supine position was 18.8%. Supine MRI appears to be suitable for informing on the extent of resection of breast cancer.

Postoperative Adjuvant Anastrozole for 10 or 5 Years in Patients With Hormone Receptor-Positive Breast Cancer: AERAS, a Randomized Multicenter Open-Label Phase III Trial.

PURPOSE: Treatment with an aromatase inhibitor for 5 years is the standard treatment for postmenopausal hormone receptor-positive breast cancer. We investigated the effects of extending this treatment to 10 years on disease-free survival (DFS). PATIENTS AND METHODS: This prospective, randomized, multicenter open-label phase III study assessed the effect of extending anastrozole treatment for an additional 5 years in postmenopausal patients who were disease-free after treatment with either 5 years of anastrozole alone or 2-3 years of tamoxifen followed by 2-3 years of anastrozole. Patients were allocated randomly (1:1) to continue anastrozole for an additional 5 years or stop anastrozole. The primary end point was DFS, including breast cancer recurrence, second primary cancers, and death from any cause. This study is registered with University Hospital Medical Information Network, Japan (UMIN) clinical trials registry (UMIN000000818). RESULTS: We enrolled 1,697 patients from 117 facilities between November 2007 and November 2012. Follow-up information was available for 1,593 patients (n = 787 in the continue group, n = 806 in the stop group), who were defined as the full analysis set, including 144 patients previously treated with tamoxifen and 259 patients who underwent breast-conserving surgery without irradiation. The 5-year DFS rates were 91% (95% CI, 89 to 93) in the continue group and 86% (95% CI, 83 to 88) in the stop group (hazard ratio, 0.61; 95% CI, 0.46 to 0.82; P < .0010). Notably, extended anastrozole treatment reduced the incidence of local recurrence (continue group, n = 10; stop group, n = 27) and second primary cancers (continue group, n = 27; stop group, n = 52). There was no significant difference in overall or distant DFS. Menopausal or bone-related all-grade adverse events were more frequent among patients in the continue group than those in the stop group, but the incidence of grade ≥3 adverse events was <1% in both groups. CONCLUSION: Continuing adjuvant anastrozole for an additional 5 years after 5 years of initial treatment with anastrozole or tamoxifen followed by anastrozole was well tolerated and improved DFS. Although no difference in overall survival was observed as in other trials, extended anastrozole therapy could be one treatment choice in postmenopausal patients with hormone receptor-positive breast cancer.

Taxane-based combinations as adjuvant chemotherapy for node-positive ER-positive breast cancer based on 2004-2009 data from the Breast Cancer Registry of the Japanese Breast Cancer Society.

BACKGROUND: Adding taxane to an anthracycline-based regimen improves survival in node-positive breast cancer patients, as shown by clinical trials and meta-analyses. However, no studies have analyzed the number of metastatic lymph nodes in patients with estrogen receptor (ER)-positive cancer. This study investigated whether adding a taxane to an anthracycline-based regimen improved prognosis in node-positive, ER-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer patients in a real-world setting. METHODS: Using Japanese Breast Cancer Society registry data, we compared disease-free survival (DFS) of patients with ER-positive, HER2-negative breast cancer, excluding those receiving neoadjuvant chemotherapy, between those who received an anthracycline-based regimen followed by a taxane-based regimen (A + T) and those who received only an anthracycline-based regimen (A w/o T), stratified by lymph node status. A Cox proportional hazards model was used to evaluate DFS in both groups. RESULTS: There were 4566 eligible patients with ER-positive, HER2-negative breast cancer. During the median follow-up period of 60 months, there were 481 recurrences and 149 deaths. There was no significant difference in DFS between the A + T and A w/o T groups among patients with 1-3 positive nodes, while there was a significant difference among patients with ≥ 4 positive nodes. CONCLUSIONS: In patients with ER-positive, HER2-negative breast cancer, adding taxane to an anthracycline regimen did not improve DFS in patients with metastasis in 1-3 lymph nodes. We considered that the group without the addition of taxane might be present in patients with ER-positive, HER2-negative lymph node metastases.

Body mass index and survival after diagnosis of invasive breast cancer: a study based on the Japanese National Clinical Database-Breast Cancer Registry.

Few studies have reported the association between body mass index (BMI) and outcome among Asian breast cancer patients. We analyzed data for 20,090 female invasive breast cancer patients who had been followed-up for a median period of 6.7 years entered in the National Clinical Database-Breast Cancer Registry between 2004 and 2006. We used mainly the WHO criteria for BMI (kg/m(2) ) categories; <18.5 (underweight), ≥18.5-<21.8 (reference), ≥21.8-<25, ≥25-<30 (overweight), and ≥30 (obese). We divided normal weight patients into two subgroups because this category includes many patients compared to others. The timing of BMI measurement was not specified. The Cox proportional hazards model and cubic spline regression were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Smoking, alcohol, and physical activity were not controlled. A total of 1418 all-cause, 937 breast cancer-specific deaths, and 2433 recurrences were observed. Obesity was associated with an increased risk of all-cause (HR: 1.46; 95% CI: 1.16-1.83) and breast cancer-specific death (HR: 1.47; 95% CI: 1.11-1.93) for all patients, and with all-cause (HR: 1.47; 95% CI: 1.13-1.92) and breast cancer-specific death (HR: 1.58; 95% CI: 1.13-2.20) for postmenopausal patients. Being underweight was associated with an increased risk of all-cause death for all (HR: 1.41; 95% CI: 1.16-1.71) and for postmenopausal patients (HR: 1.45; 95% CI: 1.15-1.84). With regard to subtype and menopausal status, obesity was associated with an increased risk of breast cancer-specific death for all cases of luminal B tumor (HR: 2.59; 95% CI: 1.51-4.43; Pheterogeneity of Luminal B vs. Triple negative = 0.016) and for postmenopausal patients with luminal B tumor (HR: 3.24; 95% CI: 1.71-6.17). Being obese or underweight is associated with a higher risk of death among female breast cancer patients in Japan.

[Assessment of post-administration body distribution of toremifene and tamoxifen, and their administration regimens].

Toremifene is an anti-estrogenic drug like tamoxifen. We assessed the body distributions after administration of toremifene and tamoxifen in order to evaluate their treatment regimens by measuring the concentrations in tissues. It is known that, after toremifene (TOR) or tamoxifen (TAM) is consecutively administered to breast cancer patients, TOR or TAM and their main active N-desmethyl-metabolites (TOR-1 or TAM-1) are detected in sera, tumor tissues, and lymph nodes. Accordingly, after we administered toremifene or tamoxifen to primary breast cancer patients previous to surgery, we measured the concentrations of TOR, TOR-1, TAM, TAM-1 in sera, tumor tissues, and lymph nodes. We found that the concentrations of TOR and TOR-1 in sera, tumors, and lymph nodes reached a peak about 2 weeks after administration of toremifene 40 mg. Likewise, the concentrations of TAM and TAM-1 in sera, tumors, and lymph nodes reached a peak about 2 weeks after administration of tamoxifen, although the peak levels were lower than those of TOR or TOR-1. The concentrations of TAM-1 in lymph nodes were significantly and positively correlated to the duration of administration of TAM, and it was predicted that the concentration of TAM-1 in lymph nodes would reach a steady state at more than 4 weeks after administration of tamoxifen. The concentrations of TOR and TOR-1 were higher in tumors and lymph nodes than in sera. Furthermore, the concentrations of TOR and TOR-1 were significantly higher than those of TAM and TAM-1 in sera and tumors, respectively. Moreover, the concentration in tissue increased in a dose-dependent manner with administration of toremifene 120 mg. There were no significant differences between breast cancers positive and negative for estrogen receptors, with regard to the concentrations of TOR and TOR-1 in either sera, tumors, or lymph nodes. In conclusion, it would be expected that treatment with toremifene might be more effective for breast cancer than that with tamoxifen.

The treatment outcome of patients undergoing breast-conserving therapy: the clinical role of postoperative radiotherapy.

BACKGROUND: Treatment outcome was evaluated in patients who underwent breast-conserving therapy and tangential irradiation. After verifying background factors including systemic therapy, the clinical efficacy of postoperative irradiation was investigated. METHOD: There were 708 study subjects, all of whom had early breast cancer treated between 1992 and 2002. The median follow-up period was 83 months. After breast-conserving surgery, in patients with negative surgical margins, only tangential irradiation at 48 Gy/24 fr was performed. In contrast, in those with positive surgical margins, 10 Gy of radiation boost to the tumor bed with electrons was administered after tangential irradiation with 50 Gy/25 fr. Treatment outcome was analyzed using the Kaplan-Meier method and Cox's proportional hazards regression model. RESULTS: The disease-free survival and no-recurrence rates within the ipsilateral breast after 5 years were 93.4 and 97.2%, respectively. Risk factors for recurrence within the ipsilateral breast included younger age of patient, the number of positive lymph nodes, and no endocrine therapy. However, the surgical margin was not a risk factor. Risk factors for relapse outwith the ipsilateral breast included younger age, the number of positive lymph nodes, and recurrence within the ipsilateral breast. CONCLUSIONS: From our analysis of 708 Japanese women who received breast-conserving therapy, which can be regarded as a standard method in Japan, the treatment outcome was compatible with previous reports from other countries.