Japanese Breast Cancer Society Research Articles

Treatment patterns and clinical outcomes in patients with metastatic triple-negative breast cancer: a large-scale data analysis using the Japanese claims database.

This study evaluated treatment patterns and clinical outcomes among patients with metastatic triple-negative breast cancer (mTNBC) in real-world clinical settings in Japan. The treatment patterns, time to next treatment or death (TTNTD), time to treatment discontinuation, adverse events of interest, and medical costs of treating patients with mTNBC in first-, second-, and third-line settings were investigated using data of patients meeting the inclusion criteria between January 2017 and March 2022 in a Japanese medical claims database. The treatment regimens for mTNBC were defined according to the Japanese Breast Cancer Society Clinical Practice Guidelines. In this study, 2236 patients with mTNBC (median age 66.0years; 99.8% female) were included in the first-line cohort. Of these, 46.6% and 20.8% were included in the second- and third-line cohorts, respectively. The two most frequently used treatments were capecitabine (19.1%) and S-1 (tegafur-gimeracil-oteracil) (14.5%) in the first-line cohort, eribulin (18.3%) and bevacizumab/paclitaxel (14.4%) in the second-line cohort, and eribulin (19.4%) and bevacizumab/paclitaxel (17.5%) in the third-line cohort. The TTNTD shortened as the line of therapy progressed (median 8.0, 6.5, and 5.2months for the first-, second-, and third-line treatments, respectively). Nausea/vomiting and neutropenia/leukopenia occurred in 62.8% and 18.3% of all patients, respectively. The medical total costs per day were 6.7, 10.2, and 12.9 thousand yen during the first-/second-/third-line treatments, respectively. This study provides insight into current treatment patterns for mTNBC in Japan. The cost-benefit balance worsens with later-line treatment and a high unmet need for mTNBC drug treatment remains.

Abstract PO3-02-14: The Safety of Breast Reconstruction: The Impact of Breast Reconstruction Surgery on Postoperative Adjuvant Therapy for Breast Cancer

Abstract Background: Postoperative adjuvant therapy is very important in treating breast cancer, and increasing numbers of patients are undergoing immediate breast reconstruction (IBR) at the same time as breast cancer surgery. However, the impact of breast reconstruction surgery on adjuvant therapy is controversial. In this multicenter cohort study led by the Japanese Breast Cancer Society, we examined the impact of reconstructive surgery on postoperative adjuvant therapy in breast cancer patients who underwent IBR. Methods: We examined the association between adjuvant therapy and complications of reconstructive surgery in 4726 patients with primary breast cancer who underwent IBR during the period from January 1, 2008 to December 31, 2016. Statistical analysis employed the χ2 test. Results: Of the 995 patients who received adjuvant chemotherapy, the median time from the date of surgery to the start of chemotherapy was 51.0 days, with 63 patients (6.2%) starting more than 90 days after surgery. Eighty-four IBR complications required surgery (8.4%), including infections and tissue expander (TE) removal. Of the 63 patients for whom chemotherapy was initiated 90 days or more after surgery, 10 patients (15.9%) had complications requiring surgery, significantly more than the 74 patients (7.9%) in the < 90 days group (P = 0.028). Post-mastectomy radiation therapy (PMRT) was performed after breast cancer surgery in 359 cases: 69 cases received autologous tissue irradiation, 46 TE irradiation, 241 silicone breast implant (SBI) irradiation, and 3 artificial material removal before irradiation. 5 cases given autologous tissue irradiation and 26 receiving artificial material irradiation (22 of whom the artificial material was removes) required surgery within 1 year after the cancer surgery due to complications of IBR. There was no significant difference in the frequency of complications requiring surgery between autologous tissue irradiation and artificial material irradiation (P=0.632). There were 33 complications (9.2%) requiring surgery in the irradiated group, significantly more than the 129 cases (3.0%) in the non-irradiated group (P< 0.001). Conclusion: Adjuvant chemotherapy was generally not delayed, but complications requiring surgery related to IBR were more frequent in those with delay beyond 90 days, suggesting that postoperative complications from breast reconstruction may have influenced the delay in initiating chemotherapy. Therefore, in cases for whom postoperative chemotherapy is anticipated, complications from breast reconstruction may have impacted outcomes, making preoperative risk assessment even more important. There was no difference in the frequency of reconstructive complication surgery according to whether autologous tissue irradiation or artificial material irradiation had been used, but further investigation is needed. Citation Format: Naomi Nagura, Akiko ogiya, Hiroko Nogi, Kazutaka Narui, Hiroki Mori, Shinsuke Sasada, Makoto Ishitobi, Naoto Kondo, Chikako Yamauchi, Ayaka Shimo, Miho Saiga, Hirohito Seki, Teruhisa Sakurai, Tadahiko Shien. The Safety of Breast Reconstruction: The Impact of Breast Reconstruction Surgery on Postoperative Adjuvant Therapy for Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-02-14.

The Japanese breast cancer society clinical practice guidelines for radiation treatment of breast cancer, 2022 edition.

The Breast Cancer Clinical Practice Guidelines, organized by the Japanese Breast Cancer Society (JBCS), were published in 2022. We present the English version of the Radiation Therapy (RT) section of the guidelines. The JBCS formed a task force to update the 2018 version of the JBCS Clinical Practice Guidelines. The Background Questions (BQs) contain the standard treatments for breast cancer in clinical practice, whereas the Clinical Questions (CQs) address daily clinical questions that remain controversial. Future Research Questions (FRQs) explore the subjects that are considered important issues, despite there being insufficient data for inclusion as CQs. The task force selected the 12 BQs, 8 CQs, and 6 FRQs for the RT section. For each CQ, systematic literature reviews and meta-analyses were conducted according to the Minds Manual for Guideline Development 2020, version 3.0. The recommendations, strength of recommendation, and strength of evidence for each CQ were determined based on systematic reviews and meta-analyses, and finalized by voting at the recommendation decision meeting.

The Japanese Breast Cancer Society Clinical Practice Guidelines for Breast Cancer, 2022 Edition: changes from the 2018 edition and general statements on breast cancer treatment

The Japanese Breast Cancer Society Clinical Practice Guidelines for Breast Cancer, 2022 Edition was published in June 2022. The guidelines were prepared while conforming as much as possible to the “Minds Manual for Guideline Development 2020 ver. 3.0.” edited by the Minds Manual Development Committee of the Japan Council for Quality Health Care in 2021. In addition, a survey of Japanese Breast Cancer Society members on the 2018 edition of the guidelines was conducted from February 19 to March 4, 2021. Based on the responses from over 600 members, original innovations were made to make the guidelines more user-friendly. The 2018 edition of the guidelines was developed to provide support tools for physicians and patients to utilize shared decision-making. The 2022 guidelines consist of two volumes: (1) an “Epidemiology and Diagnosis” section covering “Screening and Diagnosis”, “Radiological diagnosis”, and “Pathological diagnosis”, and (2) a “Treatment” section covering “Surgical therapy”, “Radiation therapy”, and “Systemic therapy”. We believe that this concise summary of the guidelines will be useful to physicians and researchers in Japan and overseas.

Trastuzumab deruxtecan for human epidermal growth factor receptor 2-low advanced or metastatic breast cancer: recommendations from the Japanese Breast Cancer Society Clinical Practice Guidelines

The Japanese Breast Cancer Society Clinical Practice Guidelines are published as timely guidance on clinical issues in breast cancer treatment in Japan. In the recent edition of these guidelines, we addressed a new clinical question 34 (CQ 34, systemic treatment part) “Is trastuzumab deruxtecan recommended for patients with unresectable or metastatic HER2-low breast cancer?” and a new future research question 7 (FRQ 7, pathological diagnosis part) “How is HER2-low breast cancer diagnosed for the indication of trastuzumab deruxtecan?”. These questions address use of trastuzumab deruxtecan in patients with unresectable or metastatic HER2-low breast cancer who have previously received chemotherapy for metastatic disease. The strengths of evidence and recommendation were determined through a quantitative and qualitative systematic review using multiple outcomes, including efficacy and safety. We conclude that trastuzumab deruxtecan is recommended for this patient population (strength of recommendation: 1; strength of evidence: moderate; CQ34) and that HER2-low expression for the indication of trastuzumab deruxtecan should be diagnosed using companion diagnostics based on appropriate criteria (FRQ7).

Survival trends and patient characteristics between 2004 and 2016 for breast cancer in Japan based on the National Clinical Database-Breast Cancer Registry.

This is a prognostic report by the Japanese Breast Cancer Society on breast cancer extracted from the National Clinical Database-Breast Cancer Registry of Japan. Here, we present a summary of 457,878 breast cancer cases registered between 2004 and 2016. The median follow-up duration was 5.6years. The median age at the start of treatment was 59years (5-95%: 38-82years) and increased from 57years between 2004 and 2008 to 60years between 2013 and 2016. The proportion of patients with Stage 0-II disease increased from 74.5% to 78.3%. The number of cases with estrogen and progesterone receptor positivity increased from 74.8% to 77.9% and 60.5% to 68.1%, respectively. Regarding (neo-)adjuvant chemotherapy, the taxane (T) or taxane-cyclophosphamide (C) regimen increased by 2.4% to 8.2%, but the (fluorouracil (F)) adriamycin (A)-C-T/(F) epirubicin (E)C-T and (F)AC/(F)EC regimens decreased by 18.6% to 15.2% and 13.5% to 5.0%, respectively. Regarding (neo-)adjuvant anti-human epidermal growth factor-2 (HER2)-targeted therapy, the use of trastuzumab increased from 4.6% to 10.5%. The rate of sentinel lymph node biopsy increased from 37.1% to 60.7%, while that of axillary dissection decreased from 54.5% to 22.6%. Improvements in disease-free and overall survival were observed in patients with HER2-positive breast cancer, but there was no apparent trend in patients with hormone receptor-positive, HER2-negative, or triple-negative breast cancers.

2020 Annual Report of National Clinical Database-Breast Cancer Registry: 10-year mortality of elderly breast cancer patients in Japan.

The Japanese Breast Cancer Society initiated the breast cancer registry in 1975, which transitioned to the National Clinical Database-Breast Cancer Registry in 2012. This annual report presents data from 2020 and analyzes the ten-year mortality rates for those aged 65 and older. We analyzed data from 93,784 breast cancer (BC) cases registered in 2020 and assessed 10-year mortality rates for 36,279 elderly patients diagnosed between 2008 and 2012. In 2020, 99.4% of BC cases were females with a median age of 61. Most (65%) were diagnosed at early stages (Stage 0 or I). Breast-conserving surgery rates varied with stages: 58.5% at cStage I, 30.8% at cStage II, and 13.1% at cStage III. Sentinel lymph node biopsy was done in 73.6% of cases, followed by radiotherapy in 70% of those post-conserving surgery and chemotherapy in 21.1% post-surgery. Pathology showed that 63.4% had tumors under 2.0cm, 11.7% had pTis tumors, and 77.3% had no axillary lymph node metastasis. ER positivity was seen in 75.1%, HER2 in 14.3%, and 30% had a Ki67 positivity rate above 30%. Across all stages and subtypes, there was a trend where the 10-year mortality rates increased for individuals older than 65years. In Stage I, many deaths were not directly linked to BC and, for those with HER2-type and triple-negative BC, breast cancer-related deaths increased with age. Within Stage II, patients older than 70years with luminal-type BC often experienced deaths not directly linked to BC, whereas patients below 80years with HER2-type and triple-negative BC, likely had breast cancer-related deaths. In Stage III, breast cancer-related deaths were more common, particularly in HER2 and triple-negative BC. Our prognostic analysis underscores distinct mortality patterns by stage, subtype, and age in elderly BC patients. It highlights the importance of personalized treatment strategies, considering subtype-specific aggressiveness, age-related factors, and comorbidities.

The Japanese Breast Cancer Society clinical practice guidelines for epidemiology and prevention of breast cancer, 2022 edition

The Japanese Breast Cancer Society Clinical Practice Guidelines for Epidemiology and Prevention of Breast Cancer, 2022 Edition.

Annual report of the Japanese Breast Cancer Registry for 2019.

This is an annual report by the Japanese Breast Cancer Society regarding the clinical data on breast cancer extracted from the National Clinical Database-Breast Cancer Registry (NCD-BCR) of Japan. Here, we present an updated summary of 98,300 breast cancer cases registered in 2019. The median age at cancer diagnosis was 61years (interquartilerange 49-72years), and 30.6% of the breast cancer patients were premenopausal. Of the 93,840 patients without distant metastases, 14,118 (15.0%) and 42,047 (44.8%) were diagnosed with stage 0 and I disease, respectively. Breast-conserving surgery was performed in 42,080 (44.8%) patients. Regarding axillary procedures, 62,677 (66.8%) and 7371 (7.9%) patients underwent sentinel node biopsy and axillary node dissection after biopsy, respectively. Whole breast irradiation was administered to 29,795 (70.8%) of the 42,080 patients undergoing breast-conserving surgery. Chest wall irradiation was administered to 5524 (11.1%) of the 49,637 patients who underwent mastectomy. Of the 6912 clinically lymph node-negative patients who received preoperative therapy, 5250 (76.0%) and 427 (6.2%) underwent sentinel node biopsy and axillary node dissection after biopsy, respectively; however, 602 (8.7%) patients initially underwent axillary node dissection without biopsy.

The Japanese breast cancer society clinical practice guidelines for breast cancer screening and diagnosis, 2022 edition

This article provides updates to readers based on the newly published Japanese Breast Cancer Society Clinical Practice Guidelines for Breast Cancer Screening and Diagnosis, 2022 Edition. These guidelines incorporate the latest evaluation of evidence from studies of diagnostic accuracy. For each clinical question, outcomes for benefits and harms were established, and qualitative or quantitative systematic reviews were conducted. Recommendations were determined through voting by a multidisciplinary group, and guidelines were documented to facilitate shared decision-making among patients and medical professionals. The guidelines address screening, surveillance, and pre- and postoperative diagnosis of breast cancer. In an environment that demands an integrated approach, decisions are needed on how to utilize modalities, such as mammography, ultrasound, MRI, and PET/CT. Additionally, it is vital to understand the appropriate use of new technologies, such as tomosynthesis, elastography, and contrast-enhanced ultrasound, and to consider how best to adapt these methods for individual patients.

The Japanese breast cancer society clinical practice guidelines for pathological diagnosis of breast cancer, 2022 edition.

The Japanese breast cancer society clinical practice guidelines for pathological diagnosis of breast cancer, 2022 edition.

The Japanese Breast Cancer Society Clinical Practice Guidelines for surgical treatment of breast cancer, 2022 edition.

The 2022 revision of the Japanese Breast Cancer Society (JBCS) Clinical Practice Guidelines for surgical treatment of breast cancer was updated following a systematic review of the literature using the Medical Information Network Distribution Service (MINDS) procedure, which focuses on the balance of benefits and harms for various clinical questions (CQs). Experts in surgery designated by the JBCS addressed five areas: breast surgery, axillary surgery, breast reconstruction, surgical treatment for recurrent and metastatic breast cancer, and other related topics. The revision of the guidelines encompassed 4 CQs, 7 background questions (BQs), and 14 future research questions (FRQs). A significant revision in the 2022 edition pertained to axillary management after neoadjuvant chemotherapy in CQ2. The primary aim of the 2022 JBCS Clinical Practice Guidelines is to provide evidence-based recommendations to empower patients and healthcare professionals in making informed decisions regarding surgical treatment for breast cancer.

The Japanese Breast Cancer Society Clinical Practice Guidelines for systemic treatment of breast cancer, 2022 edition

The Japanese Breast Cancer Society (JBCS) Clinical Practice Guidelines for systemic treatment of breast cancer were updated to the 2022 edition through a process started in 2018. The updated guidelines consist of 12 background questions (BQs), 33 clinical questions (CQs), and 20 future research questions (FRQs). Multiple outcomes including efficacy and safety were selected in each CQ, and then quantitative and qualitative systematic reviews were conducted to determine the strength of evidence and strength of recommendation, which was finally determined through a voting process among designated committee members. Here, we describe eight selected CQs as important updates from the previous guidelines, including novel practice-changing updates, and recommendations based on evidence that has emerged specifically from Japanese clinical trials.

Factors associated with financial toxicity in patients with breast cancer in Japan: a comparison of patient and physician perspectives

BackgroundFinancial toxicity (FT) is a notable concern for patients with breast cancer worldwide. The situation regarding FT in Japan, however, has not been well explored. This study examined FT in patients with breast cancer in Japan and presented an overview of the group study’s overall findings.MethodsThe survey used the Questant application and primarily targeted patients with breast cancer attending research facilities and physicians who are members of the Japanese Breast Cancer Society. The Japanese version of the Comprehensive Score for FT (COST) was used to quantify patients’ FT. Multiple regression analysis was used to identify factors related to FT in patients with breast cancer in Japan and evaluate the sufficiency of information support level (ISL) for medical expenses.ResultsWe collected 1558 responses from patients and 825 from physicians. In terms of factors affecting FT, recent payments had the highest impact, followed by stage, and related departments positively affecting FT. Conversely, factors such as income, age, and family support were found to negatively affect FT. A significant discrepancy was identified between patients and physicians in perceived information support, with patients frequently feeling unsupported and physicians believing that they have provided adequate support. Furthermore, differences in the frequency of explanations and opportunities to ask questions about medical costs across FT grades were found. The analysis also showed that physicians with a better understanding of information support needs and greater knowledge of medical costs tended to provide more support that is comprehensive.ConclusionThis study emphasizes the importance of addressing FT in patients with breast cancer in Japan and highlights the need for enhanced information support, deeper understanding by physicians, and collaborative efforts among professionals to mitigate financial burden and provide personalized, tailored support for individual needs.

The safety of breast reconstruction: The impact of breast reconstruction surgery on postoperative adjuvant therapy for breast cancer.

e12511 Background: Postoperative adjuvant therapy is very important in treating breast cancer, and increasing numbers of patients are undergoing immediate breast reconstruction (IBR) at the same time as breast cancer surgery. However, the impact of breast reconstruction surgery on adjuvant therapy is controversial. In this multicenter cohort study led by the Japanese Breast Cancer Society, we examined the impact of reconstructive surgery on postoperative adjuvant therapy in breast cancer patients who underwent IBR. Methods: We examined the association between adjuvant therapy and complications of reconstructive surgery in 4726 patients with primary breast cancer who underwent IBR during the period from January 1, 2008 to December 31, 2016. Statistical analysis employed the χ2 test. Results: Of the 1044 patients who received adjuvant chemotherapy, the median time from the date of surgery to the start of chemotherapy was 51.0 days, with 65 patients (6.2%) starting more than 90 days after surgery. 66 IBR complications required surgery, including infections and tissue expander (TE) removal. Of the 65 patients for whom chemotherapy was initiated 90 days or more after surgery, 9 patients (13.8%) had complications requiring surgery, significantly more than the 57 patients (5.8%) in the < 90 days group (P = 0.010). Post-mastectomy radiation therapy (PMRT) was performed after breast cancer surgery in 359 cases: 69 cases received autologous tissue irradiation, 46 TE irradiation, 241 silicone breast implant (SBI) irradiation, and 3 removal before irradiation. 5 cases given autologous tissue irradiation and 30 receiving artificial material irradiation required surgery within 1 year after the cancer surgery due to complications of IBR. There was no significant difference in the frequency of complications requiring surgery between autologous tissue irradiation and artificial material irradiation (P = 0.422). There were 35 complications (9.7%) requiring surgery in the irradiated group, significantly more than the 118 cases (2.7%) in the non-irradiated group (P < 0.001). Conclusions: Adjuvant chemotherapy was generally not delayed, but complications requiring surgery related to IBR were more frequent in those with delay beyond 90 days, suggesting that postoperative complications from breast reconstruction may have influenced the delay in initiating chemotherapy. Therefore, in cases for whom postoperative chemotherapy is anticipated, complications from breast reconstruction may have impacted outcomes, making preoperative risk assessment even more important. There was no difference in the frequency of reconstructive complication surgery according to whether autologous tissue irradiation or artificial material irradiation had been used, but further investigation is needed.

Alcohol consumption and breast cancer prognosis after breast cancer diagnosis: a systematic review and meta‑analysis of the Japanese Breast Cancer Society Clinical Practice Guideline, 2022 edition

Alcohol consumption is internationally recognized as one of the compelling risk factors for breast cancer, but it does not necessarily correlate with the prognosis of breast cancer patients. Alcohol consumption in breast cancer patients was addressed in the 2022 Breast Cancer Clinical Practice Guidelines. A systematic review and meta-analysis of epidemiological studies on alcohol consumption and breast cancer recurrence, breast cancer-related mortality, all-cause mortality, and cardiovascular disease mortality in breast cancer patients was performed. The PubMed, Cochrane Library, and Ichushi-Web databases were searched for relevant publications reporting cohort or case–control studies published until March 2021. A total of 33 studies (32 cohort studies and 1 case–control study) met the eligibility criteria; 4638 cases of recurrence, 12,209 cases of breast cancer-specific mortality, and 21,945 cases of all-cause mortality were observed. With regard to breast cancer recurrence, 7 studies assessed pre-diagnosis alcohol consumption (relative risk (RR) 1.02, 95% confidence interval (95% CI) 0.77–1.37, p = 0.88) and 3 studies assessed post-diagnosis alcohol consumption (RR 0.96, 95% CI 0.85–1.10, p = 0.57), and no significant increase or decrease in risk was observed. With regard to breast cancer-related mortality, 19 studies assessed pre-diagnosis alcohol consumption (RR 1.02, 95% CI 0.93–1.11, p = 0.69), 9 studies assessed post-diagnosis alcohol consumption (RR 0.96, 95% CI 0.77–1.19, p = 0.70), and no significant increase or decrease in risk was observed. With regard to all-cause mortality, 18 studies assessed pre-diagnosis alcohol consumption (RR 0.90, 95% CI 0.82–0.99, p = 0.02), 8 studies assessed post-diagnosis alcohol consumption (RR 0.88, 95% CI 0.74–1.02, p = 0.08), and pre-diagnosis alcohol consumption was associated with a significantly decreased risk. With regard to cardiovascular disease mortality and alcohol consumption, 2 studies assessed it, and the RRwas 0.47 (95% CI 0.28–0.79, p = 0.005), showing that alcohol consumption was associated with a significantly decreased risk. The limitations of this study are that drinking status was mainly based on a questionnaire survey, which is somewhat inaccurate and has many confounding factors, and the cut-off value for the maximum alcohol intake in many studies was low, and it is possible that the actual intake was only an appropriate amount. In many countries, a standard drinking amount is set, and wise decisions are required.

Abstract P1-05-06: Establishment of the breast ultrasound support system using deep-learning system

Abstract Although the categorization of ultrasound using the Breast Imaging Reporting and Data System (BI-RADS) has become widespread worldwide, the problem of inter-observer variability remains. To maintain uniformity in diagnostic accuracy, we have developed a novel artificial intelligence (AI) system in which AI can distinguish whether a static image obtained using a breast ultrasound represents BI-RADS3 or lower, or BI-RADS4a or higher, to determine the medical management that should be performed on a patient whose breast ultrasound shows abnormalities. To establish and validate the AI system, a training dataset consisting of 4,028 images containing 5,014 lesions and a test dataset consisting of 3,166 images containing 3,656 lesions were collected and annotated. We selected a setting that maximized the area under the curve (AUC) and minimized the difference in sensitivity and specificity by adjusting the internal parameters of the AI system, achieving an AUC, sensitivity, and specificity of 0.95, 90.0%, and 88.5%, respectively. Furthermore, based on 30 images extracted from the test data, the diagnostic accuracy of 20 clinicians and the AI system was compared, and the AI system was found to be significantly superior to the clinicians (McNemar test, p < 0.001). Then, we conducted a trial to introduce the system for use in clinical practice. Physicians reviewed the images and determined whether they were BI-RADS3 or lower, or BI-RADS4a or higher. Next, the classification was performed again for the same images concerning the AI diagnosis. At this time, the initial judgment was allowed to be overturned. We checked whether there was any difference in the diagnostic accuracy, sensitivity, and specificity before and after reviewing to the AI diagnosis. Reviews by 24 physicians were evaluated: 4 Japanese Breast Cancer Society breast specialists, 5 non-specialists and physicians with experience treating more than 40 cases of breast cancer, and 15 non-specialists and physicians with no experience treating more than 40 cases of breast cancer. The average rate of accuracy before confirming the AI diagnosis increased to 73.1% after confirming the AI diagnosis (p=0.00548), compared to 69.3% on average before the AI diagnosis. Compared to practice experience, the accuracy increased from an average of 77.1% to 79.6% for the 9 physicians who were breast specialists or who had treated 40 or more cases of breast cancer. For the 15 physicians with less than 40 breast cancer cases, the average rate of accuracy increased from 64.7% to 69.2%. Furthermore, sensitivity increased significantly to an average of 99.7% after reviewing of the AI diagnosis from an average of 88.8% prior to reviewing the AI-diagnosis.(p< 0.01). Specificity increased from an average of 62.4% to 63.8% (p=0.433) after reviewing AI diagnosis. We showed that our AI system, when applied to clinical practice and used by physicians, contributes to the improvement of diagnostic accuracy. Our results indicated that our AI diagnostic system was sufficiently accurate to be used in the clinical practice. Citation Format: Erina Odani, Tetsu Hayashida, masayuki kikuchi, Aiko Nagayama, tomoko seki, maiko takahashi, Akiko Matsumoto, Takeshi Murata, Rurina Watanuki, Takamichi Yokoe, Ayako Nakashoji, Hinako Maeda, Tatsuya Onishi, Sota Asaga, Takashi Hojo, Hiromitsu Jinno, Keiichi Sotome, Akira Matsui, Akihiko Suto, Shigeru Imoto, Yuko Kitagawa. Establishment of the breast ultrasound support system using deep-learning system [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-05-06.

Abstract P4-03-08: Breast cancer incidence rates in Japan turned into bimodal age distribution in this decade

Abstract BACKGROUND: Japan is the globe’s fastest ageing country: 32.0 % of the female population are 65 or older in 2021. The birth rate was 1.30 children per woman in 2021. Japan’s population has been constantly shrinking since 2011 with aging. The number of breast cancer cases has increased rapidly in the course of low birth rate and aging population. Breast cancer has increased and accounted for the first place of all of cancers in Japanese women. OBJECTIVES; Number of breast cancer has increased recently and accounted for the first place of all of female cancers in Japan. Detailed analytics of the increase and aging of breast cancer are not studied. We elucidate the transformation of Japanese breast cancer by ages at diagnosis over the past decade. MATERIALS: We used the registry data of Japanese Breast Cancer Society and Statistics Bureau of Japan in 2018. Female breast cancer new cases were 59,389 patients in 2008 and 93,858 patients in 2018, respectively. The total female population was 65.441 million in 2008 and 64.911 million in 2018, respectively. 65 years and older women accounted for 23.4% in 2008 and 31.0 % in 2018, respectively. METHODS: We compared incidences and incidence rates of breast cancer by ages in 2008 and 2018, respectively. We used the statistical method of Ameijeiras-Alonso et al for mode assessment. RESULTS; Total number of incidences and incidence rates of breast cancer in 2018 were higher than those in 2008 among all ages. Difference of number of incidences were maximum in age of 60-69 in both years. Difference of incidence rates in both years reached maximum in age of 75-79. Incidence rates in 2008 showed unimodal age distribution with the gentle peak. Incidence rates in 2018 showed bimodal age distribution with two peaks of 45-49 and 65-69. CONCLUSIONS; Incidences and incidence rates of breast cancer increased rapidly among all ages in this decade in Japan. The incidence rates increased most in ages of 75-79 and turned into bimodal age distribution in 2018. Citation Format: Ken Uchida, Hitoshi Ohashi, Hiroko Nogi, Satoki Kinoshita, Ryouko Nosaka, Makiko Kamio. Breast cancer incidence rates in Japan turned into bimodal age distribution in this decade. [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-03-08.

Abstract P2-15-09: Impact of neoadjuvant chemotherapy on the short- and long-term outcomes in patients who underwent immediate breast reconstruction after mastectomy

Abstract Background and Purpose In breast cancer patients receiving neoadjuvant chemotherapy (NAC), the use of immediate breast reconstruction (IBR) as a breast cancer treatment option remains controversial. The Japanese breast cancer society conducted retrospective multicenter cohort study in the era of IBR, and we assessed the impact of NAC on surgical and oncological outcomes in patients underwent IBR. Methods Between January 2008 and December 2016, 473 (10.0%) breast cancer cases received NAC of 4726 cases underwent IBR after mastectomy. The clinicopathological and survival data of patients who received NAC (the NAC group) and those who did not receive NAC (the control group) were compared in terms of postoperative complications (infection, hemorrhage, seroma, dehiscence, tissue expander or implant loss, flap or skin necrosis) and oncologic safety. Results Eight-hundred forty cases had minor or major complications. NAC did not increase the risk of complications after IBR (OR 1.20; 95%CI 0.95 - 1.53; p = 0.13). Smoking (OR 1.35; 95%CI 1.14 - 1.62; p = 0.001), overweight (BMI25≤) (OR 1.94; 95%CI 1.61 - 2.35; p < 0.001), PMRT (OR 1.54; 95%CI 1.20 - 1.99; p = 0.01) increased risk of complications. At the median follow-up time of 76.5 months, 36 patient (7.6%) in the NAC group and 147 patients (3.5%) in the control group had local recurrence. 35 patient (7.4%) in the NAC group and 147 patients (2.0%) in the control group had reginal recurrence. Conclusion Immediate breast reconstruction after NAC is a safe procedure with post-operative complication profile. It can be performed safely and therefore should be considered as a strategy preferred for patients with local advanced breast cancer. Citation Format: Hiroko Nogi, Akiko ogiya, Naoto Kondo, Makoto Ishitobi, Chikako Yamauchi, Hiroki Mori, Ayaka Shimo, Kazutaka Narui, Naomi Nagura, Hirohito Seki, Shinsuke Sasada, Teruhisa Sakurai, Tadahiko Shien. Impact of neoadjuvant chemotherapy on the short- and long-term outcomes in patients who underwent immediate breast reconstruction after mastectomy [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-15-09.

PS-R06-8: AMLODIPINE WELL RESPONDED TO HYPERTENSION ALONG WITH HEADACHE IN PATIENT UNDERGOING WHOLE BRAIN RADIATION THERAPY (CASE REPORT)

Objective: According to the current treatment guideline for breast cancer issued by Japanese Breast Cancer Society, surgery or stereotactic radiotherapy is recommended for patients with solitary brain metastasis (BM), while whole brain radiotherapy (WBRT) is recommended for patients with multiple BMs. Common treatment-related toxicities during radiotherapy include fatigue, drowsiness, alopecia, headache, nausea, or vomiting, however, elevation of blood pressure has not been reported. We report a case of headache due to high blood pressure during WBRT. Case: A 5X-year female was diagnosed as HER2-positive operable left breast cancer underwent radical mastectomy followed by adjuvant chemotherapy including one-year trastuzumab. Three years after surgery she was diagnosed as having cancerous pleurisy, cancerous pericarditis, and multiple bone metastases. The patient received 6 cycles of trastuzumab, pertuzumab and docetaxel and 5 cycles of trastuzumab and pertuzumab. She noticed chronic headache and magnetic resonance imaging of the brain showed metastases to the right frontal lobe and left cerebellum. She was hospitalized and underwent WBRT. She received corticosteroid and glycerin-fructose injection to reduce the intracranial pressure (ICP) along with WBRT. On the 10th day of hospitalization, she complained severe headache with numerical rating scale (NRS) of 6. While an analgesic was not effective, elevated blood pressure (160/80 mmHg) since admission was suspected as a cause of headache. High-dose amlodipine at the dose of 10 mg was prescribed and the patient well responded to amlodipine as blood pressure of 130/70 mmHg and headache was relieved. Discussion: In patients with BMs, headache is common symptom due to elevate ICP or leptomeningeal dissemination. However, analgesic and ICP relief therapy did not work in this case. Guidelines for the management of hypertension 2019 (JSH 2019) define hypertension as 140/90 mmHg or higher, and in low-risk cases without underlying disease, non-pharmacologic therapy is recommended. Ultimately, the use of a calcium channel blockers resulted in a decrease in blood pressure and improvement in headache. It is possible that the headache was caused by increased sympathetic nerve activity via ischemia in the brainstem due to increased ICP, such as in brain tumors, which can lead to hypertension. Amlodipine is recommended for patients with chronic cerebrovascular disease because of its long acting and slow onset of effect, as well as its ability to protect organ blood flow. Conclusion: This case revealed hypertension may be the cause of headaches during WBRT, in which case amlodipine was effective.