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.

Doublet or Triplet Antiemetic Prophylaxis for Nausea and Vomiting Induced by Trastuzumab Deruxtecan: an Open-Label, Randomized, and Multicenter Exploratory Phase 2 Study.

Background: Trastuzumab deruxtecan is classified as an anticancer agent that poses a moderate emetic risk in the international guidelines for antiemetic therapy. The guidelines recommend emesis prophylaxis using a two-drug combination therapy comprising a 5-hydroxytryptamine-3 receptor antagonist (5-HT3RA) and dexamethasone (DEX). However, the high incidence of nausea and vomiting associated with trastuzumab deruxtecan is problematic. The National Comprehensive Cancer Network guideline version 1.2023 classified trastuzumab deruxtecan as having a high risk of emesis and changed its recommendation to a triplet regimen including a neurokinin-1 receptor antagonist (NK1RA). However, the emetogenic potential of trastuzumab-deruxtecan and the optimal antiemetic prophylaxis are controversial. Hence, this exploratory phase 2 study aimed to assess the efficacy and safety of treatment comprising 5-HT3RA and DEX with or without a NK1RA in preventing trastuzumab deruxtecan-induced nausea and vomiting. Methods: We conducted an open-label and randomized exploratory phase 2 study at 14 centers in Japan. Patients with breast cancer who were scheduled to receive trastuzumab deruxtecan were enrolled in this study. The patients were randomly assigned to receive granisetron and DEX (arm GD) or granisetron, DEX, and aprepitant (fosaprepitant; arm GDA). The primary endpoint was complete response (CR; no emesis or no rescue therapy) during the overall phase (120 h after the start of trastuzumab deruxtecan). Results: Between September 2020 and March 2023, 40 patients were randomly assigned to the GD (n = 19) or GDA (n = 21) arm. In the GDA arm, one patient who did not complete the use of the rescue medication listed in the diary was excluded from the efficacy analysis, which included the use of rescue medication. The CR rates during the overall phase were 36.8% and 70.0% in the GD and GDA arms, respectively (odds ratio 0.1334; 95% confidence interval [CI]: 0.0232-0.7672; P = 0.0190), with a difference of 33.2%. No grade 3 or 4 toxicity related to antiemetic therapy was observed. Conclusions: Patients receiving trastuzumab deruxtecan require triple therapy, including mandatory NK1RA administration.

Computer-Aided Detection of Quantitative Signatures for Breast Fibroepithelial Tumors Using Label-Free Multi-Photon Imaging.

Fibroadenomas (FAs) and phyllodes tumors (PTs) are major benign breast tumors, pathologically classified as fibroepithelial tumors. Although the clinical management of PTs differs from FAs, distinction by core needle biopsy diagnoses is still challenging. Here, a combined technique of label-free imaging with multi-photon microscopy and artificial intelligence was applied to detect quantitative signatures that differentiate fibroepithelial lesions. Multi-photon excited autofluorescence and second harmonic generation (SHG) signals were detected in tissue sections. A pixel-wise semantic segmentation method using a deep learning framework was used to separate epithelial and stromal regions automatically. The epithelial to stromal area ratio and the collagen SHG signal strength were investigated for their ability to distinguish fibroepithelial lesions. An image segmentation analysis with a pixel-wise semantic segmentation framework using a deep convolutional neural network showed the accurate separation of epithelial and stromal regions. A further investigation, to determine if scoring the epithelial to stromal area ratio and the SHG signal strength within the stromal area could be a marker for differentiating fibroepithelial tumors, showed accurate classification. Therefore, molecular and morphological changes, detected through the assistance of computational and label-free multi-photon imaging techniques, enable us to propose quantitative signatures for epithelial and stromal alterations in breast tissues.

Non-traumatic bilateral rectus sheath hematoma during septic disseminated intravascular coagulation.

A non-traumatic abdominal wall hematoma is rare, and occurs occasionally due to coughing, physical activity, or antithrombotic/anticoagulant therapy. The condition is usually unilateral; however, rare bilateral cases have been reported. Here, we report a rare case of a non-traumatic bilateral rectus sheath hematoma. The patient was a 60-year-old woman who was urgently admitted to our hospital due to the occurrence of pneumonia during postoperative chemotherapy for breast cancer. Because she exhibited disseminated intravascular coagulation, a therapy with antibacterial agents, thrombomodulin alpha, and catecholamines was initiated. During hospitalization, hemorrhagic shock due to hematomas in both rectus abdominis muscles was observed without any discernible cause. Subsequent emergency angioembolization was successful, and abdominal computed tomography performed 3 months after the onset of the rectus sheath hematoma confirmed a reduction in the hematoma size.

[A Case of Breast Cancer during Pregnancy Treated with Neoadjuvant Chemotherapy during Pregnancy].

Although breast cancer during pregnancy is relatively rare, the number of such cases has risen in recent years owing to an increase in mean childbirth age and the increasing prevalence of breast cancer. Here we report the case of a 37-year-old breast cancer patient who received neoadjuvant chemotherapy during pregnancy. The woman previously consulted an outside physician after noting a mass in her right breast at 25 weeks' gestation. Breast ultrasonography revealed a right breast tumor and axillary lymphadenopathy. A histopathological examination indicated right breast cancer and axillary lymph node metastasis. She was referred to our department for pregnancy management. Chest X-rays and abdominal ultrasonography were utilized in the search for metastases. She received 2 courses of doxorubicin and cyclophosphamide(AC)therapy during pregnancy and gave birth via cesarean section at 35 weeks' gestation. After delivery, the AC was resumed. The patient completed a total of 4 courses of AC followed by 4 courses of docetaxel (dosed every 3 weeks). She underwent total right mastectomy and axillary dissection; because the tumor was BRCA2 mutation-positive, a risk-reducing salpingo- oophorectomy was also performed. Adjuvant therapy included radiotherapy and tamoxifen but no luteinizing hormone- releasing hormone agonists. At the time of this writing more than 1 year post-surgery, she has not experienced recurrence; although the infant has a congenital clubfoot, she suffers from no other cognitive or developmental delays.

A Case of a Rapidly Growing Granulocyte Colony-Stimulating Factor-Producing Squamous Cell Carcinoma of the Breast.

A 34-year-old woman with a rapidly growing right breast mass visited our hospital. The mass was diagnosed as a right breast cancer (cT3N1M0 stage ⦀A). Her serum leucocyte count and C-reactive protein levels were high, and she had persistent fever. However, serum procalcitonin and ß-D-glucan levels were normal, and no apparent infection focus was detected, although her serum granulocyte colony-stimulating factor (G-CSF) level was markedly elevated to 42.7 pg/mL. Therefore, a G-CSF-producing breast cancer was suspected. A pathological analysis of the surgical specimen revealed a squamous cell carcinoma of the breast (pT2N0 [i+] M0 stage ∥A). Right mastectomy (with the resection of the pectoralis major muscle), axillary lymph node dissection, and split layer grafting were performed. The leucocyte count and serum G-CSF level decreased on postoperative day (POD) 1 and normalized on POD 6. As adjuvant chemotherapy, 4 cycles of a combination chemotherapy with adriamycin and cyclophosphamide and 12 cycles of weekly paclitaxel were administered. After chemotherapy, the patient also underwent postmastectomy radiotherapy. Currently, 30 months after surgery, the patient is alive and well with neither progression nor distant metastasis. G-CSF-producing breast cancers tend to rapidly grow such as in the current case; thus, surgery should be performed immediately, followed by appropriate adjuvant treatment.

CNKSR1 serves as a scaffold to activate an EGFR phosphatase via exclusive interaction with RhoB-GTP.

Epidermal growth factor receptor (EGFR) and human EGFR 2 (HER2) phosphorylation drives HER2-positive breast cancer cell proliferation. Enforced activation of phosphatases for those receptors could be a therapeutic option for HER2-positive breast cancers. Here, we report that degradation of an endosomal small GTPase, RhoB, by the ubiquitin ligase complex cullin-3 (CUL3)/KCTD10 is essential for both EGFR and HER2 phosphorylation in HER2-positive breast cancer cells. Using human protein arrays produced in a wheat cell-free protein synthesis system, RhoB-GTP, and protein tyrosine phosphatase receptor type H (PTPRH) were identified as interacting proteins of connector enhancer of kinase suppressor of Ras1 (CNKSR1). Mechanistically, constitutive degradation of RhoB, which is mediated by the CUL3/KCTD10 E3 complex, enabled CNKSR1 to interact with PTPRH at the plasma membrane resulting in inactivation of EGFR phosphatase activity. Depletion of CUL3 or KCTD10 led to the accumulation of RhoB-GTP at the plasma membrane followed by its interaction with CNKSR1, which released activated PTPRH from CNKSR1. This study suggests a mechanism of PTPRH activation through the exclusive binding of RhoB-GTP to CNKSR1.

Metaplastic carcinoma of the breast and BRCA1 germline mutation: a case report and review.

BACKGROUND: Metaplastic carcinoma of the breast consists of both invasive ductal carcinoma and metaplastic carcinoma. This rare subtype of cancer has a poor prognosis. The development of metaplastic breast cancer and relationship with BRCA1 are not well known. Here, we report a rare case of germline BRCA1 mutation-positive breast cancer with chondroid metaplasia. CASE PRESENTATION: A 39-year-old Japanese woman with a family history of breast cancer in her mother and ovarian cancer in her maternal grandmother consulted at our hospital with a left breast mass. Needle biopsy for the mass was performed, leading to a diagnosis of invasive breast cancer with chondroid metaplasia. We performed left mastectomy + sentinel lymph node biopsy + tissue expander insertion and replaced with a silicone implant later. Pathological examination revealed that the patient had triple-negative breast cancer. Four courses of doxorubicin+ cyclophosphamide therapy were performed as adjuvant therapy after surgery. We performed genetic counseling and genetic testing, and the results suggested the germline BRCA1 mutation 307 T> A (L63*). She has currently lived without a relapse for 2 years post-surgery. CONCLUSIONS: There have been only 6 cases of metaplastic breast carcinoma with germline BRCA1 mutations including our case. Patients with BRCA1 mutations may develop basal-like subtypes or M type of triple-negative breast cancer besides metaplastic breast cancers.

Cullin-3/KCTD10 E3 complex is essential for Rac1 activation through RhoB degradation in human epidermal growth factor receptor 2-positive breast cancer cells.

Rho GTPase Rac1 is a central regulator of F-actin organization and signal transduction to control plasma membrane dynamics and cell proliferation. Dysregulated Rac1 activity is often observed in various cancers including breast cancer and is suggested to be critical for malignancy. Here, we showed that the ubiquitin E3 ligase complex Cullin-3 (CUL3)/KCTD10 is essential for epidermal growth factor (EGF)-induced/human epidermal growth factor receptor 2 (HER2)-dependent Rac1 activation in HER2-positive breast cancer cells. EGF-induced dorsal membrane ruffle formation and cell proliferation that depends on both Rac1 and HER2 were suppressed in CUL3- or KCTD10-depleted cells. Mechanistically, CUL3/KCTD10 ubiquitinated RhoB for degradation, another Rho GTPase that inhibits Rac1 activation at the plasma membrane by suppressing endosome-to-plasma membrane traffic of Rac1. In HER2-positive breast cancers, high expression of Rac1 mRNA significantly correlated with poor prognosis of the patients. This study shows that this novel molecular axis (CUL3/KCTD10/RhoB) positively regulates the activity of Rac1 in HER2-positive breast cancers, and our findings may lead to new treatment options for HER2- and Rac1-positive breast cancers.

Patient-related Risk Factors for Nausea and Vomiting with Standard Antiemetics in Patients with Breast Cancer Receiving Anthracycline-based Chemotherapy: A Retrospective Observational Study.

PURPOSE: The aim of this study was to identify a high-risk or low-risk population for chemotherapy-induced nausea and vomiting among patients with breast cancer treated with a current standard 3-drug antiemetic regimen and receiving anthracycline. METHODS: We analyzed data from chemotherapy-naive Japanese patients with breast cancer, who had received the first cycle of anthracycline-based regimen and were treated with a 3-drug combination of aprepitant, palonosetron, and dexamethasone. This study was carried out at Ehime University Hospital (Toon, Japan) using electronic medical records from May 2011 to June 2017. The primary end point was complete response (CR), which was defined as no emesis and no use of rescue medication. FINDINGS: A total of 103 patients were included in this study. The percentages of patients who had a CR in the overall, acute, and delayed phases were 35.0%, 40.8%, and 50.5%, respectively. Multivariate logistic regression analysis revealed that age <55 years and body mass index <27.5 kg/m2 were significantly associated with an increased risk for CR failure in the overall and acute phases. In contrast, a history of alcohol habit was significantly associated with a decreased risk for CR failure in overall phase. IMPLICATIONS: The present findings suggest that, among patients with breast cancer receiving anthracycline and treated with aprepitant, palonosetron, and dexamethasone, patients younger than 55 years and having a body mass index <27.5 kg/m2 are high-risk populations for chemotherapy-induced nausea and vomiting, whereas those with a history of habitual alcohol consumption is a low-risk one.

Olanzapine plus aprepitant, palonosetron, and dexamethasone for nausea and vomiting in patients with breast cancer receiving anthracycline: A retrospective study.

This study aimed to compare the antiemetic efficacy and safety of a four-drug combination with those of a standard three-drug combination in Japanese patients with breast cancer treated with anthracycline. We retrospectively analyzed data from Japanese patients with breast cancer, who had received their first cycle of anthracycline and were treated with aprepitant, palonosetron, and dexamethasone with or without olanzapine. This retrospective observational study was performed at Ehime University Hospital using the electronic medical records. Multivariable and propensity score-adjusted analyses were performed to compare the onset of complete response (CR) failure between the groups. One-hundred and thirty patients were included in this study and the four- and three-drug group had 22 and 108 patients, respectively. Similar to multivariable logistic regression analysis, propensity-adjusted logistic regression analysis revealed that the four-drug group was markedly associated with a decreased odds of CR failure in the overall, acute, and delayed phases (odds ratio [OR]: 0.27, 95% confidence interval [CI]: 0.10-0.73; OR: 0.28, 95% CI: 0.10-0.76; and OR: 0.15, 95% CI: 0.04-0.57, respectively). Additionally, treatment-related adverse events were well tolerated in both the groups. These findings suggest that the antiemetic efficacy of the four-drug combination is superior to that of the standard three-drug combination.

[A Treatment Strategy against Double Presentation of Breast Cancer and Malignant Lymphoma].

Case 1 involved a 75-year-old woman with breast cancer and diffuse large B-cell lymphoma(DLBCL).Although we initially administered the R-CHOP regimen, the breast tumor increased in size and surgery had to be performed.After surgery, the R-CHOP regimen was re-initiated and DLBCL achieved clinical complete response.Case 2 involved a 74-year-old woman with breast cancer and gastric MALT lymphoma.After administration of rituximab and H. pylori eradication, a therapeutic effect was achieved in the lymphoma.A docetaxel and FEC regimen was continuously administered and surgery was performed. Case 3 involved a 62-year-old woman with breast cancer and follicular lymphoma.She presented with a history of DLBCL treatment.We performed mastectomy and sentinel lymph node biopsy, which revealed metastasis of breast cancer, and axillary lymph node dissection was subsequently performed.Considering the pathological stage, adjuvant chemotherapy was needed.We selected the TCH regimen based on her past treatment.In conclusion, it is necessary to treat patients with double presentation of breast cancer and malignant lymphoma through cooperation with different departments.

[A Case of Microangiopathic Hemolytic Anemia with Bone Marrow Carcinomatosis from Breast Cancer].

We report a case of microangiopathic hemolytic anemia(MHA)caused by metastatic breast cancer treated with weekly paclitaxel. A 58-year-old woman was diagnosed with metastatic breast cancer 2 years earlier. She was treated with various chemotherapy regimens and hormonal therapy, before being switched to fulvestrant 3 months earlier. She presented with severe anemia, and was diagnosed with MHA with bone marrow carcinomatosis following bone marrow biopsy. She was treated with weekly paclitaxel and recovered successfully. A subsequent biopsy showed that the bone marrow carcinomatosis had decreased. MHA due to breast cancer is rare and is associated with poor prognosis; however, rapid initiation of chemotherapy may be effective.

[A Case of Stage IV Breast Cancer with Long-Term Survival by Chemotherapy Developing Pulmonary Tumor Thrombotic Microangiopathy during the Treatment Course].

Pulmonary tumor thrombotic microangiopathy(PTTM)caused by pulmonary artery microscopic tumor emboli and fibrocellular and/or fibromuscular proliferation leads to progressive pulmonary hypertension and respiratory failure.The prognosis is extremely poor and most patients die shortly after onset.We report a patient with Stage IV breast cancer and long-term survival who developed PTTM during chemotherapy treatment.A 63-year-old woman with multiple metastases in her cerebellum, bone, lung, and lymph node after left breast conserving surgery started to experience dyspnea and malaise 7 years after the surgery.Two months later, she was urgently admitted to hospital because of respiratory failure and was diagnosed with pulmonary hypertension.However, pulmonary thrombosis and tumor thrombus were not observed.We clinically diagnosed her with PTTM and administered chemotherapy in addition to treatment for pulmonary hypertension.Her medical condition improved gradually and she survived for the subsequent 2 years.When observing progressive hypoxia and pulmonary hypertension without obvious pulmonary embolism findings on imaging, PTTM should be considered.Early diagnosis and immediate induction of chemotherapy for primary disease can improve the survival of patients with PTTM.