Clinical benefit of post-trastuzumab deruxtecan treatment in patients with HER 2-positive unresectable or metastatic breast cancer: A single-institution retrospective observational study.

PURPOSE: Trastuzumab deruxtecan (T-DXd) can improve the prognosis of patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC). However, data on treatment recommendations after T-DXd are lacking. Thus, this study aimed to evaluate the treatment options after T-DXd and their effectiveness. METHODS: Patients with HER2-positive MBC were included in this study. Data from clinical records were retrospectively analyzed. The primary outcome was time to treatment failure (TTF). Secondary endpoints were TTF of each treatment and first-line treatment after interstitial lung disease (ILD) and overall survival (OS). RESULTS: A total of 29 patients were included. Among them, 18 (62%) were hormone receptor-positive. All patients had a median TTF (mTTF) of 3.5 months (95% confidence interval (CI) 2.1-10.03). The mTTF of each treatment, including HER2 tyrosine kinase inhibitor (HER2 TKI), other anti-HER2 treatments, and other treatments, was 2.6, 8.8, and 3.8 months, respectively. No significant differences were observed between treatments, but regimens that include trastuzumab showed a longer TTF than TKI. However, the mTTF among patients who developed T-DXd-related ILD was 2.33 months (95% CI 0.7-not reached), which was shorter than that among those who did not develop ILD (3.83 months, 95% CI 2.1-10.03, hazard ratio: 2.046, 95% CI 0.760-5.507, p = 0.258). The median OS was 14.9 months (95% CI 11.07-29.17). CONCLUSION: Treatments after T-DXd showed a shorter mTTF. Regimens that include trastuzumab may be more effective post-T-DXd treatment than HER2 TKI. Further data are needed to establish the best sequential treatment after T-DXd.

Single-dose trastuzumab monotherapy achieved pathological complete response (pCR) in a patient with HER2-positive breast cancer: a case report.

BACKGROUND: With advances in breast cancer treatment, the importance of de-escalation therapy to reduce harm during the treatment of elderly patients has attracted attention in recent years. Certain patient populations are expected to have a superior response to anti-HER2 drugs, particularly those with human epidermal growth factor receptor type 2 (HER2)-positive breast cancer. In this report, we describe our experience of dramatic anti-HER2 drug response in a patient who achieved pathological complete response (pCR) with a single dose of trastuzumab. CASE PRESENTATION: An 88-year-old woman presented with a 2-cm palpable mass in the left breast. Vacuum-assisted breast biopsy, ultrasonography, and positron emission tomography-computed tomography revealed estrogen receptor-negative and HER2-positive, T1N0M0, stage I breast cancer. Mastectomy was scheduled within 2 months of the initial visit; however, the patient was anxious about the length of the waiting period and requested medication in the interim. Therefore, prior to surgery, one cycle of trastuzumab monotherapy was administered at the discretion of the attending physician. Postoperative pathology showed no remnant of invasive carcinoma and pCR with only a 0.2-mm ductal carcinoma in situ remnant. The patient refused further medication after surgery because of severe diarrhea after trastuzumab administration. Postoperative treatment was limited to follow-up, and no recurrence was observed at 1 year and 6 months postoperatively. CONCLUSION: This case suggests that trastuzumab monotherapy may be effective in certain patients with HER2-positive breast cancer. In the future, identifying patients who are more likely to respond to trastuzumab, as in this case, will allow for more options regarding de-escalation therapy without chemotherapy, particularly in elderly patients who are concerned about the side effects of chemotherapy.

Satisfaction survey on a preoperative explanation method using three-dimensional breast imaging for breast cancer patients considering breast-conserving surgery.

PURPOSE: Although one of the essential factors in surgical shared decision-making is the body image, the breast morphology after breast-conserving surgery is particularly difficult to explain in a uniform manner due to large individual differences. METHODS: Patients with breast cancer eligible for breast-conserving surgery (BCS) were recruited between June 2020 and October 2021. We surveyed the patients' satisfaction with our method of explaining the likely breast morphology after BCS using three-dimensional (3D) breast imaging in the form of a questionnaire. RESULTS: A total of 162 patients were enrolled, and 137 (84.6%) answered the questionnaire. One hundred and sixteen patients (84.6%) answered that they were very satisfied or satisfied with our explanation method, and 100 (73.0%) patients were very satisfied or satisfied with the 3D breast imaging. Some patients answered that 3D breast imaging helped them prepare for BCS, or on the contrary, made them choose mastectomy with breast reconstruction because the deformation likely with BCS was considered unacceptable. Only a few patients who underwent BCS felt that their postoperative morphology was more deformed than the preoperatively imagined one. CONCLUSION: Our results suggest that our preoperative explanation method using 3D breast imaging was useful for shared decision-making.

Granulocyte colony-stimulating factor-associated aortitis in a woman with breast cancer: a case report.

BACKGROUND: Granulocyte colony-stimulating factor (G-CSF) is increasingly used to prevent chemotherapy-associated febrile neutropenia. Generally, aortitis is not considered a side effect of G-CSF and is thought to be extremely rare. Aortitis is an inflammation of the aorta and occurs mainly in connective tissue diseases (Takayasu arteritis, giant cell arteritis, etc.) and infectious diseases (bacterial endocarditis, syphilis, etc.). We report herein a rare case of G-CSF associated with aortitis in a woman with breast cancer. CASE PRESENTATION: Here, we present a case involving a 63-year-old woman with luminal type stage IIa breast cancer. The patient's treatment was initiated with docetaxel and cyclophosphamide, with pegfilgrastim (PEG-G) as support. After PEG-G administration on day 3, the patient developed an intermittent fever of up to 39.4 °C on day 10 and visited our outpatient clinic on day 13 with persistent high fever. Laboratory tests revealed a high neutrophil count (14,000/µL) and a high C-reactive protein (CRP) level (42.8 mg/dL) without any other abnormalities. Contrast-enhanced computed tomography scanning revealed soft tissue thickening with weak enhancement around the wall of the thoraco-abdominal aorta, aortic arch and left subclavian artery. The patient did not respond to antimicrobial agents. On the basis of these observations, the patient was diagnosed with PEG-G-induced aortitis, and her condition rapidly improved without corticosteroids. CONCLUSIONS: Clinicians should be aware of aortitis as a potential complication in patients undergoing G-CSF chemotherapy. In cases with persistent high fever after PEG-G administration, and in the absence of infection, aortitis should be suspected.

Time to Chemotherapy for Patients With Estrogen Receptor-Positive Breast Cancer and Cyclin-Dependent Kinase 4 and 6 Inhibitor Use.

PURPOSE: Safely postponing the use of chemotherapy is important for quality of life maintenance in patients with hormone receptor-positive advanced breast cancer. In previous studies, a combination of cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6i) and fulvestrant prolonged the time to chemotherapy (TTC). In this study, we used real-world data to evaluate TTC in the context of CDK4/6i therapy. METHODS: We performed a retrospective chart review of women with estrogen receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer treated at the Aichi Cancer Center Hospital. The patients were categorized into having received CDK4/6i therapy first (n = 41), second (n = 33), and none at all (n = 67). The change in TTC among the groups was examined. RESULTS: The median follow-up time was 13.8, 27.5, and 30.3 months in the CDK4/6i (first), CDK4/6i (second), and non-CDK4/6i groups, respectively. The median progression-free survival (PFS) with first-line therapy for metastasis was 30.0, 11.9, and 13.0 months, respectively (CDK4/6i [first] vs. non-CDK4/6i; p = 0.018, CDK4/6i [second] vs. non-CDK4/6i; p = 0.383). The median TTC was not reached in the CDK4/6i (first) group, was 39.1 months in the CDK4/6i (second) group, and was 44.2 months in the non-CDK4/6i group (CDK4/6i [first] vs. non-CDK4/6i; p = 0.880; CDK4/6i [second] vs. non-CDK4/6i; p = 0.407). The non-CDK4/6i group with TTC ≥ 60 months included more cases of secondary endocrine therapy resistance (p = 0.017), no perioperative chemotherapy (p = 0.021), and a longer disease-free interval (p = 0.093). CONCLUSION: Although PFS was significantly longer in the CDK4/6i (first) group than in the non-CDK4/6i group, TTC did not significantly differ among the three groups in real-world data. The non-CDK4/6i group showed a long TTC in patients with late recurrence and low risk at the primary lesion site, who benefited greatly from hormone monotherapy.