[A Case of Recurrent Breast Cancer with Delayed Wound Healing Induced by Bevacizumab].

Bevacizumab plus paclitaxel therapy for recurrent breast cancer did not prolong overall survival(OS)in clinical trials, but it was efficacious for treating life-threatening HER2-negative recurrent breast cancer. This regimen is often used in daily clinical practice by breast surgeons. However, bevacizumab therapy results in unique adverse events, of which proteinuria and hypertension are relatively frequent. Moreover, the symptoms often improve on reducing the dose or discontinuing the drug. In this case, bevacizumab administration caused delayed wound healing, making subsequent anticancer treatment difficult, and consequently we could not prolong the patient's life.

[A Case of COVID-19 Infection during Postoperative Chemotherapy for Breast Cancer Treated with Antibody Cocktail Therapy to Prevent Disease Aggravation].

The outbreak of COVID-19 has caused a global pandemic, and it has been reported that patients with cancer are at high risk of developing complications from the disease. However, we believe that prolonged interruption of chemotherapy due to extended COVID-19 treatment is not desirable, given the intensity of cancer treatment. We report a case of COVID-19 infection during postoperative chemotherapy for breast cancer, in which antibody cocktail therapy prevented disease aggravation and delayed breast cancer treatment. The patient is a 45-year-old woman who came to our hospital with a complaint of a right mammary mass. The mass was diagnosed as invasive ductal carcinoma with an ER and PR of 0%, a HER2 score of 1+, and a Ki-67 of 90%. After preoperative chemotherapy, she underwent a right mastectomy and axillary dissection. The pathology result showed non-pCR. The administration of capecitabine was started as adjuvant therapy. On day 8 of cycle 3, she developed a fever in the 39℃ range, and on the next day, a COVID-19 POC gene test confirmed that the patient was positive for infection. On the same day, neutralizing antibody drugs(casirivimab and imdevimab)were administered as antibody cocktail therapy. Two days after treatment(day 11), a blood test showed Grade 3 neutropenia, but there was no recurrence of fever or evidence of pneumonia. After 2 weeks, capecitabine was resumed, and the patient was able to complete 8 cycles of capecitabine therapy without any major complications.

[ESR1 Mutation-Positive Recurrent Breast Cancer Successfully Treated with Letrozole plus Abemaciclib].

Approximately 70% of breast cancers are estrogen receptor(ER)positive, an indication for endocrine therapy. The first choice of treatment for ER-positive metastatic recurrent breast cancer is endocrine therapy, which has relatively few side effects; however, many of these side effects become resistant during treatment. One of the resistance mechanisms is mutations in the ESR1 gene, which have also been found to occur after long-term aromatase inhibitor(AI)treatment. Here, we describe our experience of a case in which long-term PR was achieved with AI(letrozole)plus abemaciclib despite ESR1 mutation positivity in cancer genetic screening and review the literature.

[Olaparib Could Be Re-Administered after Chemotherapy].

Olaparib, a PARP inhibitor, was approved in 2018 for BRCA1/2 gene mutation and HER2-negative inoperable or recurrent breast cancer with previous chemotherapy. Olaparib is an important drug with minor adverse events compared to chemotherapeutic drugs. In addition, it is expected to exert a high therapeutic effect on breast cancer with BRCA mutations due to its characteristics. We report a case of BRCA2-mutated breast cancer in a patient in whom olaparib was initiated. The patient complained of strong nausea; however, the treatment could be continued by reducing the dose of olaparib to 400 mg and using multiple drugs such as antiemetics and anxiolytics in advance.

[A Case of Severe Drug-Induced Lung Injury during Preoperative Chemotherapy for Breast Cancer in the Early Stages of the COVID-19 Epidemic].

Drug-induced interstitial lung disease(DILD)is defined as a drug-related respiratory disorder that occurs during drug administration. For diagnosis, it is important to differentiate similar diseases. We report a case of severe drug-induced lung injury during preoperative chemotherapy for breast cancer in the early stages of the COVID-19 epidemic, which was difficult to diagnose. The patient was a 48-year-old woman. The chief complaint was fever and dyspnea. She was diagnosed with left breast cancer(ER 30-40%, PR 0%, HER2 1+, Ki-67 84%), cT4bN1M0, cStage ⅢB and was treated with dose-dense AC therapy and docetaxel sequentially as preoperative chemotherapy. On the 21st day of the first course of docetaxel, the patient developed respiratory failure. A CT scan of the chest showed diffuse ground-glass shadows in the bilateral lung fields, suggesting severe viral pneumonia caused by COVID-19, and the patient was admitted to the isolation ward and managed with an intubated ventilator. PCR and LAMP were negative, and COVID-19 was ruled out. Based on the clinical course and CT findings, we started steroid pulse therapy with DILD in mind. The patient was extubated on the 5th day after the onset of the disease because the steroid pulse therapy was successful and her respiratory condition was stable. Preoperative chemotherapy was stopped, and a left mastectomy and axillary dissection were performed. In this case, COVID-19 should have been suspected first, but we were able to minimize the interruption of treatment by taking early action and keeping DILD in mind.