Case Presentation
In January 2016, a 38-year-old premenopausal woman was diagnosed with right-sided breast cancer at a medical institution in her home town, Iwaki City, Fukushima prefecture, Japan. As she preferred receiving care in an urban setting, she was referred to a university hospital in Tokyo, Japan, which is approximately 200 km away from Iwaki City in February 2016. After extensive examinations, she was diagnosed with hormone receptor-positive (estrogen and progesterone receptor-positive [both 3b]), human epidermal growth factor receptor 2-negative (2+ and dual color in situ hybridization equivocal) clinical T2N1M1 Stage IV breast cancer with asymptomatic multiple metastatic bone disease (right and left ilium, thoracic vertebras 4 and 7, and lumber vertebra 4) and symptomatic metastatic disease at a sternum.
In March 2016, endocrine treatment with tamoxifen, goserelin, and denosumab was initiated; however, it was switched to exemestane, goserelin, and denosumab in June 2017, after the computed tomography (CT) and breast ultrasonography showed an enlargement of the breast tumour and deterioration of bone metastases. Because local control could not be achieved using endocrine therapy alone, mastectomy and axillary dissection were performed in June 2019. The cancer subtype determined after the pathological analysis of surgical specimen was the same as that determined from the core needle biopsy performed for the initial diagnosis (estrogen and progesterone receptor-positive [3b and 3a], human epidermal growth factor receptor 2-negative [1+], Ki67 18%), and the same medical regimen was continued thereafter. In April 2020, she underwent a CT scan and the results revealed no signs of recurrence. Her last in-person visit to the university hospital was at the end of May 2020, when she received long-acting goserelin (effective for three months). Even though the Japanese government lifted the state of emergency by the end of May 2020, she refrained from visiting the university hospital in Tokyo from Fukushima due to the persistent epidemic of COVID-19 in Japan. Thereafter, her physician provided remote video consultations, namely in July and November 2020. Exemestane was prescribed virtually, and it was confirmed that her menses had not resumed. At this stage, her physician considered that a change in the prescribed regimen was not required because of the lack of evidence indicating disease progression and the difficulty in performing extensive follow-up which is mandatory after starting a new treatment. She and her physician had been looking for a medical institution near her home where she could undergo follow-up imaging regularly. However, they had been unable to find a suitable hospital for six months.
In November 2020, the patient was referred to our hospital. She had mild symptoms with an Eastern Cooperative Oncology Group Performance Status score of 1 just before visiting our hospital. Cancer antigen 15-3 and carcinoembryonic antigen levels were elevated to 87.2 U/ml and 7.6 ng/mL, respectively, and subsequent positron emission tomography in January 2021 revealed multiple liver metastases that were not detected in the examination by her previous doctor nine months ago. Even though cyclin-dependent kinase 4/6 inhibitors were available in Japan at the time, instead of these agents, chemotherapy with paclitaxel, bevacizumab and denosumab was initiated in January 2021, because we assumed that her disease condition had been rapidly worsening. Follow-up imaging performed in October 2021 revealed that liver metastases had shrunk in size.