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.