Metastatic Breast Cancer With Recurrent Severe Hypocalcemia During Treatment - Case 1

What happened, in summary

A 35-year-old woman was diagnosed with right invasive lobular breast cancer that was estrogen- and progesterone-receptor positive and HER2-negative. The cancer was Stage II at diagnosis. She underwent a total right mastectomy with sentinel lymph-node biopsy and then received adjuvant endocrine therapy with leuprorelin and tamoxifen.

Five years after diagnosis, the cancer recurred in the bone, liver, and ovaries. She received additional endocrine treatment together with denosumab. By year 7, progression led to chemotherapy with S-1. During treatment she developed severe symptomatic hypocalcemia and required hospitalization and intensive calcium replacement. After switching to eribulin, severe hypocalcemia recurred. Denosumab was stopped and calcium plus calcitriol were used, allowing eribulin to continue at reduced doses without another episode.

In year 9, after 18 months of eribulin, treatment was changed to epirubicin and cyclophosphamide. The regimen was stopped after one cycle because her liver metastases worsened. She was transferred to a palliative-care hospital and died. Her documented course therefore spans about 9 years from the original breast-cancer diagnosis to death.