What happened, in summary

A woman in her 50s had been living with metastatic HER2-positive, estrogen receptor-negative and progesterone receptor-negative invasive ductal breast cancer for 5 years. Her cancer had progressed through several chemotherapy and HER2-targeted combinations. One month before hospitalization, she started margetuximab 15 mg/kg on day 1 with gemcitabine 1,000 mg/m² on days 1 and 8 of a 21-day cycle. Margetuximab was stopped after an allergic reaction. She then received gemcitabine with trastuzumab-anns.

Within days of the next gemcitabine dose, she developed severe throbbing pain, blue-purple discoloration in the fingers of both hands and, to a lesser extent, the toes of both feet. The tip of her right fourth finger became black and numb. She had no history of smoking, diabetes, peripheral vascular disease, Raynaud phenomenon or autoimmune illness. The timing and workup pointed to gemcitabine-induced digital ischaemia rather than an autoimmune disorder.

Gemcitabine was stopped permanently. She received aspirin 81 mg daily, heparin 5,000 units every 8 hours, amlodipine 5 mg daily and 2% nitroglycerin ointment 3 times a day, along with pain medicines. The most severe pain lasted 3–4 days. Over the following weeks, circulation and color improved in her hands and feet. A small dry necrotic area remained on the right fourth fingertip at 3 months, but she did not need revascularisation, debridement or amputation.

Her cancer treatment then changed to weekly doxorubicin. After progression, she received carboplatin with trastuzumab, followed by capecitabine with neratinib after further progression. She remained in treatment for metastatic breast cancer at the last follow-up.