HER2-Positive Invasive Ductal Breast Cancer Treated After Chemotherapy-Related Hemorrhagic Cystitis

What happened, in summary

A 53-year-old woman was diagnosed with invasive ductal carcinoma of the left breast that was estrogen-receptor positive, progesterone-receptor positive, and HER2-positive. She began neoadjuvant treatment with docetaxel, carboplatin, trastuzumab, and pertuzumab. Two days after the first cycle, she developed visible blood in her urine and abdominal discomfort. Testing did not support a urinary infection, and the bleeding resolved after several days.

For the next cycle, docetaxel was replaced with paclitaxel while the other breast-cancer medicines continued. She had no further episodes of hematuria and completed neoadjuvant therapy with a strong clinical and imaging response.

She then underwent lumpectomy with sentinel lymph node biopsy. Pathology showed only a 0.4 cm residual tumor. She completed breast radiation and 12 cycles of trastuzumab emtansine, then started anastrozole. At 2 years of surveillance, there were no signs of malignancy and the urinary bleeding had not returned.