What happened, in summary

A 43-year-old woman was diagnosed with a palpable left breast cancer that was estrogen- and progesterone-receptor negative and HER2-positive. She began neoadjuvant treatment with docetaxel, carboplatin, trastuzumab, and pertuzumab. Two days after the first cycle, she developed lower abdominal pain and visible blood in her urine with clots. Infection testing was negative, and the bleeding resolved after several days.

The same problem returned after her second cycle even though growth-factor support had been stopped. For the third cycle, docetaxel was replaced with paclitaxel while carboplatin, trastuzumab, and pertuzumab continued. She had no further episodes of bleeding and completed 6 cycles with a strong clinical and imaging response.

She then underwent mastectomy with sentinel lymph node biopsy. Pathology showed a complete response with no residual cancer. She completed radiation therapy and additional trastuzumab plus pertuzumab. At 2 years of surveillance, she had no evidence of breast-cancer recurrence and no further episodes of hematuria.