HER2-Positive Mucoepidermoid Breast Cancer With 61 Months Without Recurrence

What happened, in summary

At age 58, a woman who had previously been treated for breast cancer in 1996 found a new lump in her left breast. Imaging showed a suspicious mass without distant metastases. She underwent a simple left mastectomy. Pathology identified a rare high-grade mucoepidermoid carcinoma with an associated in-situ component. The tumor was HER2-positive by testing, had only weak low-level estrogen-receptor expression, and was progesterone-receptor negative.

The pathology differed from her earlier 1996 breast cancer, and the authors concluded that this was a second primary rather than a late recurrence. After surgery, she received 12 weekly cycles of paclitaxel and 18 cycles of trastuzumab. Aromatase-inhibitor treatment was not given because of the low estrogen-receptor expression and the expected balance of benefit and side effects.

At the latest documented follow-up, 61 months after treatment, she was alive with no sign of recurrence. This gives a documented disease-free follow-up of just over 5 years for the mucoepidermoid breast cancer.