Breast Cancer Recurrence in the Small Intestine and Bone More Than 5 Years After Diagnosis

What happened, in summary

A 50-year-old woman was diagnosed with invasive lobular cancer of the left breast in December 2018. She underwent modified radical mastectomy, and 27 of 28 axillary lymph nodes contained cancer. The tumor was estrogen- and progesterone-receptor positive and HER2-negative. She then received 4 cycles of epirubicin and cyclophosphamide followed by 4 cycles of paclitaxel, local radiation, and endocrine therapy with anastrozole and goserelin.

In June 2023, more than 4 years after her original treatment, she developed upper abdominal discomfort. Imaging and endoscopy raised concern for cancer involving the bowel and also showed widespread bone lesions. Abdominal surgery found a tumor in the small intestine. A partial ileal resection confirmed metastatic lobular breast cancer, and metastatic disease was also found in the right fallopian tube. The ovaries were free of cancer.

The metastatic tumor no longer expressed estrogen or progesterone receptors and was HER2-negative by FISH. She then received 9 cycles of trastuzumab deruxtecan. At 1-year follow-up after the recurrence, she was alive with multiple bone metastases. This places her documented survival at more than 5 years from her December 2018 breast-cancer diagnosis.