HER2-positive left breast cancer treated with trastuzumab and mastectomy

What happened, in summary

A 65-year-old woman had been diagnosed at age 53 with locally advanced grade 2 invasive ductal carcinoma of the left breast. The tumor was ER-negative, PR-negative, and strongly HER2/CerbB2-positive. BRCA1/2 testing found no known pathogenic mutation. She received three neoadjuvant cycles of docetaxel and trastuzumab at 21-day intervals. Doxorubicin was offered, but she declined because of concerns about cardiac toxicity. The tumor decreased in size, and she underwent left mastectomy with sentinel lymph-node biopsy in May 2008; the sentinel node was free of metastasis. She then received five adjuvant cycles of docetaxel and trastuzumab, followed by trastuzumab 330 mg every 21 days to complete 12 months of HER2-directed treatment. At the 12-month follow-up, a separate in situ lobular carcinoma was found in the right breast and treated independently. Later multigene testing identified a FANCA P1222L variant of uncertain significance. The finding was explored as a possible research lead, not a confirmed cause of her cancers. At the latest follow-up, she was alive, asymptomatic, and undergoing annual laboratory and imaging surveillance without recurrent disease. She said that searching for a possible explanation helped her focus on treatment and feel that the illness was not her fault.