Erlotinib-induced breast cancer regression.

Objective: To report a case of erlotinib-induced breast cancer regression.

Case Summary: A 38-year-old woman developed bilateral locoregional malignant cutaneous lymphangitis following a right subcutaneous mastectomy and 3 months of adjuvant chemotherapy. After several systemic chemotherapy regimens, the lymphangitis worsened rapidly, with progressive skin ulceration. Morphine and dexamethasone were given, with suboptimal pain control. A chemotherapy regimen of gemcitabine and vinorelbine was started. After 2 full-dose administrations, while lymphangitis continued to worsen, erlotinib 150 mg/day was added to the regimen. After 10 weeks of treatment, pain subsided and analgesics were discontinued. Physical examination revealed a partial regression of malignant cutaneous lymphangitis and pulmonary metastases, with resolution of ulceration.

Discussion: There has been increased interest in epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors in the treatment of breast cancer. Gefitinib has shown a low level of efficacy, while preliminary clinical data on erlotinib were not conclusive and suggested lack of clinical activity. Molecular analysis of the tumor in our patient revealed a profile predictive of response to EGFR selective inhibitors in some patients with lung cancer.

Conclusions: The addition of erlotinib to our patient's chemotherapy regimen resulted in antitumor activity in breast cancer in which an activated EGFR pathway was demonstrated. This finding is consistent with available preclinical and clinical data on EGFR tyrosine kinase inhibitors across tumor types and supports the efforts to optimize EGFR selective inhibitors in treating breast cancer and other malignancies.