[Locoregional recurrence of HER2-positive breast cancer - treatment after complete remission and long-term clinical benefits].

ABSTRACT

We report 7 cases of locoregional recurrence in human epidermal growth factor receptor 2 (HER2)-positive breast cancer that we treated. An early complete response (CR) and long-term response was achieved in 5 cases. There were 4 HER2- subtype and 3 Luminal HER2-type cases. Metastasis and recurrence were detected in the residual breast tissue and the supraclavicular, axillary, and parasternal lymph nodes. Chemotherapy consisting of trastuzumab was administered as first-line treatment. A CR was observed 3-4 months after the initiation of therapy in 4 cases, and the time to progression was 27.6- 65.8 months. After achieving a CR, 3 patients terminated treatment and 2 patients continued to take trastuzumab. However, due to adverse effects associated with the chemotherapy, 1 patient changed to endocrine therapy. A second, long-term, CR was achieved in 2 relapsed CR patients by re-challenging with the same chemotherapy regimen. Two patients did not achieve CR and died due to distant metastases. For a better quality of life, it is advisable to continue treatment after a clinical CR for solitary or more complex locoregional recurrences. Following the first-line therapy and a so-called chemoholiday, the patient's disease can be re-challenged using the previously sensitive regimen with careful observation.