乳がん：現在の研究

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Long Term Trastuzumab in Metastatic Setting of the Patients with HER2 Positive Breast Cancer

Smichkoska S and Lazarova E

Empirically, trastuzumab has been continued in many patients with disease progression, mainly due to its favourable safety profile and the assumption that progression was due to resistance to the co-administered chemotherapeutic agent but not trastuzumab itself. Retrospective analyses provided some support for this treatment approach. Retrospectively were analyzed records of 11 patients with relapsing HER2 overexpressed breast cancer exposed to long-term trastuzumab therapy concurrently with multiple lines of chemotherapy or hormonotherapy according to the subsequent relapse of the disease. We evaluated the initial stage of the disease, site of relapse, median time to progression (TTP), median duration of response to first line therapy for metastatic, and duration and toxicity of long term trastuzumab. The starting points were the date of initial diagnosis of breast cancer and the date in which trastuzumab-based therapy started as a result of distant relapse of the disease. The dates of tumor and tumor progression were used to calculate median TTP. Eleven women with median age of 44.0 years (range 38-57) were included. 45.5% were pre-treated with trastuzumab-based therapy in adjuvant setting. Visceral metastases were identified in 7 patients (64%) and bone/soft tissue in 4 (36%). Median time to progression (TTP) was 43 months (range 13-115 months). Median duration of response to first line therapy concurrently with trastuzumab was 20 months (range 8-45 months). Median duration of trastuzumab therapy was 44 months (range 15-93 months). No unexpected toxic effects occurred. At a median follow-up of 37 months (range 15–93 months) from the start of rechallenge with trastuzumab-based first line therapy, 1 patient had died and 10 are still on trastuzumab therapy. Trastuzumab paired with a standard chemotherapy as starting treatment can also be continued alone, with subsequent chemotherapy or with hormone-blocking medications. Long-term trastuzumab-based therapy showed clinical benefit. In women at higher risk of recurrence and with no signs of a weak heart, long term trastuzumab offers far more benefits than risks