Recombinant interleukin-2 therapy for angiosarcoma of the breast; Efficacy of daily or weekly administration

We report the first case of recombinant interleukin-2 (rIL-2) therapy for breast angiosarcoma after mastectomy. We evaluated the changes of killing activity in peripheral blood mononuclear cells (PBMC) by the 51Cr-release assay. Daily intravenous administration of rIL-2 increased the natural killer (NK) cell population and enhanced cytotoxicity. After the cessation of daily rIL-2 administration for 4 weeks, the enhanced cytotoxicity was not maintained by weekly administration of rIL-2. Months after mastectomy, local and distal metastases were observed, despite this immunotherapy. These results suggest that immunotherapy with rIL-2 is insufficient treatment for breast angiosarcoma, and that other modalities such as chemotherapy should be taken in consideration for use in combination with immunotherapy.