Trastuzumab (Herceptin) for Ductal Carcinoma in Situ of the Breast

The potential for reduction of tumor burden and abrogation or reversal of the hypothesized transition from in situ disease to invasive disease is not beyond the realm of possibility, as we know that DCIS avidly expresses Her2/neu, even more readily than does invasive carcinoma of the breast.^10-12 To test this hypothesis, a trial of neoadjuvant trastuzumab for DCIS has been opened at M. D. Anderson Cancer Center. The risk of cardiac toxicity associated with 1 or 2 doses of trastuzumab in this trial is believed to be minimal, although the safety profile of this approach will need to be closely monitored. Because trastuzumab has been shown to act as a radiosensitizing agent for Her2/neu-overexpressing cancer and because no systemic treatments are currently available for ER-negative DCIS, use of this agent in conjunction with postoperative radiation therapy may represent a novel approach to local control of disease.