Is the treatment for GATA3 and E-cadherin positive ductal carcinoma in situ (DCIS) different from that for human epidermal growth factor receptor 2 (HER2)-positive DCIS?

From the Guidelines

The treatment for GATA3 and E-cadherin positive ductal carcinoma in situ (DCIS) is generally not different from standard DCIS treatment, while HER2-positive DCIS may warrant additional targeted therapy considerations. For both types, the standard approach includes surgical excision (lumpectomy with clear margins or mastectomy) followed by radiation therapy for breast-conserving surgery. Hormonal therapy with tamoxifen (20mg daily for 5 years) or aromatase inhibitors like anastrozole (1mg daily for 5 years) is added for hormone receptor-positive cases. The key difference emerges with HER2-positive DCIS, which may be considered for anti-HER2 targeted therapy in clinical trials, though this is not yet standard practice 1. GATA3 and E-cadherin are primarily diagnostic markers that help identify the luminal subtype and confirm the ductal origin of the carcinoma, respectively, but they don't currently drive specific treatment changes. HER2 positivity, however, indicates a potentially more aggressive disease that might benefit from targeted approaches being investigated in research settings. Treatment decisions should always be individualized based on the patient's specific disease characteristics, extent, grade, and personal factors. Some studies suggest that the choice of treatment strategy is based on biology (pathology including biomarkers, gene expression) and tumour extent/location (size and location of primary tumour, number of lesions, number and extent of lymph node involvement) as well as on the age, body habitus and general health status of the patient and her/his preferences 1. The NCCN guidelines recommend surgical excision for DCIS, with options including lumpectomy plus whole-breast radiation therapy (WBRT) with or without boost, total mastectomy with or without sentinel lymph node biopsy (SLNB) and optional reconstruction, or lumpectomy alone in selected cases 1. It's also important to consider the patient's preferences and to discuss the potential benefits and risks of each treatment option. In summary, while GATA3 and E-cadherin positive DCIS may not require different treatment, HER2-positive DCIS may benefit from additional targeted therapy, and treatment decisions should be individualized based on patient-specific factors.

From the Research

Treatment Differences for GATA3 and E-cadherin Positive DCIS vs. HER2-Positive DCIS

• The treatment for GATA3 and E-cadherin positive ductal carcinoma in situ (DCIS) may differ from that for human epidermal growth factor receptor 2 (HER2)-positive DCIS, as the latter has been shown to benefit from targeted therapies such as trastuzumab 2, 3.
• HER2-positive DCIS has been found to express Her2/neu, making it a potential target for trastuzumab, a monoclonal antibody that has been effective in treating invasive breast cancer 2.
• Studies have investigated the use of trastuzumab in combination with radiation therapy for HER2-positive DCIS, with promising results 2, 3.
• In contrast, GATA3 and E-cadherin positive DCIS may not require targeted therapies, and treatment may focus on surgery, radiation, and hormone therapy, depending on the patient's specific characteristics and tumor biology.
• The decision to use targeted therapies such as trastuzumab should be based on the individual patient's tumor characteristics, including HER2 status, and should be made in consultation with a healthcare provider 2, 3.
• It is essential to note that the treatment of DCIS should be individualized, taking into account the patient's overall health, tumor characteristics, and personal preferences 4, 5, 6.

Key Considerations for DCIS Treatment

• The primary goal of DCIS treatment is to prevent the development of invasive breast cancer 4, 5.
• Treatment options for DCIS include surgery, radiation therapy, and hormone therapy, depending on the patient's specific characteristics and tumor biology 4, 5, 6.
• The use of trastuzumab and other targeted therapies may be considered for patients with HER2-positive DCIS 2, 3.
• Patients with DCIS should be closely monitored for signs of recurrence or progression to invasive breast cancer 4, 5, 6.