DCIS and aromatase inhibitors.

Area of Science:

• Oncology
• Endocrinology
• Pathology

Background:

• Tamoxifen is effective in reducing recurrence rates for hormone receptor-positive ductal carcinoma in situ (DCIS).
• Limited randomized study data exist for aromatase inhibitors (AIs) in DCIS.
• Previous studies suggest AIs may be effective in DCIS, with low event rates observed in ATAC and MA17 trials.

Purpose of the Study:

• To evaluate the therapeutic activity of aromatase inhibitors (letrozole and anastrozole) in ductal carcinoma in situ (DCIS).
• To assess the impact of AIs on progesterone receptor (PgR) expression and proliferation within DCIS.

Main Methods:

• Histological review of 27 patients with ER-positive invasive breast cancer and DCIS from a preoperative study.
• Patients received either letrozole (2.5mg) or anastrozole (1mg) for 14 days.
• Evaluated PgR activity and proliferation in DCIS from core biopsies and surgical specimens.

Main Results:

• Both letrozole and anastrozole significantly reduced PgR expression in DCIS.
• Both AIs significantly decreased proliferation within DCIS.
• Moderate agreement was observed between changes in PgR and proliferation in invasive cancer and DCIS components.

Conclusions:

• Aromatase inhibitors demonstrate significant therapeutic effects on DCIS.
• These findings indicate that aromatase inhibitors are active agents in the treatment of DCIS.
• Further research into AI efficacy for DCIS is warranted.