Chemoprevention with aromatase inhibitors--trial strategies

Area of Science:

• Oncology
• Endocrinology
• Cancer Prevention

Background:

• Estrogen and its metabolites play a key role in breast cancer development.
• Selective estrogen receptor modulators (SERMs) like tamoxifen and raloxifene are used for risk reduction, primarily in receptor-positive cancers.
• Aromatase inhibitors offer a potential alternative by blocking estrogen synthesis.

Purpose of the Study:

• To evaluate aromatase inhibitors as a breast cancer chemoprevention strategy.
• To compare the efficacy and safety of aromatase inhibitors with SERMs.
• To explore the potential of aromatase inhibitors in reducing both receptor-positive and receptor-negative breast cancers.

Main Methods:

• Ongoing adjuvant breast cancer trials are investigating aromatase inhibitors.
• Trials are comparing aromatase inhibitors to tamoxifen, or in sequence/combination with tamoxifen.
• Studies are assessing outcomes including contralateral breast cancer reduction, toxicities, and quality of life.

Main Results:

• SERMs have shown efficacy mainly in estrogen-progesterone receptor-positive tumors.
• Aromatase inhibitors have the potential to prevent cancer initiation by inhibiting parent estrogens and catechol metabolites.
• Ongoing trials aim to determine relative efficacies and toxicities of aromatase inhibitors.

Conclusions:

• Aromatase inhibitors represent a promising chemoprevention strategy for breast cancer.
• Further data from ongoing trials are crucial for guiding future prevention strategies.
• Trials are defining optimal use, including dose, schedule, and combination therapy, for high-risk populations.