Tamoxifen or Letrozole in Treating Women With Ductal Carcinoma in Situ

RATIONALE: Estrogen can cause the growth of breast cancer cells. Hormone therapy using tamoxifen or letrozole may fight breast cancer by blocking the use of estrogen by the tumor cells or by lowering the amount of estrogen the body makes. PURPOSE: This clinical trial is studying how well tamoxifen or letrozole work in treating women with ductal carcinoma in situ.

OBJECTIVES: * Determine the clinical response in women with estrogen receptor-positive ductal carcinoma in situ (DCIS) treated with neoadjuvant hormonal therapy comprising tamoxifen or letrozole, by evaluating the maximal change in tumor diameter on mammography and MRI following treatment. * Identify those cellular antigens which are altered by hormonal therapy. * Determine which cellular antigens are predictive of clinical response to hormonal therapy. * Evaluate whether genomic changes or gene expression in DCIS are altered by hormonal therapy and find candidate genes which are correlated with response to treatment. OUTLINE: This is a pilot study. Patients who are premenopausal receive oral tamoxifen once daily for 3 months in the absence of unacceptable toxicity. Patients who are post menopausal receive oral letrozole once daily for 3 months in the absence of unacceptable toxicity. After 3 months of hormonal therapy, patients undergo lumpectomy or mastectomy. After completion of study treatment, patients are followed every 6 months for 5 years and then annually thereafter. PROJECTED ACCRUAL: A total of 40 patients will be accrued for this study.