Neoadjuvant Tamoxifen in Locally Advanced Breast Cancer in a Low/Middle Income Country

This is a single arm feasibility study of neoadjuvant tamoxifen for locally advanced hormone receptor positive breast cancer in a low-resource setting in a middle-income country (Guatemala). Patients will be treated with tamoxifen for four to six weeks, then have an on-treatment biopsy to assess Ki-67. If Ki-67 is less than or equal to 10%, the patient will continue on tamoxifen for a total of 4 months; if Ki-67 is greater than 10% or there is clinical progression, patients will be taken off study. The study will evaluate the proportion of patients treated with four months of tamoxifen who undergo definitive surgery and the clinical and pathologic response rates.

Inclusion criteria

• Patient evaluated and treated at INCAN
• Patients must provide informed consent
• Patient must be ≥ 18 years of age.
• Life expectancy ≥ 6 months
• Clinical locally advance breast cancer (Stage IIB or III)
• Pathologically confirmed diagnosis of estrogen receptor (ER)-positive or progesterone receptor (PR)-positive breast cancer with ER or PR Allred Score > 4
• Patient must have an ECOG Performance Status of 0-2
• Patients must be able to swallow and retain oral medication

Exclusion criteria

• Patient must not have received any prior chemotherapy, radiation therapy, or biologic therapy for invasive breast cancer within the past five years
• Patient must not be pregnant or nursing
• Patient must not have had any prior malignancy except for adequately treated basal cell (or squamous cell) skin cancer, in situ cervical cancer or other cancer for which the patient has been disease-free for five years.
• Women of childbearing age unable or unwilling to use contraception