Introduction
cancer, tumor, primary breast cancer, breast cancer
CANCER, TUMOR, SECONDARY, BREAST CANCER
Neoadjuvant treatment of breast cancer is applied to an increasing extent with the aim of downstaging the tumor to allow for breast conserving surgery, especially in HER2 positive and triple negative breast cancerIn contrast to tocopherols, the potential of the tocotrienol isoforms has been investigated in clinical studies to a much lesser extentOnly few studies have investigated the potential of tocotrienol in a clinical cancer settingResponse to neoadjuvant breast cancer treatment is known to vary, and there is a need for sensitive and valid methods for response evaluation to ensure adequate neoadjuvant treatment for the individual patient without inducing unnecessary side effects of ineffective treatment. Circulating tumor DNA (ctDNA) has been studied as prognostic and predictive biomarkers in early breast cancer patients undergoing neoadjuvant therapy. A recent study reports that persistence of ctDNA during neoadjuvant treatment is associated with poor tumor responseThe primary aim of the present study was to investigate the clinical effect of delta-tocotrienol combined with standard neoadjuvant treatment in a randomized, controlled phase II trial in primary breast cancer. The secondary aim was to develop a universal droplet digital polymerase chain reaction (ddPCR) assay for detection of ctDNA and its possible association with treatment response and survival.