Over half of breast cancer patients discontinue their adjuvant hormone therapy, permanently or temporarily. We aimed to identify predictors of treatment restarting after discontinuation of adjuvant hormone therapy and to test the hypothesis that treatment restarting is associated with better breast cancer outcomes.
We conducted a population-based cohort study by linking data from the Stockholm-Gotland Breast Cancer Register, the Swedish Prescribed Drug Register, and a self-reported questionnaire. We followed women diagnosed with breast cancer (Stockholm, Sweden, 2005-2008) from their first prescription of tamoxifen or aromatase inhibitors through January 31, 2015, and categorized them as continuers (n?=?1 607), restarters (n?=?953), and nonrestarters (n?=?511) of adjuvant hormone therapy. All statistical tests were two-sided.
Factors that decrease the likelihood of treatment restarting included younger age (