The aim of the Karisma trial is to find out if lower doses of tamoxifen have fewer side effects without lowering the risk-reducing effect. Tamoxifen has been used to prevent breast cancer recurrence in patients for 30 years. Healthy women who take tamoxifen have a 40-50% reduced risk of breast cancer, but the medicine may cause side effects. The side effects of tamoxifen are hot flashes, sweating, mode swings, weight gain, vaginal discharge, etc. There is also a risk of more severe side effects such trombo-embolism.
In February 2017 recruitment of 1,440 women started at the South General Hospital, Stockholm. Women attending the national mammography-screening program are invited to participate. After informed consent participants are randomised to 20, 10, 5, 2.5, 1 mg of tamoxifen and placebo. Outcome is change in mammographic density and women are treated for 6 month. Mammograms are taken at baseline and end of treatment. In addition to the randomized controlled trial we measure metabolites of tamoxifen, polymorphism of key metabolising genes (e.g CYP2D6) and female sex hormones.
Inclusion and follow up of last participant was finished in October 2019. First paper from the trial published in March 2021