One of the focuses of Karma is to reduce the number of women diagnosed with breast cancer. There are several ways of decreasing the risk of breast cancer. Interventions range from increased physical activity to prophylactic mastectomy (surgically removing the breasts). The Karma Intervention Trial, Karisma, aims at identifying the optimal preventive dose of the anti-hormonal drug tamoxifen.
Tamoxifen is used by breast cancer patients to lower the risk of a breast cancer recurrence. It has been shown that perfectly healthy women lower their risk of breast cancer by 50% if they use tamoxifen. However, tamoxifen is not used for prevention due severe side effects.
It is not obvious that the same dose should be used for prevention as the dose given to breast cancer patients. We are therefore testing if lower doses of tamoxifen have the same therapeutic effect as clinically accepted 20 mg.