I MWS- studiet var den relative risiko for brystcancer med konjugeret equin østrogen (CEE) eller estradiol (E2) større, når behandlingen var kombineret med gestagen, hvad enten dette var sekventielt eller kontinuerligt og uanset typen af gestagen.
In the MWS, the relative risk of breast cancer with conjugated equine oestrogens (CEE) or estradiol (E2) was greater when a progestagen was added, either sequentially or continuously, and regardless of type of progestagen.