NCIt definition : A synthetic derivative of progesterone with antiestrogenic activity. Megestrol binds
to and activates nuclear receptors which subsequently bind to and activate target
genes for transcription. As an antiestrogen, this agent may inhibit the growth-stimulating
effects of estrogen on estrogen-sensitive tumor cells. In addition, megestrol stimulates
appetite in cachectic subjects.;
Alternative definition : NCI-GLOSS: A drug used to block estrogen and suppress the effects of estrogen and
androgens. It is used to treat breast and endometrial cancer, and is being studied
in the treatment of other types of cancer. It is also used to improve appetite in
patients with cancer. Megestrol belongs to the group of hormones called progestins.;