Lundgren S
Department of Oncology, Regional and University Hospital of Trondheim, Norway.
Acta Oncol. 1992;31(7):709-22. doi: 10.3109/02841869209083859.
The two most widely used synthetic progestins in breast cancer treatment, medroxyprogesterone acetate (MPA) and megestrol acetate (MA), are reviewed with regard to pharmacological, endocrinological and clinical aspects. In high oral doses as second- or first-line endocrine therapy in advanced breast cancer, they give a similar response rate as tamoxifen (TAM) and aminoglutethimide (AG). The mechanism of action is probably complex. Considerable changes in serum levels of different hormones are induced by progestin treatment. The decrease of serum estrone sulfate (E1S) may be part of the therapeutic mechanism. Some studies suggest that the two drugs, MPA and MA, have a different mode of action, and possibly a low cross resistance. Randomized studies using the two progestins with a cross-over design may answer these questions. Further studies on the influence of progestin on different receptors and growth factors are warranted. To determine the most effective clinical dose of the two progestins, studies with increasing therapeutic doses are needed.
对乳腺癌治疗中使用最广泛的两种合成孕激素，醋酸甲羟孕酮（MPA）和醋酸甲地孕酮（MA），从药理学、内分泌学和临床方面进行了综述。在晚期乳腺癌中，作为二线或一线内分泌治疗使用高口服剂量时，它们的有效率与他莫昔芬（TAM）和氨鲁米特（AG）相似。其作用机制可能很复杂。孕激素治疗会引起不同激素血清水平的显著变化。血清硫酸雌酮（E1S）的降低可能是治疗机制的一部分。一些研究表明，MPA和MA这两种药物作用方式不同，可能交叉耐药性较低。采用交叉设计使用这两种孕激素的随机研究可能会回答这些问题。有必要进一步研究孕激素对不同受体和生长因子的影响。为确定这两种孕激素最有效的临床剂量，需要开展治疗剂量递增的研究。
