The Risk of Uterine and Ovarian Cancer for Different Formulations of Hormone Therapy (HT)

Abstract

Little has been published about the impact of different HT formulations or ways of administration on gynecological cancer risk. Two population-based case-control studies in collaboration with regional cancer registries and tumor centers in Germany were performed. Some 777 cases of ovarian cancer (OvC) and 1026 cases of uterine corpus cancer (UC) were compared with 3211 and 3668 matched controls for OvC and UC, respectively. The adjusted odds ratios for risk of cancer were 0.7 (0.6 -0.9) and 0.8 (0.7 -0.99) for OvC and UC for ever vs never use of HT. No clinically relevant trends for OvC and UC risk were observed with increasing duration of HT or with time since first/last use for ever or current use, in all and in postmenopausal women. Oral, transdermal, and other ways of HT administration were not associated with increased OvC or UC risk: nonsignificant adjusted ORs ranged between 0.6 and 1.3. Sequential and continuous-combined HT formulations showed reduced risk of OvC and UC, predominantly non-significant. This was similar for different types of estrogens and progestins. Combinations of CEE and MPA showed no other OvC/UC risk than combinations without CEE an MPA. In this study, HT use was not associated with an increased risk of OvC or UC and did not vary markedly among different HT formulations (estrogens, progestins, oral, and transdermal administration). However, small numbers and other limitations suggest cautious interpretation.