Treatment strategies for endometrial cancer : current practice and perspective

Endometrial cancers have long been divided into estrogen-dependent type I and the less common clinically aggressive estrogen-independent type II. Little is known about risk factors for type II tumors because most studies lack sufficient cases to study these much less common tumors separately. We examined whether so-called classical endometrial cancer risk factors also influence the risk of type II tumors. Individual-level data from 10 cohort and 14 case-control studies from the Epidemiology of Endometrial Cancer Consortium were pooled. A total of 14,069 endometrial cancer cases and 35,312 controls were included. We classified endometrioid (n = 7,246), adenocarcinoma not otherwise specified (n = 4,830), and adenocarcinoma with squamous differentiation (n = 777) as type I tumors and serous (n = 508) and mixed cell (n = 346) as type II tumors. Parity, oral contraceptive use, cigarette smoking, age at menarche, and diabetes were associated with type I and type II tumors to similar extents. Body mass index, however, had a greater effect on type I tumors than on type II tumors: odds ratio (OR) per 2 kg/m(2) increase was 1.20 (95% CI, 1.19 to 1.21) for type I and 1.12 (95% CI, 1.09 to 1.14) for type II tumors (P heterogeneity < .0001). Risk factor patterns for high-grade endometrioid tumors and type II tumors were similar. The results of this pooled analysis suggest that the two endometrial cancer types share many common etiologic factors. The etiology of type II tumors may, therefore, not be completely estrogen independent, as previously believed.

Endometrial cancer is the most common gynecologic malignancy in the United States. Overactivation of the PI3K/AKT/mTOR pathway, a signaling pathway that plays an important role in cellular growth and survival, has recently been implicated in endometrial cancer pathogenesis, and as such, inhibition of the PI3K/AKT/mTOR pathway is of therapeutic interest. Preclinical and clinical studies are proving useful in elucidating the antitumor effects of different PI3K/AKT/mTOR pathway inhibitors, and in defining which patient populations these inhibitors might be most effective in. For example, an increasing amount of preclinical data suggest that loss of PTEN or genetic alteration of PIK3CA may be indicators of sensitivity to PI3K/AKT/mTOR pathway inhibition, while activating KRAS mutations may predict resistance. In the latter case, combined inhibition of the RAS/RAF/MEK and PI3K/AKT/mTOR pathways has been suggested as a therapeutic strategy. In addition, the PI3K/AKT/mTOR pathway has been implicated in conferring resistance to conventional therapies, and so PI3K/AKT/mTOR pathway inhibitors in combination with hormonal and/or cytotoxic agents are being evaluated. In conclusion, preclinical models are providing insights into the antitumor activity of PI3K/AKT/mTOR pathway inhibition, and are helping define patient populations most likely to benefit from these therapies. Clinical validation of these findings is ongoing. ©2012 AACR.