Functional estrogen receptor signal transduction pathway activity and antihormonal therapy response in low-grade ovarian carcinoma.

BACKGROUND: Advanced low-grade ovarian carcinoma (LGOC) is difficult to treat. In several studies, high estrogen receptor (ER) protein expression was observed in patients with LGOC, which suggests that antihormonal therapy (AHT) is a treatment option. However, only a subgroup of patients respond to AHT, and this response cannot be adequately predicted by currently used immunohistochemistry (IHC). A possible explanation is that IHC only takes the ligand, but not the activity, of the whole signal transduction pathway (STP) into account. Therefore, in this study, the authors assessed whether functional STP activity can be an alternative tool to predict response to AHT in LGOC. METHODS: Tumor tissue samples were obtained from patients with primary or recurrent LGOC who subsequently received AHT. Histoscores of ER and progesterone receptor (PR) were determined. In addition, STP activity of the ER STP and of six other STPs known to play a role in ovarian cancer was assessed and compared with the STP activity of healthy postmenopausal fallopian tube epithelium. RESULTS: Patients who had normal ER STP activity had a progression-free survival (PFS) of 16.1 months. This was significantly shorter in patients who had low and very high ER STP activity, with a median PFS of 6.0 and 2.1 months, respectively (p < .001). Unlike ER histoscores, PR histoscores were strongly correlated to the ER STP activity and thus to PFS. CONCLUSIONS: Aberrant low and very high functional ER STP activity and low PR histoscores in patients with LGOC indicate decreased response to AHT. ER IHC is not representative of functional ER STP activity and is not related to PFS.

The progression-free survival ratio as outcome measure in recurrent ovarian carcinoma patients: Current and future perspectives.

Objective: Clinical efficacy of cytostatic anticancer agents can be determined with the progression-free survival (PFS) ratio. This outcome measure compares PFS achieved by a new treatment (PFS2) to the PFS of the most recent treatment on which the patient has experienced progression (PFS1). Clinical benefit has been defined as a PFS-ratio (PFS2/PFS1) > 1.3. However, in order to demonstrate significant benefit, trial designs require an assumption on the proportion of patients who reach this ratio during palliative options. For ovarian carcinoma, data is lacking to support this assumption. Therefore in this study, we assess the PFS-ratio in recurrent ovarian carcinoma patients treated with current palliative options. Methods: We included 67 patients with recurrent high-grade serous (HGSC, 73.1%) or low-grade (LGOC, 26.9%) ovarian carcinoma. We determined the median PFS-ratio and investigated the association with clinicopathological characteristics. Results: Overall, we observed a median PFS-ratio of 0.69. The proportion of patients with a PFS-ratio > 1.3 was 22.4%. For HGSC patients, the median PFS-ratio was significantly lower than for LGOC patients (respectively, 0.58 and 1.26, p = 0.007). Multivariate logistic regression analysis revealed that the LGOC subtype and CA125 tumor marker concentration were independent factors related to a PFS-ratio > 1.3. Conclusions: Although the PFS-ratio represents a meaningful outcome measure in studies investigating cytostatic anticancer agents, we conclude that it is influenced by tumor histology and biological behavior. In future research, these factors should be taken into account when determining thresholds for clinical benefit in trial designs.