Updates and emerging therapies for rare epithelial ovarian cancers: one size no longer fits all

Low-grade epithelial ovarian cancer: a number of distinct clinical entities?

PURPOSE OF REVIEW

The purpose of this study is to summarize the contemporary understanding of low-grade epithelial ovarian cancers.

RECENT FINDINGS

Low-grade serous ovarian cancer is biologically distinct from high-grade serous ovarian cancer. It is associated with a high incidence of K-RAS and B-RAF mutations. Although described as indolent due to median progression-free and overall survivals of 20 and 99 months, respectively, with a median age of diagnosis of 43 years, it accounts for a significant number of patient-years lost. Retrospective studies suggest response rates of 5% for chemotherapy and 9% for antioestrogen therapy. A prospective study of the mitogen-activated protein kinase kinase inhibitor selumetinib (response rate 15%) and retrospective bevacizumab studies suggest that these may be more effective approaches.Limited retrospective clinical data and even more sparse molecular data suggest that similar distinctions may exist between low-grade endometrioid and mucinous ovarian cancers and their respective high-grade counterparts, but more research is required in order to clarify the biological differences and the implications that these have for management.

SUMMARY

The results of phase III mitogen-activated protein kinase kinase inhibitor studies in low-grade serous ovarian cancer and further clinical and biological assessment of low-grade endometrioid and mucinous ovarian cancers are urgently required.

Current and emerging treatment options in the management of advanced ovarian cancer

INTRODUCTION

Epithelial ovarian cancer is the most lethal gynecologic malignancy. Recent advances in understanding the biology and its molecular and histological diversity have led to mechanism based therapeutic strategies such as poly-ADP-ribose polymerase inhibitors (PARP) targeting homologous recombination deficient tumor cells and anti-angiogenic therapies. Clinical trial designs in ovarian cancer have to evolve to incorporate assessment of the genomic complexity and identify predictive biomarkers to improve precision of treatment and outcome.

AREAS COVERED

This review summarizes present-day strategies used in the management of ovarian cancer and novel promising therapeutic approaches in development. The article is based on English peer-reviewed articles located on MEDLINE and related abstracts presented at major international meetings.

EXPERT OPINION

Two types of molecular targeted therapies, anti-angiogenics and PARP inhibitors, have been shown to be active in randomized clinical trials and approved by regulatory agencies. Management of ovarian cancer is poised to change with the continued advancement of precision medicine that is founded upon improved understanding of disease biology; separation into histologically and molecularly defined subgroups; and the incorporation of this new knowledge into early phase drug development and novel clinical trial design.

Paradigm Shift in the Management Strategy for Epithelial Ovarian Cancer

The hypothesis on the pathogenesis of epithelial ovarian cancer continues to evolve. Although epithelial ovarian cancer had been assumed to arise from the coelomic epithelium of the ovarian surface, it is now becoming clearer that the majority of serous carcinomas arise from epithelium of the distal fallopian tube, whereas clear cell and endometrioid cancers arise from endometriosis. Molecular and genomic characteristics of epithelial ovarian cancer have been extensively investigated. Our understanding of pathogenesis of the various histologic types of ovarian cancer have begun to inform changes to the strategies for management of epithelial ovarian cancer, which represent a paradigm shift not only for treatment but also for prevention, which previously had not been considered achievable. In this article, we will discuss novel attempts at the prevention of high-grade serous ovarian cancer and treatment strategies for two distinct entities in epithelial ovarian cancer: low-grade serous and clear cell ovarian carcinomas, which are relatively rare and resistant to conventional chemotherapy.

Ovarian cancer outcomes: Predictors of early death

OBJECTIVE

To describe the outcomes and mortality in advanced ovarian cancer patients in a population-based cohort in the 90 days after diagnosis.

METHODS

Using the linked Surveillance, Epidemiology and End Results (SEER)-Medicare database, we identified a cohort of women with stage III/IV epithelial ovarian cancer diagnosed between 1995 and 2007. A χ(2) test was used to assess demographic and clinical factors. Kaplan-Meier curves and Cox proportional hazards models were used to assess factors associated with variation in survival.

RESULTS

Of the 9491 patients with stage III/IV ovarian cancer identified from the SEER/Medicare system, 4131 (43.6%) patients died in the first year after diagnosis. Of these, 2472 (26.0%) patients died in the first 90 days after diagnosis. Over the study period, the number of patients who died in the first 90 days after diagnosis slightly increased (p=0.053). Older age (>75 years of age), increased comorbidity, stage IV disease, lack of a visit with a gynecologic oncologist, and surgery were associated with an increase in 90-day mortality. Chemotherapy was associated with a reduction in 90-day mortality.

CONCLUSIONS

Approximately 25% of patients with advanced ovarian cancer in our study period died within 90 days of diagnosis, and more than 40% died within the first year of diagnosis. In addition, a substantial proportion of patients did not receive any treatment. Further research into the characteristics of these patients should be performed to elucidate clinical areas for intervention to either prevent these poor outcomes or allocate appropriate resources to patients with extremely poor prognoses.