Making a difference in the lives of women with rare ovarian cancers
David M. Gershenson, M.D.
The Holy Grail of oncology is personalized cancer therapy. While patients with either malignant ovarian germ cell tumors or ovarian sex cord-stromal tumors, constituting two of the three major categories of ovarian cancer, have historically been treated on separate clinical trials, women with all types of epithelial tumors have been treated identically on the same trials over the past several decades.
With the explosion of information related to the molecular biology of ovarian cancer coupled with technological advances, continuing to study these epithelial cancers as a single disease entity is no longer acceptable.
In 2005, the Gynecologic Oncology Group (GOG), a National Cancer Institute - sponsored cooperative group, established the Rare Tumor Committee. The formation of this committee provided the impetus to begin to develop separate trials for women with three rare epithelial ovarian subtypes--clear cell carcinoma, low-grade serous carcinoma, and mucinous carcinoma.
These three subtypes each have a molecular signature distinct from the most common subtype, high-grade serous carcinoma, and several studies have underscored the fact that they also have very different clinical behavior.
Although this research strategy initially met with some resistance, since the GOG had built its reputation on completion of large phase III randomized trials, most oncologists and pharmaceutical companies are finally embracing it. At two recent national or international consensus conferences--the NCI Clinical Trials Planning Meeting in 2011 and the Gynecologic Cancer InterGroup Consensus Conference in 2010--these principles were endorsed.
The study of rare ovarian cancers is quite challenging. For clinical trials, the statistical design is of great importance. What is the research question? Are there a sufficient number of patients to complete accrual on the trial in a reasonable amount of time? Is this the best drug to study?
New focus by researchers stirs pharmaceutical company interest
For malignant germ cell tumors, we have had effective therapy since the 1980s. But now the emphasis is on postoperative surveillance for those girls and young women with early stage disease and avoidance of chemotherapy altogether.
For the other rare subtypes--sex cord-stromal tumors and the uncommon epithelial subtypes--current systemic treatments are not optimal. Thus, we need to continue the search for more effective agents. Within the GOG, essentially all of the trials for these rare tumors include the study of a novel targeted agent and a translational research component aimed at correlating treatment efficacy with molecular/genetic changes expressed as biomarkers.
In general, pharmaceutical companies have not been interested in developing drugs for orphan or niche diseases. However, with our enhanced understanding of the genes and pathways involved in the growth of these rare subtypes, the landscape is changing.
Increasingly, it is being recognized that these rare subtypes may be easier to conquer than high-grade serous carcinoma because of the latter's myriad complex molecular aberrations. More than ever before, this climate will be strengthened by the reverberating voices of patient advocates and their friends and families.
Our multidisciplinary group at MD Anderson has had a longstanding interest in the study of rare ovarian cancers. Over the next several months, we would like to feature various blogs focused on these rare subtypes. These articles will include patient stories, general information, and newsworthy scientific reports. Although progress is always slower than we wish, I am confident that a laser-sharp focus on our goal of eradicating rare ovarian cancers will result in ultimate success.