Maintaining Remission in Ovarian Cancer: Does More Chemotherapy make a Difference?

For women diagnosed with ovarian cancer, a significant and constant fear is recurrence. It always strikes me as nothing short of amazing that when faced with a potentially life-threatening diagnosis, women show such strength and resilience for the battle they now face: undergoing extensive surgery and then chemotherapy for 18 to 24 weeks. Some describe the chemotherapy as armor—weapons to fight the war raging inside of them. So, once it comes to stop treatment, what should be a time of joy for the battle won, is often not the case. It is a time of extreme anxiety as physicians and these women put away their weapons, to adopt a strategy of "watch and wait" or else known as "expectant observation."

Specialists in gynecologic cancer recognize that women diagnosed with ovarian cancer, particularly late ovarian cancer, do face significant odds that their disease will recur. In order to deter this risk, much effort has been placed in to the concept that more treatment may in fact decrease the risk of relapse, and prolong the period of being cancer free (so-called, relapse free survival). The use of chemotherapy in this context is referred to as "maintenance therapy." Yet, the use of chemotherapy in a maintenance strategy remains quite controversial.

In to this debate comes an interim analysis from Europe, published in the Journal of Clinical Oncology as an early release article. In this report by Pecorelli, et al, women with Stages IIB (pelvic extension) to IV (disease that has left the abdominal cavity to involve the liver, lungs, or other organs) were first treated with standard of care therapy (platinum+taxane based treatment); those who achieved a complete response (ie, remission) were then randomized to observation or to further treatment using paclitaxel for 18 weeks (6 courses given every 3 weeks). The study only enrolled 200 patients over a 7-year span, prompting the authors to perform an analysis so as to decide whether or not the trial was futile. In this analysis, there was a more than double risk of significant numbness, tingling, or functional deficits associated with paclitaxel at this schedule. In addition there was no benefit in either the progression-free or overall survivals noted at 2-years. This suggests that maintenance therapy in this setting is likely not effective.

For now, the use of maintenance treatment should be reserved on clinical trials. Currently the Gynecologic Oncology Group has such a trial ongoing; in GOG 212, women are being randomized to paclitaxel or paclitaxel poliglumex (CTI-2103 or Xyotax) or to placebo. It is an important trial that may hopefully once and for all answer the question of whether or not maintenance therapy is associated with improved relapse free survival, and ultimately, whether or not it also improves overall survival. These results are anxiously anticipated.

For more information:

S. Pecorelli, et al. Phase III Trial of Observation Versus Six Courses of Paclitaxel in Patients With Advanced Epithelial Ovarian Cancer in Complete Response After Six Courses of Paclitaxel/Platinum-Based Chemotherapy: Final Results of the After-6 Protocol 1. Journal of Clinical Oncology, 10.1200/JCO.2009.21.9691

C. McCourt, et al. Is there a taxane-free interval that predicts response to taxanes as a later-line treatment of recurrent ovarian or primary peritoneal cancer? Int J Gynecol Cancer. 2009 Apr;19(3):343-7.

Paclitaxel or Polyglutamate Paclitaxel or Observation in Treating Patients With Stage III or Stage IV Ovarian Epithelial or Peritoneal Cancer or Fallopian Tube Cancer. http://clinicaltrials.gov/ct2/show/NCT00108745.