Journal Club - September 2004

Survival outcomes in patients with recurrent ovarian cancer who were treated with chemoresistance assay-guided therapy.
Loizzi V, Chan JK, Osann K, Cappuccini F, DiSaia PJ, Berman ML.
Am J Obstet Gynecol 2003; 186: 1301-1307. [Abstract]

Summary
This was a retrospective case-control study to determine the effect of extreme drug resistance (EDR) assay directed chemotherapy on the survival outcome of patients with recurrent epithelial ovarian cancer. The study group consisted of 50 patients who had recurrent ovarian cancer and were treated with EDR assay directed therapy, while the control group consisted of 50 patients who were matched according to other prognostic variables but received empirically chosen chemotherapy (at the discretion of the treating physician). Patients were analyzed separately according to whether they had platinum-sensitive disease (n=31 in each group) or platinum-resistant disease (n=19 in each group). Within the platinum-sensitive cohort, 28 patients in both the EDR assay directed group and the control group underwent secondary cytoreductive surgery prior to receiving salvage chemotherapy, although data on the volume of residual disease was not reported. In the platinum-sensitive group, patients with EDR assay directed therapy were found to have a superior clinical outcome compared to patients receiving empiric therapy along the following parameters: overall response rate (65% vs 35%, p=0.02), median progression-free survival (15 months vs 7 months, p=0.0002), and median overall survival (38 months vs 15 months, p=0.005). In patients with platinum-resistant disease, the use of EDR assay directed therapy did not have a measurable effect on clinical outcome. In a multivariate analysis controlling for the effects of other clinical variables, platinum-sensitive disease, the use of EDR assay directed therapy, and early-stage ovarian cancer were independently associated with an improved survival outcome.

Discussion
The limitations of this study are its retrospective design and the relatively limited number of patients in both the platinum-sensitive and platinum-resistant groups. In addition, the absence of information regarding residual disease following secondary cytoreductive surgery makes it impossible to control for this important survival determinant. The strengths of this study are the well-balanced stratification of patients between the experimental and control groups and the relative uniformity of the treatment approach.

Conclusion
The results of this study suggest that the use of EDR assay directed chemotherapy following secondary cytoreductive surgery for recurrent ovarian cancer may be associated with improved clinical outcome compared to patients that are treated on an empiric basis. Further study of this use of the EDR assay, preferably through a randomized and prospective study design, is warranted.

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