Chemotherapy resistance as a predictor of progression-free survival in ovarian cancer patients treated with neoadjuvant chemotherapy and surgical cytoreduction followed by intraperitoneal chemotherapy: a Southwest Oncology Group Study.

Purpose: In vitro testing of the activity of chemotherapeutic agents has been suggested as 1 method to optimally select drugs for patients with ovarian cancer. There are limited prospectively obtained data examining the clinical utility of this approach. We sought to obtain a preliminary assessment of this strategy in a trial that examined the administration of neoadjuvant chemotherapy followed by surgical cytoreduction and intraperitoneal chemotherapy in women with advanced ovarian cancer.

Methods: Women with stage III/IV epithelial ovarian carcinoma that presented with large-volume disease were treated with neoadjuvant intravenous paclitaxel and carboplatin for three 21-day cycles followed by cytoreductive surgery. If optimally debulked, patients received intravenous paclitaxel, intraperitoneal carboplatin and intraperitoneal paclitaxel for six 28-day cycles. Tumor cloning assay results (Oncotech) were correlated with progression-free survival.

Results: Sixty-two patients (58 eligible) were registered from March 2001 to February 2006. Thirty-six eligible patients had interval debulking and 26 received postcytoreduction chemotherapy. Twenty-two patients had tumor cloning assay results available. The clinical features of this population were similar to those of the larger group of women who entered this study. There was no difference in progression-free survival between patients whose cancers were defined as 'resistant' or 'nonresistant' to either platinum or paclitaxel.

Conclusions: While the small patient numbers in this trial do not permit definitive conclusions, these data fail to provide support for the argument that prospectively obtained in vitro data regarding platinum or paclitaxel resistance will be highly predictive of clinical outcome in advanced ovarian cancer.