Early CA-125 Rise With Liposomal Doxorubicin May Not Reflect Response in Ovarian Cancer

A retrospective analysis of data from a previously reported randomized clinical study suggested that increases of the tumor marker CA-125 after cycles 1 and 2 of doxorubicin HCl liposome injection (Doxil) were not always reflective of the response in recurrent ovarian cancer patients. The results of the analysis were presented at the Annual Meeting on Women's Cancer hosted by the Society of Gynecologic Oncologists (SGO). In the analysis, any increase in CA-125 during the first two cycles of treatment with liposomal doxorubicin or topotecan (Hycamtin) was documented for patients who had a response to treatment as defined in the study protocol.

Further Study Needed

"Rising CA-125 levels are a cause for concern among ovarian cancer clinicians and patients. This study suggests that early increases in CA-125 levels may not reliably reflect those in whom a response will ultimately occur," said Robert L. Coleman, MD, of the University of Texas Southwestern Medical Center, who presented the results of the analysis at the SGO meeting. "Given the limitations of this analysis, further investigation is needed to evaluate the possible relationships between changes in CA-125 levels and response by specific agents in treatment of recurrent ovarian cancer."

The analysis showed that for 8 patients who achieved a complete response, and for 38 patients who achieved a partial response with liposomal doxorubicin, increases in CA-125 from baseline to the end of cycle 1 occurred in 50% and 41% of these patients, respectively. For 10 patients who achieved a complete response, and for 25 patients who achieved a partial response with topotecan, increases in CA-125 from baseline to the end of cycle 1 occurred in 20% and 8% of these patients, respectively.

By the end of cycle 2, no patients who achieved a complete response with doxorubicin or topotecan had elevated CA-125. For those patients achieving a partial response, 19% of doxorubicin-treated patients and 8% of topotecan-treated patients had CA-125 levels above baseline.

Liposomal doxorubicin is indicated for the treatment of patients with ovarian cancer whose disease has progressed or recurred after platinum-based chemotherapy. Use of the drug may lead to cardiac toxicity.