Among women with advanced ovarian cancer, a decline in serum levels of CA-125 during platinum-based chemotherapy was linked with better survival. These results were published in the journal Gynecologic Oncology.
Over the past 10 years, platinum-based chemotherapy regimens (regimens containing carboplatin or cisplatin) have become the mainstay of treatment for women with advanced ovarian cancer. Most commonly, the chemotherapy regimen containing a platinum plus paclitaxel is used for the treatment of advanced ovarian cancer.
Advanced ovarian cancer refers to cancer that has spread from the ovary to several or distant sites in the body. Survival with advanced ovarian cancer is often poor, but can vary noticeably from woman to woman. Researchers therefore continue to search for patient and tumor characteristics that predict response to treatment and survival.
CA-125 is a substance produced by several types of cells, including ovarian cancer cells. Women with ovarian cancer frequently have high CA-125 levels, and changes in level of CA-125 may be used to monitor response to treatment. Falling levels of CA-125 during treatment for ovarian cancer suggest that a patient is responding to treatment.
To evaluate the relationship between survival and early changes in CA-125 during treatment, researchers conducted a study among 101 patients with stage III or stage IV ovarian cancer. The patients with stage III cancer had “suboptimal residual” cancer, meaning that after surgery they had at least one remaining area of tumor that was larger than 2 cm in diameter.
The patients were treated with either cisplatin and cyclophosphamide or carboplatin and cyclophosphamide. Changes in CA-125 were measured during the first eight weeks of chemotherapy (this corresponded to the first two cycles of chemotherapy).
- There was no link between pre-treatment CA-125 level and survival.
- By eight weeks after the start of chemotherapy, women with lower levels of CA-125 had better survival. Median survival was 26 months among women with CA-125 levels less than 35 U/ml, compared with 15 months among women with CA-125 levels greater than 35 U/ml.
- Survival was also better among women who experienced the greatest drop in CA-125 levels. Women who had a 50% or greater drop in CA-125 level over the first eight weeks of chemotherapy had a median survival of 21 months, compared to 10 months among women who had a less than 50% drop in CA-125.
The researchers conclude that women with advanced ovarian cancer who experience a reduction in serum CA-125 levels during the first two cycles of chemotherapy have better expected survival.
Reference: Markman M, Federico M, Liu PY et al. Significance of Early Changes in the Serum CA-125 Antigen Level On Overall Survival in Advanced Ovarian Cancer. Gynecologic Oncology. 2006; Published online April 2, 2006.