Low CA-125 Suggests Better Prognosis for Stage I Ovarian Cancer
According to a study published in the Journal of Clinical Oncology, women with stage I epithelial ovarian cancer have better survival if they have low pre-treatment levels of CA-125.
Although only 15-25% of ovarian cancers are detected early, before the cancer has spread outside the ovary, women who are diagnosed with early (stage I) ovarian cancer generally have a good prognosis.
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.
Researchers are also interested in whether CA-125 levels can be used to predict prognosis for ovarian cancer. It’s possible that patients with high pre-treatment levels of CA-125 may have different treatment outcomes and different survival times than patients with low pre-treatment levels.
In order to assess the relationship between pre-treatment level of CA-125 and survival among women with early ovarian cancer, researchers in Australia conducted a study of 518 women who were treated for stage I epithelial ovarian cancer between 1990 and 2002. The researchers found that women who had high pre-treatment CA-125 levels (more than 30 U/mL) were more likely to have high-grade cancer (cancer cells that looked more abnormal) and more likely to have stage IB or IC cancer (more advanced stage I cancers). The factors that predicted survival were CA-125 level, grade of the cancer, and complete surgical staging. Women survived longer if they had low pre-treatment CA-125 level (equal to or less than 30 U/mL), lower grade cancer, and complete surgical staging. Complete surgical staging involved checking lymph nodes and other tissues for signs of cancer that had spread. Some women did not have complete surgical staging because they refused or had other health problems that would have made the more extensive surgery too risky. Among women who had complete surgical staging, 95% of the women with low CA-125 levels survived for at least five years, compared to 82% of women with high CA-125 levels.
The researchers conclude that pre-treatment CA-125 levels, along with cancer grade and complete surgical staging, predict survival in women with stage I epithelial ovarian cancer. The researchers recommend that these factors be considered when making decisions about chemotherapy. An accompanying editorial, however, suggests caution: While CA-125 appears to predict survival time, it may be premature to base treatment decisions on CA-125 level.
Reference: Paramasivam S, Tripcony L, Crandon A et al. Prognostic Importance of Preoperative CA-125 in International Federation of Gynecology and Obstetrics Stage I Epithelial Ovarian Cancer: an Australian Multicenter Study. Journal of Clinical Oncology. 2005;23:5938-5942.
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