Early treatment for recurrent ovarian cancer based on a rising CA125 marker does not appear to improve overall survival compared with treatment that is started upon presentation of symptoms, according to the results of a study presented at the 2009 annual meeting of the American Society of Clinical Oncology (ASCO) in Orlando, Florida.
Ovarian cancer has the highest mortality rate of all gynecologic cancers. It is the fifth leading cause of cancer death among U.S. women, with approximately 21,650 new cases and 15,520 deaths each year.
One of the reasons that ovarian cancer tends to be so deadly is that it is often detected at a late stage when it is difficult to treat. CA125 is an important tumor marker in ovarian cancer and can be measured with a simple blood test. Women who have undergone treatment for ovarian cancer typically have their CA125 levels tested regularly for several years following treatment. However, there is limited evidence to suggest that initiating treatment early because of an elevated CA125 level offers any benefit.
Researchers in the UK conducted a study that involved women with ovarian cancer who had completed first-line platinum therapy and were in complete remission. CA125 levels were measured every three months, and patients were blinded to the results and randomized to one of two arms: 265 women with rising CA125 levels began second-line therapy immediately and 264 women with rising CA125 levels delayed second-line treatment until symptoms of relapse (such as pelvic pain or bloating) appeared.
The overall survival between the two groups was the same (41 months from completion of first-line treatment). This was despite the fact that the early treatment group started second-line therapy an average of five months earlier than the delayed treatment group.
The researchers concluded that initiating second-line treatment earlier based on elevated markers offered no survival benefit; they suggest that there is no value in the routine measurement of CA125.
 Rustin GJ, van der Burg ME, et al. A randomized trial in ovarian cancer (OC) of early treatment of relapse based on CA125 level alone versus delayed treatment based on conventional clinical indicators (MRC OV05/EORTC 55955 trials). Presented at the 2009 annual meeting of the American Society of Clinical Oncology, May 29-June 2, 2009, Orlando, FL. Abstract P1.
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